[Elecraft] [K2] Diode types for connecting both paddle & straight key

[Steve Kavanagh]

Thanks for your comments, Sverre and Mike.  Yes, I believe I have had RF-induced odd keying problems (with a transverter/amp on 144 MHz at about 100-300 W out, the key being around 5m from the antenna, but not in the main beam).  They seemed to respond to moving cables around, putting ferrite chokes on cables and the like, but it was never very certain what was happening.
 
I have a whole bunch of TCG125 general purpose rectifiers (1 kV, 2.5 A) so I tried a pair of them last night.  They seem to work, though the only real test will be extended operating time.  I measured the voltage on each of the dash and dot paddles with the straight key down (0.53 and 0.42 volts) and the total current through the straight key (0.7 mA).  With half this current through each of the 220 ohm filter resistors I should have 0.61 and 0.50 V at the PIC, so this would appear to be adequate according to the criterion suggested in Sverre's link.
 
I hope it works ok...if not I do have a few 1N5818 Schottky rectifiers which haven't made into projects yet....
 
73,
Steve VE3SMA