Quote:
Originally Posted by SiriusHardware
.... Unfortunately what that does not tell us is what numbers the IF-150 sends to the radio when you send those psuedo-english commands to the IF-150 from a terminal. But it gives us an idea of the full command set available through the keypad interface.
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Yes, I suspect that the IF-150 doesn't actually send the frequency as it is entered but as a number of 8Hz steps, possibly including an offset. Since the receiver has a tuning range of 30 kHz-30 MHz, this could possibly take the form of a number ranging from, say, 0 to 3750000, so 3750 could represent 30kHz, 24750 might represent 198kHz and 3750000 may represent 30mHz for instance. Looking inside the IF-150 (attached), you can see that the circuitry is rather more advanced than the basic keypad and includes a micro that could easily handle the data entry, conversion and validation. In any case, the output is very different compared to that from the keypad unit.
A quick look on the scope reveals that most, integer, frequency commands seem to output six packets of "bits", regardless of the frequency. However, when a decimal point is included in the data, as in the 28734.324 example, an extra couple of packets are added. The MOD commands just seems to output a single packet to represent the chosen reception mode. It looks very similar to typical output from an infra red remote control - probably using Manchester encoding etc. Sadly, I haven't really got the time or inclination to study this in depth but it's certainly "crackable" with a bit of effort. Either that or find John Thorp and see if he remembers how he did it !
Jerry