[Icom] Send Relay "real scoop" from ICOM

Wed, 20 Feb 2002 00:32:20 -0500

I don't have a relay problem with my homebrewed 8877, but if I did, I would
put a resistor in series with the amp relay contacts so the initial current
rush wouldn't weld the transceiver relay contacts.
I had a relay problem with a homebrewed keyer and the DRAKE C line many
years ago and I solved the problem with a 4.7 ohm resistor in series with
the keyer relay contacts.
WA1WLA

----- Original Message -----
From: "Jerry Flanders" <[email protected]>
To: <[email protected]>
Sent: Tuesday, February 19, 2002 11:14 PM
Subject: Re: [Icom] Send Relay "real scoop" from ICOM

> I wonder if he made a typo in his email reply ;)
>
> Seriously, if there is any inductive kickback at all in a 12V keying
> circuit, you will exceed that 16V greatly. I think ICOM is telling us that
> in a 12V inductive circuit, make SURE you have a properly designed circuit
> to absorb that back emf. My AL-1200 has a snubbing diode across the relay
> that works for me, but if it failed I wouldn't know it before the damage
> would likely occur. Might be good insurance to add another diode to backup
> the first. I wonder if some of those failures we heard about occurred
> because the diode smoked.
>
> To those who say just add another relay - timing goes to pot quickly. Most
> mechanical relays are already too slow to avoid some hot-switching with
> just the one relay. Another conventional relay doubles the delay, and with
> a homebrew isolation relay you need to worry about snubbing it also.
>
> Jerry W4UK
>
> At 08:09 PM 2/19/2002 -0500, you wrote:
> >My response from ICOM:
> >
> >
> >The real scoop is UP TO 16V -OR- UP TO 2 amps.  We always recommend the
> >use of an isolation relay, such as that manufactured by Ameritron.  Good
> >insurance for a rig like this.
> >
> >Nick Sutton, NS7DX
> >Technical Service Representative
> >Icom America, Inc.
> >---
>
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