Choosing "hobbyist grade" spectrum analyzer - Page 1
Forum section: electronics / testgear

author: Dan Moos
author_rank: Frequent Contributor
timestamp: August 16, 2020, 05:20:23 pm
content: Looking for input on spectrum analyzers .I'm a hobbyist wanting to explore rf stuff. I'd say the analyzer that I'm most looking at is the Rigol DSA815. I see them on Amazon with tracking gen for ~$1,100. I also see the Siglent SSA2031X-TG for ~$1,400. I have seen Dave's comparison video, so I do have a rough idea of the major differences.I also have been stalking Ebay, and am intrigued by some of the old HP units I see. I'm a bit leary of buying such a complex device used at the relative high price they seem to sell for. Despite having watched Shariar repair many of them, I don't feel remotely qualified for that! (He makes it look so easy!)The price of the Rigol is what I'm wanting to pay. I'm willing to spring for the Siglent if you convince me I will have use for the extended frequency range, and tighter RBW.I have no idea what specific uses I need. I plan to experiment with AM receivers and see where my interests go. I really want a unit that won't limit me if my interest a take an unforseen path.I guess I'm asking two things. To those of you that do rf, how important is the greater bandwidth, and tighter RBW in real world use? Second, which one has the least annoying quirks, ect.

author: bob91343
author_rank: Super Contributor
timestamp: August 16, 2020, 06:15:29 pm
content: I have an IFR 7550 that I like. Also I believe the nanoVNA has come out with a spectrum analyzer version. Of all my SAs I have never spent even as much as $100 on one.

author: tggzzz
author_rank: Super Contributor
timestamp: August 16, 2020, 06:32:44 pm
content: If you can wait, you can pick up bargains; I've got a Tek492 and HP8652B for £250/350. One was from on here, one was from a local auction house and it turned out to be a company bankruptcy sale. If I'd known that I'd have bought other items! It might be worth considering what the effects of covid and the recession will have.Decide whether you need a tracking generator.If you want to use an SA "connected to an antenna", then you will need to get a sensitive unit, which will be relatively expensive.If you want to use an SA to look at equipment, you probably don't need the sensitivity and could use a much cheaper device. Start by considering whether a nanaVNA might be useful.

author: RoGeorge
author_rank: Super Contributor
timestamp: August 16, 2020, 07:01:50 pm
content: - If by exploring RF you mean learning basic stuff, like making a mixer and watching the output spectrum, then an RTL-SDR might be enough (about $20-50), and you'll also have a nice USB radio receiver and TV tuner.- For a little more, a nanoVNA ($50-100) seems to be very useful tool even for experienced hams. Probably the best investment for learning RF, and also a good portable instrument in real life, for situations like tuning an antenna out in the field, or on a roof.- For about $100-150 you can buy a Pluto SDR that can both receive and transmit up to 6 GHz, and even higher if you consider the harmonics. Good if you want to experiment with SDR in either Rx or Tx, digital modes, etc. Pluto has an FPGA with a dual core ARM and can run Linux, both its HW and SW are open source.- Unless you plan to go in the RF business, and build/repair RF equipment on a daily basis, you probably won't need to lock $1000-1500 in an instrument you'll use just for a couple of measurements.Maybe try a nanoVNA at first (there are a few versions already), then buy something more expensive only if you really need the extra performance of a bench SA?

author: 0culus
author_rank: Super Contributor
timestamp: August 16, 2020, 07:20:14 pm
content: Quote from: Dan Moos on August 16, 2020, 05:20:23 pmBandwidth is determined by your needs. If you want to play in the 2.4 and 5 GHZ ISM bands, you need at least 6 GHz, and twice that if you want to be able to see first harmonic. Once you get to this area, even the Chinese OEMs start to get pretty spendy and you will want to start considering older used units if you want big bandwidth. HP, Anritsu, R&S, etc.I primarily use the HP 8568B and 8566B. I can't say as I regularly use 100 Hz RBW (the narrowest on those). A lot of newer analyzers offer 1 Hz RBW filters anyway, so you may not be able to avoid it except on the cheapest stuff.Repairs are daunting but, the good thing about older units is you are more likely to get detailed service information and there are a lot of people on the internet with experience who are willing to help if you are willing to learn (this forum and the HPAK mailing list are prime examples). There really are two big trouble areas you can run into with used spectrum analyzers. The first is that someone before you was a complete moron and keyed a transmitter into the input, which (at best) will cook the attenuator and (at worst) will also ruin the first mixer. Expensive, may not be worth fixing or might even be unfixable if parts are unobtainium. There are special radio communications test sets that are designed for this (HP 8920 series, for instance), with 50-60W input power handling (or more with options). NEVER use a spectrum analyzer for this.The second is YIG oscillators. These are pretty much a marvel of physics black magic and they can develop problems, especially in portable units that may have been bumped around a lot in the field. Rebuilding a YIG is possible but requires experience and special equipment, so replacement is generally the most useful option. Everything else is the same stuff you worry about with any other equipment. Power supply electrolytics, RIFA line filters, and all that sort of thing.One thing is for sure, you can get a lot more spectrum analyzer for your $ with used HP and the like than you can buying from our favorite China OEMs. You do assume some risk, but on the hobby budget (unless you are the next Alfred Loomis), it's way more palatable. I recently priced out a new Keysight SA for work that would essentially be the rough equivalent of what my 8566B can do (except for real time operation, of course) combined with a PC and MATLAB, and it came to well over $100k.

author: Dan Moos
author_rank: Frequent Contributor
timestamp: August 16, 2020, 07:32:38 pm
content: Concerning low priced options like the Nano VNA:I'm not opposed, but a possibly silly, but very real part of this is just enjoying cool gear. A stand-alone proper analyzer is just more interesting to me. Doesn't have to make senseFor purposes of this conversation, let's assume I'm hell bent on an actual stand alone SA. I'm actually not (although for stated reasons, its my leaning), but for now, that's the conversation I want to have.I am more and more shying away from used HP's and the like. Just too gun-shy about possibly getting something I can't fix. For the right price though...

