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@lint.mv.com>
> To: "'Paul Kraemer'" <elespe@lisco.com>; "Amps" <amps@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@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@lint.mv.com>
> To: "Amps" <amps@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@contesting.com
>> http://lists.contesting.com/mailman/listinfo/amps
>>
>>
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