[Amps] Adding 10 meters to a SB-221?

Richard 2@mail.vcnet.com
Wed, 8 May 2002 08:49:48 -0700


>You will also have to change the plate tune cap to one of lower value plus
>change the value of padding cap on 40 meters...

The padding C is for 80m-loading.  The tune C on my SB221 was identical 
to that in my SB-220.

>Heath really wanted the favor
>of the FCC when they designed the 221....Made it very difficult for the
>"Criminal Band guys to adapt to 11 meters.

Putting a SB-221 on 27MHz involves wiring around the CB filter; moving 
the 15m tap on the tank L; and installing a Q=2, 27MHz tuned input in the 
15m slot.  Elapsed time c. 20min.  Any gen-coverage ham transceiver that 
delivers 140w will drive a SB-22_ to full suds.   

>Jim, K7RDX
>----- Original Message -----
>From: <W0YR@aol.com>
>To: <kg7da@foxinternet.net>; <amps@contesting.com>
>Sent: Wednesday, May 08, 2002 2:46 AM
>Subject: Re: [Amps] Adding 10 meters to a SB-221?
>
>
>> Hi Marty,
>>
>> I, too, have an SB-221 which is still "cherry."
>>
>> First, you'll have to take out a trap in the input circuit which will not
>> pass anything above about 25 mhZ.
>>
>> A second problem is that there are not enough positions on the band
>switch,
>> but if you're willing to skip 15 meters, you can make out.  If you really
>> watch for them, sometimes band switches can be found, or another with 5
>> positions can be subsituted.
>>
>> The third problem is the input matching network and you'll have to start
>from
>> scratch on that.  Also, you have to change the input band switch.
>>
>> Fourth, you'll have to find or make a 10M inductor, though that should not
>be
>> a big problem.
>>
>> All in all, it's just a big mess and you will pretty much ruin the re-sale
>> value of the amplifier.  That's why I haven't dove (or diven? HI) into the
>> project.
>>
>> If you do, please share your results with the rest of us trepidacious 221
>> owners.
>>
>> 73
>>
>> Mike
>> WØYR/4
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-  R. L. Measures, a.k.a. Rich..., 805.386.3734,AG6K, 
www.vcnet.com/measures.  
end