[Elecraft] [KX3] SWR Reading Instability Follow-up

[VaibhaV Sharma]

Thanks for repeating the tests.

I started paying close attention to the SWR meter after I got the Alex
Loop. The antenna has a very narrow window where the SWR is low (receive
noise high). I try not to use the ATU with the loop. Even touching the loop
capacitor dial changes its behavior and it is often hard to calibrate it
for a low SWR while watching the SWR meter.

The KX3 SWR indication hopefully is only a UI issue. Is there a way to
stream SWR and other data off the radio so one can watch what the radio
sees?

-- 
VaibhaV Sharma
W7VAI



On Thu, Apr 10, 2014 at 1:26 PM, Mark Petiford <rv6amark at yahoo.com> wrote:

> Re: Can you redo the 1-2-1-2 test with FM?
>
> I just duplicated the original test with my KX3 (FW 1.94/1.28) and got the
> same results. I repeated the "1-2-1-2" voice test and the SWR remained
> stable as it did in AM as well.
>
> It looks almost like the KX3 is calculating the SWR using a good current
> value for forward power (dropping off to zero as the voice trails off
> between syllables or words) but using a stale value (not updated often
> enough) for reflected power. When the forward power goes to zero or near
> zero as it does on SSB between syllables, it doesn't take much reflected
> power to give you the appearance of high SWR if you are using a stale
> reflected power value. In AM and FM, the carries remains relatively high
> stabilizing the calculation by never letting forward power drop to, or
> near, zero between voice syllables.
>
> Of course, it could also be related to the time constants in the hardware,
> but now I am speculating too much...and being a hardware guy, I love to
> blame things on the software guys! ;-)
>
> Mark
> KE6BB
>
>