VNA-nuts ? Show your VNA - Page 1
Forum section: electronics / testgear

author: PA4TIM
author_rank: Super Contributor
timestamp: January 04, 2014, 08:59:04 pm
content: I'm a bit VNA addicted. I have 3 of them. One I build a few years ago as a kit, the VNWA from SDR-kits. a 0-1300 MHz digital vna/lcr meter/ SA/ signal generator/counter/powermeter. But there are people who run it over 2GHz. And one user I know, uses some simpe extra HW to get over 10GHz. The software has that option so that makes it easy. The second I have is a newer version from the kit and came ready for use. The first is build in a 19"cabinet and in my lab, the second I have build in a shielded old RF amp housing together with a PSU. Together with all accesoiresand laptop it fits in a small suitcase.I also wrote a series of tutorials for newby's VNA-nuts.The 3rd one is the grandfather of VNA's. The HPO-8704+8601 1-110 MHz VNA. I have the CRT and analog dB meter plugin.The vnwa, small but very capable In the link more pictures and on an other page of my side there are pictures from building ithttp://www.pa4tim.nl/?p=1546(in Dutch but there are pictures for the monolingual.http://www.pa4tim.nl/?p=676The portable one, pictures of accesoires, suitcase etc (in English)http://www.pa4tim.nl/?p=1594My tutorials (in English, some also in German and French.http://www.pa4tim.nl/?p=646the HP-8407 made in 1968.

author: DonRon
author_rank: Regular Contributor
timestamp: January 04, 2014, 09:06:53 pm
content: I have the minivna plus from miniradiosoliutions. Very nice and small - use it mainly to check antennas.Great to use via bluetooth in combination with an android-tablet and the android-app bluevna from YO3GGX.

author: PA4TIM
author_rank: Super Contributor
timestamp: January 04, 2014, 09:40:08 pm
content: A friend of my has the miniVNA, that is also a very nice vna. We have tested it here because he was curious how good it was and that was very usable. Like you he uses it only for antennas.I know some users of the VNWA also use it remote via Wifi (if I remember well) but I do not know how. I have used mine once as a test through vnc but for my use that is not handy. I use it for the strangest things but not often on antennas. My dipole is 50 meters and static allready killed a transceiver so if I measure it I use the HP with a 40 dB directional coupler and 100 K bleeders.I also like to read about network analyses. I have the books from Hiebel (R&S) and Joel Dunsmore (HP) My first book that made me interested in network analyses was the book from Hans Nussbaum about the Funkamateur analyser. I wanted to buy that because my Russion SNA died beyoind repair (and believe me, I have tried, and I had some wobbulators too)But just at that time a usb interface for the VNWA was anounced. I liked it allready but I had no PC with parallel port (only laptops)So I ordered a kit that was delivered 1 day befor my holyday .

author: DonRon
author_rank: Regular Contributor
timestamp: January 04, 2014, 09:50:47 pm
content: I bought that book "HF-Messungen mit dem Netzwerktester" from Hans Nussbaum at the last year ham meeting in weinheim. Even if he relates to the FA network analyzer in this book it is from great value for me - I wanna learn more about measuring coils and capacitors, LC-circuits .... And this is well written in this book for a newby like me.I wanted to buy the Funkamateur kit - but I waited too long. They are sold out and they will not offer the kit any longer.Concerning BOOKS:I too have the book from R&S and several App Notes from HP/Agilent.Greet'sRonald

author: KJDS
author_rank: Super Contributor
timestamp: January 05, 2014, 12:05:35 am
content: My 6GHz HP8753C. It's a little worn but works well enough. At some stage I'll upgrade it to an ES.

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: January 05, 2014, 12:19:01 am
content: Hi,IONLYhave two, does that qualify me for this thread?I have an HP8753C the 3 GHz version with an 8502A T/R test set.I also have 3577A with both S-parameter test sets 50 Ohms and 75 Ohms. 35667A and 35667BRegards,Jay_Diddy_B

author: DL8RI
author_rank: Regular Contributor
timestamp: January 05, 2014, 12:20:43 am
content: A VNA is still on my wishlist... (numer one)Right now I use a R&S ESVP and a HP 8502A Opt H26 for transmission/reflection. But maybe I go for the SDR-Kits this year until I get a real one (R&S ZVRE or somthing of that caliber).

author: G0HZU
author_rank: Super Contributor
timestamp: January 05, 2014, 01:49:55 am
content: I have an old HP8714B 3GHz VNA. It's only a T/R VNA but I've developed a method to get good 2 port s parameter data from it. However, this involves mucho swapping of connections and use of attenuators for the S21 and S12 measurements.I get the raw vector data via GPIB and then gradually build up a 2 port s parameter file for S11, S21, S12, S22. I've also created my own user cal files for it to enhance the accuracy when taking 2 port data.It takes a few minutes to do it all.It has the biggest/nicest smith chart display of any VNA I've used but I do want to upgrade it to something like a 6GHz 8753ES. I will miss the nice display of the 8714B when I upgrade and I've been using it for so many years (at work and now here at home) that I've grown quite attached to itI have also recently bought an old HP8405A vector voltmeter and I sometimes also use a simple 2 channel scope and a sense resistor or a coupler to make vector measurements with a scope.I'm playing around with negative impedances at the moment eg negative capacitor and negative resistor circuits and the HP8405A VVM is an ideal tool for this

author: Mr Simpleton
author_rank: Unknown
timestamp: January 05, 2014, 05:21:33 pm
content: Have the VNWA v 2.3 and love it. Almost finnished the N2PK v4.3 just need attach power and start debugging the PCB's and the I do have the HP 85046A S-parameter testset for HP 8753A/B... still would love to have the whole machine though. Daytime I do use the HP 8753ES...

