PK232SAT.4 Frequencies are plus or minus doppler shift. An oscilloscope connected to the PK-232 will simplify keeping up with the doppler shifted tones on AO-13 as a shift in the cross pattern is seen easier than a shift of the PK-232's leds. Tones do not change with doppler on the Uosat birds as they are FM AFSK. RXR does not operate above 300 baud because of hardware limitations. As Uo-9 sends normal shift this is no problem. But to copy Uo-11's inverted shift an unused inverter in the PK-232 (U15 pins 1 and 2) must be wired to a switch in series with the output to JP4 as follows: 1. Solder a jumper wire between U15's pins 1 and 6. 2. Cut the circuit board trace connecting U15's pin 6 to the inside pin of JP4. This trace is easiest to cut where it comes out from under R20 on the top (component side) of the PC board. Be sure to double check that this CONTINUED IN FILE PK232SAT.3 Downloaded From P-80 International Information Systems 304-744-2253