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?
Beware of cheap underperforming clones
As of 2022 there are many badly performing clones on the market. V2/3GHz NanoVNA uses parts like ADF4350 and AD8342 which are costly and clones have been cutting costs by using salvaged or reject parts.
See official store and look for V2 Plus4/V2 Plus4 Pro versions only to avoid getting a bad clone. We have stopped selling V2.2 versions since October 2020, so all V2 hardware that are not Plus or Plus4 are not made by us and we can not guarantee performance.
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Looking for 100 Hz frequency res - buy or fork?
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.
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:
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.
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