Batboard

Can PL deviation be adjusted separate to voice deviation? I tried the deviation balance adjustment and it didn't seem to do much. My problem is that PL deviation is way too high. If I lower the deviation, it lowers the voice deviation as well. I have converted an 800 MHz model to 900 MHz by putting an RF board from an MTX9000 into it. Managed to get most of the alignment issues straightened out, but PL deviation is still running about 650 Hz, way too much. I know these are way old radios, and what am doing is way out in left field, but I am close to getting the thing to work. I don't mind going inside and fooling around a little if need be, but if I can do it through programming, that would be best.
Thanks in advance.

John G wrote:Can PL deviation be adjusted separate to voice deviation? I tried the deviation balance adjustment and it didn't seem to do much. My problem is that PL deviation is way too high. If I lower the deviation, it lowers the voice deviation as well. I have converted an 800 MHz model to 900 MHz by putting an RF board from an MTX9000 into it. Managed to get most of the alignment issues straightened out, but PL deviation is still running about 650 Hz, way too much. I know these are way old radios, and what am doing is way out in left field, but I am close to getting the thing to work. I don't mind going inside and fooling around a little if need be, but if I can do it through programming, that would be best.
Thanks in advance.

On a wide band radio, the normal PL deviation is 650 Hz. It is fixed and the only way to lower it is to change some internal resistor values.

Jim

Thanks, I am aware of that. It seems that an adjustable PL deviation is a novelty. I think I have seen it maybe twice. In looking at the theory book, it says in one place that PL and speech are summed in an attenuator, seemingly inside an IC. In another place, it says that PL is applied to the synthesizer IC in a digital form. Neither looks promising. I think I will try adjusting the deviation downward as much as possible. I might have to add a preamp to the microphone. Based on what I have already seen, I will likely have to settle for about 450 Hz PL deviation. Since there isn't any 900 MHz activity around here, it doesn't really matter any way. I was just doing this to see if I could. I have learned a fair amount about HT1000 programming and the ins and outs of the codeplug, so if it doesn't end up working, I still come out ahead.