author: nctnico
author_rank: Super Contributor
timestamp: January 05, 2014, 05:32:14 pm
content: Its a pity the SDR-kits website is such an uncomprehensible pile of words. I tried to look for the kit, a simple explaination on how to use it or specs but they don't seem to exist. If it can be tricked into going over 3GHz at reasonable sweep speeds I might consider buying one. I just have to get my head around to read those Smith charts.

author: Mr Simpleton
author_rank: Unknown
timestamp: January 05, 2014, 06:54:25 pm
content: The VNWA is not offered as a kit anymore...Just had a look at the SDR Kit webpage and it's notthatbad, reallyThere are a number of links to external sites offering documents, including one from PA4TIMNow, some have been able to run the VNWA above the 1.3GHz, but the dynamic range will suffer. If you do have to make serious measurements on 2-3 GHz this instrument may not be the best for you!

author: DonRon
author_rank: Regular Contributor
timestamp: January 05, 2014, 07:11:38 pm
content: concerning SDR-Kit VNWA:http://sdr-kits.net/VNWA3_Description.htmlu will find some infos - also u can download the Help-File (pdf) and the software to checkThere is a yahoo-group too:http://groups.yahoo.com/neo/groups/VNWA/infoBut I think it is not possible to work up to 3 GHz. It is specified up to 1.3 GHz with limited dynamic range, so going > 1.3 GHz performance will decrease extremely.

author: PA4TIM
author_rank: Super Contributor
timestamp: January 05, 2014, 10:39:32 pm
content: It is remarkable that many VNA-nuts also work with a vna professional.The VNWA is indeed not as kit for sale. I think the last kit was 2 years ago. When the sales increased Jan could not make enough kits for the demand. I build two kits and they were very complete. All smd parts color coded by Jan and strips cut to the right number. That must be a hell of a job. And Tom spend so much time in supporting the builder problems that the software development went a bit slow. After the kits stopped the number of software updates and new functions increased.I have never used a modern Agilent or R&S (I have not even seen on in real) But I am very curious to how they work. But I think the digital ones are far out of my league and the VNWA does everything and more as I need. But the 3GHz theHP's mentioned here is a very nice and usable bandwidht for the higher HAM bands. My first VNA was the HP. A friend bought a 8405 for 25 euro and got the 8407 for the same money. He did not wanted it but I did. But I had no clue about VNA's other then the fact that they are cool and can do more things as my wobbulators. But the first drawback was that it was just part of a setup. I needed a display, cables, calkit and a sweeper. I found a dead 8601 sweeper for 100 euro (the seller told me it was perfect working) and later I found a second 8407 with a display. It should be in working condition but the attenuators missed some parts so I save iot as a parts mill vor my working version.Today I made a GR call kit. I allready had an Original GR load and now I made a short and open. The GR connector is briljant for VNA user. No male/female calkit, no portextentions for a tru.When I got the russian analyser it took me weeks to get useable results because nobody told me I need a diodedetector.

author: Po6ept
author_rank: Regular Contributor
timestamp: January 06, 2014, 03:52:05 pm
content: I recently picked up an unbuilt N2PK VNA kit and am wondering if it is worth building because it has a parallel port interface. Does anyone have one? If so, does it work well?

author: Mr Simpleton
author_rank: Unknown
timestamp: January 06, 2014, 07:54:34 pm
content: The N2PK is extrememly powerful, and if you only have to measure up to 60 MHz the dynamic range goes up to roughly 120 dB! You may be able to find a supplier for a USB to parallell too. I am almost certain you can get one of those cheap logic analyzers (i.e. Saleae knock-offs at $10) and use these. Same chips and you may only to have to program an EE-Prom to get it operative. I am about to put my N2PK in operation, it has been assembled for a number of years but never got round to start using it (for a number of reasons, not for missing performance though)When you say unbuilt kit, you should really think about getting the latest PCB i.e. version 5.2 (www.makarov.ca), mostly uses the same components, but refined design. You will have two detectors which speed up measuring and make sure you use the newer A/D as they are vastly faster the the old ones! You need to tell us more what is included in your unbuilt kit.

author: Rufus
author_rank: Super Contributor
timestamp: January 06, 2014, 09:02:49 pm
content: I also own an SDR VNWA - no point showing it you know what it looks like.

author: G0HZU
author_rank: Super Contributor
timestamp: January 06, 2014, 09:28:30 pm
content: It would be nice to see some critical side by side comparison tests of these mini VNAs against a classic HP/Agilent VNA.I did find a few quick comparisons online but they all seem a bit crude and clumsy and some tests make even the HP VNAs look poor (obviously they are not poor).Has anyone here done a direct and critical comparison?

