[Boatanchors] keying

[Rob Atkinson]

You have to let the VFO free run while you transmit.  Don't key it;
key the transmitter.  The manual for the HA-1 TO Keyer has
instructions and charts for constructing a simple RC combination on
the rear panel octal jack (you wire the cap and resistor to the octal
plug that connects the line between the keyer and the rig) so the
keyer will handle the particular keying v. and current you have.  The
purpose is to simply prevent long term damage to the P&B wetted relay
contacts.

You'll have to experiment with small pie chokes, resistors, and
capacitors in series with and across the hot to ground keying line to
see what is effective at reducing the spark both on make and break.
It is helpful to see the keying envelope on a scope and have a friend
a mile or two away tune around listening for clicks.  There are two
kinds of clicks--those that are only in the shack from the key
contacts and the ones that travel a long distance due to a vertical
rise and cutoff of the keying envelope.  I put a 4 mfd 600 v. oil cap
between the cathode and ground on the 807 to give a nice keying
envelope shape because I got complaints of key clicks.   I
experimented with various values looking at the keying envelope on a
scope and found that 4 or 5 uF did the job.  If I recall correctly, I
also put a 2 watt 10 or 20 ohm resistor in series with the hot contact
on the key.

73

Rob
K5UJ

On Sun, Mar 17, 2013 at 11:17 AM, Charles Ring <w3nu at roadrunner.com> wrote:
> I'd like to use my Novice transmitter from 1963, a Johnson Adventurer, with
> my Globe V-10 VFO and/or my WRL 755 VFO. The Adventurer has rather heavy
> cathode keying current, over 120 mA at over +150 volts, and draws a spark on
> my bug. Either VFO has much lower positive keying voltage and current. I'd
> like to use my HA-5 T.O. keyer on this combination without ruining its
> sealed mercury-wetted contact keying relay, and without another
> electromagnetic relay. Thinking that this has been solved long ago, where
> can I find a circuit to accomplish this? The Adventurer has no cutoff bias
> so it puts  out a lot of diode noise if keyed with no drive. I have no
> objection to using modern techniques with my old gear.
>
> --
> *Charles Ring W3NU*
> ______________________________________________________________
> Boatanchors mailing list
> Home: http://mailman.qth.net/mailman/listinfo/boatanchors
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Boatanchors at mailman.qth.net
>
> List Administrator: Duane Fischer, W8DBF
> ** For Assistance: dfischer at usol.com **
>
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html