The usual rule of thumb is to run the AM carrier at 24% of the tubes anode
dissipation.
Figure on an average of 50% efficiency at full DSB AM PEP.
Tune up as you normally would for 1500W and keep the drive as low as
possible, about 20-25W should be fine with a fairly high gain tube. Thats
all I need for a 350-400W carrier with the LK-500ZC and the external Dahl
transformer option runs comfortable even after hours of use, OTOH Im not
into old buzzard monologues. It weighs about 14# more than the far from CCS
Ameritron iron which even needs to run less power in RTTY contests.
The CW position would be fine but the only reason being the bias is more
which reduces the idle current, there IS NO plate voltage change. Id be sure
the output remains linear with that bias. Ive changed bias on many amps to
reduce the wasted heat and with the AL-1200 there were 3 different tubes
used and I havent tried them all.
Carl
KM1H
----- Original Message -----
From: "Tony Brock-Fisher via Amps" <amps@contesting.com>
To: <Amps@contesting.com>
Sent: Thursday, October 30, 2014 7:13 AM
Subject: [Amps] AL1200 on AM - max carrier?
I want to run my AL-1200 on AM for a short stint (2 hours operating time,
50% overall duty cycle). I have tested it at about 225 watts carrier
output, and with moderately high duty cycle transmissions (known in the AM
crowd as 'Old Buzzarding'), it gets quite hot.
What is the max recommended AM carrier power for long-winded
transmissions?
Also, I'm assuming it should be tuned up for proper operation at double
the carrier power.
I searched the list finding no real answers.
Thanks,
Tony, K1KP
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