[Elecraft] K3 Variable amp keying delay >>not long enough!!??

[Eric Swartz - WA6HHQ, Elecraft]

Hi George!

We start to bump up against shortening the first dit on CW when delays 
longer than 20 mS are selected. We'd certainly like to support longer TX 
delays, but it will take a little head scratching and f/w work to make 
it happen. We'll certainly strive to do as much as we can in this area.

If you and other members on the list can send me the max delay supported 
by other rigs currently on the market, that will help us figure out if 
this is reasonable.

I was unaware of any commercial rig supplying much above 20-25 mS of 
keyout to RF delay.  The K2 provides 10-12 mS of delay and we've had 
very few complaints even with that. What delay does the Pro-III support? 
Were you able to drive your amplifier in semi-break-in with it? I am 
unaware of any current production Ham rig that supports directly keying 
high current AC relays with greater than 20-25 mS long delays. (But I 
could be wrong :-) That's why many VHF ops, who require long delays for 
their transverter and antenna switch chains, usually use a foot switch 
to manually key everything before generating RF.

One other thought, just looking at the theoretical worst case relay 
settling time may overstate the delay required. What is the time delay 
for the amp RF path itself? Also, the worst case settling delay is 
usually specified for DC or low freq AC loads. At RF, the contacts may 
be close enough, with enough contact to provide a very low impedance RF 
path well before this time, even if they are still settling.

In any case, we'll keep looking at this.

73, Eric   WA6HHQ
======

George wrote:
> I don't think 20 ms is enough in my case, based on my primitive research.  Several "experts" have said mine might need as much as 30-35 ms.  My amp's relay is a 30 yr old Potter & Brumfield open frame model with a 120vac  coil.
>
> To make things worse, since the K3 will not switch 120vac, I must use another relay with a 12vdc coil in the line between the K3 and the amp, which in turn pulls in the P&B relay.  This exacerbates the matter by taking even more time, and I'm afraid to try anything for fear it will damage the K3 and the amp.  Am I wrong??  Anyone care to comment??
>
> One of the many reasons I bought the K3 was to be able to operate at least semi break in CW and VOX with my old amp without hot switching, by virtue of having ample switching delay.  I've waited months for the feature and am disappointed..
>
> However, I hasten to add this:  As a K2 user/owner/builder, I expected much in the K3.  I got much more than I expected.  I gave up a nice Icom Pro 3 for the K3 and don't miss the Pro 3 one iota.  The K3 is unbelievable in what it can do and how superbly it does it. And getting new firmware is icing on the cake.
>
> But I sure wish I had 0-50ms amp delay capability!  How about it, Wayne?
>
> George, N4YM
>
> K2 # 4758
> K3 # 340
>
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