>
>> Doesn't the Alpha 76 use the broad band transformer along
>> with a bank of resistors to present the proper load?
>
> Yes, but it is not a good design for solid state rigs.
> The bank of resistors only tempers the impedance swings
> they don't provide the energy storage flywheel of the
> tuned circuit. Without the flywheel, IMD issues are not
> resolved.
>
> 73,
>
> ... Joe, W4TV
I wonder how much it really hurts the IMD. The 8874 is capable of much
better IMD than most SS exciters and GIGO still rules the band.
The SB-230, MLA-2500 and all those Alphas used resistive inputs and are
known to be clean amps when not overdriven.
Carl
KM1H
>
>
>
>
>> -----Original Message-----
>> From: amps-bounces@contesting.com
>> [mailto:amps-bounces@contesting.com] On Behalf Of Roger
>> Sent: Sunday, March 14, 2010 9:02 PM
>> To: James Colville
>> Cc: Amplifier Reflector
>> Subject: Re: [Amps] GI7B Question - Input Matching
>>
>>
>>
>>
>> James Colville wrote:
>> > You need the flywheel effect that a C-L-C tank circuit can
>> provide. A
>> > broad band transformer is not the answer. This was just
>> discussed here
>> > at length not long ago.
>> >
>> Doesn't the Alpha 76 use the broad band transformer along
>> with a bank of
>> resistors to present the proper load?
>>
>> 73
>>
>> Roger (K8RI)
>> > 73
>> > Jim W7RY
>> >
>> >
>> >
>> >
>> > On Sun, Mar 14, 2010 at 2:58 PM, ZL2AAA <zl2aaa@paradise.net.nz>
>> > wrote:
>> >
>> >
>> >> I think you will find it's nearer 35ohms.Morrie
>> >> ----- Original Message -----
>> >> From: "Lee Buller" <k0wa@swbell.net>
>> >> To: <amps@contesting.com>
>> >> Sent: Monday, March 15, 2010 9:30 AM
>> >> Subject: [Amps] GI7B Question - Input Matching
>> >>
>> >>
>> >>
>> >>> I have been reading about the GI-7B Russian made tube. It seems
>> >>> that the input impedance of two tubes is around 100 ohms.
>> Could you
>> >>> not just use
>> >>>
>> >> a
>> >>
>> >>> 2:1 transformer to make a match from 50 ohms to 100 ohms?
>> What am I
>> >>> missing here.
>> >>>
>> >>> Lee - K0WA
>> >>>
>> >>> Ham Radio Operators: Kansas QSO Party is August 28-29,
>> 2010. See
>> >>> www.ksqsoparty.org for details
>> >>>
>> >>> In our day and age it seems that Common Sense is in short
>> supply.
>> >>> If you don't have any Common Sense - get some Common
>> Sense and use
>> >>> it. If you can't find any Common Sense, ask for help
>> from somebody
>> >>> who has some Common Sense. Is Common Sense divine?
>> >>>
>> >>> Common Sense is the image of the Creator expressing
>> revealed truth
>> >>> in my mind. - J. Wolf
>> >>> _______________________________________________
>> >>> Amps mailing list
>> >>> Amps@contesting.com
>> >>> http://lists.contesting.com/mailman/listinfo/amps
>> >>>
>> >> _______________________________________________
>> >> Amps mailing list
>> >> Amps@contesting.com
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>> >>
>> >>
>> > _______________________________________________
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>> >
>> >
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>
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