[Elecraft] KPA100: PA KEY OUT & Bouncing Relays

Wed Feb 12 19:17:00 2003

As long as it is a positive voltage the K2 will key the 922 OK. Also, we 
already sequence our keying line to activate 15-20mS  before RF is applied, so 
there is no need for an external sequencer.

We also have the '8R Hold' option in the menu to holt the TR line active for 
the same time as the t/r delay to keep your amplifier relay from chattering. 
there is no need to add additional external delays or diodes.

73, Eric   WA6HHQ

John-Morrow wrote:
> ----- Original Message -----
> From: "Dominik Bugmann" <[email protected]>
> 
>>Might Anti-Diode and C to GND help or shall I even use a small relais?
>>BTW: I will never use QSK with the TL-922. The relais are to noisy.

> 
> The relays on a TL922 operate at 100V. Is the switching circuit in the
> K2
> able to switch this directly?
> The relays are not only too noisy, they are too slow and the contacts
> will
> eventually fail because rf is being applied before they have completely
> changed over. This is known as hot switching.
> To prevent 'hot switching' a TL922 needs a sequencing circuit between it
> and a modern rig or the relays should be changed to vacuum types.
> 
> 73
> John Morrow GI4KSH