[Top] [All Lists]

[AMPS] 6m amp

To: <>
Subject: [AMPS] 6m amp
From: (Steve Thompson)
Date: Mon, 15 Feb 1999 07:11:50 +0000
In message <>, W7XU Arliss <>
>I think the efficiency of my homebrew 6m 8877 amp is 
>lower than it should be (currently about 50 %), and am
>looking for some suggestions on how to improve the
>The amp runs about 2800 V key down at 1 amp, with 50 mA
>of grid current, into a 50 ohm load.  Idling current 
>(set with a 12V Zener) is about 75 mA.  The plate 
>circuit is a Pi-L network patterned after Lauren Libby's
>(W0LD) HR article from July 1986, using a vacuum variable
>tuning capacitor, 3/16" copper tubing for the coil, and
>a 250 pF air variable for the loading coil.
>I've tried varying the coil size somewhat but that hasn't
>made any difference.  I also tried increasing the plate
>voltage to 3500 V, which reduced the drive requirement, 
>but didn't make a significant difference in the amp's
>efficiency.  The coil is about 1.5" away from the cabinet
>Other suggestions?
>Thanks & 73,  Arliss  W7XU

How are you measuring the output power?


FAQ on WWW:     
Administrative requests:

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