My eyeballs arent calibrated in mm, whats that in good old American? (-;
When the Q gets excessive is when sparks fly from voltage buildup.
Id add a contact to the existing one if possible, find a different switch,
or use vacuum relays to switch in whats needed for 160. Im not about to make
guesses and assumptions over such a frequency extreme.
Carl
KM1H
----- Original Message -----
From: "David Feldman" <wb0gaz@yahoo.com>
To: <amps@contesting.com>
Sent: Wednesday, March 28, 2012 2:38 PM
Subject: Re: [Amps] Sharing 15 and 10M on a single band switch position?
>
> Ceramic/porcelain, contacts are about 3-4mm diameter each.
>
> Is the likely problem excess RF current through the contacts on 15M at
> maximum output due to insufficient inductive reactance on 15M? What about
> designing the tank for 15M then using it on 10M? What about derating the
> RF deck on 15M? I don't need full output on 15M or 10M, just exploring
> options to make use of my 5-position switch and get some usability on the
> two bands...
>
> Dave
>
>
>
>
> ------------------------------
> On Wed, Mar 28, 2012 8:10 AM MDT Carl wrote:
>
>>Besides possibly blowing the switch? Not much.
>>
>>It will have the same messed up Q that takes out the 15M contacts on
>>several amps when trying to run full bore on 17.
>>
>>What sort of switch will you be using?
>>
>>Carl
>>KM1H
>>
>>
>>
>>
>>----- Original Message ----- From: "David Feldman" <wb0gaz@yahoo.com>
>>To: <amps@contesting.com>
>>Sent: Wednesday, March 28, 2012 9:32 AM
>>Subject: [Amps] Sharing 15 and 10M on a single band switch position?
>>
>>
>>>
>>> My emerging project amp (a reconstituted Alpha 76A that is missing it's
>>> tank circuit) would normally require a 6-position band switch, but the
>>> switches I have (one and a spare) are 5-position. I'm thinking of
>>> designing the tank circuit to share 15 and 10M on one switch position,
>>> by having the PI network designed for around 24 MHz, on the theory I
>>> could use it on 21 and 28 MHz. I don't plan operate 24 MHz itself with
>>> the amp. Losing a bit of efficiency on 21 or 28 MHz isn't a concern.
>>> Anything else I should be concerned with?
>>>
>>> Thanks,
>>>
>>> 73 Dave WB0GAZ wb0gaz@yahoo.com
>>>
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>>>
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>>
>
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