PACKET RADIO: Running FSK with the Kenwood TS-450
Steve Wolf, W8IZ@W8IZ
(This text from the W8IZ packet radio bulletin
board. It's formatted to fit a 80 character screen.)
MSG # TR SIZE TO FROM @BBS DATE TITLE 45034 B$ 1883 KAM NO8M WW 940228 Pactor FSK w TS-450, KAM+ & MSYS
USING FSK RATHER THAN AFSK WITH THE KAM+ AND KENWOOD 450
A number of users had been using AFSK to operate pactor with the KAM+ and a Kenwood TS-450 under MSYS. Attempting to hook the radio up to the FSK showed that the radio just did not want to cooperate.
VE7CIZ found a way to allow the combination to be hooked up using the radio's FSK mode. This mode is reported to be better suited due to its bypassing the microphone audio circuitry. The other advantages are in the radio's ability to indicate mark frequency (rather than mark plus 2.1 KHz. as it does under AFSK). Also, the radio's IF shift is centered in the detent, rather than off to the side as is required with AFSK when using a 500 Hz. filter.
The KAM+ uses the Kenwood ACC-2 connector pins 11 (transmit audio in from TNC), 9 (PTT) and 3 (receive audio out to TNC) when used for AFSK. When used for FSK, the audio from the radio and PTT from the KAM+ is taken from the same pin. The transmit keying, however, is taken to pin 2 rather than pin 11 above. This line goes to the KAM+'s HF connector pin 5. The KAM toggles this line to tell the radio to transmit a mark or space tone. Switch both the KAM+ and the 450's connector wiring.
Firmware setups in both units must now be changed. First, the 450 must be told to use the pactor tones of 1275 and 1475. You do this by changing programmable function 39 as described in the manual. The KAM must now be instructed to use both the low tones and what they are. These commands must be added to your MSYSTNC.# startup file:
LO ON MARK 1275 SPACE 1475
That should do it for you. You may now use the 500 Hz. filter without adjusting the IF shift. VE7CIZ also reports he is able to switch the KAM+ with the Paccom PTC for his other uses.
*** END OF MSG # 45034 from NO8M @ NO8M.#NEOH.OH.USA.NA
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