Best VNA for around or under $2000? - Page 1
Forum section: electronics / testgear

author: Battle
author_rank: Contributor
timestamp: October 12, 2024, 04:10:37 am
content: I've been hunting a good VNA for duplexer tuning & other things. Six cavity 7" vhf duplexers that can go down past 100db a good ways. I currently just have a Lite VNA 64. I figured something under 2k might get me what I need, hopefully.I've seen a few other nano vna type that are more expensive with more range. But i don't know if I trust spending more on the same type of device as being wise. I've seen some other devices that sound promising. Though a couple of them only go to 100db for range. Products made by Measall & a few others look a bit more promising than the lite vna styles.I'd like some suggestions so that's why I'm making this post. I appreciate the input for making a decision on some.

author: Bryn
author_rank: Regular Contributor
timestamp: October 12, 2024, 05:35:26 am
content: The NanoVNA V2 Plus 4 is a popular choice, costing just $299.

author: nctnico
author_rank: Super Contributor
timestamp: October 12, 2024, 03:02:56 pm
content: What kind of frequency range?100dB of dynamic range is going to be really tough with a low cost VNA. There is also a device called 'Libre VNA' which claims 95dB of dynamic range up to 3GHz.On the used market you can also find base station analysers within your budget. For example the ones from JDSU / Viavi. I have a JDSU JD745A which can also use the spectrum analyser input to do scalar analysis instead of vector analysis giving much more dynamic range.

author: Battle
author_rank: Contributor
timestamp: October 12, 2024, 03:12:43 pm
content: Im interest in something from low band vhf up to 1.2ghz. Currently the VHF 6 cavity cans I have will likely tune down around or past 110db. I noticed some siglent devices online that might do it. But I dont know anyone with those to ask them questions.

author: Grandchuck
author_rank: Super Contributor
timestamp: October 12, 2024, 04:03:29 pm
content: You could search this forum for Siglent SNA and VNA. Then, perhaps you could identify some owners/users to contact.Also:https://www.eevblog.com/forum/rf-microwave/

author: joeqsmith
author_rank: Super Contributor
timestamp: October 12, 2024, 05:30:31 pm
content: Quote from: Battle on October 12, 2024, 03:12:43 pmI would start looking for a used 8753. You can get an ES for around that price. Don't forget the cost of cables, adapters, standards.....

author: tautech
author_rank: Super Contributor
timestamp: October 12, 2024, 08:12:03 pm
content: Quote from: Battle on October 12, 2024, 03:12:43 pmThe SVA1000X range is spec'ed with a dynamic range of 90 dB.SVA1015X will cover your frequencies.https://int.siglent.com/u_file/download/24_05_17/SVA1000X_DataSheet_DS0701X_E05F.pdf

author: nctnico
author_rank: Super Contributor
timestamp: October 12, 2024, 08:54:57 pm
content: Quote from: tautech on October 12, 2024, 08:12:03 pmNot over the entire frequency range! Read the specs carefully; it is good custom to skip any specification on the first page as this is typically bogus.

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: October 13, 2024, 02:37:56 pm
content: I think many folks use a HP Service Monitor for tuning duplexers.The HP 8920-8935 group on groups .io is a good source of info.Edit: Here is a link to some info on HP Service monitors, including tuning duplexershttps://www.amtronix.com/aism.htm

author: Marcel G
author_rank: Contributor
timestamp: October 13, 2024, 02:59:59 pm
content: Buy a real one, all those amateur solutions are just not enough.Slowwwww, Trace noise and a small dynamic range.Tried a converted Siglent, a waste of money.Take a look at an (used) Agilent E5062A (for example) and the world opens up for you, not particularly good but 100x more usable than the above solutions.

author: Bud
author_rank: Super Contributor
timestamp: October 13, 2024, 03:03:18 pm
content: Do you really need phase information? If not then a spectrum analyzer with a tracking generator may be a better choice.

author: Marcel G
author_rank: Contributor
timestamp: October 13, 2024, 03:26:32 pm
content: Bud nice idea, but dynamic range is too smal is completely not usable with duplexers.SA + TG max -60/70db is to low.

author: Bud
author_rank: Super Contributor
timestamp: October 13, 2024, 03:40:24 pm
content: No man, forget the Chinese toys, look for a used HP gear.

author: knudch
author_rank: Regular Contributor
timestamp: October 14, 2024, 05:00:52 am
content: I have a LibreVNA and a NanoVNA-F V2I am quite sure that the NanoVNA can not do the job.LibreVNA will come close or match your req.If you give some specific measuring ranges (frequency ranges, allowed average,speed needed) I can make a checkKnud

author: pdenisowski
author_rank: Super Contributor
timestamp: October 14, 2024, 08:28:41 am
content: Quote from: nctnico on October 12, 2024, 03:02:56 pmThis.Question: if this is a limited-time need, have you considered renting a (professional) VNA? Plenty of reputable rental companies out there.

author: Battle
author_rank: Contributor
timestamp: October 14, 2024, 09:31:35 pm
content: I'm mainly interested in something that can cover HF thru 70cm. This particular instance is for a 2 meter repeater. I have a set of Sinclair 6 cavity Q201GC cans. I've made a new harness for it. The notches should go down to about 120db. So that seems to be the problem with many of these handheld VNAs.I live out in the country. I enjoy learning how to do things myself. But I'm a hands on way of learning type of person. So having this little lite vna to get me started has been great. But I've hit it's limit of dynamic range for deep notches. I was hoping to find something better for a little more $ up to 2K. But it's been hard to find something that isn't a dinosaur with a floppy drive on it.I believe they sell these things to people who make money with the units. So they can justify the crazy expenses of them. But for someone like me who does this as a hobby. Then also likes to help others around me out if I can for free. It's hard to justify such cost on something I don't use every day.I see the rentals as an option. But I'd like something to have on hand for this duplexer tuning & anythings else I decide I'd use it for ham radio wise. Plus having something of your own you get to know using it better.

author: nctnico
author_rank: Super Contributor
timestamp: October 14, 2024, 10:09:11 pm
content: If you have an RF generator and a power meter (AKA RF voltmeter), you can sweep manually. If you roughly know where the notches are and want to know their attenuation, then this is a very low cost solution which isn't super time consuming either.

author: Momchilo
author_rank: Regular Contributor
timestamp: October 14, 2024, 11:48:46 pm
content: You can get a two port Siglent SVA1032X VNA for the price of a Siglent SSA3021X Plus (1500€ without VAT).Probably the best for under 2k€. You can buy cheap N and SMA calibration kits athttps://www.sdr-kits.net. With some adapters and cables you should be at around 2k€.

author: Battle
author_rank: Contributor
timestamp: October 14, 2024, 11:57:51 pm
content: I was looking at the Siglent SVA1015X it says it's s Spectrum Analyzer with tracking generator & VNA. I mean that sounds pretty sweet. But I can't confirm the dynamic range of it for measuring a duplexer 120db down. I emailed the company asking some questions but they haven't responded yet.I don't really need anything past 1.5ghz so that's one reason that model seemed more suited to my needs. The others say more frequency range & more money.

author: KungFuJosh
author_rank: Super Contributor
timestamp: October 15, 2024, 12:10:11 am
content: Dynamic ranges (from their datasheets):SVA1000X 90 dBSNA6000A 135 dBSNA5000A 125 dBMore datasheets:https://siglentna.com/resources/documents/Thanks,Josh

author: Battle
author_rank: Contributor
timestamp: October 15, 2024, 12:17:21 am
content: Ah..ok thanks..damn it.

author: joeqsmith
author_rank: Super Contributor
timestamp: October 15, 2024, 01:54:00 am
content: If you don't need phase and you want something small and brand new, maybe a Signal Hound spectrum analyzer and tracking generator would fit your needs. Cost would be close to your budget.I don't own these and did not watch the video below but I do own the BB60C and have been very happy with its performance.https://signalhound.com/products/usb-sa44b/https://signalhound.com/products/usb-tg44a/

author: Battle
author_rank: Contributor
timestamp: October 15, 2024, 02:34:05 am
content: Anyone have any experience with this handheld unit? NanoRFE VNA6000-B model?Says it will do 110db of dynamic range.https://nanorfe.com/vna6000.html

author: Battle
author_rank: Contributor
timestamp: October 15, 2024, 02:51:33 am
content: There's also the MEASALL KC901K handheld. Says 100db of dynamic range.Heck even a Agilent 8753ES has only like 110db of dynamic range if google results are correct.

author: bergenhut
author_rank: Contributor
timestamp: October 15, 2024, 06:27:23 am
content: Hi, you are going to struggle to get much better than 100db dynamic range, especially in a portable device. I have several VNA’s including fieldfox, anritsu, HP, Agilent, Measall KC901 and others. The Measall does just give approximately 100db range, but a lot of the Chinese cheaper units won’t meet their specs. My best unit for the frequency range that you are looking at is the HP 4396a which gives me a min of 130db dynamic range. As others have suggested, a good spec analyser with a tracking generator will give at least 110db, usually 120db or more. The HP 8920 radio test set with its spec an and tracking gen will give 110+ db dynamic range, and you can use a return loss bridge with it for S11 measurements. Beyond the 100db point in VNA’s, things get very difficult in engineering to maintain isolation and keep internal losses down from bridges, impedance matching etc as well as getting detectors sensitive enough for phase measurements. For tuning tight notches, we often just use a spec analyser with tracking, as it has a slightly better dynamic range than using the equivalent VNA.

