[Elecraft] KPA100: PA KEY OUT & Bouncing Relays

[Eric Wosten]

At 23:39 12-02-03 +0000, John-Morrow wrote:

>----- Original Message -----
>From: "Dominik Bugmann" <hb9czf@swiss-artg.ch>
> >
> > 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.
> >
> > 73 de Dominik, HB9CZF
>
>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.


Right!

Howto:

http://www.vcnet.com/measures/

Did all these mods to prevent glitches, just started working on the vacuum 
relay mod.

When finished the TL922 will switch rx/tx in 2 ms, resulting in true QSK. 
The K2 will
not be able to keep up with this, as it is semi QSK.


Eric PA3CEV