On Fri, 6 Jun 1997 13:07:36 -0400 (EDT) KR4DAGRIP@aol.com writes:
>In a message dated 97-06-06 12:15:58 EDT, you write:
>
><< The power output differences are marginal, so where is the benefit?
> Besides those 4CX800 tubes are in AB1 and require constant ALC
>attention.
>
> 73....Carl KM1H >>
>
>91b manuel
>IF EXTERNAL ALC is used, amplifier grid current peaks greater then
>approximately
>3ma will initiate ALC. At grid current of 5-10mA, ALC output is
>nominally
>-10v.
>If the transceiver requires less ALC voltage, adjust the rear panel
>ALC
>potentiometer counterclockwise until smoth ALC action results.
>Increase the
>exciter RF output
>untill the red GRID LED just illuminates on voice peaks.
>
>
>
>Ok so what am I doing wrong????????????? IT ALL SEEMS TO BE WORKING.
>Let see I have the 91b hooked up to the FT 990 and I have a coax cable
>to the antenna and a cable from thye FT 990 for relay control. I have
>the
>drive level set at 40 watts for 1500watts RF output per the LEDS.....
>
>BUT I DO NOT HAVE a cable from the FT 990 to the ALC of the 91b
>So again please what am I supposed to be concerned about.
>YES I DO NOT UNDERSTAND.
>
>Please be nice I really do want to understand obe wan kanoobie.
>
>73 de KR4DA Bob LAwrenceville GA
If I understand you correctly Bob, you have no ALC control at all. The
first step is to install that cable from the 91b back to the
FT-990....then pray it works.
The comments here that past few days bring the whole ALC issue to the
surface.
Stand by.... we can probably all get a few good ideas!.
BTW, even 3ma of grid current in an AB1 amp will cause splatter. If you
can see that much on a meter, the real peaks are a lot worse.
73....Carl KM1H
--
FAQ on WWW: http://www.contesting.com/ampfaq.html
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|