author: Po6ept
author_rank: Regular Contributor
timestamp: January 06, 2014, 10:03:28 pm
content: Quote from: Mr Simpleton on January 06, 2014, 07:54:34 pmThe kit was shipped March 2011. I have the board shown at this web site but he doesn't mention the version:http://www.seed-solutions.com/gregordy/Amateur%20Radio/Experimentation/N2PKVNA/BoardsAndParts.htmIt's kind of hard to figure out exactly what I have but there are a lot of parts in the bag. There is no ADC in the kit so I can elect to buy the LTC2440 instead of the LTC2410. I do have the 148.344 MHz oscillator module, so I don't need to find a substitute for that part. There is no T1-6T reflection bridge board in there.

author: Mr Simpleton
author_rank: Unknown
timestamp: January 06, 2014, 11:35:58 pm
content: Had a quick look at the W8WWV page, and it looks pretty much as the original N2PK pcb layout... but with the improvements added.Still it depends on what you want, I would rather save up for the makarov.ca pcb set which is what most people do use now.Still, I am sure you will be able to put it all together! It is a marvellous thingyBTW It seems your kit is a carbon copy of the N2PK by looking at this page:http://www.seed-solutions.com/gregordy/Amateur%20Radio/Experimentation/N2PKVNA/Kits.htm

author: Rufus
author_rank: Super Contributor
timestamp: January 06, 2014, 11:42:45 pm
content: Quote from: G0HZU on January 06, 2014, 09:28:30 pmYou could read SP4SKR's comment herehttp://www.eham.net/reviews/detail/10893on the SDR Kits/DG8SAQ VNWA.VNAs have the property that you can obtain very precise results with very little in the way of precision circuitry. It is mostly down to calibration. People spending a few hundred on a VNWA are not going to spend a few thousand on a cal kit. The cheap VNWA's calibration will likely drift more and be less repeatable. The dynamic range is limited especially above 400MHz (or whatever) because it is running on spuria from a DDS generator. The 'dirty' excitation means it may not play well with non-linear or active devices.Of course they are not going to be as good as the 'real thing' but they really are very capable at a small fraction of the price. I love the way they manage to get so much out of cheap circuitry by being clever.

author: Po6ept
author_rank: Regular Contributor
timestamp: January 07, 2014, 12:31:00 am
content: Quote from: Mr Simpleton on January 06, 2014, 11:35:58 pmThanks for letting me know about the makarov.ca boards. I would much rather build the dual detector one with a USB interface instead of the parallel port. The PC boards are a small part of the overall cost and at $36 are a bargain.This is one of the reasons I enjoy this forum so much. No matter how unusual the project, someone on here knows about it and is willing to share what they know. I appreciate the help, Mr Simpleton.

author: G0HZU
author_rank: Super Contributor
timestamp: January 07, 2014, 12:49:32 am
content: QuoteIt's a very positive review but I was kind of hoping to also see some critical test data. None of the test data I've seen seems to have much in the way of control so you end up not knowing the limits of each instrument.I mostly use my VNA (and the ones at work) for generating n port models of components or small circuits to allow me to simulate as accurately as possible on a PC. So the accuracy of vector based measurements is very important to me.I like the fact the VNWA3 goes down to 1kHz and obviously it is also very portable. But it's really frustrating that nobody on the planet seems to review these mini VNAs critically. You get a few half baked and poorly controlled tests that don't really stretch any of the instruments and (to me) they just demonstrate the limits and flaws of the test procedure rather than any of the VNAs on test.

author: Rufus
author_rank: Super Contributor
timestamp: January 07, 2014, 01:25:11 am
content: Quote from: G0HZU on January 07, 2014, 12:49:32 amYou could join the yahoo group (if you can - yahoo changes made such a mess I couldn't log on any more so gave up and haven't been there for ages). There are a lot of files in the group I think I remember some comparison plots. The best place to make enquires about the SDR Kits version anyway.

author: G0HZU
author_rank: Super Contributor
timestamp: January 07, 2014, 01:28:28 am
content: OK thanks, I'll have a look at the yahoo group tomorrow.I have to agree that yahoo groups are generally not very well organised and I have had similar problems as yourself with other yahoo groups but I'll give it a try

author: PA4TIM
author_rank: Super Contributor
timestamp: January 09, 2014, 09:08:35 am
content: The vnwa, when calibrated carefull and the right way gets a very good result on the R&S T-check. Some members of the yahoo group have tested it against professional VNA's and it scores very good. It gives very good results upto 800-1000 MHz, above that it is usable but in that case you need a very good documented calkit. My kit is usable upto 1300, my V3 gives usable results upto 1500 MHz.But even if it does not performs as good as a >10k or > 100k analizer it is still a real bang for bucks and not in the way that counts for the cheap scopes and meters. (low performance/low price)I do not get notifications for my own topic ??

