NanoVNA – First Thoughts

At some point in your amateur radio adventures you’ll eventually want to make your own antenna or you’re not certain about the antenna you have and want to make sure it’s working properly. You’ll have to get some type of analyzer. For many years the MFJ-259 series was a staple in the amateur radio community and you’ll still find them in many shacks. But at around $299, it’s a hefty investment for a lot of hams. You’re not going to spend hundreds of dollars to measure your $20 dipole. Just like with boats, you would rather find a friend that has one and use theirs instead. You may be lucky and your local amateur radio club might have a loaner. For a long time, this was the only way… Until now

With advances in technology, mass production and shipping, hobbyists can get their hands on some really advanced stuff without it doing much wallet damage. The prices for components are now at the level where it’s worth tinkering. For the amateur radio operator, it’s a blessing. Some really nice projects are being developed to where almost anyone can participate. Plus these projects are being shared with the general public which can be a blessing or nightmare depending on the circumstances.

The MiniVNA

Before when the MFJ-259 reigned, there wasn’t much out there unless you started getting to lab grade equipment which is not priced for the hobbyist. Now the market is flooded with all types of analyzers. Some are cheaper and some are more expensive when compared to the 259. They may or may not be better. When I was first in the market, I gravitated towards the mini radio solution’s miniVNA pro. I got a used one for a really great price. It had bluetooth connection and there was an app developed for android based devices where adjustments can be made at the antenna while the analyzer was hooked up at the other end. If you follow my blog, you’ll see many times where I’ve used it.

I liked that I could analyze antennas, measure coax (see if there is any breaks/shorts), sweep filters and I even measured LC circuits with some degree of accuracy. However, I’ve made a big mistake … I sold it and regretted it almost immediately.

After about the 12th time I kicked myself in the butt, I started looking at getting an analyzer or hobbyist grade VNA. The RigExpert brand of analyzers looked tempting and there were some kit style VNA’s but their prices didn’t justify the purchase .

The SI5351

One of the things I’ve noticed in my very limited electronics skill set is the Silicon Labs Si5351 programmable clock generator chip. Considering they cost around $1USD, I was excited to see what hams would do with the style of chip and there are many kits and products. I could imaging many projects that would need a VFO would use this chip. I’ve purchased breakout kits thinking I would be able to make something from it but my lack of knowledge and time stopped me. However, there are some really cool projects that use the type and style of chip.

New VNA on the block

One of those people was twitter user @eddy555 He was developing a small handheld VNA with a touch screen using the Si5351 Chip. He made it available so that anyone could make it but I just didn’t have time to source the parts and build it. It made having an “affordable” VNA within reach.

Due to the project being completely out in the open, Chinese electronic manufacturers noticed the demand for these kits and started mass producing these VNAs. The market recently flooded with them to where the prices are getting lower and lower. You can now obtain one, assembled with an internal battery for about $50 USD. You can’t really beat that and I feel that they will even get lower in price. Word of mouth is spreading quick in the amateur radio community. So of course I had to get my hands on one.

I purchased mine from the Chinese exporter Aliexpress. People have mixed results when dealing with Aliexpress but from what I’ve read the units coming from a particular vendor were very decent and compared to the likes of lab grade equipment.

After 3 weeks from purchase, I received a box containing the VNA, SMA calibration kit, two SMA patch cables, SMA barrel connector, USB-C Charge/Data cable and a plastic case. The VNA itself is about the size of a credit card and about 1/2″ (11mm) thick. It uses standoff and PCB boards as a case. I removed the screen protector (involves unscrewing the top board) and eventually 3D printed a case I found on thingiverse

First Thoughts

You get a lot for your money. Of course I had to immediately calibrate and test all my HT antennas. Since I’ve had experience with the miniVNA PRO, I felt right at home. It didn’t take me long to figure out where everything is and how to see the measurements I want.

Next was the 3 element tri-band Yagi antenna that is on my roof. I am doing just basic SWR plots. I guess my antenna is still good! Well… At least SWR wise. The screen is indeed tiny so I have a feeling that the older hams might take issue with that. The software that is publicly available has issues as well. But other than that, I really like this unit. For the price you can’t really complain

Possible Future

I feel the NanoVNA went viral and I feel that you’ll see many ham shacks with their own in the near future. It’s spreading which I feel is a great thing. The prices will lower and you’ll have many more contributors working on the project. There are people working on some new software that will make reading the VNA results much easier. I’m excited about the future of this device

Update: 9/25/19 – Rune Broberg (5Q5R) has been working on his own software for the NanoVNA that can run on windows and other systems. Check out his github page dedicated to it (also download it from there)

Final Thoughts

If you are looking for an analyzer, for the price of the NanoVNA, I’d strongly suggest you get one. Small enough to fit in a tool bag and it has many uses that can benefit the amateur radio operator.