author: 0culus
author_rank: Super Contributor
timestamp: August 16, 2020, 07:36:33 pm
content: Don't be gun shy about it, is my advice. Perhaps it won't be your first purchase, but there is a lot to learn by diving into HP designs in particular. They had the best RF engineers in the world working for them in their heyday!

author: aristarchus
author_rank: Regular Contributor
timestamp: August 16, 2020, 07:39:27 pm
content: Some ideas to consider as cost effective spectrum analyzer1. An RSP1a, it cover lots of bandwidth (goes higher than my DSA815), it has an application to make it act as a spectrum analyzer and it is quite decent, for a 100$-something, is great VFM.2 TinySA, new gizmo for 49$, from one of the NanoVNA developers, it looks though temporarily as out of stock as it became really popularhttps://www.alibaba.com/product-detail/Pre-sale-Hand-held-tiny-Spectrum_1600085564565.html.As mentioned already, do consider getting also a NanoVNA, its a must nowadays, got NanoVNA-H4 and love it.https://www.aliexpress.com/store/all-wholesale-products/5800447.htmlThose little things are very powerful and can get you into the spectrum analyzer stuff without breaking the bank and if something go wrong from your side on their use you will not find yourself cryng over a fried expensive instrument.If you do want to have a 'real' instrument though on your bench, then you cannot go wrong with DSA815, got it for three years and is doing its work just fine, very reliable, lots of radio amateurs got it.Siglent looks a bit more expensive and a bit more recent design, it is tempting.

author: fourfathom
author_rank: Super Contributor
timestamp: August 16, 2020, 08:26:06 pm
content: And whatever analyzer(s) you end up with, be sure to get the tracking generator.

author: tautech
author_rank: Super Contributor
timestamp: August 16, 2020, 08:38:38 pm
content: Dan, don't overlook the improved SSA3021X Plus that for a little more $ is a much nicer beast than the older and more basic SSA3021X.I've chosen to stock only the Plus version due to its better feature set.

author: tautech
author_rank: Super Contributor
timestamp: August 16, 2020, 09:50:09 pm
content: Quote from: tautech on August 16, 2020, 08:38:38 pmScratch that ^^^There's a new model just out apparently, SSA3015X Plus for $1295 .....

author: mawyatt
author_rank: Super Contributor
timestamp: August 16, 2020, 11:56:17 pm
content: Quote from: tautech on August 16, 2020, 09:50:09 pmWhat are the details of the new SSA3015X Plus, is it "hobbyist upgradable" to the SSA3012X or 32X?Best,

author: tautech
author_rank: Super Contributor
timestamp: August 17, 2020, 01:27:00 am
content: Quote from: mawyatt on August 16, 2020, 11:56:17 pmNot sure but don't suspect so. Check the datasheet:https://siglentna.com/wp-content/uploads/dlm_uploads/2020/02/SSA3000X-Plus_DataSheet_DS0703P_E03A.pdf

author: Johnny B Good
author_rank: Frequent Contributor
timestamp: November 18, 2020, 04:36:12 pm
content: Quote from: tautech on August 17, 2020, 01:27:00 amThanks for that link to acomplete specifications tableof thefull rangeof theSSA3000X Plus series.I know it's some three months late but after checking out whether the 3015 model was a possible starting point to hacking it to the 3021 or 3032 performance level and seeing the conflicting/confusing information on Labtronix and Telonic's web sites here:https://labtronix.co.uk/drupal/shop/analysers/ssa3015xplushttps://www.telonic.co.uk/siglent-s/2130.htmIt's now clear to me, thanks to that table you linked to and after viewing the EEVblog #1101 - Siglent SVA1015X VNA Teardown video, that the 3015 is a radically different beast from the 3021 and 3032, which are different again to the 3075, simply going by their Flatness and DANL figures.The 3015 is clearly a dead end as far as hacking it to a higher spec, The 3021 looks like a contender for a BW upgrade to the 3032 spec but not to that of the 3075.TBH, I don't really need a SA right now (maybe later, perhaps) but I do have a hankering for owning the one reviewed here :as a poor man's version of the unrealisable urge to possess the 2.7M dollar(?) Keysight 110GHz BW 4 ch dso reviewed by Sharia (whatever his name actually is) in that famous TSP teardown review where the price wasn't mentioned, untilafterI'd been well and truly impressed by the extreme design effort that had been invested, to the point where my first thought on hearing the price had been "Damn! That's awfully cheap for what it is!" rather than amomentThe danger here is that, because I could actually afford the asking price in this case, I might actually end up liberating some 1500 quid of my hard earned from out of the clutches of my bank (and be all the richer for it).John

author: tautech
author_rank: Super Contributor
timestamp: November 18, 2020, 06:04:25 pm
content: JBGFor some clarification if you are not aware, there are 4 different families of SA based devices from Siglent:SSA3000X, SSA3021X and SSA3032X, both are the first models of this new generation of SA's from Siglent.Then came:SVA1015X, then SVA3032X and later SVA1075X, all with slightly different features and specs as you have noticed.Meanwhile;SSA3021X Plus and SSA3032X Plus were released with the touch and mouse capable display to align to SVA models.SSA3075X Plus was also added later ~ the same time as SVA1075X was released.SSA3015X Plus was the last model added to this range.Recently for the observant, firmware for all has been closely aligned for all models to the limits of the capability of the above.Further a RT SA range has also been added:SSA3032X-R, SSA3050X-R and SSA3075X-R and again for the observant there is some crossover in the capability these offer added into selected models of the lower cost ranges.So while study of one series of S*A* datasheets identifies the similarities in performance of models in that range, careful study of all datasheets is required to see the bigger picture.

