[TowerTalk] FA-VA5 question

[Lux, Jim]

On 11/6/21 7:30 AM, Michael Tope wrote:
> You can save raw impedance data to memory on the FA-VA5 while using it 
> standalone in the field and then download it later to the VNWA 
> software. The one frustrating limitation of using the unit standalone 
> is that you are limited to 101 frequency points per memory register 
> (IIRC, the unit has 10 memory registers). For typical antenna 
> impedance measurements, that is fine, but for TDR measurements, it can 
> limit resolution. You can get around this somewhat by saving 
> sub-segments to different memory registers and then combining them 
> after download. In theory this would allow you to achieve the 
> equivalent of saving 1010 frequency points while using the unit 
> standalone. 


I've been fooling with 101 point TDR and a NanoVNA recently - you can 
actually get finer resolution with interpolation (zero pad the data 
before transforming, is one way). The constraint is that there are 
potential ambiguities. And it depends on the SNR. And, if there are 
multiple faults, then life gets more complex.

Someone posted a way to determine the position of a short/open with 
three measurements.  101 measurements has to be better!