author: knudch
author_rank: Regular Contributor
timestamp: October 15, 2024, 06:39:48 am
content: I made a few test @ 145MHz span 2 MHzMy LibreVNA make it to approx 105 dB at 10Hz BWMy Anritsu MS2721B (SA+TG) make it to 125dB at 30Hz BW (VBW 3Hz) display range 0 - 150 dBm

author: Battle
author_rank: Contributor
timestamp: October 15, 2024, 07:01:41 am
content: I am finding this out to be true. I appreciate the input. I still wonder about the Siglent SVA1015X. It says it's a SA with tracking gen & VNA. The specs say the VNA will do 90db of dynamic range. But I wonder about the SA & TG part of it. Then using that to finish the job that the VNA portion doesn't cover.As for handhelds the Measall seems more appealing than the other nano type vnas in a few ways.

author: joeqsmith
author_rank: Super Contributor
timestamp: October 15, 2024, 02:18:30 pm
content: Quote from: Battle on October 15, 2024, 02:34:05 amMake sure you read and understand their specs. Goes for ANY setup. If I were trying to tune a filter, I would want something that provided me with a fast enough visual feedback that I didn't have to tweak, then wait several seconds to see the effect.On these low cost VNAs, sure you can set the IFBW low and average the crap out of it, but that is not the mode the are running when they provide you with the sweep rate.Some of the VNAs will allow you to bypass various internal circuits, achieving lower noise.While your title states VNA, looks like you are now considering ditching the vector. My BB60C Signal Hound spectrum analyzer is new enough it supports real-time mode with a BW of 27MHz. Shown looking at a 140MHz, -120dBm signal. Notice the sweep time is 33ms. It uses USB3 and can dump that data to the PC fast. The serial interface is well documented allowing you to do some pretty cool stuff with it. Attached video was my attempt to review it by using it to decode some serial data from a cheap DMM.It does support swept mode as well. Shown with the same -120dBm signal with a 10Hz filter. Even with this setup, the sweep time is 1.1 seconds. While they do support using a tracking generator with it, I have never had a need for it, or I would demo it for you. If you have questions, you can call Signal Hound or use their forum. They are very responsive.

author: nctnico
author_rank: Super Contributor
timestamp: October 15, 2024, 11:13:50 pm
content: Quote from: KungFuJosh on October 15, 2024, 12:10:11 amBe aware these are just best-case banner specs. Actual specs over the entire frequency range are 30dB to 40dB worse. You have to be really careful when looking at VNA datasheets (or test equipment datasheets in general). Better start at the last page of a datasheet as this is where the nitty-gritty but super important details are hidden.

author: KungFuJosh
author_rank: Super Contributor
timestamp: October 15, 2024, 11:30:31 pm
content: Quote from: nctnico on October 15, 2024, 11:13:50 pmBest case scenario, specific frequencies, phase of the moon, etc. 😉

author: Battle
author_rank: Contributor
timestamp: October 16, 2024, 12:01:45 am
content: That's funny..phases of the moon.I'll be honest..I'm a bit bothered by spending around 2k for a used HP something from 1980/90s with a floppy drives & CRT displays in the year 2024. I worry about age of equipment vs soon to have component failures. Plus as far as name brand VNAs go some of those I've seen mentioned only do about 100/110db of dynamic range for the price range I mentioned. A lot of the big name equipment old & new is not priced for the hobbyist. They are made/sold as tools to make money for people who are either government or commercial funded with deep pockets.I'm just the little guy who likes to learn stuff & work on his own stuff. Plus use what I have & what I learn to freely help others. Just to make life a bit better or easier for their fellow hobbyist. I've never charged a dime to anyone for helping them in ham radio stuff. From climbing towers to repeater work.For now id like something just better than my Lite VNA 64. But for what it cost me vs what some other stuff cost in comparison. I'm not sure there's much to choose from. I was leaning towards the Siglent models with SA, TG & VNA. But they seem limited too in some ways. I was thinking the SA & TG features could pick up where the VNA falls short on dynamic range. For tuning duplexers at least. But I'm not certain that's a good choice. Heck even the NanoRFE VNA6000 seemed like it might be a little better than my Lite VNA 64. But it's base model is about $800 & the B model sells for about $1600. Idk wtf is going on there. I can't justify 10/15 extra db of range for double the price. Another reason the smaller units appeal to me is storage size. I live in a small house with my kids still at home. So I try keeping all my hobby stuff put out of the way. It's becoming hard when your someone with multiple hobbies

author: egonotto
author_rank: Super Contributor
timestamp: October 16, 2024, 03:55:42 am
content: Hello,maybe it's stupid what I'm saying now, but isn't it possible to achieve the required dynamics in two stages in the case of the tuning duplexer? With a VNA you first determine the frequencies in which the signal is below e.g. -50 db. In this range, you amplify the signal and then tune the duplexer with a higher effective dynamic range than the VNA provides.The error caused by the amplifier can be accepted in this case, can't it?Best regardsegonotto

author: knudch
author_rank: Regular Contributor
timestamp: October 16, 2024, 05:52:58 am
content: @BattleI understand your concerns about buying a old/used "Big" lab VNA equipmentI payed approx 1200$ for my used Anritsu SA+TG which is portable (new batteries then really portable)I dont believe any of the Nano flavours will do the job...my libreVNA (design/support is in EU) which is significant higher price can not do it (required 125dB dynamic).Maybe a Siglent SVA1015X / SVA1032X owner can make a quick check to see what real dynamic range you have with a acceptable low BW and no trace average (takes to long in your case). SVA1015X VNA should be in your price range.The SVA 1032X seems to have better DANL (-137dBm gainst -128dBm 10M-200M), so far I remember you cant not "hack" a 1015 to 1032.1032 is above your price range

author: Performa01
author_rank: Super Contributor
timestamp: October 16, 2024, 09:25:02 am
content: I have checked the Signalhound SA44/TG44 SNA combination and found the dynamic range to be 102 dB at 2 m, 100 dB at 70 cm and 98 dB at 23 cm. All this with 1 MHz span, 5 kHz frequency step (200 points total) and ~1 second update speed.Maybe the BB60 can do a little better, but it is also considerably more expensive.

author: nctnico
author_rank: Super Contributor
timestamp: October 16, 2024, 09:39:49 am
content: Quote from: Battle on October 16, 2024, 12:01:45 amPersonally I would strongly recommand against buying such old equipment. The prices these systems fetch are partly due to people not realising how old & fragile they are. When I look for equipment nowadays it must have a USB socket and a TFT screen. That is why I ended up with a basestation analyser as a crude VNA (and it needed some repairs as well). So yes, decent VNAs are still eye watering expensive :'(

author: joeqsmith
author_rank: Super Contributor
timestamp: October 16, 2024, 12:24:20 pm
content: Quote from: Performa01 on October 16, 2024, 09:25:02 amThat's too bad, but thanks for checking. Is it limited by their TG? I'll watch that video review I previously linked and see what they came up with.Shown with the Marconi 2024 at 0dBm, floor is about 90dBc. When I reviewed that GigaWave scope, I had to make a custom filter to use with the generator to measure the THD.Also shown is an GHz interdigital filter attached to the LiteVNA. The RED trace is with averages turned off. Yellow is with an average of 3500. sweeps. I guess they could sell it with a dynamic range of 110dB but customers would be very disappointed to find out it took all day to get one sweep.

author: Performa01
author_rank: Super Contributor
timestamp: October 16, 2024, 01:36:53 pm
content: Quote from: joeqsmith on October 16, 2024, 12:24:20 pmThere is not much control in SNA mode. You set a frequency span and the number of points. This determines frequency step and/or update speed, but I did not observe any obvious effect on the noise floor, when using 100, 200, 500 and 1000 points. We shuld not forget that the SA44 can do RT only for up to some 100 kHz span, so at 1 Mhz span it already operates in traditional swept mode - or at least a combination of both modes. In other words: it is not entirely clear how the settings affect RBW of the SA.

author: joeqsmith
author_rank: Super Contributor
timestamp: October 16, 2024, 02:08:15 pm
content: Looking at their review for the SA44B/TG44, they start out making a big deal about the warning about the DC coupled input and the need to add a block to protect it. Then they proceed to talk about connecting it directly to their radio and proceed to inject a 40dBm signal. Did I see that right??https://youtu.be/9wYDpzf-sl8?t=3368Here he talks about the slow update rate and trying to align a filter:https://youtu.be/9wYDpzf-sl8?t=5526From the tests he ran, we can't really get a feel for the dynamic range, but seems to be well under 100. So, not a good choice for the OP, but good to know.

author: KungFuJosh
author_rank: Super Contributor
timestamp: October 16, 2024, 04:58:08 pm
content: Quote from: Battle on October 16, 2024, 12:01:45 amYeah, I'd be careful looking at old gear. You might need some crystals to keep it safe.

author: Battle
author_rank: Contributor
timestamp: October 16, 2024, 05:14:59 pm
content: The mysterious moon phase vnas.

