To all who responded to my question about distorted SSB audio with the KXPA100,
thanks!
My antenna is a Hy-Gain AV620 elevated vertical, fed with 100 feet of Davis
Buryflex (direct bury, feedline loss comparable to Belden 9213). SWR is 1.5 or
lower on 20 through 6 meters.
Don makes an interesting point about power supply voltage. As I mentioned, it
is 13.7 on receive and 13.1 with 100 watts output. That is on 20 meters. On
10 meters, it is 12.7 with 100 watts output. By Don's figures, that is a
possible problem.
I've got lots of receivers. I tried listening to myself on a KWM-2, chosen
because it's got vacuum tubes. There is distortion at all power levels with
the KXPA100, but no distortion with the barefoot KX3. That argues against
supply voltage being the sole cause, but there could be more than one.
I want to try one more thing: the Elecraft mike. I've had RF problems with
several other mikes and rigs, and I want to try a mike that I know is clean.
Unfortunately it has an 8-pin Yaesu cable, so I've ordered an adapter that
plugs into the KX3. When it comes, I'll post the results.
73 Ray W2RS
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Today's Topics:
1. K3: Adjusting SSB modulation for proper PEP rating (Edward R Cole)
2. Re: K3: Adjusting SSB modulation for proper PEP rating
(Don Wilhelm)
3. Re: WTB: Loaded KX3 (Petr, OK1RP/M0SIS)
4. Re: Packing Peanuts Are Of the Devil!
(Eric Swartz - WA6HHQ, Elecraft)
5. KXPA100 SSB Distortion (rsoif...@aol.com)
6. Re: KXPA100 SSB Distortion (Kurt Cramer)
7. Re: KXPA100 SSB Distortion (rsoif...@aol.com)
8. Re: K3: Adjusting SSB modulation for proper PEP rating
(Edward R Cole)
9. Re: Elecraft Digest, Vol 168, Issue 25 (Frank)
10. Re: KXPA100 SSB Distortion (Don Wilhelm)
11. KXPA100 SSB Distortion (j...@kk9a.com)
12. Re: KXPA100 SSB Distortion (David Gilbert)
13. Re: KXPA100 SSB Distortion (Don Wilhelm)
14. KXPA100 SSB Distortion (James Wilson)
15. KX3 (john daws)
16. Re: KX3 (Don Wilhelm)
17. PX3 Green Cursor Opacity (John_N1JM)
18. PX3 Green Cursor Bar Color Inverting (John_N1JM)
19. How do I change my email address? (Grady Harper)
20. KAT500 memories (Harlan Sherriff)
21. Re: KAT500 memories (Ken K6MR)
22. Re: How do I change my email address? (Charlie T)
23. Elecraft newsletter (John Gibson)
24. Re: KAT500 memories (Don Wilhelm)
25. Re: Elecraft newsletter (hawley, charles j jr)
26. Re: Elecraft newsletter (hawley, charles j jr)
27. Re: How do I change my email address? (Don Wilhelm)
--
Message: 1
Date: Mon, 23 Apr 2018 00:56:43 -0800
From: Edward R Cole
To: Elecraft Reflector
Subject: [Elecraft] K3: Adjusting SSB modulation for proper PEP rating
Message-ID: <201804230856.w3n8upzk023...@mail47c28.carrierzone.com>
Content-Type: text/plain; charset="us-ascii"; format=flowed
Since the K3 operates so differently (than traditional radios) for
proper modulation I thought I'd ask this:
In olden days amplifiers were rated in PEP typically as 2x average
(or CW) power, so for AM one had to set carrier at 1/4 full carrier
output to stay linear. (1/2 carrier for SSB).
But now I am setting up a 600w linear amp to run at P1 which is about
0.9 of P3 (saturated power) and wondering what level of carrier power
to run in SSB to stay linear and also not to overdrive and stress the
expensive LDMOS device in the amplifier.
I'm running the K3 in transverter mode on 28-MHz so max output is
1.5mw. I can view this with a scope. The amplifier is running at
1296-MHz which is too high a freq to monitor with my scope. I can
only observe average RF power from a directional coupler and diode
detector (like a Bird meter).
Normally, I just set power on the K3 to drive my amp to nominal full
power and select SSB mode. Modulation level is set by observing ALC
meter. I is ALC showing five bars when saying the word "five" loudly
and six bars with compression. So does this mean the K3
automatically adjusts RF power in SSB to stay linear with proper
modulation audio setting?
My reason is when running 1296 SSB to avoid overdriving the amplifier
into P3 possibly causing harm, as much as not wanting to produce
non-linear products.
73, Ed - KL7UW
http://www.kl7uw.com
Dubus-NA Business mail:
dubus...@gmail.com
--
Message: 2
Date: Mon, 23 Apr 2018 06:52:06 -0400
From: Don Wilhelm
To: Edward R Cole ,Elecraft Reflector
Subject: Re: [Elecraft] K3: Adjusting S
