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M1225 PL/DPL Strip?
Posted: Sun Feb 18, 2007 12:26 pm
by cracked
According to the online help in the M1225 RSS , I'm supposed to be able to program an accessory connector input pin for "PL/DPL Strip" operation, but I don't actually see this option. What's the deal?
Posted: Sun Feb 18, 2007 1:28 pm
by Al
If I'm remembering correctly, the PL/DPL strip option is only available if you're using an R1225 as a base/repeater station. That
option isn't available with the M1225 mobiles and [obviously] the
P1225 portables, all of which are programmed with the same RSS.
Posted: Sun Feb 18, 2007 1:51 pm
by cracked
Al wrote:If I'm remembering correctly, the PL/DPL strip option is only available if you're using an R1225 as a base/repeater station. That
option isn't available with the M1225 mobiles and [obviously] the
P1225 portables, all of which are programmed with the same RSS.
That's what I was afraid of. Unfortunately, I happen to be using an M1225 as an exciter in a repeater and would like to strip PL when COS drops. My controller already introduces a PTT delay after the COS drops, but not all user radios support reverse-burst, so they get a squelch "tail" noise.
Perhaps this could be accomplished with a hard-wired connection into the radio some place (anybody?)...
Posted: Sun Feb 18, 2007 7:18 pm
by Al
The CM200 & CM300 have accessory pins that can be programmed for PL/DPL strip......however, with the CM series, the strip pin must be in the active state before PTT goes active. If strip goes active while PTT is active, it doesn't strip PL/DPL.
In the M1225, PL/DPL baseband modulates the tx synthesizer's reference oscillator while the voice band stuff modulates the tx VCO directly. That method is standard with most if not all M products. I don't have a schematic in front of me, but if you could locate a convenient point where subaudible signalling baseband is injected into the tx reference osc and use a simple FET transistor switch to allow or disallow injection, that would do what you want.