author: Battle
author_rank: Contributor
timestamp: October 17, 2024, 03:02:27 am
content: Well i decided there isn't much out there that isn't dirt old or ridiculously expensive. Most I seen was possibly 110db for the $1500+ price range. I settled on a Libre VNA that will do 100db for $600. Seemed like the best bang for your buck. I couldn't see spending $1500 for something that did 110 db.

author: KungFuJosh
author_rank: Super Contributor
timestamp: October 17, 2024, 04:37:22 am
content: If that's literally the only feature that matters to you, then sure. But if you want your VNA to also make you coffee, that's a whole different story. 🍵

author: Battle
author_rank: Contributor
timestamp: October 17, 2024, 04:44:41 am
content: My main focus is antennas, feedlines & duplexers mostly on HF thru 70cm. I could care less about Ghz stuff. What else could be better than the LibreVNA for $600 new? Vs what an extra 10db that gets you closer to the 2k mark.

author: KungFuJosh
author_rank: Super Contributor
timestamp: October 17, 2024, 04:54:48 am
content: I was just teasing. I can't tell you what your needs are. For me, I want something standalone with a screen, but that's me, not you. Like you, I also don't want to pay for it. 😉

author: Battle
author_rank: Contributor
timestamp: October 17, 2024, 05:20:22 am
content: I feel ya! I didn't like the lack of a screen & had to use the PC. It's one reason I kept avoiding it at first. But after searching for days it really seemed like the best solution vs cost. Plus I like the person who develops it is active in the support groups.

author: joeqsmith
author_rank: Super Contributor
timestamp: October 17, 2024, 02:44:56 pm
content: Quote from: Battle on October 17, 2024, 03:02:27 amConsider making a video that shows using the VNA to tune your filter. I just now checked again and there are really no good reviews for this product available. Just typical talking heads. I saw where you posted on their group and the responses. I didn't read it all in detail but saw that first comment from the designer:QuoteDuring the review of the Signal Hound, they were complaining about the slow updates (800ms) when trying to tune. I can't imagine 8 seconds.Quote from: egonotto on October 16, 2024, 03:55:42 amI know very little about the LibreVNA, but all of the low cost VNAs I have looked at use a squarewave. I made a video once exploiting this property by making a purpose built amplifier that you can not measure. You also have the concern that an amplifier could easily overdrive the VNAs input and damage it. However, there are cases I would certainly consider it. See the following paper from HP:https://anlage.umd.edu/Microwave%20Measurements%20for%20Personal%20Web%20Site/5980-2778EN.pdfAttached showing a simple LC circuit. Not a good example of a narrow band filter but we can see the insertion loss is somewhere around 30dB. Adding a wideband LNA, we of course amplify the noise as well.

author: Battle
author_rank: Contributor
timestamp: October 17, 2024, 03:19:10 pm
content: So far I've used my Lite VNA 64 to tune the cans individually. It seems to work fine for that. I was getting about 38 db on the reject notches. Plus easily setting the passes & the insertion losses with the loops.For tuning these to the 145 from 170mhz. I had to make a new harness out of RG214U & silver N & silver Tees for my repeater frequency.It's when I start hooking the cans together individually that the reject notches get fuzzy where they start exceeding the Lite VNA 64 range. I can still adjust the passes & insertion losses easily though.I didn't buy the Libre VNA thinking it's going to tune these Sinclair Q201GC-2 cans & solve my problem that the Lite VNA 64 can't do. I got it because it (Libre) sounds like it can look a little deeper than Lite 64. Plus has some other features that can be useful for other things in the hobby.I've found if I narrow the frequency range on the Lite 64 to say 145/146 or from 144/145 then the scanning isn't extremely long like 8 seconds as said. Even with avrg at 20x. But it's still a bit aggravating I'll agree.The main goal is to tune these up well on the passes & insertion losses with what I have. Get the notches the best I can. Then I'll get a friend to help fine tune the reject notches. Whos has more test equipment than what I have in my limited tool box here of things.I originally was willing to spend a little to get something of my own. So I started asking questions as to what's out there to be looking at. But it seems most things are super old & the age vs cost factor seemed off. Because the older something is the more chance something might go out. Plus having to buy calibration kits for those units that cost about as much as they were running. Then that totally exceed the budget. Or some newer things that still were only in the 95 to 110db ranges that were $800 to 1500 dollars. But still semi questionable, to put it lightly. I figured if that's what I was stuck with then $600 on a device that can do very similar things 100/105db wasnt too bad. Plus it has the SA & TG features too. It's just not great for my 6 cavity cans.

author: nctnico
author_rank: Super Contributor
timestamp: October 17, 2024, 03:27:31 pm
content: I'm looking forward to reading your experiences with the Libre VNA. I hope you want to share some thoughts on it after you have used it for a while.

author: joeqsmith
author_rank: Super Contributor
timestamp: October 17, 2024, 05:00:03 pm
content: Quote from: Battle on October 17, 2024, 03:19:10 pmMy experience with buying used equipment from eBay, if it says working, it doesn't. Consider repairs may require custom parts that are no longer available. Then manufacture's may not have released service manuals for newer equipment. It's certainly not for everyone, but I enjoy digging into some of the high end equipment an seeing what design choices were made.I couldn't justify the cost of brand new high end equipment and sometimes feel my electronics hobby is more museum curator.

author: hendorog
author_rank: Super Contributor
timestamp: October 17, 2024, 09:02:46 pm
content: Quote from: nctnico on October 15, 2024, 11:13:50 pmThere are significant differences between the meaning of the SVA and SNA figures:The SVA datasheet quotes 90dB, and this the the best caseTypicaldynamic range.The SNA5k datasheet quotes 125 dB, which is the best caseGuaranteeddynamic range.Best case figures are irritating, but this is a guaranteed spec, not typical performance.Drilling down to the frequency dynamic range table, the spec says the dynamic range is guaranteed to be better than 119dB from 300kHz to 8GHz.Typical performance is somewhat better than this and better than 125dB from 300kHz to 8.5GHzPerformance drops off under 300kHz - which IMHO is a completely reasonable tradeoff to me on an 8.5GHz VNA.The other question, how is dynamic range measured - for these datasheets?Keysight procedure:Quote

author: knudch
author_rank: Regular Contributor
timestamp: October 18, 2024, 07:16:20 am
content: I got my LibreVna in may 2024Before that I bought a NanoVna-F V2 in april 2022Years ago I have used PRO vna's in professionel life HP'sFirst: You get a lot for the money on the NanoVnaNanoVna F v2 is 200eurLibreVna is a BIG step up, quality wise, performancemore dynamic range, full 2 port parametre S11,12,21,22Much more flexibility in settings etc, BW adjustable, number of measuring pointsYou need a computer, not a problem in the "lab" but not portable as the NanoVna...gives other advantage storing data..Super support from the German designerLibreVna is 575eurYou can test the user interface by downloading the GUI it can run without HW, using some example files which give you an idea of itIf you have a specific question about the LibreVna you are welcome

author: Battle
author_rank: Contributor
timestamp: October 30, 2024, 02:32:59 pm
content: So I have used a the Libre VNA for a little while now.I like it much better than my Lite VNA 64. So that was a definite improvement. Seems real good to about 95-100db. I have seen it near 105-110. It seems more accurate & displays more information. The software features & PC use has been more beneficial in a few ways.It does include a Spectrum Analyzer & TG. Also a signal generator. Though it is hinted that the extra features aren't exactly precision instruments. At least there is honesty there.So for a $600 VNA I suppose it was a worthwhile purchase.Plus there is an external auto calibration unit being released soon or has been in some areas already. So that sounded a bit promising as an additional item feature.Keep in mind I'm just a hobbyist ham radio guy that's still learning about VNAs & also Spectrum Analyzers with TGs. So my opinion should be taken with a grain of salt.Initially I was going to do the best I could tuning these duplexers with what I have. As a learning experience. Then take them to a friend to get the reject notches & all final tuned with his equipment (SA & TG). I have changed my mind about doing this now. Mainly because its a ways drive. Plus I dont have a good way to haul these where they are standing straight up vs laying sideways. I dont want to lay them sideways for travel.So after using the Libre VNA & exploring its SA & TG plus the signal gen features. I'm thinking about just getting my own dedicated Spectrum Analyzer with TG. I've been in the hobby for over 24yrs. I enjoy trying to learn things & feeling accomplished doing them myself too. Hands on learning just absorbs better for me as well. I just need some advice on selecting between a couple of spectrum analyzers.I'm swayed toward two options made by Siglent. The SVA1015X or the SSA1021X Plus. Both are the $1600 range that about tops my budget.I know the SVA has a dynamic range of 90db of its VNA. I already have the Libre VNA that does about 100db so theres that.What Id like to know is will the Spectrum Analyzers of both units pick up where my VNA leaves off? Can I tune the reject notches that go down 120db with either of those Siglents?Ive also seen some info about conversions of the SSA into a SVA. But since I'm new to these units & learning. I'm in no hurry to worry about bricking one. But I like knowing that if I bought the SSA1021X Plus I could maybe later convert it. Once I have had more time to get familiar with it & read more here.

