In article , Edward Knobloch
writes:

Dave Edwards KD2E wrote:
I had my novice just before VFOs were allowed.
I had a question about their use.
They all seem to have an RF output, and a keying jack.
So, did you have to run two wires from your bug/key/keyer
.....one to key the rig, and one to key the VFO??
I'm thinking either that, or you ran a wire from one
of the accessory contacts of your dowkey to
the keying jack of the VFO. This would keep the VFO on
during transmit mode.
Just wondering what was typical.

Looking at the Heath HG-10 VFO (mates with the DX-60,
DX-40, DX-20, etc.), they provided a key jack
on the back of the VFO.

The VFO itself is wired to the keying line of the rig,
with different circuits in the VFO for either cathode keyed,
or grid block keyed rigs. A spot switch on the VFO
allows VFO spotting without transmitting.

If the VFO doesn't suffer from chirp, you can key it
at the same time as the rig, resulting in full break-in (QSK)
operation using a separate receiver antenna,
or perhaps an electronic TR switch. Only chirpy VFO's
must be left oscillating all the time, which causes a back-wave
(tone heard during key-up) if you are transmitting
on the same frequency as you are receiving.

Since the VFO output frequency is multiplied
in the associated novice class transmitter, chirp becomes
more of a problem on the higher frequency bands.

In my experience, almost all vintage VFOs chirped when keyed. Some were better
than others, and a few, like the HG-10B/HW-16 combo, were chirp-free.

What I did back in the day was to use a 3PDT relay for transmit-receive
control. The relay could be any convenient voltage and mounted in a small
minibox with suitable connectors.

#1 pole switched the antenna between receiver and transmitter
#2 pole shorted the receiver antenna line to ground when in transmit
#3 pole had the moving contact grounded. On receive, it grounded the mute line
to the receiver, allowing the receiver to work normally. On transmit, it
grounded the VFO key line so the VFO would turn come alive.

73 de Jim, N2EY