|[AMRadio] The Ranger Keying Problem|
ranchorobbo at gmail.com
Tue Dec 31 11:45:39 EST 2013
You can fix up the click problem with a cathode keyed rig by
experimenting with combinations of chokes, low value resistor and
capacitor. choke in series on the key line; resistor in series or
bypass, cap bypass. run the rig into a dummy load and look at the
keying envelope with a scope sending a string of dits. I found that
around 4 to 5 mfd bypass cap to ground on the cathode gave a nice
shape. The make and break originally was vertical and the cap
introduced enough angle to the rise and fall to get rid of the clicks
and make a nice sounding note.
Some clicks are in the shack only. Those are produced with arcs at
the key. Choke or resistor at the key help with that. The clicks
that go out on the antenna have to be fixed at the rig's keyed
cathode--same passive components but inside the rig.
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