Decode DPL (CDCSS)
or PL (CTCSS) with your HP 8920A/B or 8924C Amtronix
Instruments, Inc. 2009
If you want to decode PL or DPL on your HP
8920A/B or HP 8924C unit, here is the setup procedure for your HP
Service Monitor. By saving this procedure in memory, you can easily
recall it to quickly decode off the air.
1) Press "TX Test", set the "input port" to Ant (this is for easy
"off the air " decoding. If you want to use the I/O port for radios
connected directly to the I/O port, you can leave the input port to I/O.
2) Go To the decoder screen ( on the 8924C, press the blue
"shift" key then the "decode" key).
3) Scroll to the "mode" field and set to "CDCSS" for DPL decode.
(set to "Function Gen" for CTCSS decode)
4) Scroll to "Arm measurement" field and set to "continuous".
5) Set AF analyzer in field to "FM Demod".
6) Set input level to "0.30 KHz".
7) Set Polarity field to "normal". Now, when you key a
portable near the HP Service monitor, you can read DPL / PL off the air
on the left side of the decoder screen. The HP Service Monitor will
display several DPL codes - generally, the correct DPL code is the
8) To save this screen in memory for future use,: Press blue
"shift" key, then "save" key. I suggest labeling this screen to
"DPL_DEC" or if using PL (CTCSS), label PL_DEC.
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