author: Mechatrommer
author_rank: Super Contributor
timestamp: November 18, 2020, 06:32:50 pm
content: Anritsu is another brand. i got a 13GHz MS8609A Mobile Tester for $1000 a while a go, well just because my $600 Advantest R3465 went wonky (still works but unable to calibrate, still in "to repair" list for so long time thats the risk with used gems) another option is buy 3-5GHz Lecroy DSO boat anchor, install SA option and you can see 3-5GHz SA and 4G or possibly 5G signal in real time domain if you really want to search for itwell for 1.5GHz range (snort) for hobby use, you can still get cheaper China version 3-6GHz, but i cant recommend one since i dont own a good working one. i have China USB NWT4 Spectrum Analyzer 35-4400MHz w Tracking Generator for maybe $50 iirc, but its not working right the last time i tested it, so its not recommendedand for track generator, NanoVNA is readily available $50 up to 3GHz, support is here.

author: mawyatt
author_rank: Super Contributor
timestamp: November 18, 2020, 07:15:55 pm
content: John,I bit the bullet awhile back and got the SSA3021X Plus, then upgraded to 3.2GHz, then "enabled" to the SVA1032X. This is a superb instrument, you'll like the reference oscillators it's very stable and low Phase Noise as required, you can lock it to your GPS source if you wish.The NanoVNA's are a nice little VNA for under $140, there are many versions and evidently some that are clones that are "supposedly" not very good (follow NanoVNA threads and sites). I decided on the NanoVNA SAA-2N awhile back, and quite impressed. Waiting on the newest version from Tindie.Here's a simple comparison of the "enabled" SSA3021X Plus --> SVA1032X to the NanoVNA SAA-2N when both calibrated to the SAA-2N supplied type N cal kit (nice kit). The DUT is a cheap SMA 50 ohm load on a cheap Type N to SMA adapter utilizing a port extension of ~19ps on the SVA1032X using the SAA-2N supplied RG142 cal cable (also nice).As you can see the little NanoVNA SAA-2N is pretty goodBest,NanoVNA SaverSVA1032XNanoVNA SaverEdit Added Data:Freq R +- jX R +- jXSVA1032X NanoVNA SAA-2N100K 51.32 + j0.24 51.2 + j0.0031100M 50.79 - j3.1 50.8 - j3.141G 31.46 - j4.75 31.6 - j4.762G 34.94 + j 20.09 35.8 + j 21.23G 94.70 - j 18.48 94.7 - j 17.1

author: thinkfat
author_rank: Unknown
timestamp: November 18, 2020, 07:21:05 pm
content: What do you intend to do with a spectrum analyser? It's only useful to look at signals, oszillator circuits, transmitters etc. Be prepared to spend another lot of money on a high-z active probe. If you have a tracking generator, it becomes a much more useful scalar network analyser that will let you look into filters and amplifiers, too. But if you want to design RF circuits, match antennas, etc then a vector network analyser is a must-have tool.

author: mawyatt
author_rank: Super Contributor
timestamp: November 18, 2020, 07:27:17 pm
content: Quote from: thinkfat on November 18, 2020, 07:21:05 pmExactly, with the SAA3021X Plus you can enable bothBest,Edit: BTW I just used the SAA3021X plus as a scalar NA with tracking generator to test some of my various BNC, SMA and N cables with the different type coaxial cables (and adapters). There is quite a variability in cables even within the same connector type & length using the same cable type, RG58 for example. With this setup you can use 0.1dB/div and show fine detail.Caution, be prepared to "see" how bad some of your cables and connectors might be

author: Johnny B Good
author_rank: Frequent Contributor
timestamp: November 18, 2020, 08:50:33 pm
content: @tautech,Thanks for clarifying the situation regarding the sheer variety of SA kit and the myriad related variants on offer by Siglent. I've seen references to pretty well most of those models and this observant consumer's main observation has been that of a very confusing choice of options, seemingly designed to confuse the end user into purchasing more than one model or else plump for the most expensive model that seems to encompass all of the variations into a single unit (assuming that such a model even exists).This echoes the situation regarding the endless number of models of TV sets each of the manufacturers keep adding to their product range, seemingly to confuse the customer into buying something that doesn't quite offer the feature set the customer had reasonably assumed he would be getting, forgetting that 'reasonableness' just doesn't apply in this case where the manufacturers have employed modern automated factory production as a weapon against the consumer to help boost the 'obsolescence effect' to create a higher rate of product 'churn'.In any case, it seems I still have a lot more research ahead of me before I can even consider making any informed investment in this particular class of test equipment. Luckily for me, there's no immediate rush.John

author: tautech
author_rank: Super Contributor
timestamp: November 18, 2020, 08:57:41 pm
content: Quote from: mawyatt on November 18, 2020, 07:27:17 pmOh yes, played around doing just that when I got my SVA and it's something you need consider, the quality of your cables and adapters.Up to a few 100 MHz it matters little unless you're chasing fine accuracy however when doing SVA Cals adapters do matter and one might have to do and store several Cals to cover the adapters you might use/need for certain projects.Most of Siglent's cables and adapters are rated to 6 GHz and cables in particular come with Cal sheets with sweeps over their rated frequency range.Recently 18 GHz cables have been added to the range however at some $200ea they are outside the budget of most hobbyists.

author: Johnny B Good
author_rank: Frequent Contributor
timestamp: November 18, 2020, 09:11:53 pm
content: @mawyattI was coming to the conclusion that the SSA3021XPlus was going to be my best option for the very reasons you've just outlined. Until now, I wasn't entirely sure just how far I could upgrade it. Thanks for that heads up and the pretty graphs.BTW, what accessories were supplied with your 3021XPlus? I've just been checking out Telonic and Labtronix's offerings. Labtronix price is £1600 inclusive of VAT and don't mention any accessories whilst Telonic's price is slightly dearer at £1602 but does include a TBCAAS1 RF Accessory Set for free as well as a PDI & Safety Test (Telonic Instruments documented pre-delivery inspection including electrical safety tests) which presumably is some form of certificate since it remains undescribed as to exactly what format this 'documentation' is provided in.On the face of it, Telonic's deal looks to be the best offering but since there's no real rush, that's just something else to keep in mind.John

author: Noy
author_rank: Frequent Contributor
timestamp: November 18, 2020, 10:24:54 pm
content: Batronix is offering 6% if you ask them.Got my for 1608€ inkl. German vat shipped.Don't know if they are shipping to UK.Accesory is nice but i think not better than Aliexpress stuff for this price.