author: Po6ept
author_rank: Regular Contributor
timestamp: January 09, 2014, 07:11:44 pm
content: Quote from: PA4TIM on January 09, 2014, 09:08:35 amI don't believe that starting a topic changes notification settings. Under your profile settings, you can select whether or not to enable notifications. Go to Profile, Modify Profile, Notifications

author: The Electrician
author_rank: Frequent Contributor
timestamp: January 09, 2014, 10:17:40 pm
content: The cal-kit is all important, and there's no reason not to buy one of these--good up to 6 GHz!http://www.ebay.com/itm/RF-Network-Analyzer-Calibration-Kit-2-Kits-included-Plug-and-Jack-/370981777421?hash=item56603cb00d

author: branadic
author_rank: Super Contributor
timestamp: January 09, 2014, 10:33:53 pm
content: I've one of those VNWA 2.6 at home and developed those 36MHz TCXO upgrade kits for the 2.x series a few while ago, as a direct replacement for the internal crystal.By the end of the last year we ordered the latest model for work.

author: G0HZU
author_rank: Super Contributor
timestamp: January 14, 2014, 10:44:35 pm
content: I suppose I should also mention I also have an Advantest TR4172 1800MHz spectrum analyser + TGen that has an impedance measuring option fitted.You are supposed to buy an external RLB from Wiltron with this option but I don't have the RLB. But I do have several home made bridges that seem to work well.However I rarely use this feature on the analyser as the VNA calibration procedure is quite lengthy and very strange! Also, the HP8714B is so much nicer to use as a VNA.But the TR4172 is probably the 'strangest' VNA on here so far. I'll post up some pics the next time I have the RLB handy and I can spare the time to set up the calibration on itOMG I just remembered... I've actually got TWO of these TR4172s now. I recently bought a non runner for spares (now fixed) for £250 a few months ago. So I am in the VNA qty3 club as wellNote: If you google TR4172 and look at the images you can see one in VNA mode with the smith chart display turned on.It's one of the ugliest analysers on the planet but it was one of the very best (and one of the most expensive) spectrum analysers in the world in the 1980s.

author: chscholz
author_rank: Regular Contributor
timestamp: January 15, 2014, 02:03:07 am
content: Quote from: PA4TIM on January 04, 2014, 08:59:04 pmMe too. I work for R&S America and specialize in VNAs; I am a marketing guy.

author: marshallh
author_rank: Unknown
timestamp: January 15, 2014, 02:25:39 am
content: Can anyone recommend a book/website detailing VNA usages and what the numbers mean?

author: PA4TIM
author_rank: Super Contributor
timestamp: January 15, 2014, 07:34:31 am
content: http://www.microwaves101.com/encyclopedia/couplers.cfmWebsite with lots of infoThe agilent impedance measuremet handbook :https://www.home.agilent.com/agilent/editorial.jspx?cc=GB&lc=eng&ckey=2162694&nid=-34051.536879632&id=2162694One off the two vna "bibles"http://www.books.rohde-schwarz.com/the second book on this page from M. HiebelAnd the one from J. Dunsmore, the vna desinger from Agilenthttp://books.google.nl/books/about/Handbook_of_Microwave_Component_Measurem.html?id=GEnBhrvPFQwC&redir_esc=y@chscholtz:QuoteOK, because it is VNA marketing we forgive youThat must be a great job. To be surrounded by those wonderfull instruments . I have never used a modern professional VNA, so I know those only from books, but i like the R&S VNA's very much. (but they are waaaaay out of my hobby budget)When I bought my Hameg the guy who demonstrated the scope was from the service department and we had a nice chat. It turned he knew my website because he used to work at Fluke working on the calibrators I have. And now he did support on the R&S VNA's and offered me to analyse my calkit. To bad I had a computer crash and lost his email adres (and can not remember his name)

author: PA4TIM
author_rank: Super Contributor
timestamp: January 16, 2014, 12:18:46 am
content: Tonight a friend came by and he gave me 3 sealed bags from Huber-Suhner. Inside 3 sucoflex 104E cables with N connectors. They have serial numbers and a test certificate. They are very beautifull. I did some tests and they perform very well. Even better as my amphenol sma cables (the vnwa has sma so I had to use SMA to BNC and BNC to N to mount them and because I have no N cal kit I used N to GR-874 and calibrated the set with a GR calkit and results were above expectation. .

author: KJDS
author_rank: Super Contributor
timestamp: January 16, 2014, 12:46:53 am
content: I'm still looking for a proper set of Gore cables for mine. They also make the Agilent ones. So beautiful to use. Very flexible but with no spring to them and also no phase change with flex. They'll also last forever.

author: marshallh
author_rank: Unknown
timestamp: January 16, 2014, 01:09:27 am
content: Thanks PA4TIM for those links.

author: TerraHertz
author_rank: Super Contributor
timestamp: January 16, 2014, 02:10:39 am
content: Yes, thanks PA4TIM. And everyone for this thread. Lots of interesting reading.Quite a while ago I too decided I wanted to learn about VNAs, or rather high frequency RF design in general.I've been gradually building up a pile of RF test gear, starting with the really early basic stuff like slotted lines, through phase/gain meters, and early VNAs. All very old stuff, on the principle that the service manuals are available, the operating principles are discussed in practical terms in the manuals and app notes, it's all relatively cheap (ie I can afford it), and who cares if the accuracy is not so great any more.I'm not afraid of fixing stuff where necessary. Also, I just like old test gear. Love the way it's built, and the awesome manuals.Unfortunately the 'too many time demands' syndrome has defeated me so far, and all the gear has just been sitting idle while other life issues get sorted out. Or not.Anyway, here's some of it. Top down:HP 8405A vector voltmeter,HP 8418A aux display holder, with 8414A polar display (also have the 8413A Phase-gain meter)HP 8410B Mainframe, with 8412B Scope (rectilinear)HP 8411A Harmonic freq converterHP 436A Power meter (also have some assorted sense heads)HP 8750A Storage normalizer (not sure I have the right interface card and cables for this and the 8410B)HP 8743A Trans/Refl TS (2-12.4GHz)(and a bunch of other stuff elsewhere)I didn't know there were small USB-based VNAs these days. Interesting.