author: tautech
author_rank: Super Contributor
timestamp: October 30, 2024, 07:04:27 pm
content: Battle, a couple of threads I started exploring SVA1015X then later SVA1032X VNA capabilities that could interest you for antenna work.https://www.eevblog.com/forum/rf-microwave/antenna-project-log/https://www.eevblog.com/forum/rf-microwave/what-really-is-this-antenna/I certainly don't have the ~25 yrs RF experience you do but have enjoyed the journey with tools suited to this work.SSA3015/3021X Plus will get you started with a reflection bridge however SVA1000X models offer more complex measurements ......study the screenshots.

author: bg8npk
author_rank: Newbie
timestamp: November 01, 2024, 03:13:32 pm
content: I checked this using adeepace KC901Kwith a frequency range of 1MHz to 1GHz, no connections to the ports, 30dB output gain, RBW 1KHz, and it showed a noise floor of around -105dB. Measurement points 401, each refresh time is about 1sIf you only need to measure to 1GHz, the KC901J sold by deepace may be a cost-effective choice. The ability to work independently without a PC will be beneficial when go to field...

author: Battle
author_rank: Contributor
timestamp: November 01, 2024, 03:36:13 pm
content: Quote from: bg8npk on November 01, 2024, 03:13:32 pmThank you for the information on that unit. I was curious about them. I do like having a display vs using the PC. Makes something a little more portable for sure.On another side note related to the Libre VNA. The LibreCal unit is being sold on AliExpress by zeenko an official dealer. It's soon to also be in the USA at R&L.

author: virtualparticles
author_rank: Regular Contributor
timestamp: November 14, 2024, 01:43:53 pm
content: The TR1300 has a dynamic range of 130 dB. You won't find that kind of performance with a low-cost box.https://coppermountaintech.com/vna/tr1300-1-2-port-1-3-ghz-analyzer/Best of Luck!

author: Battle
author_rank: Contributor
timestamp: November 14, 2024, 01:56:22 pm
content: Quote from: virtualparticles on November 14, 2024, 01:43:53 pmDoesn't quite meet the mark of the topic of the post though does it?

author: points2
author_rank: Regular Contributor
timestamp: November 15, 2024, 03:02:53 am
content: hi Battle,another option => wait for the release of the very nice project of EggertEnjoyer123=> here =>https://www.eevblog.com/forum/rf-microwave/building-a-22-ghz-network-analyzer-for-under-$1000/

author: virtualparticles
author_rank: Regular Contributor
timestamp: November 26, 2024, 11:46:23 am
content: Quote from: Battle on November 14, 2024, 01:56:22 pmDoesn't meet the price target, but it's an actual VNA with metrology. I wouldn't spend $2k for a random number generator myself.

author: joeqsmith
author_rank: Super Contributor
timestamp: November 26, 2024, 02:37:09 pm
content: CMT appears to define three different grades of VNAs, metrology, laboratory and economy. Maybe there are others. I could not locate where they define these terms.Quotehttps://coppermountaintech.com/laboratory gradehttps://www.microwavejournal.com/articles/25273-vnas-support-need-for-higher-frequencieseconomy-gradehttps://coppermountaintech.com/what-can-be-measured-using-a-network-analyzer/When looking for used VNAs, I tried to sort out what the "P" stood for in PNA. Some sources stated Precision, others Performance. Saw an interview with someone at Agilent that was saying they were not sure.

author: hendorog
author_rank: Super Contributor
timestamp: November 26, 2024, 06:14:50 pm
content: Quote from: virtualparticles on November 26, 2024, 11:46:23 amGreat point.What about the CMT single port VNA's for the price point. I sometimes see those on eBay pretty cheap.Edit: My bad, I thought this thread was about testing antennas, clearly the OP would need two ports.Also, Brian, please (for the love of god) speak to your web dev about the menus on the CMT site.The menu pop's up on mouse over and then often disappear when the mouse is moved to select something in the menu. So the site is impossible to use at times.Very frustrating.Keep it simple: Show the menu on click, and hide the menu when an item is clicked, or there is a click elsewhere on the page.

author: KE5FX
author_rank: Super Contributor
timestamp: November 26, 2024, 06:46:35 pm
content: Quote from: joeqsmith on November 26, 2024, 02:37:09 pmP=Performance, E=Economy in Agilent-speak. Relatively speaking.

author: joeqsmith
author_rank: Super Contributor
timestamp: November 26, 2024, 07:32:55 pm
content: Quote from: KE5FX on November 26, 2024, 06:46:35 pmGoogle search, first hit, two employees chime in:https://community.keysight.com/s/question/0D52L00005Ie2tXSAR/pna-definitionI can't think of where I saw that interview but remember being surprised that the employees were confused.My vintage PNA part number starts with E (E8357A), so maybe it was an economy high performance VNA. Marketing....That's been a good unit.

author: hendorog
author_rank: Super Contributor
timestamp: November 26, 2024, 07:53:10 pm
content: Quote from: joeqsmith on November 26, 2024, 07:32:55 pmLegal and Marketing always manage to overcomplicate the simplest things...

author: bg8npk
author_rank: Newbie
timestamp: November 26, 2024, 09:54:02 pm
content: This item looks very similar to theDeepace KC901Q 20GHz VNA... It does not have a built-in coupler, you can go for a coupler depending on the frequency range needed. According to thetutorial posted by the manufacturer, the KC901Q seems to work up to 30GHz(Sorry for going a bit off topic, but that project is really interesting)

author: joeqsmith
author_rank: Super Contributor
timestamp: November 26, 2024, 09:55:37 pm
content: Quote from: knudch on October 18, 2024, 07:16:20 amI've often wondered about the LibreVNA and have yet to see a decent review of one from someone that actually knows what a VNA is. I assume there would be a lot of hype surrounding it as it costs more and people want to feel good about the cash they spent. But, again, I have no data outside of what was provided to me from one owner showing the floor.They only spec the LibreVNA to 100kHz. I am not sure if it will run lower. Can it be used for narrow band measurements? Is it still a square wave drive? ...Quote from: knudch on October 18, 2024, 07:16:20 amI see the LibreVNA range from about $600 to $800, compare to say the LiteVNA64 + H4 at maybe $250. This combo gets me measurements down to 1.6kHz now with a dynamic range of 80dB, and no harmonics to 6.2GHz. Some usable date to about 9GHz with mine.Quote from: knudch on October 18, 2024, 07:16:20 amQuality wise, I've been impressed with the LiteVNA64. Firmware has been solid. For the H4, current firmware is much better than when I first played with it. Still not as stable as the Lites. HW wise, I did damage my H4 as it has no protection and I must have made some idiot move with ESD. Overall, I rate the quality good for all of these low cost units.What I see with the LibreVNAs, owners shove them on top of large heatsinks, fans..... If these are actually required to get the VNA to perform well, that hardly gives me confidence in the quality of the design.Firmware wise, outside of what I have seen posted for the LibreVNA with lockups and what not, I can't say.Quote from: knudch on October 18, 2024, 07:16:20 amAttached showing the latest LiteVNA64, 1kHz IFBW with data provided by owner of LibreVNA.While the LibreVNA is not spec'ed to run below 100kHz, the H4 is only spec'ed to 50kHz. Recently it was brought to my attention thatQuoteI ran a few experiments with a couple of modified H4s that were better than 70dB dynamic range down to 1.6kHz.https://www.eevblog.com/forum/testgear/affordable-lt200mhz-pdn-analysis-hardware/msg5717859/#msg5717859The group that refers to the VNA as antenna analyzers I'm sure are clueless about the need to run down this low, but for the few of us wanting to measure PDNs for our designs, this is very nice seeing how well these perform.Quote from: knudch on October 18, 2024, 07:16:20 amWell, I guess you got a point there. Or do you?? I have shown using a transfer relay with the NanoVNA, V2Plus4, and more recently with the LiteVNA64. A friend of mine and I both purchased a used Transco brand relay for about $100 USD. Plus the driver, RF cables, and USB cable, lets be generous and call it an even $200 with everything. Added to our $250, for a grand total of $450 for the entire setup.It can pass the T-Check test to about 4GHz. I have no idea how well the LibreVNA does. I had looked at their software for it, and it does not allow different standards to be used for the two ports. It assumes the device is noninsertable. This would be fine for the T-Check experiments I ran.https://www.eevblog.com/forum/rf-microwave/nanovna-custom-software/msg5685217/#msg5685217Quote from: knudch on October 18, 2024, 07:16:20 amI can adjust the IFBW with the LiteVNA64. Same for the number of points. For that matter, I've been told by a few from the antenna analyzer group that Solver is way too complex. I really don't know how it compares with the LibreVNA software. The upcoming version of Solver will be even more feature rich... Of course, that comes with a stiff learning curve. Solver certainly isn't for the beginner. Then again, I would hope a beginner doesn't spend $500+ just to join the LibreVNA club.Quote from: knudch on October 18, 2024, 07:16:20 amI have no need for the standalone, battery operated features the low cost VNAs I have looked at offer, except in cases where the firmware does not allow me full access to all of the settings. That IMO, is just bad programming.Quote from: knudch on October 18, 2024, 07:16:20 amSolver will also run without hardware. New manual is about 250 pages long.Maybe the LibreVNA is the hot ticket but your posts certainly have not convinced me to go out and buy one. One advantage to the H4/LiteVNA combo is that the software interface layer is well defined. The designer of the LibreVNA did eventually release a spec to allow software to directly control it but I was told that may all change. So even if I purchased one, there was no point in investing any time trying to get Solver running with it. The designer had also posted about the next generation of the LibreVNA. That's been a few years ago but when I saw it, I thought no point in buying something at that price that was going obsolete soon.So, is it just hype from the people that spent the $500 + wanting to claim that they have the best thing out there? Or does the LibreVNA actually do something that I can't do with the lower cost units?****Just to add a few other comments, Dislord has provided very good support. I did a test once where we opened up the sample rate of the LiteVNA. Using Solver, it was fast enough I could tune to a local AM radio station and directly decode the audio. One of the members here was using this high speed to attempt to measure human vitals. A pretty cool project. Not wanting to be outdone, I had constructed a frequency converter (Solver supports external mixers) allowing the LiteVNA to be used up to about 12GHz. Using this, I built and demonstrated a working Electron Paramagnetic Resonance spectrometer. Thinking the features of the LiteVNA are limited compared with the LibreVNA, seems naive. The Solver + LiteVNA + H4 combo certainly has it's limitations but my guess is that LibreVNA also has similar limitations. Sadly though, there is no one out there it seems able to do a critical review of one.https://www.eevblog.com/forum/rf-microwave/nanovna-custom-software/msg5581183/#msg5581183

