[Heathkit] Amp Keying Interface?

[jeremy-ca]

In a straight TX/RX setup the relay is SPDT; with an amp it is usually a 
DPDT wired as a transfer relay so you can still operate barefoot. Most 
common SS relays are simple SPST.

Carl
KM1H


----- Original Message ----- 
From: "Rick Brashear" <rickbras at airmail.net>
To: "'Peter Markavage'" <manualman at juno.com>; <heathkit at mailman.qth.net>
Sent: Tuesday, July 31, 2007 8:10 PM
Subject: RE: [Heathkit] Amp Keying Interface?


> When the amplifier is not keyed it's a straight though connection, so it
> would automatically go back to the receiver.  Am I thinking incorrectly?
>
> Rick/K5IAR
>
>
>
> Sure, you can shut the driver down, but how does that get the antenna
> connection hanging on the output of the amplifier back over to the
> receiver.
>
> As Carl said, for switching 1 to 2KW RF, vacuum relays are also a good
> way to go. I don't know of any off-the-shelf solid-state relays that can
> handle that much power.
>
> Pete, wa2cwa
>
> On Tue, 31 Jul 2007 18:36:24 -0500 "Rick Brashear" <rickbras at airmail.net>
> writes:
>> Why not switch pre-amplifier and avoid the high rf problem?  Of
>> course, if
>> you're switching a high wattage transmitter instead of using an
>> outboard
>> amplifier the situation would be different.
>> Rick/K5IAR
>>
>>
>> -----Original Message-----
>> From: heathkit-bounces at mailman.qth.net
>> [mailto:heathkit-bounces at mailman.qth.net] On Behalf Of jeremy-ca
>> Sent: Tuesday, July 31, 2007 4:21 PM
>> To: heathkit at mailman.qth.net; Peter Markavage
>> Subject: Re: [Heathkit] Amp Keying Interface?
>>
>>
>> I dont know of any SS relays that can handle 1-2KW of RF. Correct me
>> if I'm
>> wrong.
>> Most SS switching that I'm aware of is via pin diodes and big ones
>> aint
>> cheap. If you want a circuit you can get it off the Ameritron web
>> site. Be
>> advised that they do not like high VSWR.
>>
>> The old Johnson T/R unit sucked out some RX signal and was also a
>> TVI
>> generator.
>>
>> A relatively inexpensive way to switch is with vacuum relays. New or
>> barely
>> used surplus is quite reasonable.
>>
>> Carl
>> KM1H
> _______________________________________________
> List Administrator: Duane Fischer, W8DBF
> ** For Assistance: dfischer at usol.com **
> $$ See the vintage area on the HCI web site - http://www.w9wze.org $$
> Heathkit mailing list
> Heathkit at mailman.qth.net
> http://mailman.qth.net/mailman/listinfo/heathkit
>
> _______________________________________________
> List Administrator: Duane Fischer, W8DBF
> ** For Assistance: dfischer at usol.com **
> $$ See the vintage area on the HCI web site - http://www.w9wze.org $$
> Heathkit mailing list
> Heathkit at mailman.qth.net
> http://mailman.qth.net/mailman/listinfo/heathkit
>