I would recommend a home made choke wound on a teflon former with a
length of ferite rod inside. It is quite easy to obtain some 500
microhenries of inductance with resonance around 700 kHz (really, medium
wave!). Try some 100 turns 18 AWG on a teflon former of 1" dia. Drill a
hole into a teflon rod and put there a piece of ferite. Take into
account the thermal dilatation which can destroy the precious ferite rod
inside, so the dia of the hole must be slightly larger than the diameter
of the ferite rod. The ferite should be fixed inside the former with
something soft (tape, tubing etc.)
73,
Martin, OK1RR
Joe Subich, W4TV napsal(a):
>> it tune on
>> 12 using 10 position but perhaps modification would be better.
>
> Be very careful using the Alpha 76 series amplifiers on 12 meters.
> ETO used a plate choke that was intentionally resonant around 26 MHz
> to prevent use of the amplifiers on 11 Meters. The amplifier has
> a well documented tendency to blow the choke on 12 meters.
>
> 73,
>
> ... Joe, W4TV
>
>
>
>> -----Original Message-----
>> From: amps-bounces@contesting.com
>> [mailto:amps-bounces@contesting.com] On Behalf Of Andy Pfeiffer
>> Sent: Tuesday, September 18, 2007 12:45 PM
>> To: amps@contesting.com
>> Subject: [Amps] Alpha 76 PI-EL modification for WARC bands
>>
>>
>> Hi there
>> Is anyone has modification to Alpha 76 PI-EL and Plate choke to put it
>> on 30, 17 and 12 Meters.
>> It tune on 30 using 20 position, on 17 using 20 position and
>> it tune on
>> 12 using 10 position but perhaps modification would be better.
>>
>> _______________________________________________
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>> Amps@contesting.com
>> http://lists.contesting.com/mailman/listinfo/amps
>>
>>
>
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>
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