author: knudch
author_rank: Regular Contributor
timestamp: November 26, 2024, 11:19:16 pm
content: I don't think there is more hype than people are general very satisfied with LibreVNA"lower than 100kHz"It is uncalibrated if you go lower ... exact how low I dont knowNo is not square waveIt is sine wave but not special filtered, it can do harmonics measurement eg higher than 6G, limit dependig on individual device, have not tried it as that frequency band has no interest for me....should be 10G + for me if it should be higherNarrowband: is 10Hz ok ?As mostly 50% more performance/features cost 100% moreThe HW is of significant higher quality than My NanoVNA, milled/casted ALU housing with internal shielding chambersUsing separate receivers for port 1, 2 and measuring of the reference signals gives better isolations between th internal signalsAlso the internal shielding improves this.Much higher communication speedHeatsinks...is not absolute needed I have not seen any measureble differenceThe ALU housing makes it also feel hotter (the chips have cooling pads to the housing)If you place it vertical the convection cooling is betterThink lockups is rare...On the other side if you have problems the help from the designer is very efficientI dont know where you have the LibreVNA dynamic data from but it is not what I seeI dont care about below 100kHz...that is nothing for a VNAI would use signal analyzers for that rangeFull 2 port:"it does not allow different standards to be used for the two ports. It assumes the device is noninsertable."What do you mean ?You cant achieve anything like real full 2 port by the relay arrangementIf it was so "easy" why do 100k$ instrument not use such technicsThe calibration section is way more comprehensive compared to NanoVNAIf you only would analyze antennas nanoVNA is sufficientI dont know the Lite VNA in detailsBut the LiBreVNA GUI is not hard to learn and the nifty things are in deeper menus, of course you need to understand VNA technics to get the full use of a LibreVNANifty things:Calibration of reference signal, calibration of receiver, Ref frequency IN/OUT"Hot ticket"To my opinion it is a significant step up from my NanoVNAIf you need that is your choiceI dont recommend people to spend money on LibreVNA just to learn what a VNA is and if they can use it anythingThere the simple devices do the jobI think the designer is very honest about the project what will maybe come and what not....no vapor ware promisesSorry I couldn't get quoting to work correctBrKnud

author: joeqsmith
author_rank: Super Contributor
timestamp: November 27, 2024, 12:39:11 am
content: Quote from: knudch on November 26, 2024, 11:19:16 pmFirst, thanks for posting.That sinewave is a huge deal. Please post a scope shot of output set to 100KHz.A while back there was that guy from Tektronix posting how some of the low cost VNAs, use a sinewave but of course that is incorrect.Quote from: knudch on November 26, 2024, 11:19:16 pmI'm surprised they could get harmonics with a sinewave drive. Curious now how it even works.... Let's see a scope shot first.Quote from: knudch on November 26, 2024, 11:19:16 pmThe LiteVNA can sort of look at a crystal, if you apply lots of filtering. But it is very slow and the shape is highly distorted. The H4 will make these measurements faster, more accurate. What does the LibreVNA do? Say with an IBFW of 4kHz, what does it look like? Post a screen shot if you don't mind.Quote from: knudch on November 26, 2024, 11:19:16 pmSo, is it a four or two receiver design? Does it support unknown thru?Quote from: knudch on November 26, 2024, 11:19:16 pmAs I stated, Lite can decode audio live. Poor quality but fairly fast. Would be interesting to compare the two.Quote from: knudch on November 26, 2024, 11:19:16 pmIt seemed like the buyers want the biggest heat sinks. I've seen custom holders now with cooling fans. All these posts really turn me off of the product as I assume there is something really wrong with the design.Quote from: knudch on November 26, 2024, 11:19:16 pmJust upload a new Touchstone file and I will add it. Just sweep over the entire range with both ports terminated and let me know the settings.Quote from: knudch on November 26, 2024, 11:19:16 pmOdd post. I think CMT has one that supports 9kHz. If I can get 2kHz with decent dynamic range on a cheap VNA, I am certainly going to put it to use.Quote from: knudch on November 26, 2024, 11:19:16 pmM/M or F/F. When I looked at their software, they only supported one set of standards for both ports. You would want a different set for each port. Male standard on port1, female on port2. Maybe SMA on port1, N on port2? Solver is pretty limited. You can do this but the standards would need to be databased, or some combination of databased and polynomial fit.Quote from: knudch on November 26, 2024, 11:19:16 pmI did post my data comparing the two VNAs. (LiteVNA vs E8357A) so I am not sure what you mean. The PNA is a four receiver design, so sure it does support features that I can't do with Solver + Lite or H. Solver does support full 12-term model when used with the transfer relay. It also supports the same standard coefficients as my PNA and now databased standards as well. It sounds like you are suggesting much more. Fill in the blanks.My old HP8754A worked like this (transfer relay to swap the two ports). Grease pen on screen and thumb wheel switched sort of thing. This is where Solver started.I was recently posting with a gentleman named Kurt who has posted a fair amount of data with the T-Check. He had brought up the lack of the 12-term model but that is something Solver has supported for a while.Quote from: knudch on November 26, 2024, 11:19:16 pmAgain, thanks for the post. Really would like to see one actually in use. All the reviews I have found are not much more than an unboxing.

author: knudch
author_rank: Regular Contributor
timestamp: November 27, 2024, 09:34:38 am
content: @joeqsmithI will make it a little short because I am on the way for a small vacationSinewave:I made quick check yesterday @150MHz the 2nd harmonic is 25-30dB downCorrection:It depends very much of the selected frequency, there are different ways the signal is generatedSo I would not considered it as sinewaveHarmonics mode:You enable a setting in the GUI...what it actually do I dont know, not tried itCrystal sweep:Is general very difficult due the high Q nature of the crystal (special Xtal sweepers are made)You can adjust almost all parameters, stepsize, ifbw, amplitude...maybe it will workReceiver design:You might say it is a 2 receiver design1 receiver for each of the ports1 receiver for setting the REF amplitude (32dB step attenuator in 0,25dB steps)Output can be leveled during sweep or you can do power sweepA useable signal generator function and a even more useable spectrumanalyzer with tracking gen.But as the designer says: only added because is was relative easy to do, not prinary goal.More info about the design/sw can be taken from the github pagehttps://github.com/jankae/LibreVNAEvery thing is there...CAD files etc..built one by selfFrom the designer there is a new product working together with LibreVNA:LibreCAL electronic cal set, price in EU 165 eurKnud

author: joeqsmith
author_rank: Super Contributor
timestamp: November 27, 2024, 01:12:35 pm
content: After suggesting the S21 data that was provided to me wasn't what you measure, I was hoping to see some actual data.Quote from: knudch on November 27, 2024, 09:34:38 amMultiple scope shots, maybe show the spectral content with an SA. At least we now know it is not a sinewave drive. After your post, I almost bought one, just to see that waveform. When I brought up the squarewave drive to the Tektronix guy, they had started to head down the path of at high frequencies, it's not so square. I'm not sure if that was some attempt to save face with viewers but it is why I asked you to show the LibreVNA at 100kHz.I had designed an unstable amplifier that I used to demonstrate the potential problems when using a squarewave drive. I wonder if the LibreVNA would pass that test or fail like every other low cost VNA I have looked at. Hard to say without seeing any data for it.Quote from: knudch on November 27, 2024, 09:34:38 amI think your retraction about the sinewave answers this question.Quote from: knudch on November 27, 2024, 09:34:38 amThat's not good if it can't measure such devices. This it the problem with the LiteVNA/64 and the V2Plus/4. The easy and cheap solution is buy the original NanoVNA or H4. Again, all I have seen are unboxing videos, mostly by hams. I am guessing the developers sent the free ones to these people knowing that the reviewers would not go into any details. I get the feeling if I were to compare it head to head with the combination I mention, it would not fair so well. Could be wrong. Again, no data.Quote from: knudch on November 27, 2024, 09:34:38 amFor each port, both the incident and reflected data are measured. I was asking if there was a separate receiver for each.Quote from: knudch on November 27, 2024, 09:34:38 amI wouldn't have a use for the spectrum analyzer or using it for a signal generator. That said, to directly decode the audio from the local AM radio station, that is basically what I am doing. CW, and pumping that data out as fast as the VNA allows.Quote from: knudch on November 27, 2024, 09:34:38 amI know it is an open source design but I have no desire to reverse engineer to try and answer basic questions. I would expect for the cost, it would be well documented, not the schematic is the documentation.Your posts were on par with what I was expecting. I'll stick to my thoughts of it's about being part of the elite group of LibreVNA owners and wanting to feel good about your purchases. It has very little to do with performance/cost. Maybe in the future someone will step up and make a critical review of it showing some actual data that sways my thoughts about it.