author: marshallh
author_rank: Unknown
timestamp: January 16, 2014, 02:50:00 am
content: Quote from: TerraHertz on January 16, 2014, 02:10:39 amMind if I move in?

author: TerraHertz
author_rank: Super Contributor
timestamp: January 16, 2014, 06:17:25 am
content: Quote from: marshallh on January 16, 2014, 02:50:00 amHeh, usually it's Chinese and Russian ladies wanting to marry an Aussie for citizenship.Even if you were cute enough, there are other... difficulties.Hey, does anyone have a list of the best HP App Notes on this topic?I have a few, like 117-1 Microwave Network Analyzer Applications, and the HP soft-cover book Microwave Theory and Measurements.If only I had time to read them! (Motivation is also a factor, sigh.)After investigation I'm kicking myself, in that the HP 8410B apparently isn't easy to convert to computer controlled operation, while the 8410C is.

author: PA4TIM
author_rank: Super Contributor
timestamp: January 16, 2014, 07:53:29 am
content: That is a nice stack of HP gear. (I have all my calibrators in a 19" rack)I have the 8407 with 8412 and the analog gain/phase meter. But not the 8414 polar display.I stil use the 8407 but not much, because that little German wonderbox can do the same and much more. One cool thing I did with the HP is using it as a RF-IV analyser. I made a S21 setup but used a Tek CT1 inline current probe for the reference channel and a T to measure the voltage over the DUT with the test channel. That worked very well but involved some math to translate it to impedance .HP has some nice appnotes made in the 60-70's when they made the first vna's. I learned my first vna steps from those. The reason I made my serie of tutorial is because it is very hard to find information for starting vna-nuts. The books I mentioned are great but a bit overwelming for starters.I found the smith chard picture for the advantest vna.http://www.technologymuseum.eu/phpwebgallery/picture.php?/196/category/60&pwg_id=ab6a46a1fbd069bc1c507aa3f4de2311I do not think it is an ugly vna, I like the looks of crt's with readout.

author: chscholz
author_rank: Regular Contributor
timestamp: January 16, 2014, 08:01:09 pm
content: Quote from: PA4TIM on January 15, 2014, 07:34:31 amBest job I ever had (not necessarily the easiest, I guess that is sort of related). It's amazing what difference it makes to work for a privately held company.

author: ivaylo
author_rank: Frequent Contributor
timestamp: January 17, 2014, 06:28:05 am
content: QuoteIs it worse or better? Also are you comparing with publicly traded companies or with government organizations?

author: larry42
author_rank: Regular Contributor
timestamp: January 17, 2014, 10:37:44 pm
content: Quote from: nctnico on January 05, 2014, 05:32:14 pmThe website is indeed pretty confused and messy ("Documents" links to some random data sheets ,but not to the VNA) then the "webshop", sometimes referred to the the "e-shop" on the site will bring you to buy the thing.But the Help file (which is just a PDF version of the Windows Help) is filled with references to the Version 3, the 3E, expansion boards etc. Page two then shows a board with a serial connector and a USB interface board. Talks about LPT interfaces (parallel).I've just gone back to the webshite now - Apart from a couple of sets with cal kits, you can buy the VNWA3 or the 3E, which is referred to as a 3+ with expansion board. Finally on page 11 of the help file:"VNWA3E was formerly named VNWA3+ but both are the same product. The DG8SAQ VNWA3E is the VNWA3 fitted with the VNWA3 Expansion Board which provides additional functionality as follows:..."I wish they just had a line on the webshop description that said: "1kHz-500MHz (1300MHz with reduced performance) 2-port VNA with integrated Transmission/Reflection test set"Anyway after I figured out which one to buy, I received it and promptly had lots of issues getting the thing to work at all. Admittedly with a Win7 VM. The problem is that the Setup routine was very un-polished, with a confusing (IMO) method of calling the items e.g. there is a Window area called "Auxiliary Audio Settings"with text that says "Aux. Audio measure THRU", but then a pulldown for "Aux. reference = right channel")The software has some quirky UI, that is definitely not according to any UI guidelines - something like a utility you might get from a motherboard maker.I was rather chagrined when I initially received the item after the poor purchasing experience due to the confusing website. Which was then promptly followed by the audio setup that had to be done each time I plug it in, a VMware issue, but still the setup was just strange - requiring me to follow the precise procedures in the manual each time, because the names and placement of the controls (choice between left/right, main/aux and thru/reflect). Afterwards I was rather vocal on the Yahoo site, complaining about the interface* and that for 500 quid it should be a bit more polished, I ended up giving some constructive criticism and Tom Baier (DG8SAQ) incorporated my suggestion of an auto-setup for the mapping of thru, reflect, left, right, main and aux. Therefore for most people they just have to disconnect cables and press "auto setup".*I have used VNAs, programmed them and written cal routines for them since 1998, so I consider myself fairly au-fait with the concepts. Moreoever, I had lent the VNWA to a university professor, who is also a practical engineer running a successful radar company, and he had problems following the setup as well.So the conclusion is that yes, it's pretty good for what it does. I don't consider it a wonder box. I really wish that the interface was open source, because there are a number of dialog boxes I want to change, the calibration is not what I'm used to (HP VNA background), but probably no worse than the R&S analyzers I have fought with. The thing is not very good as a spectrum analyzer, it's very rudimentary for that. Tom Baier is responsive and helpful for those that are experiencing problems.It's certainly lighter than any other VNA!I'm in the process of making an S-parameter set for it, and maybe swapping out the mixers, to give better performance at the higher frequencies.I've not been able to do any real comparisons to Agilent VNAs. Much of the accuracy comes down to the cal kit, but as most people don't have 3 grand to spend on a real cal kit, I wouldn't worry too much about it. Above 500MHz the lack of DR will play a role. I assume there will be a few spurs as well due to the use of the DDS aliases.

