Inexpensive VNA

[Teotwaki]

I may get one to have in a field kit for quick checks of antennas

[Rob.]

I picked one up off eBay for $33 shipped. Very neat device and pretty easy to use. I can see lots of uses for it around the shack. NanoVGA Saver software makes it easier to view the data.

[Josh]

A Guide to the NanoVNA: Kindle eBook for $2.99

With the NanoVNA (and upcoming NanoVNA 2.0) being so affordable and readily available many budget focused RF enthusiasts and hams are now adding a tool to their arsenal that used to only be for the wealthy and commercial users. Vector Network Analyzers (VNAs) allow you to do things like make SWR measurements on antennas, characterize RF filters and detect coax cable faults, among other applications.
https://www.rtl-sdr.com/a-guide-to-the-nanovna-kindle-ebook-for-2-99/

[Matt285]

It's so great that antenna analyzers are becoming affordable. One thing I find funny is that for years MFJ led the market on these products. Don't get me wrong I've owned many MFJ tuners over the years and have no complaints. Most of their other products aren't so desirable though.

[Josh]

Yeah this thing is way cool and great price.
Was thinking the other day with this thing having that fat display and processing ability it's not too far fetched for someone to roll out a similar in size and price fft/waterfall display with say 70MHz, 45MHz, 10.7mHz, 9MHz, and 455kHz inputs as a stand alone panadaptor that can be bodged into just about any rx. I'd love to have one.

Like this thing but rationally priced;
https://www.heinzstampfl.ch/en/shop/mr-pan/

[JimIO]

"Like this thing but rationally priced;"

Start here:

https://www.ebay.com/itm/STM32F103C8T6-ARM-STM32-Dev-Development-Board-Module-Blue-Pill-w-ST-Link-V2-USA/292142597005?epid=2212881423&hash=item44050e438d:g:dVwAAOSwYS9ZauEa

~

[Matt285]

Christmas gift? I'm not waiting 11 months!

[Matt285]

Finally got around to ordering the NanoVNA. Better start watching Youtube videos about it. Cant wait to be able to analyze antennas in the field. Among many other uses. Going to purchase a cell phone type cover for it as well.

[Matt285]

One thing I've noticed from the brief reading and short videos is that , it seems to me measuring and trimming antennas to proper SWR is going to be a bit more complex than say the MFJ analyzers where you just set the frequency and adjust from there. I'm hoping i'm wrong and that it will be easy to learn on this new contraption I already ordered. If any one has any insight to this normally easy procedure please share. Thanks

[nickcarr3151]

I have the NanoVNA-F model which is the 'upgraded' version.  It has a larger screen and better shielding.  It also has the 1.5 Ghz update and works very well.  I almost spent $2000 on a proper Spectrum Analyzer (with TG) but now I don't have to!  I can test all of my filters and antennas.

[Matt285]

I was watching a video where it shows what looks to be a tiny SMA 50 ohm dummy load for calibration. Does anyone know if this is included in the package and if not where to pick one up? Thanks

[nickcarr3151]

I was watching a video where it shows what looks to be a tiny SMA 50 ohm dummy load for calibration. Does anyone know if this is included in the package and if not where to pick one up?

They're all over E-Bay but yes it generally comes with everything you need to start...

FWIW here's the model I got:  https://www.ebay.com/itm/Vector-Antenna-Network-Analyzer-50K-1GHz-Real-Time-NanoVNA-F-VNA-VHF-UHF-US-Ship/164051384904

[Brian]

One thing I've noticed from the brief reading and short videos is that , it seems to me measuring and trimming antennas to proper SWR is going to be a bit more complex than say the MFJ analyzers where you just set the frequency and adjust from there. I'm hoping i'm wrong and that it will be easy to learn on this new contraption I already ordered. If any one has any insight to this normally easy procedure please share. Thanks

It's very easy.
If you're using the SWR setting, it will display a curve that shows you exactly where the antenna is resonant. You can see instantly whether it's too long or short.
The only part which may seem slightly tedious is the calibration. It must be calibrated for the frequency range that you using it on or the results may not be accurate.
You can save up to 4 (I think) calibrations.
I calibrated mine to cover the 2 HF frequencies that I usually use (+/- about 100 Khz), the FM broadcast band and the section of the MW broadcast band that I transmit on.
Once calibrated, it shouldn't require re-calibration unless you need to use it on a different band.

[nickcarr3151]

It must be calibrated for the frequency range that you using it on or the results may not be accurate. Once calibrated, it shouldn't require re-calibration unless you need to use it on a different band.

I'm not sure this is completely true Brian.  I've calibrated mine for 100khz to 1.5 ghz and it seems pretty consistent across the spectrum.  Perhaps if you're looking for extremely precise measurements then the specific calibration may be necessary; however, I can only speak for the NanoVNA-F model.

FWIW, I haven't used it on the HF spectrum that much -- but again, it seems consistent across entire range for me.

I think the key is proper calibration (performing all of the required measurements) and then you're good to go.

[nickcarr3151]

Here's a quick demo of my comparison of the RTL-SDR and GPIOLabs FM Trap filters:



At quick glance it would easy to conclude the GPIO the winner but for me personally, the RTL-SDR performs better -- since I need the notching at the top-end of the FM broadcast band.  The GPIO does a better job at the lower end.  The RTL-SDR is a bit wider too.