[TowerTalk] VNA

[Wes Stewart]

I second Jim's remarks about the VNWA 3E (and Dan's, AC6LA, software).  I use 
mine in the field with a 10" touch screen tablet computer (Motion) running, uck, 
Windows 10.  Not quite as friendly as a laptop but much more rugged.  If need 
be, I can save measurement data in a file and transfer it to the desk computer 
via Wi-Fi for additional analysis.

I have a couple of 50KW BC stations nearby that I've measured at -3dBm on my 
inverted-l.  As long as I start a sweep at 1.7 MHz or above I have no issue with 
them.

Wes  N7WS


On 10/30/2017 8:08 PM, Jim Brown wrote:
> For about four years, I've been using the VNWA 3e, designed by German EE prof 
> DG8SAQ and built by some hams in the UK under the name SDR-Kits. It's not a 
> kit, it's fully built and tested. I paid about $770 then, delivered to my 
> door, with calibration loads and a carrying case; thanks to Brexit, it's about 
> $100 less today. It's quite well supported both by SDR Kits and by DG8SAQ via 
> an email reflector.  In addition to the standard VNA functions, it does 
> excellent TDR by taking the inverse FFT of a wide sweep. The unit has full 
> spec to 500 MHz, and reduced dynamic range to 1.3 GHz.
>
> The file export functions work well, there are built-in math functions that 
> can, for example, transform an SWR sweep to 75 ohms. The unit is also 
> supported by AC6LA's excellent Excel spreadsheets. SimSmith and most of 
> AC6LA's spreadsheets are freeware. I regularly use his ZPlots to compute the 
> fundamental parameters of coax by importing S11 data from the VNWA into ZPlots.
>
> I regularly make Z measurements of antennas in the shack, measure the line 
> with TDR to find its length, and export the data to SimSmith to transform the 
> measurement to the antenna's feedpoint. I also use TDR to look for any 
> problems along a transmission line. The unit stores multiple calibration 
> files, so once you've done a calibration for one measurement setup, you can 
> recall it on another day without the need to redo the calibration. The 
> measurements in this report were done with the VNWA 3e.
>
> http://k9yc.com/BandpassFilterSurvey.pdf
>
> So were these measurements of DX Engineering's excellent NCC-1 phasing unit.
>
> http://k9yc.com/VE3DO.pdf
>
> 73, Jim K9YC
>
> On 10/30/2017 5:29 PM, Neal Sulmeyer wrote:
>> ​My MFJ 259B is 25 years old and obsolete. Time for an upgrade.  I'm 
>> considering the AIM 4300 (updgrade to the AIM4170 recommended by ON4UN).
>>
>> I would like to hear some opinions on this device and others from my fellow
>
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