[TenTec] Quiet Full Break In Keying for Orion - Followup

[Len Umina]

A few weeks ago I posted a note on how I got the Orion to quietly key in
full break in mode.  Although the note is accurate, it rambles a bit as
I was writing it while investigating the issue.  This is the summary:

If you are hearing loud relay clicking when in full break in mode, you
are hearing a relay inside the Orion that operates whenever there is
voltage on the amplifier keying line.  If you have a home made keying
circuit (as I do) which interfaces to a high voltage keying line, it's
likely you have 12 volts on the amp keying line to the Orion all the
time.  The open collector output of the Orion pulls this voltage low to
key your amplifier.

I also believe several ICOM amplifiers run the 12 Volt power supply for
antenna switching, even when the amplifier is off if you configure it
this way.

In either case, if 12 volts is present on the amplifier keying output of
the Orion you will hear a keying relay make and break with each morse
element if you have 0 delay set in Menus/TX/EXT T/R Delay for the
antenna output you are connected to.

If you remove the 12V on the amplifier keying output, the radio will
work fine, but the larger relay will not operate, and the keying of the
radio in full break in will be almost silent.  This accounts for the
heated discussions on this site regarding "it's quiet" and "it's loud"
opinions on the subject!

You can put a switch in series with your keying line to remove the
voltage when you do not require the amplifier.  You can also use the
other antenna output (since each one has a different keying output) if
you don't want to mess with a switch, or unplug the cable.  If you have
your amplifier connected to ANT 1 and it causes the Orion keying relay
to chatter even when you are not using it, switch to ANT 2 and put an
antenna on that connector.  Because there will be no voltage on ANT 2's
Amplifier Keying Output, the radio will be quiet.

Tomorrow I may have time to look into the relay issue a bit further to
see why this happens.  I suspect its related to the Keying Loop logic.  

If you operate semi-breakin when you run an amplifier, the keying relay
isn't much of a problem since it only opens and closes at the end of
your transmission (based on the settings of Menus/TX/EX T/R Delay
[1/2]).

If you operate a full breakin amp that does not require a keying loop,
it should be possible to eliminate the relay.  I'll try to look into
this before November!

73,
Len WT6G