SWR sweep with Wizkers and KX3?


#1

Have you thought about a simple antenna analyzer function for Wizkers?

I got started on that with the rigcontrol Python package, but controlling the KX3 was a bit flaky. I put the ATU in bypass mode, then stepped it in TUNE across the band. Reading back the SWR was messy, because it is display data, not actual numbers. The result was written out in CSV.

Glad to share the code, it might give you a starting point for doing it in Wizkers.

The rigcontrol package is here. I made a few changes for the KX3. Probably should contribute those, but I can’t test that the K3 stuff still works.

https://pypi.python.org/pypi/rigcontrol

wunder


#2

You can see the code here:

Glad to share a full runnable distro, but the key information is in the commands sent to the KX3. That is all in this file. It even has comments!

wunder


#3

Sounds like a great idea, Walter.

Since in a way, this is a bit of a poor man’s antenna analyzer, I’m wondering whether this should be an additional feature on the KX3 interface, of if I could actually create a “KX3 Antenna Analyzer” instrument with its own dedicated interface - it’s pretty easy to switch between instruments quickly.

This way, the SWR plot and overall interface could be consistent with the one that already exists for the Sark110…


#4

The KX3 is a pretty decent signal generator, too. :slight_smile:

wunder


#5

Is this what you had in mind, @K6WRU ?

Just a 30 minute job to test the concept, but it’s promising. I want to add control on the tuner power too. At least it looks like my dipole is decent on 20m :slight_smile: I need to understand this weird peak though, it happens at each sweep.


#6

Try a slower slew rate, I guess. Or ask on the Elecraft list.

Another idea: tune the ATU at each step and read back the L and C values. That would give a conjugate match and we should be able to calculate a complex impedance for the antenna. A bit convoluted, but it should work.

wunder


#7

Also, that looks great.

wunder


#8

The 3 W power level probably gives the best resolution for SWR measurement. I remember some comment from Elecraft about that.

wunder


#9

Would sure like to add this capability to my copy of Wizkers on the KX2.

Would you be so kind as to steer me in the direction to get it?

Thanks, and 73

Jim N3SZ