author: mawyatt
author_rank: Super Contributor
timestamp: November 18, 2020, 11:44:49 pm
content: John,Basically nothing comes with the SAA3021X Plus. It has type N connectors, so you'll need a cal kit of some sort, adapters and cables.Best,

author: tautech
author_rank: Super Contributor
timestamp: November 18, 2020, 11:51:02 pm
content: Quote from: mawyatt on November 18, 2020, 11:44:49 pmNormally yes however Telonic does offer that RF adapter kit with them for free and while it's only 70 Pound/Euro value it's enough to get one up and going except for cabling where for a few $ea a selection of SMA cables and a Cal kit completes the basic SVA requirements.

author: Johnny B Good
author_rank: Frequent Contributor
timestamp: November 20, 2020, 05:34:16 pm
content: Quote from: tautech on November 18, 2020, 11:51:02 pmThis is the RF adapter kit that Telonic provide as a free addition:-https://www.telonic.co.uk/productdetails_popup.asp?productcode=TBCAAS1JOOI, here's the description of the SSA3015XPlus :-https://www.telonic.co.uk/SIGLENT-SSA3015X-PLUS-Spectrum-Analyser-p/ssa3015x-plus.htmwhich rather suggests that, unlike the SVA3015X, it is based on the same hardware as the 3021 and 3032 models. If true, this would seem to be the cheapest base jump off point for hacking to the 3032 option level. I also noticed that despite the thumbnail implying otherwise, this also comes supplied with a free TBCAAS1 RF adapter kit.Can anyone confirm that this is actually the case rather than an error in the description being offered by Telonic?John

author: Noy
author_rank: Frequent Contributor
timestamp: November 20, 2020, 07:18:53 pm
content: As far as i know SSA3015X Plus is not the same HW Mike SSA3021X Plus. 1.5GHz is not upgradeable to 2.1/3.2.Look at the datasheet, different DANL values!Read the hacking thread. It is not the same. You can hack SSA3015X Plus to SVA1015X probably but i think nobody has done this now.You should look in the market here . Sighound36 is selling bis less used SVA1015X for 950£. He is also in the UK. Makr him an offer if 1.5GHz is enough for you.

author: tautech
author_rank: Super Contributor
timestamp: November 20, 2020, 07:50:10 pm
content: Noy is spot on !SVA1015X was Siglent's first venture into VNA's and where inside the TG port (Port 1) circuitry, the coupler used for VNA capability had some bottom end limitations which was changed in later models for better low end VNA performance.Presume SSA3015X and SVA1015X use the same HW however other than identical SA specs cross flashing has yet to be proven.There is much more to gain with SSA3021X Plus.

author: Noy
author_rank: Frequent Contributor
timestamp: November 20, 2020, 08:08:59 pm
content: :rant:Ssa3015X andSVA1015X has also some limitaions in TG and VNA lowest frequency..Again look inzo the datasheets. If its suitable for you. Write a PN to sighound36.

author: Johnny B Good
author_rank: Frequent Contributor
timestamp: November 20, 2020, 09:37:08 pm
content: @noy@tautechThanks very much for dispelling the "Myth" being perpetrated by Telonic's confusing description.I rather suspected the description's veracity, hence my question. What had raised my suspicions about the SSA3015XPlus's hackability was the lack of any customer feedback on this model (and that of the 3075 for obvious price based reasons) versus the five stars given only to the 3021 model, echoing the situation with the SDS2104XPlus DSO/MSO.mawyatt had not only neatly summed up the situation but had proved what I'd suspected (and hoped) would be possible only in the case of the SSA3021XPlus. Thus armed with this new found knowledge, I rather fancy I'll be placing an order with Telonic in the next few days, depending on whether Labtronix had merely forgotten to mentiontheirfree TBCAAS1 or equivalent and whether I can wring a better discount than Telonic's out of them.Ever since I'd started looking at what else Siglent had to offer in the £1000+ price bracket that might appeal to me, having broken my "Spending a £1000+ on T&M Virginity" on that SDS2104XPlus just over two months ago, I've been hankering after one of these SSA3000XPlus models ever since.The main reason I'm not going to even consider the merits of the cheap sub 100 dollar VNAs is simply because I've moved beyond the cheap FY6600 toy AWG class of T&M kit (as fine as that surprisingly turned out to be for the money) and feel it's high time to indulge myself with a better class of T&M kit rather than carry on struggling with any more bargain basement test kit, especially with Xmas being so close (an SSA3021XPlus would make an excellent early Xmas pressy right about now).Like Dan Moos admitted, It's more a case of the pleasure of owning a nice shiny chattel than that of the pure utility of a 100 dollar cheapy that can suffice for my initial needs. If he's still monitoring this topic (and it's not already too late), I'd advise him to go for the Siglent rather than the Rigol. After all, if you're considering a 1000 dollar plus spend for an inferior (IMHO) offering when for just another 3 or 4 hundred dollars more you can have so much more SA for your money, you might as well push the boat out just that little bit further and be hung for a sheep as for a lamb.John

author: tautech
author_rank: Super Contributor
timestamp: November 20, 2020, 11:35:30 pm
content: JBGTelonic's free TBCAAS1 is just their promo, it's not something that's offered by Siglent. That they choose to offer such a kit to get you started is great and commendable on their part.