author: G0HZU
author_rank: Super Contributor
timestamp: January 17, 2014, 11:32:05 pm
content: I also had a look at the VNWA website a few days ago and wasn't too impressed...The pdf help file has some good and bad points. But I find the user interface to be poorly designed and visually unappealing. It's easy for me to sit here in a chair and criticise but I can't understand why the interface is so poor when you have more display and control versatility/area on PC screen compared to a typical HP/Agilent VNA.QuoteMaybe it could be rewritten to allow a degree of external control. eg the ability to use a custom 'skin' and also allow the user to change labels and menu names to something more intuitive.

author: KJDS
author_rank: Super Contributor
timestamp: January 17, 2014, 11:36:16 pm
content: Quote from: larry42 on January 17, 2014, 10:37:44 pmDoes anyone like the R&S user interface? I quite like the ZVF analyzers capabilities but using it drives me round the twist.

author: G0HZU
author_rank: Super Contributor
timestamp: January 17, 2014, 11:46:37 pm
content: LOL!At work we have various R&S VNAs from the very strange 20GHz ZVM to the cute little two and 4 port jobbies. eg the ZVB range.I like the RF performance but hate the user interface on all of them. Plus the ZVM isn't easy to use via GPIB when importing data into Genesys. It doesn't export the corrected data and often goes a bit loopy afterwards.The little ZVB VNAs are very portable and pretty but I feel like I've captured a VNA from another planet when I try to use one as the user interface seems to have been deliberately designed to be 'different' to Agilent.

author: G0HZU
author_rank: Super Contributor
timestamp: January 18, 2014, 02:02:38 am
content: QuoteWhat do people use for a VNA cal kit here? At work I have access to the usual HP/Agilent cal and ecal kits which is useful.However, for casual research work at home I often use a homemade SMA based system that works very well with my HP8714B. It was extremely cheap to make and I don't have to worry about losing parts of it or it wearing out as it is so cheap to make a replacement.I have access to the Agilent kits at work if I need to make critical measurements at home but I get pretty good results with the homemade kit.There does seem to be a recent influx of cheap(ish) VNA cal kits appearing on ebay etc and I wonder if anyone has tried them?

author: KJDS
author_rank: Super Contributor
timestamp: January 18, 2014, 05:52:29 am
content: Until recently I was using a home made short and open and a Narda load.I've now picked up a couple of HP cal kits, one I'll keep and the other is for sale.

