Joe Smith 2021/06/29 04:50
Back to your topic of having a VNA shootout.
"Since both the nanoVNA's and the SDR-Kits VNA's are designed for hams, I simply want to compare them in applications a ham might use - return loss of antenna, insertion loss and skirt shape of filters, etc - across the range of frequencies for which they are designed."
It looks like you have made a few updates to your blog. I understand a few radio hobbyist have attempted to make their own narrow band filters. I bought a V2Plus and Plus 4 to replace the original NanoVNA and discovered that it lacks the resolution needed to make these measurements.
Recently I have been playing around with using the original NanoVNA to measure power distribution networks. The V2Plus4 is limited to 50kHz on the low end. The firmware I use with the original NanoVNA supports 10kHz but once we get below 20kHz, the noise gets pretty bad. Along the same lines, I recently bought an H4 for testing. Sadly, the firmware wasn't stable enough to use. Interestingly, someone was changing the firmware to allow it to run sub 1kHz. If you check the following link, I posted some test results with this firmware compared with what was supplied and the noise is so poor they basically had made the unit useless.
https://www.eevblog.com/forum/rf-microwave/nanovna-custom-software/msg3586018/#msg3586018
You may want to consider adding the various firmware to your matrix as that will play a big part in how the product behaves.
Speaking of IF, how many times were you in the middle of a project and noticed some abnormal spur, shift in the signal, etc in your data only to discover it was the VNA?
You mention dynamic range. I had looked at a LibreVNA and once you get below 1MHz, the performance is pretty poor.
After reading several posts where people had damaged their low cost VNAs (looking at antennas) I made a video presenting ideas on how you could possibly protect one (using both hardware and gray matter). You may want to consider looking into how robust they are. Not just mechanically but electrically.
I saw people posting about battery indicators. Maybe you will want to consider battery life as well.
People have written me about procuring an 8753 to measure antennas. Really! I consider that series the workhorses of the industry. Many are still in use today. You may want to consider adding a few flavors of this particular boat anchor to your list. Of course, if you detail your test procedure I suspect you would get a lot more feedback.