author: Johnny B Good
author_rank: Frequent Contributor
timestamp: November 22, 2020, 05:54:47 pm
content: @tautechI've been chewing it over and concluded that Telonic are effectively offering a "5.5% discount" which they've spent on a useful connector adaptor kit on the customer's behalf. That however, won't stop me asking them for some discount when I make my enquiry on their "Best Price"If you don't ask, you don't get and it's always worth asking since the worst they can say is that they can't offer any further discount over and above the effective discount already provided in the form of that 'free' Tekbox 'gift'.They only had one each in stock (understandable for such high priced gear) and they've sold the 3021, hence the one and only 5 star customer feedback on only the 3021 model. I notice they've since sold the 3015 and 3075 units (but no further customer feedback) with only the 3032 remaining in stock. The 3021 I'm interested in purchasing is now only "Available on back-order, delivery normally 1 week". If I place an order on Monday, I may just beat the Xmas rush and receive it in time to place under the Xmas tree.I've just used the "Quick quote" button to enquire after a discounted price to get the ball rolling. I may have submitted an order by Monday afternoon, with or without discount (hopefully, they don't monitor EEVBlog topic threads on a regular basis).I'll report back on the result of that sales enquiry in due course.John

author: tautech
author_rank: Super Contributor
timestamp: November 22, 2020, 06:13:13 pm
content: JBGLet me throw out more for you to think about as a result of another SA thread question.Have a look at this post and follow the links for the promo's running on Siglent SA's.https://www.eevblog.com/forum/rf-microwave/which-one-would-you-recommend-siglent-ssa3032x-r-or-rigol-rsa3030n/msg3337310/#msg3337310Specifically if you are planning to do any EMI work the EMI bundle is pretty good value compared to normal pricing.

author: Noy
author_rank: Frequent Contributor
timestamp: November 22, 2020, 06:30:32 pm
content: Hm, EMI licence is hackable.And on Aliexpress you get really cheap near field probes which work quite well.Also see daves video on diy probes. Siglents offer is not worth it.And calkit offer is only available with VNA device for VNA price.. But you can hack..

author: tautech
author_rank: Super Contributor
timestamp: November 22, 2020, 06:41:17 pm
content: Quote from: Noy on November 22, 2020, 06:30:32 pmYes to all however for accurate EMI work you need properly characterised EMI probes.I've bought a few sets of the AliExpress EMI probes and they are just OK however the Siglent ones are much nicer.FYI after nearly 2 years owning my SVA1032X the 120 hrs of free trial licenses are not even close to expiring so there is little need to be in some hurry to hack these unless youmustmake a SSA3021X+ a SVA1032X for urgent jobs at hand.YMMV

author: Noy
author_rank: Frequent Contributor
timestamp: November 22, 2020, 07:42:11 pm
content: Siglent ones are tekbox ones or ?Same Dave reviewed. And with SA/VNA you can check characteristics by yourself or am i wrong?Sure there is no hurry to hack. As far as i know you can revert hack if you need. But maybe siglent is closing this in a future update so im more comfortable with an already opened up device.And if your searching hobiest grade things 400$ additionally is expensive. I also looked for rigol 815-tg because for hobby its close to magic 1k mark. But then did the jump because of the hack to VNA but even this are additional 600€ + ca. 150€ for Rosenberg parts as "cheap" VNA calkit + China Nearfield probes so ending up with 1750€ ca. Thats a big "hobby" budget..

author: Johnny B Good
author_rank: Frequent Contributor
timestamp: November 23, 2020, 04:27:33 pm
content: @tautechAs promised, I'm happy to report that I did get a favourable response to my sales enquiry with Telonic this Monday morning. I've just made payment on a nicely discounted SSA3021XPlus (still including the TEKBOX TBCAAS1 RF Accessory Set) just a few minutes ago.It's on back order so I don't expect to see delivery until next week which is fine - I did state I wasn't in any great hurry in my previous posts here. Hopefully, it should turn up in plenty of time for me to tie a bow on the box and wedge it under our Xmas tree.==============================================================================================[EDIT 2020-12-09]Ididreceive my SSA just over a week after placing my order as anyone subscribed to the thread linked below will doubtless know :https://www.eevblog.com/forum/testgear/siglent-ssa3000x-spectrum-analyzers/msg3355838/#msg3355838Apologies for taking so long to report back tothis topic threadbut I think anyone not already aware of my post to the other thread will understand why once they've read it.==============================================================================================John

author: Elasia
author_rank: Frequent Contributor
timestamp: November 24, 2020, 12:31:07 pm
content: I thought you caved and bought one a long time ago? welcome to the club

author: Johnny B Good
author_rank: Frequent Contributor
timestamp: November 24, 2020, 12:36:33 pm
content: Quote from: Noy on November 22, 2020, 07:42:11 pmVNA calibration kits can cost anywhere in the region of 500 to 1500 dollars which seems staggeringly expensive when you consider what they are. With a bit of care, it's possible to make a perfectly serviceable set for less than fifty dollars.I did a search for youtube videos on DIYing a VNA Cal kit and found these two videos by W0QE which nicely describe how to make a set of open/short/load adapters. He was, imho, the only one who actually understood the requirements and the issues in home fabrication of VNA calibration kits.The relevant videos are here:I highly recommend that anyone, interested in avoiding spending half as much again on a VNA calibration kit as they did on their Siglent/Rigol VNA/SA, view them, even if only to get a better understanding of just exactly what your 500 dollars buys you.John

author: tggzzz
author_rank: Super Contributor
timestamp: November 24, 2020, 12:51:50 pm
content: Quote from: Johnny B Good on November 24, 2020, 12:36:33 pmYou are buying a calibration kit that has itself been calibrated, and you therefore have a paperwork trail all the way to national standards.If that doesn't matter to you, then you can indeed make uncalibrated calibration kits that may be perfectly suitable for your purposes.