author: hendorog
author_rank: Super Contributor
timestamp: November 27, 2024, 06:15:47 pm
content: QuoteI was interested in checking out the internal differences between the LiteVNA and LibreVNA.I own neither and have not closely followed either of them. Since it was pointed out that the LiteVNA was much cheaper I wondered why.So I searched for the LiteVNA block diagram and found a chat group with various bits and pieces of information including a block diagram, and a google drive with a user manual.The User Manual did not have the block diagram.The LibreVNA had a block diagram easily accessible and a github repo.So using the chat group block diagram for the LiteVNA and the LibreVNA one on github (both attached)The LiteVNA is a 1.5 port deviceThe LibreVNA is a two port deviceThe LiteVNA shows no filteringThe LibraVNA has some harmonic filters on the sources, frequencies are shown.The LiteVNA has a built in re-normaliser.The LibreVNA does not have this functionThe LibreVNA is a 3 receiver design. The Ref receiver is behind a switch.The LiteVNA block diagram does not show the receivers and so I could not tell if it used switches or individual ADC's.The LibreVNA is a much easier device to understand because the internals are well documented.The LiteVNA would require more research, I did find a teardown video.The LiteVNA will require more research. The lack of documentation is a big turn off, as reverse engineering would be required to understand it.The LibreVNA information was available easily.Both have chat groups.Based on this quick assessment, for a person interested in VNA internals, I would favour the LibreVNA.Is there good information on the LiteVNA internals somewhere that I have missed?

author: joeqsmith
author_rank: Super Contributor
timestamp: November 27, 2024, 06:55:15 pm
content: Quote from: hendorog on November 27, 2024, 06:15:47 pmAs the story goes from OWO, the LiteVNA was based on the V2Plus4. There was a schematic released but both groups do not appear to make the newer revisions public. As I understand it, OWO's company never released the full source code for the V2Plus4. See the following posts from Dislord:https://www.eevblog.com/forum/rf-microwave/nanovna-custom-software/msg4015222/#msg4015222https://www.eevblog.com/forum/rf-microwave/nanovna-custom-software/msg4020526/#msg4020526OWOs site is here:https://nanorfe.com/nanovna-v2.htmlQuoteI would say they are a 2-port 1-path but sure. This is the reason I mentioned the transfer relay.

author: hendorog
author_rank: Super Contributor
timestamp: November 27, 2024, 07:25:13 pm
content: Quote from: joeqsmith on November 27, 2024, 06:55:15 pmNitpick but more correctly 2-port 1-path is a type of calibration you can do on a 1.5 port VNA (or T/R VNA) to get a full set of S-Params.I assume your transfer relay is effectively doing the swap after the ports - like adding a test set to an 8753.Thanks for the info, I will have a read.

author: KungFuJosh
author_rank: Super Contributor
timestamp: November 27, 2024, 07:56:38 pm
content: Quote from: joeqsmith on November 27, 2024, 01:12:35 pmThey should send you one for free. 😉

author: joeqsmith
author_rank: Super Contributor
timestamp: November 27, 2024, 09:00:33 pm
content: Quote from: hendorog on November 27, 2024, 07:25:13 pmI have never heard of a 1.5 port VNA until you mentioned it. T/R seems common. I couldn't tell you when/where I first heard of a 1.5 port VNA being referred to as 2-port 1-path VNA. Something from the dark ages. See the following for example:Quotehttps://www.tek.com/en/documents/primer/what-vector-network-analyzer-and-how-does-it-workQuotehttps://www.anritsu.com/en-us/test-measurement/products/ms2034bQuotehttp://sine.ni.com/apps/utf8/niid_web_display.model_page?p_model_id=24027Anyway... Solver expects the transfer relay is located between the VNA and DUT. In the case of my HP8754A, they offered a T/R test set, or in my case, I have the 8748A test set. This uses a mechanical transfer relay from the two directional couplers to the A & B ports of the VNA. There is a mechanical switch on the front to change the direction, or in my case, I automated it with my own software. This was basically carried forward to my current software for these low cost VNAs.

author: hendorog
author_rank: Super Contributor
timestamp: November 27, 2024, 09:25:44 pm
content: Quote from: joeqsmith on November 27, 2024, 09:00:33 pmThe point being that 2 port 1 path is a calibration, and not a VNA architecture, is that the 2 port 1 path calibration option is not available on all T/R type VNA's.Siglent for example have not implemented it on the SVA range, and it wasn't on the old Nano's either IIRC. No idea about the new Nano's.It makes a lot of sense to me to add the DIY test set as you have done, I did something similar with an HP 8515A Test Set on my 8753.Currently though the 8515A has been reconfigured and is being put to use as a two port front end for a very nice four port Siglent SNA - thanks to tautech

author: Bud
author_rank: Super Contributor
timestamp: November 27, 2024, 09:43:41 pm
content: Quote from: joeqsmith on November 27, 2024, 01:12:35 pmThat is one bizarre application for a VNA. Why are you doing this, what is wrong with a $5 radio?

author: tautech
author_rank: Super Contributor
timestamp: November 27, 2024, 09:57:38 pm
content: Quote from: hendorog on November 27, 2024, 09:25:44 pmFTFY.That I'll want back at some point.

author: joeqsmith
author_rank: Super Contributor
timestamp: November 27, 2024, 10:47:24 pm
content: Quote from: Bud on November 27, 2024, 09:43:41 pmThat's a legit question. Because we can!!For the few of you that get it, a very old commercial from my youth answering the same question

author: joeqsmith
author_rank: Super Contributor
timestamp: November 27, 2024, 11:36:57 pm
content: Quote from: hendorog on November 27, 2024, 09:25:44 pmI'm just pointing out how a few of the big players refer to these VNAs. When discussing calibration, I may say, Solver supports the 12-term error model with a transfer relay to perform a full 2-port SOLT calibration. Or, I frequently normalize the data. Of course that doesn't tell you if it is a 1 or 2 port normalization... You can certainly use 1.5 or any other terms. Just be aware others may not understand what you are referring to. Having used HP, I tend to follow their lead.Where does that 1.5 come from?Test set to me suggests directional couplers, bias Ts, attenuators. A transfer relay to me is just that. It can be part of a S-parameter test set.

author: joeqsmith
author_rank: Super Contributor
timestamp: November 28, 2024, 06:36:18 pm
content: Quote from: hendorog on November 27, 2024, 07:25:13 pmShown are my two attempts at making a transfer relay for the low cost VNAs along with the used Transco relay that I currently use. Sadly the VNA designers never settled on a standard form factor and connector spacing but you can see how my intent was to have it connected directly to the VNA. These both have bias Ts for each port. The silver one is using GaAs switches, the other RF mechanical relays. Sadly the isolation for both were poor. I think I demonstrated the T-Check to 50MHz was all back then. Far short of the 4GHz I recently achieved with the LiteVNA + Transco relay shown.Even with the bias-Ts, I wouldn't consider these a test set as they don't contain the couplers. Rather they just route the signals after the fact.

author: Kahooli
author_rank: Contributor
timestamp: November 28, 2024, 07:46:53 pm
content: Someone had asked about libreVNA harmonics in this thread, so I thought I'd fire it up and show a small sample at 65M, 500M, 1G at different power settings. Due to the Architecture, it's square from Fmin to around 500M where the 900Mhz lowpass has any effect. I also tossed a couple sweeps of spurs at 144M, 500M, and 1G in the folder. Measurements were captured with my PXIe-5644R, so nothing below 65M. If I get some time I'll capture ffts with my oscope for under 65MHz. If anyone has other specific measurements or evaluations they'd like to see let me know, I'll do what I can. I do like the LIbreVNA, but it is nothing near the performance of "real" hardware I use at work.As for the dynamic range problem, as was said earlier in the thread: tune the Fc of the filter with the VNA alone, tune the notches and depth with an LNA to extend the dynamic range. It's not rocket surgery.

