"Low" cost legit VNAs


#1

Just a PSA:

One option is a used, 20 year old HP 8753E series. I had one of these. They work fine, but they are enormous, and you need to use a floppy disk or a GPIB to get data off it – not such a blast from the past.

I replaced it with what appears to be a Chinese knock-off of a Rhode-Shwarz portable VNA. Was $1700, IIRC, now is $1999. Perhaps tariffs, I suppose. Although there is a 4GHz version now that’s a bit cheaper.
(http://www.deepace.net/store/)

I was prompted to take a chance on it after Shariar did a review.
http://thesignalpath.com/blogs/2017/05/14/deepace-kc901v-6-8ghz-handheld-network-analyzer-review-teardown-experiments/

I compared it to my 8753 (before I offloaded the 8753), and the performance was favorable. Hooray for 20 years of amortization of digital VLSI! It’s very small, which is also awesome. I like it quite a lot.


#2

Thanks for sharing, after this weeks Amp hour I was curious about people’s experience with miniVNA Tiny.

Regarding the VNA that you mentioned, can it do spectrum analysis, how about power sweeps to get amplifier compression and TOI? Those were convenient measurements I liked to do on the R&S ZVB that I had at a previous employer.

I don’t think that R&S ZVL3 is too far away from $3k, that would do similar functions bu only up to 3GHz. (I don’t have much reason to go past 3GHz)


#3

It does these features. I don’t generally need above 3GHz, but it’s nice to know that I can cover 5.8 GHz if necessary.


#4

For an even smaller budget, there’s the N1201SA vector impedance analyzer.

I picked up one of these just to play around with some 2.4GHz chip antennas. It doesn’t have all the bells and whistles, but let me tune a chip antenna for 2.4GHz. If I were doing serious work, I’d consider something better, though it is reported to be pretty accurate for what it does. It measures s11, vsrw, impedance, and a handful of others, but lacks smith charts.

Having no prior experience or skills in the RF domain, I found this video very helpful, and sold me on that model:

I also found this a handy resource: http://colinkarpfinger.com/blog/2010/the-dropouts-guide-to-antenna-design/

Are there other/better references, perhaps taking it a level deeper? Favorite books on the subject? I don’t intend to design my own antennas, but knowing a bit more theory would be handy!


#5

Have not listened to this THA episode yet, but got miniVNA Tiny in 2014 and works quite well for most simple antenna applications. Need to be careful with calibration drift and temperature compensation. Right now using R&S entry level FPC1500 SA with 1-port VNA option for quick antenna measurements (over LAN, up to 3 GHz). Quite happy about it. Has much lower noise floor, faster speed and smaller drift.

miniVNA Tiny performance improved a bit after reworking the circuit a bit (decoupling, filtering, shielding). Wish I could redo most of its PCB layout to perform better. Exactly the same story with DG8SAQ VNWA3 – there is room for improvement. Also have not used them as SA, only as VNA.