author: mawyatt
author_rank: Super Contributor
timestamp: November 24, 2020, 03:42:10 pm
content: If the cal kit is just for hobby use and not required to be traceable to a proper cal standard I use the cal kit that came with the NanoVNA SAA-2N. This is a type N male cal kit and has two RG142 cables (trying to find a source for these cables but no luck, seller (Zeenko) hasn't been helpful either after numerous requests). I recall someone did a comparison of this kit vs. a standard precision cal kit and the result was this SAA-2N cal kit wasn't too bad.Earlier I had purchased a cheap type N Cal kit from eBay, the Open and Short compare favorably with the SAA-2N kit, but the Load doesn't. It's much longer than the Load on the SAA-2N, so not surprised it's different.For SMA cal kit I'm waiting on the NanoVNA V2 Plus4 from Tindie (want to support the NanoVNA developers on both sides of the coin) which has a SMA cal kit included, I also recall someone did a comparison and the result was pretty good. In the meantime I've constructed my own very crude SMA cal kit using some SMA adapters and a cheap eBay SMA Load. The Open is just an SMA M-F extension. The Short is a SMA M-M extension type which has male pins on both ends, the external threaded end was filled with solder for the "short".Anyway, think there are a few options for hobby type cal kits that don't break the bankBest,

author: Noy
author_rank: Frequent Contributor
timestamp: November 24, 2020, 03:43:21 pm
content: Of course i dont need the paperwork.I think i will order the SDR-Kits SMA Rosenberger parts from Mouser.https://www.sdr-kits.net/Female-12%20GHz-KitI can measure the load with my Fluke 8840a with 4 wire. And i don't need a wooden box. And its better/cheaper to order from Mouser instead of UK from germany.Im only unsure if i need only female ones or additional male ones. All cables i have are male so i need only male ones if i don't want to use cables directly on the Adapters...I think BNC ones aren' affordable.. SDR kits are saying their bnc calkit is only gold to 600MHz. So i think SMA is the way to go for good / widely spread usability.Additional purchased some Delock N to SMA Adapters (10GHz 89983 ones not the cheaper ones)

author: switchabl
author_rank: Frequent Contributor
timestamp: November 24, 2020, 06:03:45 pm
content: Quote from: Johnny B Good on November 24, 2020, 12:36:33 pmI think those videos show a couple of things:- At 200-300MHz almost anything will do.- Making a pretty good 2-3GHz 50 load is not too hard with a bit of care and a decent connector (at higher frequencies, it gets a lot more tricky). But then this is also pretty easy to buy. A cheap Minicircuits ANNE-50X+ would probably be fine. A while ago I bought a whole bag of Huber&Suhner 18GHz SMA terminations for 2€/piece on eBay.- If you have a proper calibration kit already, you can easily make your own. In principle, if you get it properly measured, any set ofstablestandards that is sufficiently spread out on a Smith chart can be used for calibration. That is essentially how E-cals work.- The naive approach without any characterisation/optimisation is okay-ish at 3GHz. If you used his first attempt for calibration without entering the correct delays there is an error of more than 3ps, you will probably end up with a residual source match error a bit worse than -30dB (assuming your load is sufficiently good not to be a limiting factor). Also of course your reference plane will be way off.I would also recommend against trimming the open to have the same delay as the short. Unless you are making standards for ascalaranalyzer or there is no way to enter cal-kit definitions on your VNA it really serves no purpose. If they have very different lengths, at some frequency the phase delay of the open and short will become very close/identical and the calibration math falls apart. But a few degrees really don't matter. Measure them and enter the correct values so the VNA can take them into account during calibration.Quote from: Noy on November 24, 2020, 03:43:21 pmStandard BNC connectors don't maintain 50ohm impedance, so they are not really suitable for calibration (at more than a couple 100MHz at least). There are special precision BNC connectors for 10GHz+ (often 75Ohm for broadcast applications) and expensive cal-kits for those, but it doesn't really make sense to mate those with normal BNCs.

author: Noy
author_rank: Frequent Contributor
timestamp: November 24, 2020, 06:42:46 pm
content: THX for clarification.So definetly the Rosenberger SMA parts because delay and other parameters are provided by SDR Kits.But do i need female and male parts?

author: switchabl
author_rank: Frequent Contributor
timestamp: November 24, 2020, 07:13:57 pm
content: It all depends on the devices you want to measure. Do they have female connectors (at least on one side)? Then you need the female calkit. Many PCBs, Minicircuits modules, filters, attenuators etc do. For simple things that don't need great accuracy (like maybe an occasional antenna with a male SMA), you can also get away by calibrating with the female kit and adding a f-f adapter. But everyone's needs are different. If you want to measure devices with male connectors frequently/accurately, you should get a male kit as well.I'm also not sure what to recommend for a cheap male kit. I'm not as confident about the male SDR kits one as the female one. It may be fine, but I haven't seen any real data for it and I am skeptical about the dust cap open (as you probably know by now).That being said, having a male load (or ten) is definitely useful. E.g. maybe you have something with more than 2 ports and need to terminate the rest. Any 12-18GHz name brand one (Rosenberger, Suhner, Minicircuits, Telegärtner etc) is probably ok. Just don't get those tiny ones where the pin is always rotates with the rest of the connector.

author: mawyatt
author_rank: Super Contributor
timestamp: November 24, 2020, 07:51:45 pm
content: The NanoVNA SAA-2N has cal kit parameters for the supplied type N cal kit for use with NanoVNA-QT, they are both male and female. I got these files from one of the on-line tutorials.Best,

author: hendorog
author_rank: Super Contributor
timestamp: November 24, 2020, 07:56:57 pm
content: If you know someone with a proper cal kit then they can measure whatever parts you choose to use. Then you can try to fit the 'standard' properties to the measurements using software discussed here in the past. Metas VNA tools is one way.That gives you a fitting error, which will have some effect on real world measurements depending on its magnitude. Better quality parts will fit better over a wide bandwidth. Crappy parts can still fit well, but only over a narrow bandwidth.Instead of fitting, the better option is to just use your mates measurements directly, but that generally requires a pc, as many vnas don't provide that option.Another consideration when buying cal kits is the variation between cal kits, when the cal kits all share one set of characterisation data. All cheap kits and most low cost kits are like this. High quality kits must be either individually characterised (as above) or mechanically tuned to fit the parameters. So by simply measuring a cheaper kit properly it can be improved.So, if you have access to someone with a proper VNA cal kit, then get a kit with the highest quality parts in it. I have seen a Siglent 3.5mm/sma kit, and it has higher quality parts than my Kirkby kit. My sdrkits Rosenberger kit is lower quality IMHO.If you don't have access to a proper cal kit, then characterisation data is king. Kirkby is the best here by far, of the low cost ones I have seen.I'm happy to measure cal kit parts against my Kirkby one for the cost of postage. If that was done by a proper lab with calibrated gear then your cal kit would be traceable as pointed out by tgzzzz.

