HI,
some week ago I bought a second-hand Alpha 78 linear amplifier. I read
in the manual the best ratio of dc plate voltage to dc plate current is
1972. The manual suggest to tune the amplifier for a plate current of
0.71 A for CW (that corresponds with about 1 kW input) and of 1.06 for
SSB (that corrisponds with 2.2 kW input). So I deduce the right output
power is about 500 W in CW and 1.1 kW in SSB, but I read on the web
Alpha 78 is a linear amplifier running 1.5 kW output. So what is the
right plate current values (CW and SSB) to maximize the power capacity
of my Alpha 78 without compromise, of course, the tubes life?
I noted the output power is decreasing with the frequency increasing:
more than 1 kW on 160 m. and minus than 900 W on 10 m. during the SSB
tune-up: is this behaviour regular?
Any other suggestion or trick by some long-time Alpha 78 user are
welcome.
Thank you
Aldo IK2ANI
--
FAQ on WWW: http://www.contesting.com/FAQ/amps
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
|