[Swan] Mic. impedance question (one last time)

[Steve Harrison]

At 05:59 PM 6/19/2002 -0400, you wrote:
>PS: FOR CW OPERATIONS, can the radio be set to TX via the PTT button for CW
>TX? My logging software offers automated CW operations (TRLog).

Not unless modified. You normally have to switch into CW mode to transmit
on CW; it won't transmit CW in the LSB or USB modes (I guess your older 250
only has USB?). There should be some sort of modification instructions on
N0QMO's site (which, IIRC, is as applicable to the 250 as to the HF radios
(350 and 500). Basically, when the switch is put into CW, it closes the
transmit-receive relays; the mod would break that connection so the relays
don't close unless you close the PTT line. BTW, DO NOT attempt to key the
PTT line of the Swan radios with your computer; you need a simple interface
circuit which can handle a coupla hundred mils at 12VDC. Your computer's
COM board cannot switch more than a couple of milliamperes and you'll blow
the board's switching circuit. The interface circuit will easily key the
radio's PTT circuit when you close the key or PTT line.

There may be more involved in this mod, I can't remember right now.

Steve, K0XP