[Elecraft] K3 SSB transmit IMD

[Dave Hachadorian]

----- Original Message ----- 
From: "Darwin, Keith" <Keith.Darwin at goodrich.com>
To: "Elecraft Reflector" <elecraft at mailman.qth.net>
Sent: Friday, February 29, 2008 6:41 PM
Subject: RE: [Elecraft] K3 SSB transmit IMD


I got a different read.

- ARRL measured -23 dB on the QRP rig.

- ARRL checked the K3/100 (which they have) at the QRP level 
and got -27
dB.

- ARRL called Elecraft.  They talked.

- ARRL published the value from the K3/100 number.

- ARRL reported that Elecraft suggested those worried about 
the IMD
performance on 17m could QRP to 8 watts.

I didn't see anything in there where either the ARRL or 
Elecraft
admitted that there is any problem; only some confusion and 
disparity on
the measurements.

- Keith N1AS -
- K2 5411.ssb.100 -
- K3 Wave 3 -
--------------------------------

The key statement is that ARRL tested the second radio "in 
accordance with (Elecraft's) new guideline..."

To me, that means they had to throttle the 10 watt PA back 
to 8 watts (Elecraft's new guideline) to get the -27 dB 
reading. If you run the 10W PA at full power on 17 meters 
and above, IMD will be worse than -27dB.

N6KR's message earlier this morning indicates that Elecraft 
is working to improve the SSB setup procedure or SSB 
algorithm to improve the real-world (tones externally 
applied) IMD. I think I've got it straight.

Dave Hachadorian, K6LL
Yuma, AZ