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Re: Topband: Vac relay keying

To: MU 4CX250B <4cx250b@miamioh.edu>
Subject: Re: Topband: Vac relay keying
From: MR TREVOR DUNNE <ei2glb@eircom.net>
Date: Wed, 15 Nov 2017 14:09:12 +0000 (GMT)
List-post: <mailto:topband@contesting.com>
Hi Jim

I'm trying to detune my TX vertical on RX, I want to use the tx out on my flex 
6500 to do the switching I can add in delays using the flex software which is 
handy,

So basically when I tx I want the relay to close and when I un-key it opens and 
it shorts the tx antenna to ground,

It's how the 26v supply with effect the flex Im worried about? I don't want 
anything to damage it, I have a small circuit keying the 12v relay I'm 
currently using but moving to 26v has me confused,

Thanks
Trevor
EI2GLB 


----- Original Message -----
From: MU 4CX250B <4cx250b@miamioh.edu>
To: MR TREVOR DUNNE <ei2glb@eircom.net>
Cc: topband List <topband@contesting.com>
Sent: Wed, 15 Nov 2017 13:24:55 -0000 (GMT)
Subject: Re: Topband: Vac relay keying

Trevor,
It’s unclear to me what you’re looking for. One transistor and a 24V power
supply can activate a vacuum relay, but are you trying to key up an
amplifier with the relay, ground a receive antenna, implement a QSK
circuit, or what? Do you want to sequence the relay to prevent
hot-switching. What kind of delay time (e.g., 10 mS) is acceptable? If you
specify your needs more completely, I’m sure people on the list can
recommend solutions.

BTW, i don't care for “hot shot’ circuits that pulse relays with a
momentary voltage spike to speed them up. They work okay on large open
frame relays, but can damage small vacuum relays that have a much more
fragile internal construction. In tests here, I found that they can also
lead to excessive contact bounce, sometimes as many as 15 bounces. There
are better solutions!

73,
Jim w8zr
Sent from my iPhone

On Nov 15, 2017, at 2:01 AM, MR TREVOR DUNNE <ei2glb@eircom.net> wrote:

I'm still looking for a way to do this can't see anything on W8JI's site
suitable and the fast relay link isn't what I'm after,

Thanks
Trevor
EI2GLB
----- Original Message -----
From: MR TREVOR DUNNE <ei2glb@eircom.net>
To: 'topband List' <topband@contesting.com>
Sent: Tue, 14 Nov 2017 19:51:18 -0000 (GMT)
Subject: Topband: Vac relay keying

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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