author: joeqsmith
author_rank: Super Contributor
timestamp: November 28, 2024, 08:14:23 pm
content: If you have time, measure the dynamic range of yours over the entire operating range, both ports terminated. Upload the Touchstone file along with the settings you used. I am curious about Knudh's comment:QuoteOf course, they originally stated it was a sinewave drive. So how well they really understand what they have.....No need for the scope FFT on my account. What you show is good enough. If you are going to connect it up, maybe show the time domain.What is your take on these owners with their crazy heatsinks. Just for looks? Bad design? Maybe you could some basic temperature tests to give some idea of the drift? Maybe as a minimum, provide the case temperature vs ambient after it has warmed up (no heat sink, flat on bench).Could you run a T-Check with it?It was mentioned it could run below 100kHz but uncalibrated. Could you run it as low as possible and show maybe the dynamic range and maybe insert a step attenuator and sweep it in say 10dB steps to give me some idea how it behaves?I am still wondering how it would handle measuring a quartz crystal. Could you measure one and post plots or data?Again, thanks for that initial data.

author: Kahooli
author_rank: Contributor
timestamp: November 28, 2024, 08:33:54 pm
content: I probably don't have all the equipment close at hand for what you described, But I'll see what I can pull together.

author: joeqsmith
author_rank: Super Contributor
timestamp: November 28, 2024, 09:06:02 pm
content: I would appreciate any data you could provide for your LibreVNA.Here is a typical post from LibreVNA owner:QuoteCheck out their thread showing fans and heat sinks.https://www.eevblog.com/forum/rf-microwave/clone-85033e-vna-cal-kit-measured-against-pico-cal-kit-using-librevna/msg4349998/#msg4349998So, maybe there was a problem with the design and so much for the quality that was mentioned.

author: hendorog
author_rank: Super Contributor
timestamp: November 28, 2024, 10:53:27 pm
content: Quote from: tautech on November 27, 2024, 09:57:38 pmI am sure we can come to some sort of arrangement fella. I think the SSA would look good on your desk.

author: hendorog
author_rank: Super Contributor
timestamp: November 28, 2024, 10:58:06 pm
content: Quote from: joeqsmith on November 28, 2024, 06:36:18 pmNice work, thanks I had not seen that.

author: Kahooli
author_rank: Contributor
timestamp: November 28, 2024, 11:34:16 pm
content: The thermal drift issues are real, surely. Even just viewing the comm log of self reported temperatures you can see a swing of 10-15C at the end of a sweep versus at the beginning. Some of it is minimized by waiting for 30 minutes after boot to cal, but realistically the performance is a bit disappointing. I have not used it terribly much since I have access to much better hardware at work. I bought it shortly after it became available when I was working remotely and thought it'd be fun to have. I took a few sweeps earlier I'll post showing the drift (will post tomorrow, have to do holiday things now). If I knew about this before purchase I probably would have passed. I spent $429.95 USD at RL for it. At some point it may become a project to "fix" it. AS others have stated, all the design files are available so having a custom thermal solution machined, adding gap pads etc are all on the table. Though may be throwing good money after bad.

author: joeqsmith
author_rank: Super Contributor
timestamp: November 29, 2024, 12:32:33 am
content: Quote from: hendorog on November 28, 2024, 10:58:06 pmThat was back in 2019. Post below showing very poor results with the original NanoVNA, transfer relay and T-Check to 500MHz. With +/-10% criteria, you can see I didn't have much frequency range to work with. Maybe 5 - 60MHz.https://www.eevblog.com/forum/rf-microwave/nanovna-custom-software/msg2638257/#msg2638257Attached showing the inside of my old HP S-parameter test set. Sorry about the poor quality photos. Also a very early screen capture of my software from roughly 22 years ago.

author: joeqsmith
author_rank: Super Contributor
timestamp: November 29, 2024, 12:44:10 am
content: Quote from: Kahooli on November 28, 2024, 11:34:16 pmThis may be the most helpful post I have seen. I had seen the new ones with the heatsink clam shells. It may slow down the heating but I wounder if a beach towel would be just as effective. Looks like R&L now sells it for $550 + tax.https://www2.randl.com/index.php?main_page=product_info&products_id=75413The LiteVNA drifts a bit as well. One advantage I saw with the LibreVNA that doesn't seem to get mentioned a lot is that external 10MHz reference input. I had modified one of my LiteVNAs to remove the internal clock so I could drive it with an external GPS reference. Normally, this would never be a problem as I can't really use it to measure crystals. But that spectometer I built has a high Q cavity and the frequency drift was a problem.

author: tautech
author_rank: Super Contributor
timestamp: November 29, 2024, 06:58:42 am
content: Quote from: hendorog on November 28, 2024, 10:53:27 pmThen you'd be without an analyzer.I'm already covered to 7.5 GHz with SHA852A.

author: Technical Ted
author_rank: Contributor
timestamp: November 29, 2024, 04:14:09 pm
content: Battle, where did you buy your LibreVNA? I'm thinking about getting one, but see there are some versions that claim to be hardware version 2. According to the goups.io where Jankae updates, it's claimed that no version 2 yet exists... So, looks like if I want the real McCoy I should stick to the one from the link on his group's site. I guess the others are ones modified by certain manufacturers/resellers which, being open source, is always happening with nanos etc..Thanks! Ted

author: tszaboo
author_rank: Super Contributor
timestamp: November 29, 2024, 04:39:55 pm
content: Quote from: Technical Ted on November 29, 2024, 04:14:09 pmThere isn't a V2 by the original designer. These are modified by some randos in China, without documenting what they did, without compensating the original author.The issue with OSHW is that they just copy it and start a race to the bottom, with completely unpredictable performance with using the original naming.

author: knudch
author_rank: Regular Contributor
timestamp: November 29, 2024, 05:56:22 pm
content: There is nothing like V2 yet (or ever)According to the designer and the manufactuer (hugen, NanoVNA)There might be a Ver 1 issue 2, small changes which improves fx heat transfer, isolation between ports, etc.I think the one I have look slightly different from the pictures on designers GIThub pageZeenko is the main distributor, look at there sitehttps://www.zeenko.tech/librevnaThey list there regional distributorsKnud

author: knudch
author_rank: Regular Contributor
timestamp: December 05, 2024, 12:42:12 pm
content: I have made some measurements...Lately I have focused on S21 measurement.Here are 3 results made on a step attenuator in 90dB setting, old one not specified for the entire range but that does not matter.Same cable hardness in all 3 casesSorry for camera pictures but I am not good of getting screen shots out of all the devices.1. Made with my NanoVNA-F V2 made by Sysjoint2. Made with my LibreVNA latest version3. Made with my Anritsu MS2721B in S21 mode (internal TG, normalization)This devices is capable of measure something like -125dB with stable and acceptable precision to at least -120dBYou can judge for self about the resultsTo be clear I think that both NanoVNA & LibreVNA gives incredible value for the money.The Anritsu was from new in another financial class, I bought it used for approx 1200eur.BrKnud

author: knudch
author_rank: Regular Contributor
timestamp: December 05, 2024, 01:00:49 pm
content: A few commentsThese ADC based devices showing a interesting behavior when you reach the bottom of there dynamic range.There noise floor seems to "drop" or the accuracy is getting worse...but I guess it is result of digitizing/calculation process.Values close to "noise floor" seems to be more "guess work" than measurements.My learning's is to evaluate the "noise floor" don't measure with zero signal but with 5-10dB before the apparent noise floor.The measurement with Anritsu was added for comparison which of NanoVNA & LibreVNA is more "correct".BrKnud

author: joeqsmith
author_rank: Super Contributor
timestamp: December 06, 2024, 12:40:16 am
content: I used two 40dB ZDTECH (cheap parts from another experiment) + 10dB Midwest Microwave.LiteVNA 3.2, 50k - 1GHz, 1601 points, normalized using 500Hz IFBW. Green 90dB attenuator with 500Hz IFBW. Blue is with both ports terminated.Our two H4s, after sorting out the problems, have a 70dB dynamic range down to around 1.6KHz. They are both better than what I have been able to achieve with any of the LiteVNAs in this region.OF course, 1601 points and 500Hz IFBW is slow. I posted some data where I averaged 3000+ samples with the Lite to get the floor below 110dB but that took several hours to run.***QuoteAs a general rule, I am wanting at least 10dB of head room.H4 dynamic range at lower frequency after repairs/mods. I doubt if you buy a new one that you would get this level of performance.https://www.eevblog.com/forum/testgear/best-vna-for-around-or-under-$2000/msg5679611/#msg5679611H4 measuring a step attenuator from 0 to 80dB and sweeping from 50k to 2GHz. Also 11th order lowpass filter with 90dB rejection at 30MHz.https://www.eevblog.com/forum/rf-microwave/nanovna-custom-software/msg5698991/#msg5698991LiteVNA64 measuring an interdigital with 3500 averages. Skirts are around 110dB down.https://www.eevblog.com/forum/testgear/best-vna-for-around-or-under-$2000/msg5679611/#msg5679611

author: knudch
author_rank: Regular Contributor
timestamp: December 06, 2024, 12:29:48 pm
content: I forgot the LibreVNA settingsWas:-3 dBm output1001 point, RBW 1 kHz, sweep time was approx 1-2 sec301 point RBW 1kHz, sweep time is approx 0,5 sec401 points RBW 100Hz, sweep time is approx 10secNo average in any caseNanoVNA sweep time is approx 1-2 sec for 301points, RBW is not known

author: joeqsmith
author_rank: Super Contributor
timestamp: December 06, 2024, 02:54:24 pm
content: Quote from: knudch on December 05, 2024, 01:00:49 pmWhen I have looked at sub 50kHz with the LiteVNA, seemed non-linear. As long as I stay in that 50k - 4GHz, 10dB headroom it performs well for what it is. You can get some useful data down to about 20Khz and up to about 9HGz with it.Shown is an old Weinschel 63dB attenuator that I mounted some drivers to. The plan was to use this to automatically sweep the floor of my original NanoVNA much like you are showing, but I never added software to support it. For that matter, I am not even sure if this attenuator works. It's only rated to 2GHz and a 1dB resolution.LibreVNA is not all that expensive but I think getting to the point where I could automate some of the tests to evaluate it would be a big investment. It it offered some sort of gains over the LiteVNA/H4/transfer relay/Solver combo, I would have pulled the trigger on it. The lack of a real review of it, the closed serial interface and then locking me out of their original Groups was more than enough to deter me. Granted, designer has opened up the serial interface and the groups was a SNAFU on seller's part (why they have two groups now). Still waiting on an actual review of it beyond an unboxing.

