[Top] [All Lists]

[AMPS] Alpha 78 Input matching unit

To: <>
Subject: [AMPS] Alpha 78 Input matching unit
From: (Arturo Gargarella)
Date: Mon, 2 Mar 1998 18:28:12 -0300
I can remember I read in this reflector someone saying "I can´t achieve
more than 840 Watts with very low grid current (something like 20 mA)".
I experienced the same on 10 and 15 meters. From 20 to 80 I can run a
little more than 1 KW.
I use a TS850 to drive it.
I think there is a problem with the input matching unit.
They use a resistor pack which total resistance is about 22 ohms and it
is in paralell with the input.
Maybe it was ok at the time the 78 was designed (high output electron
tubes transceivers) but now with solid state ones there must be some
changes. I tried giving more output (140 W) to the 850 and I could
achieve 1 Kw on 10 meters and 1.3 KW on 80 meters. That was only for
test purposes.

Is that the problem ?

Does anyone know the reason of such input matching unit design ?.

Is there anything to improve ?

Thanks in advance for the help 
73 de Arturo, LU6ETB

FAQ on WWW:     
Administrative requests:

<Prev in Thread] Current Thread [Next in Thread>