author: PA4TIM
author_rank: Super Contributor
timestamp: January 18, 2014, 09:14:02 am
content: For sma I have a Rosenberger and amphenol calkit, for bnc I have 3 homemade kits. I also have a HP and narda load but I get better results (in a t-check) with my homemade ones. For N I have only very nice cables and a load at this moment. But my most used kit is a GR-874 calkit. I made the open and short but found a brand new 50 Ohm load. I use that because I have a whole bunch of GR stuff.For those not familiar with that, here are some examples. I also have trompones, an adjustable stub, cables etc and a collection of bridges and generators.About the vnwa, it is not a >15K R&S or agilent that need calkits more expensive as the vnwa and cables you do not dare to touch without gloves ;-)But I call it a wonderbox because fot that money I can not get a better one and it performs very well (in my opinion, I have measured the strangest things with it from fF and mOhm upto things like impedance of mud)It can be used as counter, can be used as signal generator, the TDR is neet, it has a LCR meter so for that money I will not complain. (I do not needs all those functions because I have like 5 counters, 10 LCR meters, a bunch of generators, timestandards, etc but if you have not, I think its handy)Indeed Jan is not a webside builder, he is a HAM and a retired engineer. Tom is a professor on a university in Germany. SDR-kits is more or less a hobby and they had not expected the VNWA to become so populair. But they mean well, ar far from commercial and are very helpfull. If you find a bug or have a good idea Tom solves it very fast or adds it and I think some professional companys can learn from that. So for me it's great but if I was used to digital R&S or Agilent I maybe had an other opinion. Concidering the price (the cheapest R&S or Agilent is far outside my range ) I am afraid I will never have that exerprience. I envy you guys who are allowed to play for a job with those great toys for boys ;-)So now I know who to thank for the auto setup. That is a very good feature. I never had problems on my XP computerr but then came that bloody W7 and it drove me nuts. If all worked and I used it the next day W7 replaced drivers and this other stupid things but because I use it for years it takes me less as a minute to get it working again but the autoset option is very nice because W8 (i use now) is even worse in this, (for me as Linux user)I have no experience with other user interfaces so I do not know better and I use it for something like 4 years now. For me it is good. It can be easy customized with other background, colors, size of markers, grids, custom traces . The trace can be saved to files and used in things like qucs or other software (I have no experience with that but I know people who use that a lot. The help file has lots of info but I agree it can be confusing because it is grown a bit out of it's shoes. It is becoming a bit better over time. The first versions where just dumps from the helpfile and there was no index, pagenumbers and subjects were spread all over the file. That is the downside from amateurs making stuff, but I am sure if they were commercial we had to pay for things like updates , would have to live with bugs and the thing would cost over 1000 euro and still sell because the first better alternatrive would still be unobtainium, it probably had a more impressive looking cabinet, nice manual etc. But thanks to this I got VNA's as a nice hobby and learned a lot and some functions in it are made on my request, I do not think R&S or Aghilent would do that.So that's why I like it so much and I tend to be a bit over enthousistic, but, hey, I'm just a hobby network analist (and I know, we are a rare unusual breed)

author: larry42
author_rank: Regular Contributor
timestamp: January 18, 2014, 07:17:39 pm
content: Yep I will agree that once one acutally understand the website and the product, both Jan and Tom are nice and helpful individuals.I feel that the VNWA could actually be a much better product with a few improvements. Improved website, the help file edited by someone skilled in writing user manuals (right now too many words and German-> English grammar construction, which is completely understandable, just a slight nuisance when trying to understand the thing quickly), and some of the diaog boxes and cal stuff could be improved.Further afield - electrically I would like it if a few changes where made - I wonder if the newer 1 and 2.5GHz DDS's could be integrated (along with a better mixer) - but I fear that would add at least 100 USD to the BOM.About to make my own cal kit soon. And have to remind Poul on the importance of cables in the cal process - he seems to neglect this in all his otherwise useful documents.

author: G0HZU
author_rank: Super Contributor
timestamp: January 28, 2014, 01:40:54 am
content: QuoteHere's a quick comparison I did today where I compared the same RF choke (on a test fixture) on my HP8714B with one of the Hp8753ES analysers at work. The HP8753ES is cal'd with a HP 85033E 3.5mm calkit and my HP8714B is calibrated with my homemade calkit.The test was only carried out up to 3GHz because that's the limit of my HP8714B but you can see how well my calkit agrees.To get this level of accuracy I had to Dremel the homemade cal kit to fine tune it and also I run it with a 'user' cal file. But I use this cal kit all the time and it cost me nothing to make because I made it from salvaged 18GHz SMA partsTo build it from new parts would cost about £20.Obviously, this isn't exactly a conclusive test but you only need to add a 0.2ps delay error in one set of results to see the results diverge.The plot below shows the real and imaginary components of the complex impedance of the SMD choke. The results agree so well that the 2 pairs of traces are sat on top of each otherThe second plot is of a 1K 0805 SMD resistor in a test fixture measured on both analysers.

author: PA4TIM
author_rank: Super Contributor
timestamp: January 28, 2014, 07:41:34 am
content: Very nice result.Larry, I would like to see the same improvements like you but I do not think that will happen. I have asked Tom that a few months ago. The majority of the users seems to be not interested in higher as 430 MHz but would have to pay more because some would like >1300 MHz. I think 3 GHz would be nice. But most user buy it because it is not much more expensive as a simple antenna analyser. There are users who used it higher, I'v seen sweeps upto 6 GHz but they used external hardware. One of the swedish guys, Dan, has used it on very high frequency with some extra external hardware.Tom wrote an article about how you could do that. I still want to try that but to be honest, most of my use is under 10 MHz (1kHz to 10 MHz) for component behaviour measurement. But on serveral occasions I wiched it would go above 1500 MHz.I measured a 23cm antenna for a friend. That is no problem. Mine is real good upto about 900 MHz, very usable with good cables and cal kit to 1300 and limited usable for a raw indication upto 1500 MHz but my V2.6A does not get that high.I think you are talking about Kurt instead of Paul ? His last name sounds like Paul.

author: kg4arn
author_rank: Unknown
timestamp: January 29, 2014, 12:46:24 pm
content: Thanks to all for an interesting thread.A company in the USA is selling this unit:http://arraysolutions.com/Products/VNAUHF.htmLooks like about twice the cost. Has anyone here heard of it or does anyone know how it compares to the SDR device?