author: joeqsmith
author_rank: Super Contributor
timestamp: December 07, 2024, 03:01:34 am
content: LiteVNA64, normalized with both ports terminated. Showing 500 and 200Hz IFBW. I was using the LiteVNA to run some experiments in the X-band by upconverting the 4GHz to 12GHz. To achieve the highest dynamic range, I was limited to about 10GHz. The LibreVNA has about the same dynamic range (from data that was provided to me). It's real advantage is having that 10MHz reference. For these tests, I had pulled the LiteVNA's internal oscillator and mounted another SMA to the board which I drove from my RF generator (which is locked to the GPS). This solved the drift problem I was having.

author: mark432
author_rank: Newbie
timestamp: December 07, 2024, 06:47:30 am
content: Does LiteVNA64 actually allow you to define cal standards?From looking at the manual it seems that it just assumes the SOLT are perfect devices.This seems a bit bonkers to me for something that is going up to 6 GHz.I doubt that the short and open standards they provide line up perfectly with the reference plane. You would think you could at least set the parameters of the thru.But the even bigger point is cables/adapters. Sometimes you need to measure things at the other end of cables and adapters.I have a regular nanoVNA, and I didn't worry much about it because of lower frequency limit.I suppose you just have to measure a reference standard and then correct your data after the fact.Still, I wonder what the phase error after calibration is.Regarding the LibreVNA. I see that an electronic calibration module is hitting the market. I wonder why they made it a 4 port cal module, when the only librevnas I can find are 2 port?Is there a 4 port model in the works? I doubt it, but I would love a dual-source 4 port LibreVNA.

author: knudch
author_rank: Regular Contributor
timestamp: December 07, 2024, 02:21:54 pm
content: You can do 4 port by using 2 LibreVNASupported in SW, called compound deviceAs understand it, 4 port can be done with 2 of shelf LibreVNA8 if you some additional PCB'sBut you will not have phase information between each unit...as I understand itHave never tried it as I don't have 2 LibreVNA'sThere also something called Mixed Mode....please read the support mail list or ask the designerKnud

author: joeqsmith
author_rank: Super Contributor
timestamp: December 08, 2024, 12:04:48 am
content: Quote from: mark432 on December 07, 2024, 06:47:30 amGoing thought the menus of a fairly recent version of firmware, it does not appear to.Quote from: mark432 on December 07, 2024, 06:47:30 amWell, it was designed for a certain price. I am not sure if the hardware has enough resources to support it (code space, processing power...).Quote from: mark432 on December 07, 2024, 06:47:30 amBigger point? Normally I would cal these out. I normally have cables attached and measure on the other end.Quote from: mark432 on December 07, 2024, 06:47:30 amLike how the LibreVNA requires a PC, if you want to perform more advanced math with the LiteVNA, you also would need a PC.***Same for any of these low cost VNAs, not just the LiteVNA.***Link showing LiteVNA HW rev 3.2 + PC + Solver to perform T-Check (after sorting out a few problems). The only way to get that level of performance was to characterize the cheap standards and enter that data into Solver. The LiteVNA is the limiting factor, not the standards.https://www.eevblog.com/forum/rf-microwave/nanovna-custom-software/msg5685217/#msg5685217Someone had attempted a similar test using the LibreVNA and I think they achieved 3GHz. Similar the the 4GHz I saw with the LiteVNA.

author: joeqsmith
author_rank: Super Contributor
timestamp: December 08, 2024, 08:49:00 pm
content: I put together some quick software to try out that old Weinschel 63dB step attenuator and all of the stages are fine.Using an IFBW of 500Hz, I stepped from 0 to 60dB, then inserted that 40dB fixed attenuator.

author: joeqsmith
author_rank: Super Contributor
timestamp: December 08, 2024, 11:39:18 pm
content: Showing 80, 90 & 100dB with 4kHz IFBW and 1000 averages.

author: mark432
author_rank: Newbie
timestamp: December 10, 2024, 01:10:15 am
content: Quote from: joeqsmith on December 08, 2024, 12:04:48 amIt's not really a "horsepower" limitation as the calibration only needs to be calculated once when you are doing it.You're solving for a matrix, that you're going to multiply by your measured data matrix, to give the actual result.There's definitely more code involved in allowing definable cal sets, but it's all math that you only calculate once at cal.( I wouldn't expect code space to be a problem these days.)Once it's done, you're doing the same number of calculations every sweep regardless of the cal type.Quote from: joeqsmith on December 08, 2024, 12:04:48 amYeah, but often at the other end of your cable you might have other sex or other gender connectors than the supplied cal standards.Like when measuring at the end of a several foot SMA to N cable. Best case, you're using a decent adapter than only adds half an inch of phase shift and has a 30 dB RL.Quite likely you're doing worse.VNAs are about the best example of "garbage in, garbage out" for test equipment.I don't see anything else better for the price, but I'm leaning towards LibreVNA if I ever want upgrade from my NanoVNA.It seems to have much closer to a normal VNA functionality.The NanoVNA reminds me more of something like an Anritsu Sitemaster than a full VNA.I would think the best way to cover cal for super low cost VNAs would be to allow known s-parameter cal for the datasets.The manufacturer can take 1 minute and measure the standards on a traceable VNA and then provide those files with the standards. No need to try and make them perfect SOLT. Just use decent repeatable connectors and stable resistors.Many of us will have access to a lab-grade VNA and it would be easy to measure a handful of parts as home standards.

author: joeqsmith
author_rank: Super Contributor
timestamp: December 10, 2024, 02:36:55 am
content: Quote from: mark432 on December 10, 2024, 01:10:15 amThe files I used for the T-Check experiment are 512kB, male only, and limited to 1601 points. LiteVNA support more points and we would expect to support both M/F. Trivial for the PC.

author: knudch
author_rank: Regular Contributor
timestamp: December 10, 2024, 06:47:32 am
content: Quote from: mark432 on December 10, 2024, 01:10:15 amThere is a Guy Kurt Poulsen , search for him in the LibreVNA forum, he has written a article about "transfer" all CAL parametre from a lab-grade to home standards in the LibreVNA.Knud

author: Miek
author_rank: Regular Contributor
timestamp: December 10, 2024, 12:27:31 pm
content: The LiteVNA64 does allow you to define cal standards, it's under Calibrate -> Calibrate -> Calibration Standard. I checked on v1.3.31 and the latest v.1.3.36

author: joeqsmith
author_rank: Super Contributor
timestamp: December 10, 2024, 02:01:07 pm
content: Quote from: Miek on December 10, 2024, 12:27:31 pmNice find. Mine is much older (07) and appears to at least have some limited settings. They do not allow a loss term for any of the standards. The only standard that allows you to define Z0 is the load. The load also allows an L & C term which at least METAS does not. It assumes everything is coaxial.mark432 suggested ditching the polynomial for the database. My friends new H4 and the LiteVNA do have that card reader which would easily hold what ever files I would come up with. May be an option if there was a need for it.

author: theblinkingman
author_rank: Newbie
timestamp: December 13, 2024, 05:47:43 am
content: I ran a T-check on a LibreVNA and it seems to only make it up to 1.25 GHz under 15%, which doesn't seem that great.I used the same T-check on a higher quality VNA and got under +/-4% up to 8 GHz. I used the built in calibration procedure on each, so it's possible something went wrong with that on the LibreVNA.Also did a S21 measurement with both ports terminated.

author: DiSlord
author_rank: Regular Contributor
timestamp: December 21, 2024, 09:21:36 pm
content: QuoteYes, LiteVNA allow define calibration standard:Calibrate->Calibrate->Calibtation standardRemove Use Ideal flag and defineOpen: Z0, Delay, Offset Loss, C0, C1, C2, C3Short: Z0, Delay, Offset Loss, L0, L1, L2, L3Load: R, Z0, Delay, offset Loss, L, CThru: Z0, Delay, Offset LossYou can change values and in real time see changesAdditional possible save and load standard settings to/from sd card.PS calibration standard settings equal as on LibreVNA / NanoVNA Saver (NanoVNA saver not use Offset loss settings)PSS my tests cheap China calibration kit, define calibration standard settings and improve ithttps://groups.io/g/nanovna-beta-test/message/4538