Hey all,
I'm looking for a highly portable solution for measuring some resonant LF antennae in the field, checking for tuning drift. From what I can see the V2 has a 10kHz IFBW and the V3 can go down to 0.8kHz. Are measurements with a frequency res of ~100Hz plausible with either, is there a known NanoVNA based design that can do high res LF measurements, or do I need to explore a hardware fork for that?
Thanks

Good Day,

I'm not anywhere close to an expert at this, but I believe the adjustable IFBW requires an additional hardware filter in the signal path.

One possible option for you, the ($300) SYSJOINT SV4401A (I have this unit). It allows adjustable IFBW down to 30Hz & 50kHz-4.4Ghz coverage. Here is a screenshot:

Using modes below 1kHz is incredibly slow. At full range, 30Hz IFBW, 1001pts, measurement takes around 2 minutes.

I also can't speak to the accuracy at small IFBW, I have no DUTs to really push it. If you have a suggestion for a test I can do, I'm open to it.

This model has a larger capacitative touchscreen, N connectors, is heavier, and less portable than the regular nanoVNAs, but it might be OK for your use. It's about the size of a 9" tablet, 1.25" thick and about 2 lbs.

People around here have had hit & miss with SYSJOINT products. Personally, I've hit software bugs, but the hardware has been OK. Caveat Emptor though.

Dave

An HP3561a might meet your needs. Would 640uHz RBW meet your needs? If
so you can pick up an HP3561a at a reasonable price if you look long
enough. I have one but NOT willing to part with it. Hope that helps.
Here's a link to the page explaining it:

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwjp0Y-miP37AhWqSzABHbVgAeEQFnoECBEQAQ&url=https%3A%2F%2Faccusrc.com%2Fuploads%2Fdatasheets%2F5350_3561a.pdf&usg=AOvVaw25-yl4b1fhZ8Q6dIBCNLTq

Mike C. Sand Mtn GA

On 12/12/2022 3:16 PM, DaveWJ wrote:

> Good Day,
>
> I'm not anywhere close to an expert at this, but I believe the
> adjustable IFBW requires an additional hardware filter in the signal path.
>
> One possible option

I purchased a Plus 4 Pro after looking at a number of options. I do a lot of crystal filter work and 800 Hz is still a limitation when working with narrow filters - 300 and 600 Hz. At $400 the Plus 4 Pro is not cheap but does offer some really good performance over the less expensive units. Especially the time between calibrations. That said, I hope in the future, the design team updates the firmware to allow us to go to 100 or even 10 Hz bandwidths. I fully understand that the sweep times will get very long but that is the trade off.