[Amps] Revamping a really ugly amp

[Roger]

Rex Lint wrote:
> URL?
>   
http://www.multi-tech-industries.com/rswitches.html

73

Roger (K8RI)
>     -Rex-
>
>      Rex Lint, Consultant
>      26 Brek Drive
>      Merrimack, NH 03054
>      PH:    603-860-7651    
>
> -----Original Message-----
> From: Roger [mailto:sub1 at rogerhalstead.com] 
> Sent: Saturday, March 13, 2010 10:35 PM
> To: Carl
> Cc: Rex Lint; 'Paul Kraemer'; Amps
> Subject: Re: [Amps] Revamping a really ugly amp
>
>
>
> Carl wrote:
>   
>> Multi Tech, formerly Radio Switch Corp, will build you a Type 86 switch to
>>     
>
>   
>> your hearts desire. And a lot cheaper than a litter of vacuum relays.
>>   
>>     
> Man! They have some nice looking switches!
>
> 73
>
> Roger (K8RI)
>   
>> Carl
>> KM1H
>>
>>
>>
>>
>> ----- Original Message ----- 
>> From: "Rex Lint" <rex at lint.mv.com>
>> To: "'Paul Kraemer'" <elespe at lisco.com>; "Amps" <amps at contesting.com>
>> Sent: Saturday, March 13, 2010 4:36 PM
>> Subject: Re: [Amps] Revamping a really ugly amp
>>
>>
>> A variable inductor makes band changes too slow in contests (unless I make
>>     
> 6
>   
>> amps!)
>>
>>       -Rex-
>>
>>        K1HI
>> Rex Lint
>>   Merrimack, NH
>>
>>
>> -----Original Message-----
>> From: Paul Kraemer [mailto:elespe at lisco.com]
>> Sent: Saturday, March 13, 2010 3:34 PM
>> To: Rex Lint
>> Subject: Re: [Amps] Revamping a really ugly amp
>>
>> Rex
>> I would keep the variable inductor as it represents an ideal situation for
>> an all band all mode amp, IMHO
>> In power rf smaller may not be better, IMHO
>> If I were going to use relays they would be vacuum type as are used in
>> commercial designs. I've seen it done at Collins Rockwell .
>>
>> Paul K0UYA
>> ----- Original Message ----- 
>> From: "Rex Lint" <rex at lint.mv.com>
>> To: "Amps" <amps at contesting.com>
>> Sent: Saturday, March 13, 2010 1:04 PM
>> Subject: [Amps] Revamping a really ugly amp
>>
>>
>>   
>>     
>>> I bought an old H/B amp that I'm totally revamping.
>>>
>>> It's 2 x 3-500Z's with a 4KV power supply.  It USED to have a pi-network
>>> with a vacuum variable plate capacitor and a regular variable loading
>>> capacitor, and the tank coil *was* a variable inductor so that the tank
>>> could be adjusted for any transformation (within reason).  I want to keep
>>> the caps, but change the coil to discrete inductor(s) with taps.
>>>
>>> I wonder if anyone uses relays instead of a rotary switch to select the
>>> desired taps?  What are the parameters I need to consider in trying this?
>>> In my thinking, I'll just be switching the output side of the inductor,
>>> and
>>> the impedance at this point (when tuned) should be about 50 ohms, so the
>>> voltage isn't that high (350 V.?),  and the current would be about 6
>>>       
> amps.
>   
>>> Relays for this should be a dime (well, $20) a dozen?  As a mtter of
>>>       
> fact,
>   
>>>     
>>>       
>>   
>>     
>>> I
>>> see one like this would handle the job if never switched "hot" which you
>>> wouldn't want to do with a rotary switch either!
>>> http://www.mv.com/ipusers/lint/K1HI/RelaySpecs.pdf
>>>
>>> I'm also looking at compact tank coils in the literature.  How much power
>>> could I expect to run with two muffin fans to cool the tubess and
>>> operating
>>> CW contests?
>>>
>>> Thoughts?
>>>
>>>    -Rex-
>>>
>>>     Rex Lint, Consultant
>>>     26 Brek Drive
>>>     Merrimack, NH 03054
>>>     PH:    603-860-7651
>>>
>>>
>>> _______________________________________________
>>> Amps mailing list
>>> Amps at contesting.com
>>> http://lists.contesting.com/mailman/listinfo/amps
>>>
>>>     
>>>       
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