Whilst finishing the arcusfivus vfo to drive a fine glowebugge rig
to speed in the variable oscillatory mode, I thought I would pass 
along a few thoughts on keying glowbugs with the arcusfivus vfo's.

1.  Although QSK is possible with a glowbug, it is usually done
    with two antennas for convenience or occasionally a tr switch.
    Most of the time `semi-qsk' with a delay circuit and an antenna
    relay is reasonable to shoot for.

2.  Using the average rockbound glowbug rig with a vfo can be a bit
    tricky, since they need to key together such that the vfo makes
    first and then the transmitter keys and then the transmitter unkeys
    and then the vfo unkeys.  So for stability the oscillator needs
    to come on when the antenna changeover relay fires, and stay with
    it timingwise.  Also, the keying on the glowbug can be positive
    keying or negative keying of widely varying voltages.  (Note that
    if a glowbug is keying a line of greater than about 50 volts you
    really should be keying it with a relay.)

3.  So, for convenience, assuming you are keying your glowbug with a
    relay, it can be sequence keyed with the oscillator in semi-qsk
    mode, fairly simply, as follows....

    a) Take a relay for keying of any handy voltage and put a diode
       in the low side of the relay key line such that it protects the
       relay from reverse currents.  Usually the cathode goes to ground
       in a positive keying relay circuit.  A 12 or 24 volt relay is fine.

    b) Take a similar relay and diode and use that to key the arcusfivus
       vfo (if you have a junker arcusfivus like mine that had to be
       rebuilt from scratch).  A 12 or 24 volt relay is fine and can
       be run from the dc filament line quite effectively.

    c) Connect together the key lines from the vfo and the rig to the
       key and test that they key together.  If they do, all is fine.
       If they don't check the polarity of the diodes --- they should
       be the same with cathodes to ground for a positive keying line.
       Note that the diodes come together at the key to ground end of
       the line.

    d) Now for the fun part of timing the the semi-qsk delay in the
       vfo half of the circuit.  Take a capacitor rated at about two
       times the dc supply voltage of the relays (50 volts is fine and
       a value of about 3000 to 5000uf is a good starting value) and
       connect it in the vfo line between the high side of the relay and
       the low side of the relay taking care to make sure the polarity
       of the capacitor matches that of the power source for the relay.


SORTOF SCHEMATIC THEREFOR:

+vdc                                                                 +vdc
+---+---relay--+--vfokeyline--diode>|--+--|<diode--rigkeyline--relay---+
    |          |                       |
    +--timing--+                       |
      + cap -                          |
                                      KEY
                                       |
                                      gnd


Bingo!  You now have a fine semi-qsk circuit that will key the oscillator
and the rig together, but, since the oscillator vfo has the capacitor
across its relay, it will hold in for the RC time constant of the relay
resistance and the capacitance.  You may have to adjust the value of the
capacitance to suit.  On small relays it may be as little as 1000ufd, but
on larger relays it may be as much as 10000 ufd.  That will give around
a 3 second holdin on the vfo relay.  If the vfo keying relay has a double
contact set, you can use the second contact set to key the antenna change-
over relay along with the vfo for perfect semi-qsk glowbugging!  In this
latter case, bend the antenna changeover relay contact to make slightly
ahead of the vfo keying relay contact so the the antenna circuit is
completed before the rig is actually keyed.

If you don't use a relay to key the glowbug rig (or other rig) and that
rig has a negative keying line, then you MUST reverse the vfo relay
power source, timing capacitor, and diode polarities.  I do this on
the AN/SRT-14 which has a -30v keying line.  The only thing that it
does is make the arcusfivus vfo filament supply be reversed so that
it is negative grounded on the filament battery.

If you are keying a high voltage grid block line (like the older ham
rigs that sometimes key a couple of hundred volts of grid block), you
must make SURE you have a high voltage diode (like a 1 amp 1000v diode)
or it will blow the diode and possibly the relay winding.  Other than
that, it is a good use for the old junk box diodes that never seem
to get used or are mostly unmarked.

I am sure lots of folks have done this sort of thing before, but I have
used this to key everything from my novice days up to the present, and
it works for me.  Size yer relays for the task to be keyed and tally
ho!

73/ZUT DE NA4G/Bob UP