author: Noy
author_rank: Frequent Contributor
timestamp: November 24, 2020, 08:12:05 pm
content: Nice but kirkby ones are also nearly 1/3 of the VNA price..

author: hendorog
author_rank: Super Contributor
timestamp: November 24, 2020, 08:46:11 pm
content: Quote from: Noy on November 24, 2020, 08:12:05 pmYes - but the VNA is nothing more than a (fairly simple) tool for comparing an unknown against a characterised cal kit.The VNA is not the part you should be investing all of your money into...Edit: And as indicated, I did point out the cheap option - buy parts and get someone to measure them...

author: 0culus
author_rank: Super Contributor
timestamp: November 25, 2020, 12:05:37 am
content: Quote from: Noy on November 24, 2020, 08:12:05 pmGet used to it. The cal kit is the heart of everything you do with a VNA; without a good one the instrument is pretty darn useless. I wasecstaticto find a great condition HP 3.5mm cal kit for a grand. That was a steal.

author: tggzzz
author_rank: Super Contributor
timestamp: November 25, 2020, 08:28:09 am
content: Quote from: hendorog on November 24, 2020, 08:46:11 pmDon't forget to include the cables and connectors in the parts that are measured.And don't forget to look at the price of reputable RF cables/connectors, i.e. not those that you can buy on fleabayPlus be aware of the spec for the number of mating cyclesOf course amateurs that are playing around (e.g. me) may choose not to worry about such considerations.High quality RF stuff isexpensive, and it is a rathole as deep as voltnuttery and timenuttery.

author: switchabl
author_rank: Frequent Contributor
timestamp: November 25, 2020, 10:23:39 am
content: I think there is room for a bit more nuance here. You can do incredibly accurate measurements with a VNA. On a properly calibrated lab-grade VNA you are looking at residual directivity and mismatch of -40 to -50dB for 3.5mm ports. But that doesn't mean you need that kind of performance. Outside of metrology applications chances are you don't.The home-made standards from the video without any characterization should (by my rough estimate) be good for a residual directivity of ~-45dB (which is great) and a residual source mismatch of -25 to -30dB @3GHz. Which is not great but it is not horrible either. In the worst case, depending on the DUT, that adds an uncertainty of +-0.5dB. That doesn't quite meet my standard for "useless". I would expect your average SDR kits part with the generic delays from HHFT or Kurt Poulsen to get more like -35 to -40dB as long as the load isn't too bad and/or you are at least correcting for DC resistance. A bad load is a much bigger problem. Heck, on a decent VNA you can do a lot of useful measurements with just the factory calibration.So after you have adjusted your expectations, the harder question is how to establish confidence that your particular standards actually meet those. This is, of course, especially problematic with parts that are not originally specified for calibration purposes (or just home-made). But for something like a used HP kit this isn't totally clear either. And I agree that generally you can't be sure unless you have a traceable characterization. For commercial or research applications this is quite likely unacceptable (also, why aren't you using an e-cal?). With something like the SDR kits one, the fact that other people have measured them and they are usually quite decent can get you some of the way. You could still have a bad batch. With a decent load, if DC resistance is close to 50 ohms, it will probably be quite good to 2-3GHz (beyond that, or with an aliexpress special, don't rely on it). If you have them, you can measure other known devices (I have a 15cm beadless air line and a 20dB reference attenuator). There are some sanity checks you can do. The (in)famous T-check looks for reprocity violations (S21 =/= S12). If you see ripple on your measurements that could not possibly be from you DUT (because it is not electrically long enough), your cables/calibration may be off. In the end, YMMV, depending on your needs.Another example: I have two 6.5 digit multimeters at home. It is not worth it for me to have them calibrated regularly. They are known to be quite stable (usually significantly better than the specs) and normally I don't get close to needing the full accuracy. So I am fine with some spot checks and for more critical things, I measure with both and compare.If you actually need higher performance then you are not done with a good 3.5mm calkit either. What about phase stability of your cables? Repeatability of your connectors? Don't forget a torque wrench. You never really appreciate those until you have seen your S11 jump by more than 10dB because of a connector that wasn't properly tightened.Also, we are not talking about a PNA here. The Siglent is not a full 2-port VNA, so as soon as you want to measure S21, you have an uncorrectable load match error. The port-2/spectrum analyzer input is specified as "VSWR <1.5", that is a -14dB mismatch right there.

author: tggzzz
author_rank: Super Contributor
timestamp: November 25, 2020, 11:35:27 am
content: As I wrote..."Of course amateurs that are playing around (e.g. me) may choose not to worry about such considerations"

author: tautech
author_rank: Super Contributor
timestamp: November 25, 2020, 12:40:27 pm
content: Quote from: switchabl on November 25, 2020, 10:23:39 amCertainly and my first use of a VNA for a real job proved just that:https://www.eevblog.com/forum/rf-microwave/antenna-project-log/Then some experimentation with various antennas I have on hand....which reminds me, I still have one more to characterise and addhttps://www.eevblog.com/forum/rf-microwave/what-really-is-this-antenna/Then I replaced my SVA1015X with a SVA1032X......QuoteKinda lucky here as a VNA nutter lives not far from me with some legacy equipment and a good pile of Cal kits, some of high quality.....but this luck only leads to another rabbit holewhere as you say the Cal kit is everything !So after another $400 on a Siglent F603FE 4.5 GHz SMA Cal kit plus a pile of SMA fittings finally we have most of the tools to start experiments building fixtures and the like but the temptation to get some of Siglents new 18 GHz cables is strong.QuoteCable torque is fun to play with and N type needs be really tight for best repeatability while SMA is a little more forgiving where the correct torque is just tightly nipped ....if we are to do these things by just 'feel'.Learning about VNA's is fun for the inquisitive but you need decide how far you will venture down this rabbit hole........ if you can !

