[Elecraft] K3: Now I've heard everything

[Joe Subich, W4TV]

 > Can anyone else confirm or deny that their PA talks back to them?

Does not do it here.  I've made the same tests using the SDR-IQ
with the directional coupler from my LP-100 and additional
attenuation for the input to the SDR-IQ.  IMD was stable as long
as the power level was stable (Keep ALC at 5 bars and adjust power
with the power control) and not particularly temperature sensitive
although I did not push long key down times.

I also made measurements of transmit image (+/- 30 KHz) using the
FM filter for transmit in SSB and CW (no measurable image within
the range of the SDR-IQ) using the same test set-up.

The only thing I found necessary was to keep the SDR-IQ and K3
separated (could not leave the SDR-IQ set on the top of the K3)
and use good quality cable between the SDR-IQ and directional
coupler to limit any direct pick-up.

73,

    ... Joe, W4TV

On 7/12/2010 1:25 PM, Wes Stewart wrote:
> Having just acquired an RFSpace SDR-IQ I thought I'd take a look at
> the K3's transmit IMD, particularly with respect to input voltage and
> output power.
>
> So I engaged the 2-tone generator, connected a dummy load and
> proceeded to take a look at the output spectrum.
>
> I haven't gotten very far with this because 1) the IMD is apparently
> temperature sensitive and drifts, becoming a moving target and 2) I
> can hear the two tones acoustically emanating from the PA. The level
> is somewhat proportional to RF power and goes away completely when
> the power is reduced to the point where the PA drops out.
>
> Can anyone else confirm or deny that their PA talks back to them?
>
> Wes  N7WS
>
>
>
>
>
>
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