Topband: Vac relay keying

[David Cutter]

Trevor

That circuit works well if you only have a 13V typical radio supply.  You 
can string several relays from the T/R line but remember to fit a 1N4000 
type diode across the relay, + end to supply, -end to the T/R line.

It's important to take into account your linear amplifier (if you are using 
one) as well.  If you have a radio that can delay RF after sending the 
PTT/transmit signal, that is an advantage to avoid hot-switching.

The slowest relay in your system might be the one in the amplifier, but 
that's slow to energise and slow to de-energise.  Make yourself a little 
timing diagram of what you need.  I think this is in various handbooks.

Give more info on your *complete* set up.

David
G3UNA



----- Original Message ----- 
From: "Richard (Rick) Karlquist" <richard at karlquist.com>
To: "MR TREVOR DUNNE" <ei2glb at eircom.net>; "'topband List'" 
<topband at contesting.com>
Sent: Tuesday, November 14, 2017 9:37 PM
Subject: Re: Topband: Vac relay keying


> See:
>
> www.k6xx.com/radio/fastrely.pdf
>
> Rick N6RK
>
> On 11/14/2017 11:51 AM, MR TREVOR DUNNE wrote:
>> Hi Guys
>>
>> Can someone point me in the direction of a circuit I can use to key a 26v 
>> vacuum relay using the tx out on my rig,
>>
>> I have a 24v PSU I just need to know how to switch on the feed to the 
>> relay as quick as possible when I TX,
>>
>> Thanks
>> Trevor
>> EI2GLB
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