First I want to establish that I'm in the market for a
K3 and will definitely buy one---just as soon as I can
get one 2-3 weeks ARO. (Hint)
I read the digest and I saw the question was raised
about the poor transmit IMD performance of the K3 as
reported in the QST review. If this was addressed by
Well, I've seeming stirred up a hornets' nest, or as
we have in Southern Arizona, an Africanized ("killer")
honeybees' nest.
I do stand corrected about a response from Elecraft
regarding this subject that I failed to see.
http://www.mail-archive.com/elecraft@mailman.qth.net/msg50667.html
Furthe
Wes Stewart wrote:
So I humbly propose a new transceiver "composite"
test. Receiver performance shall be measured by using
two other like transceivers, operating at full output
power, as the signal sources for the measurement(s).
Wes, I understand what you're saying, but IMO this idea doesn't
--- "Eric Swartz - WA6HHQ, Elecraft"
<[EMAIL PROTECTED]> wrote:
> The K3 firmware used for the original QST review did
> not turn off the
> K3's RF speech compressor clipper even when the
> compressor was set to
> zero for their TX IMD two tone test. This resulted
> in a significant
> increase
Wes Stewart wrote:
>
>
> --- "Eric Swartz - WA6HHQ, Elecraft"
> <[EMAIL PROTECTED]> wrote:
>
>> The K3 firmware used for the original QST review did
>> not turn off the
>> K3's RF speech compressor clipper even when the
>> compressor was set to
>> zero for their TX IMD two tone test. This re
If we distort our SSB audio by compression etc, then let's hope that the
sideband filter will limit the bandwidth. (I don't know where the
compression or whatever is done in a K3).
But if the PA distorts the signal even more, there is no filter to limit
this within a few kHz.
So I think the IMD me
Arie Kleingeld PA3A wrote:
>
>
> If we distort our SSB audio by compression etc, then let's hope that the
> sideband filter will limit the bandwidth. (I don't know where the
> compression or whatever is done in a K3).
> But if the PA distorts the signal even more, there is no filter to limit
>
Julian G4ILO wrote:
In any event, ALC
should not have an effect on a laboratory IMD test since the two tones are
not varying in amplitude, unlike a real SSB or PSK signal. So the
laboratory
IMD test bears little relationship to the real world.
Perhaps. In the case of two constant level test
Geoffrey Mackenzie-Kennedy wrote:
>
> Julian G4ILO wrote:
>
> The design of ALC systems is not a casual matter especially when dealing
> with human speech, and the points which you raise have to be addressed by
> the designer if the ALC might be used improperly. It would appear that ALC
> syst
In light of the Sherwood presentation referenced in the thread about K3
audio, I haven't seen much comment on the spectrum analyzer plot of the K3
transmit IMD. Is this still an artifact of the (now fixed) firmware error
mentioned by Eric earlier in this thread?
> The K3 firmware used for the o
Yes - That firmware fix improved 3rd order TX IMD by 3-5 dB on the worst
case band (12M) and it is better than that on all other bands. We also
made other firmware changes in the gain of various stages to improve TX
IMD. Those changes have been in every firmware release for many months.
One no
There is apparently some confusion about how the K3 ALC works. Just to
help muddy the waters a bit, I'll toss in what little I know about it.
We recommend setting the Mic (or LINE IN) Gain so you get 5 bars of ALC,
with possibly the 6th bar occasionally flickering, with CMP set to 0.
No, thi
Hmmm. Your advice to:
"...*please* set it to 4 bars in soundcard "digital" modes..."
contradicts the direction given here (in step 7):
http://www.elecraft.com/K3/k3_operating_tips.htm#psk%20audio
viz. "You should not see any ALC bars on the K3 display (when set to CMP/ALC)"
This always confus
In a message dated 4/6/2008 3:07:22 P.M. Eastern Daylight Time,
[EMAIL PROTECTED] writes:
Note: For PSK and other operation, you want to set things to the level
where the 5th bar just comes on -- or just doesn't. If you have only 4
bars in digital modes, that's OK. With less than 4, you are
The suggested "4 Bar" system does seem to work using SSB for the PSK.
Sorry for adding yet more confusion to the mix. I am running firmware
that is in field test and should be released next week. The statement I
made I believe to be true for the firmware I am running. I haven't gone
back
Hello Lyle,
You said:
There is apparently some confusion about how the K3 ALC works. Just
to help muddy the waters a bit, I'll toss in what little I know about it.
Thanks for doing so. Excellent explanation!
73,
Joe - W1AIU
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