Have had to replace the input T/R relay on my amp (Henry).
Relay is a small Guardian electromechanical unit, probably
takes 10 or so milliseconds to switch.
Suspect the replacement was because of burned contacts
from "hot switching". The Omni was deaf at key up; the input
relay had not returned to the receive side. Couple of key
taps, or PTT pushes would return "hearing" on rcv.
The Omni VI+, uses a mechanical relay
to signal the amp's T/R switching relays. Figure at least 10 ms
for this relay to operate. Then RF output appears less than
5 ms after the contact closure since per the ARRL lab tests,
my Omni keying has about a 15msec delay between key down
and RF output, and 17 msec delay between key up and the
5 to 7 milliseconds is less time than the amp Guardian input relay
needs to operate. Therefore when the input relay contact opens, it
is carrying RF current, and so it will arc as it opens. Every time.
Prowling about in the Omni manual, I just discovered the news that
the OSK Slow relay delay is adjustable over a range given as
01 to 15 (what, milliseconds?). Anyway, following the manual
instructions, have checked and found my rig, at the moment
is at "position" 07. If I increase this to 15, will both of the amp
relays not open for at least 15 milliseconds after key up? Even
then that might not be long enough if the Omni requires some
17 mS for RF to shut down after key up. And, would RF not
"leave" the Omni until 15 mS after key down in this setting;
probably faster as this is called "relay delay".
Maybe I just don't understand what is going on here. Anyone
use the Ameritron QSK-5 unit along with some other non-
Ten Tec linear with their Omnis? Maybe that unit would solve
73, Jim KH7M