author: switchabl
author_rank: Frequent Contributor
timestamp: November 25, 2020, 12:42:42 pm
content: Quote from: tggzzz on November 25, 2020, 11:35:27 amYes, this was more a response to the concerns that a VNA might be pretty much useless without a proper calkit. It is not just about amateurs either. Not every measurement needs a fresh, traceable calibration and Phaseflex cables. And it often makes a lot of sense to have some lower-quality "working standards" for simple measurements, too.Even for critical measurements, I would argue that it is usually good practice to do a quick and dirty one first. If something is way off, you have a chance to fix it first without having to waste a lot of time re-doing everything.The important thing is to have a good sense of how good is good enough for your particular application (and maybe do a back-of-the-envelope estimate of the uncertainties you can expect).EDIT: Maybe it is also helpful to make this distinction: if your goal is to make the most accurate measurements you can, i.e. you see the metrology side as a hobby in its own right (which is totally legitimate), then you should probably put a proper 3.5mm cal-kit at the top of your shopping list. If you just want a tool to work on antennas or filters etc, then it makes more sense to ask: What level of accuracy do I need? How much am I willing/able to pay to ensure that this is actually reached?

author: thinkfat
author_rank: Unknown
timestamp: November 25, 2020, 01:39:38 pm
content: And, wouldn't something like the NanoVNA (V2 or some other) be a good enough solution. Of course only if you don't need a spectrum analyzer, too.

author: tggzzz
author_rank: Super Contributor
timestamp: November 25, 2020, 02:42:23 pm
content: Quote from: switchabl on November 25, 2020, 12:42:42 pmWe are in violent agreement on all countsI wish all posters had a similarly sane and pragmatic view of the issues relating towhyyou are making a measurement!

author: mawyatt
author_rank: Super Contributor
timestamp: November 25, 2020, 03:27:18 pm
content: In our case we needed a good moderate cost SA that could cover a few GHz, and because of the our experience with the SDS2102X Plus and SDG2042X selected the SAA3021X Plus. As with the prior experience the SAA3021X Plus has exceeded expectationsWith the help of folks here, the SA was "expanded" to 3.2GHz, then "enabled" as a VNA, so starting out needed a SA that covers a couple GHz and ended up with a SAANDVNA that covers 3.2GHzThis all led to getting a NanoVNA SAA-2N to play around with, as I was very interested in the actual design and how it was implemented. Very clever and simple concept that is quite effective utilizing some of the newer chips that pack a lot of performance in a single chip.Anyway the type N cal kit & RG142 cables that are supplied with the NanoVNA SAA-2N are our best reference resource kit & cables at the moment, and since we don't need standards type performance and only intend to work to ~3GHz, this seemed a reasonable for now. The cheap eBay type N kit load doesn't agree well with the NanoVNA kit load but the short and open do agree very well. For the SMA cal kit & cables we've ordered a NanoVNA V2 Plus4 which "supposedly" has decent performance like the SAA-2N.Should we get involved with something that requires publishing or otherwise reference traceability, then a proper cal kit is in order. For now the cal kit with the NanoVNA's seem "good enough", later we may try and get these "verified" with a known cal kit from another source (maybe university where I was an adjunct).It's amazing what you can getgrad studentsto do for a few beersWait I resemble that when I was agrad studentWait I still resemble that now that I'm retiredBest and Happy Thanksgiving,

author: hendorog
author_rank: Super Contributor
timestamp: November 25, 2020, 06:30:09 pm
content: Quote from: switchabl on November 25, 2020, 10:23:39 amI agree with you. We all need/want a cal kit that meets our needs.The simplest way to do this (and I've been fiddling around trying to do this cheaply and in a remote part of the world since about 2012) is:* to get someone to measure your cal kit (low cost, easy, high quality)* or get a brand new, characterised cal kit. (expensive, easy, exchange money for quality)* If those options are not available then we are destined to journey down the rabbit hole of trying to validate our standards based whatever means are available. (low in hardware cost but expensive in time, difficult, quality variable but good results are possible)Therefore, I believe that access to that equipment to do the measurement is key to "good enough, fast, low cost".Which is why I made the offer of measuring for people. If others (in different locations) did the same then life would be much simpler for people starting out on the VNA journey.I've pushed Siglent on the port 2 mismatch issue. Obviously it can be worked around by using an attenuator to improve the match, or by exporting the data to a PC and using 2 path one port cal in software.

author: Noy
author_rank: Frequent Contributor
timestamp: December 10, 2020, 08:15:40 am
content: Maybe interesting.Bought a "cheap" torque wrench from Aliexpress. It's looking decent but i cannot measure it. But probably better / more accurate than by hand.Something like this:https://de.aliexpress.com/item/32615318002.html?spm=a2g0o.productlist.0.0.5d4ddf684o3k9O&algo_pvid=9113c218-a0db-4614-873b-48f53ea8591a&algo_expid=9113c218-a0db-4614-873b-48f53ea8591a-2&btsid=2100bdf016075865089484506e43d6&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_But i bought it from another seller.The "Certificate" is looking "real" it has other values than on the pictures shown there.. :-D But description is on chinese..

author: autoelectra
author_rank: Contributor
timestamp: March 10, 2021, 11:10:32 pm
content: @Dan Moos: I got the DSA815 with tracking generator from ebay in used but very good condition with trial time left: 34 hours,so only 2 hours used for 850 Euros,approx. 10% more fore USD, before 2 years. I`m very happy with this guy. I upgraded with current firmware version, trial times away,after 34 hours back again.The switch is is installed again, so full performance with trials again.