PL latency

[eportel6607]

Guys I find the old Maxtrac/Radius M series to have very slow PL detection. The latency is not only slow but it's very inconsistent. Some times it's around 190ms and others it's over 220 or more. Comparing other brands like Vertex and Kenwood the Maxtrac/Radius line is slow. Is there any mod to make this process a bit faster?

 

[ElroyJetson]

It's a known issue with some radios. Having correct PL deviation is always helpful but some radios are just slow, end of story.

The specification for PL or DPL deviation is 8 percent of max audio deviation, IIRC. Motorola's service manuals usually specified 300 Hz for 5 KHz deviation (wideband) and 150 for narrowband. That's actually a bit low at 6 percent.

 

[eportel6607]

Thanks. There are conclusive tests that DPL is more consistant but maybe a "tune up" on each radio might be in order?

 

[kayn1n32008]

Odd, I find Maxtrac/GM300 radios to have some of the fastest PL decode times. Much faster than most other radios. So fast that using a pair back to back to link two MSR-2000 repeaters with no tails, causes the repeaters to continously cycle.

I would run the radios through a tune up. I do not experience what you are with about 30 GM300/Maxtracs in infrastructure(some as link radios, some as repeatets) use on an amateur radio network.
The fastest radio to decode PL/DPL I have ever used was a P110.

Edit. Majority of these radios are using PL on both transmit and receive.

 

[eportel6607]

Odd, I find Maxtrac/GM300 radios to have some of the fastest PL decode times. Much faster than most other radios. So fast that using a pair back to back to link two MSR-2000 repeaters with no tails, causes the repeaters to continously cycle.

I would run the radios through a tune up. I do not experience what you are with about 30 GM300/Maxtracs in infrastructure(some as link radios, some as repeatets) use on an amateur radio network.
The fastest radio to decode PL/DPL I have ever used was a P110.

Edit. Majority of these radios are using PL on both transmit and receive.

That's really strange. Ironically I too am using all of this equipment as infrastructure. I'm also using them in a PL Decode/Encode configurations. CDM750 (UHF narrowband) wired to a Maxtrac 2ch low band radio. The CDM is wired from the 20pin acc. connector and the Maxtrac is wired to the mic jack with a COR mod to pin 2.

When I compare the decoding times five VX5500L the VX5500 is faster and more consistent.

The system core transmits a 400ms tone. This tone duration is the same every time. On system remote relay systems that contain the CDM/Maxtrac combo for nearly the whole day the tone would be fully heard over the system. I left for lunch shutting down the system for about an hour. When I can back and turned on everything again this same tone would something not be heard and other times it would be. This is the case on two different remote controller link stations with two different sets of radios. If I do the same thing with the VX series radios it works fine every time. The VX series radios are five times the price of the Moto Maxtrac so the VX isn't an option.

This article seems to back up my finds with the Maxtrax. It also shows the PL being must less consistent than the DPL.
Measuring PL Response Time

 

[cmdrwill]

There was a problem on Maxtracs and some Radius mobiles. The input capacitor to the logic board's audio/PL amp leaked and distorted the audio. We replaced the cap with a 4.7 uF 16 volt cap.

 

[eportel6607]

Very good to know!
Thanks very much.

 

[n1das]

It's a known issue with some radios. Having correct PL deviation is always helpful but some radios are just slow, end of story.

The specification for PL or DPL deviation is 8 percent of max audio deviation, IIRC. Motorola's service manuals usually specified 300 Hz for 5 KHz deviation (wideband) and 150 for narrowband. That's actually a bit low at 6 percent.

That does seem low for PL deviation. I recall the spec from using many non-Moto radios for "wide" was 750Hz and 350Hz for "narrow" deviation. DPL deviation for wide and narrow were similar but don't recall any exact numbers.

My Hytera DMR radios in analog mode are factory set for 800Hz PL dev for wide mode (5kHz max dev) and 400Hz for narrow mode (2.5kHz max dev). 800 and 400 are close enough to 750 and 350 Hz PL deviation. If anything I like the PL deviation to be slightly on the loud side to ensure I've always got enough deviation for talking to radios from multiple manufacturers.