[Elecraft] Re: K2/100 High Refl shutdown driving amp

[Floyd Sense]

I looked at the amplifier schematic, and there's already a diode across the
relay coil.  Also, found some info that indicates that it takes
approximately 15 seconds for the antenna transfer relay to change states.


----- Original Message ----- 
From: "Vic Rosenthal" <vic@rakefet.com>
To: "Floyd Sense" <sentek@sprintmail.com>
Cc: "Wayne Burdick" <n6kr@elecraft.com>; "Elecraft"
<elecraft@mailman.qth.net>
Sent: Tuesday, October 28, 2003 3:01 PM
Subject: Re: [Elecraft] Re: K2/100 High Refl shutdown driving amp


> Floyd Sense wrote:
>
> > It uses a small fast relay so there isn't much added
> > delay, but there is some.
>
> Unless it's a reed or vaccuum relay it probably adds at least 10 ms.
>
> > I NEVER have the problem on the first key closure of a transmission -
it's
> > only when the relay drops in the middle of a transmission.
>
> I've seen this kind of thing in other situations.  I think the relays
> tend to bounce more when they get hit with a voltage while they are in
> the process of opening.  Maybe the back EMF caused by the magnetic field
> collapsing as the coil is turned off opposes the turn-on current,
> slowing the closure.  In this case it might help to have a diode across
> the relay coil (a good idea anyway).
>
> Vic K2VCO
>
>