K2/100 Transition back to Receive in CW

[Jim Brassell K4ZMV]

I am using my K2/100 Ser. 5731 to drive an Ameritron ALS-600 and I am experiencing a problem when the K2 switches back to receive.  It is switching back before the RF completes and the amplifier T/R relay contacts are arcing and causing the the relay to stick in the transmit position.  My ALS-600 has a QSK mod by AD5X to accommodate fast QSK (3 ms or so).  I used one of my K3's to drive this same amplifier and never had a minutes trouble.  Is there a mod to the K2 that can lengthen the switch to receive delay?  I have found a mod to the amplifier done by Phil Salas, AD5X, that will hold in the T/R relay to accommodate the exciter RF, but nothing for the K2.  Thanks for your help.

[Don Wilhelm-4]

  Jim,

Check the menu setting of "t-r"  It should be as great (or greater than)
the release delay for your amplifier relay.
In addition, tap the DISPLAY button while editing the t-r menu parameter
to toggle between 8R 'nor' and 'hold'.  You want it to be in 'hold' for
your situation.

A note on the relay time - that 3 ms is the time for the relay to pick
(go from Receive to transmit) - the release time may not be the same.

A typical K2 asserts the Amp Keying output 12 to 15 ms before the onset
of RF, so with 3 ms relays there should be no problem on the pick
timing, but the release timing can be a problem as you have observed if
your K2 is set for 8R Nor rather than 8R hold.

See page 86 of the K2 manual for more information.

BTW, if you have already pitted the contacts of the relay, you may need
to replace it.

73,
Don W3FPR

On 9/12/2010 5:03 PM, Jim Brassell K4ZMV wrote:

> I am using my K2/100 Ser. 5731 to drive an Ameritron ALS-600 and I am
> experiencing a problem when the K2 switches back to receive.  It is
> switching back before the RF completes and the amplifier T/R relay contacts
> are arcing and causing the the relay to stick in the transmit position.  My
> ALS-600 has a QSK mod by AD5X to accommodate fast QSK (3 ms or so).  I used
> one of my K3's to drive this same amplifier and never had a minutes trouble.
> Is there a mod to the K2 that can lengthen the switch to receive delay?  I
> have found a mod to the amplifier done by Phil Salas, AD5X, that will hold
> in the T/R relay to accommodate the exciter RF, but nothing for the K2.
> Thanks for your help.

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