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WB4IUY > ALL 22.02.11 18:25l 33 Lines 1420 Bytes #999 (0) @ WW
BID : 1311_W4RAL
Read: GUEST
Subj: Operating AM on Icom IC-756
Path: IZ3LSV<IV3YXW<HB9TVW<DB0ANF<CX2SA<KD4GCA<NN4NC<W1REP<W4RAL
Sent: 1110222/0246Z @:W4RAL.#RTP.NC.USA.NOAM #:1311 [Wendell, NC] FBB5.15c
From: WB4IUY@W4RAL.#RTP.NC.USA.NOAM
To : ALL@WW
I've tried using my IC-756 on AM from time to time, as I enjoy this mode on
75, 40, 20, and 10 meters. Unlike my Yaesu 901 and Heathkit equipment, the
output power of my 756 Icom would drop considerably when I would modulate
the transmitter with voice. In order to get decent power out, I would have
to run my amp harder than I care when operating AM.
When operating at 25 watts carrier from my 756, I was producing about 25 watts
pep when modulated at 100% (because the power output would drop to about 8
watts!). My amp (AL-82) would run about 350 watts carrier, and would fall back
to about 85 watts or so when I would speak (still about 350 watts pep).
I built the little curcuit from W8JI's page this afternoon. I now operate the
rig at about 10 watts carrier, which drives the amp to about 150 watts. When
modulated the amp produces about 600 watts pep, but runs very cool.
Listening to it on my Yaesu 901, it seems much cleaner, but I can't hear any
difference on my Heathkit SB-301. I guess this is partly determined by the
detector used in the receiver of the receiving station. The amp is much
happier, though, and runs much cooler. I can run a much higher PEP with a
lot less heat!
I've posted info about it on my AM Mode page at:
http://www.ipass.net/wb4iuy/radio/wb4iuy2l.htm
Dave WB4IUY
www.WB4IUY.net
wb4iuy@wb4iuy.#rtp.nc.usa.noam
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