author: PA4TIM
author_rank: Super Contributor
timestamp: January 29, 2014, 02:49:50 pm
content: I have only read about it. It should have slightly higher dynamic range (according to what someone wrote me) , Software seems to be influenced by some agilent software. It goes from 300kHz upto 1300MHz and dynamic range also seem to drop above 600 Mhz. As far as I know it can only do S11 and S21 (the VNWA can do S11, 12, 21, 22 and three port measurements (indirect, you have to switch connectors . The software tells you when and what to do, and than does the rest as if it had 3 ports.It looks nice with the N connectors but it is a rather high price difference. I think if it did 3 GHz for that price it could be a winner.

author: PA4TIM
author_rank: Super Contributor
timestamp: February 01, 2014, 10:30:34 pm
content: This has been an analyser month. First I got 3 beautifull calibrated coax cables with N connectors, then I received a SDR-Kits Rosenberger sma callkit. Did some tests and that was a bigger positive difference as I would have thought. I allready had a homemade and amphenol calkit ,I Used the data delivered with the kit and made calibration from 10 kHz upto 1500 MHz and this improved as I hoped the response above 1GHz.Today a General Radio collector came by to see my GR collection. He has a very big collection. As a supprise he had some GR goodies for me. Some GR874 adapters, some component fixtures, T- pieces, a krystaldiode modulator , GR adjustable capacitor for use on GR-874 and 3 Original shielded banana wires for my GR1603 and GR1620.But the nicest thing was a beautifull wooden box with a GR1602 UHF/VHF 20MHz to 1500 MHz admitance meter. Including a short and a load. No I have to study the manuals. This is the grandmother of VNA's. I allready had the mixer/ detector , some unit oscillators, adjustable stub (but only the 50 cm), an other load, trombone and some airline. Only things still missing are the short adjustable stub, the GR-874 LK , the GR-874 LB balun and the 100 Ohm load. Now I have to learn to operate it.I had no time for pictures yet.

author: KD0CAC John
author_rank: Frequent Contributor
timestamp: February 01, 2014, 11:06:14 pm
content: Fred , just looked up your call on QRZ and see we got our tickets - ham license with about 1 yr. apart .Wanted to thank you ham related VNA website , it makes more sense to look at them from a ham perspective for me ,doing self talk about all these toys , I picked up a miniVAN Pro recently and it helps to get a handhold on all the RF values and understand .Now if there is enough yrs. left to get good at it

author: DL8RI
author_rank: Regular Contributor
timestamp: February 02, 2014, 11:41:31 am
content: Quote from: TerraHertz on January 16, 2014, 02:10:39 amNice to see someone using this stuff today.I scrapped two of this VNAs recently (didn't have the room for such a "spacy" unit at that time). If you ever need spare-parts, write me a PM I ripped some stuff out of the generators.

author: PA4TIM
author_rank: Super Contributor
timestamp: February 05, 2014, 12:07:00 am
content: Admittance measurement in 50's pre-vna style. It can do 10 MHz to 1500 MHz but I can only use it to 450 MHz because I do not have the sliding short that is used as suseptance standard.

author: joeqsmith
author_rank: Super Contributor
timestamp: January 12, 2015, 04:30:43 am
content: Some pretty neat looking antique equipment posted here. I have an old HP3589A w/o the S-parameter set. My other one is a real old HP8754A.The following video shows my 8754A in action.

author: PA4TIM
author_rank: Super Contributor
timestamp: January 12, 2015, 07:29:36 am
content: That is a nice VNA set you have there. I love your collection of cal kit pcb's. I soldered capacitors straight on sma connectors but that gave mechanical problems. The capacitors broke because the centrepin moves a tiny bit while mounting it on the analyser. Dit you buy those pcbs somewhere or made them yourself ? Nice software too. It is very impressive the way yours measures such a small capacitance.By the way, double sided pcb is great for making capacitance standards, you can easy trim then by changing the size with a file. I have made a some this way (10pF upto 100 pF). Soldered a piece of 1mm silverplated wire to each side and use them to test LCR meters. (calibrated them with a GR1620. Mine is Ex-GR and was used in GR's own standards lab)In your video you are testing a probe. I have done the same thing a few years ago. Did you measure the probe while it was connected to the scope input ? I found out recently that makes a difference. (I read something about input capacitance of a probe in some pdf, but can not remember where or what. It was not about testing probes but they needed that value for something related to the testing. I forgot about it until a friend asked something about probe capacitance and I put an LCR meter to the tip. It was still on the scope. I then remembered I read about this and disconnected the probe to see if there was a difference, and there was.I now finaly have another stone age impedance measure instrument. A GR 900 slottedline including cal kit and a bunch of GR-900 adapters, amongst others for GR-900 to bnc, sma, N.Also found the adjustable stub for the GR admittance meter.http://www.pa4tim.nl/?p=4978for the slotted linehttp://www.pa4tim.nl/?p=3059my probe test, it is still in Dutch but has a lot of photo's and pictures

author: KJDS
author_rank: Super Contributor
timestamp: January 12, 2015, 07:31:15 am
content: I picked up an HP8510 a few weeks ago, still need to find a signal source for it.

author: Howardlong
author_rank: Super Contributor
timestamp: January 12, 2015, 11:45:27 am
content: Quote from: chscholz on January 15, 2014, 02:03:07 amCue tumbleweed...http://youtu.be/iIIuR-HjFhoSorry, couldn't resist!