>Oops -- some clarificaton needed.
>The load is 50 ohms, non reactive.
? What is the resistance of your termination R when Measured with a DMM?
>The coil is 3/8" tubing, not 5/16".
>Sorry for the confusion. 73, Arliss
>Rich Measures wrote:
>> >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
>> ? What is the resistance of your termination R when measured with a DMM?
>> >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,...
>> ? Due to skin effect, the circumference of conductors needs to be
>> greater as f increases. IMO, for good tank efficiency, 3/16" tubing is
>> ok for an 8877 on 160m. For 10m, it is not.
>> - later, Arliss
>> R. L. Measures, 805-386-3734, AG6K, www.vcnet.com/measures
R. L. Measures, 805-386-3734, AG6K, www.vcnet.com/measures
FAQ on WWW: http://www.contesting.com/ampfaq.html
Administrative requests: amps-REQUEST@contesting.com