Monroe TRS (Middlesex County)

[TAS]

I was curious to see if anyone else is having difficulty programming the Monroe Township (Middlesex County) TRS into their 396XT. I have programmed several other Moto UHF TRS’s into the XT with FreeSCAN with no problems.

I have it set up as follows:

Type: Mot Type II / P25
Site Type: Mot UHF Band
Freqs: 507.66250, 507.91250, 508.38750, 508.78750 (CC only)

System Band Plan: (correct as per Radio Ref and JR2)
Lower Freq: 507.0125
Step: 25.0k
Offset: 380

Upon clicking “Auto Upper” in FreeSCAN it enters 516.4875 into the Upper Freq

After uploading to the XT I had it on search but wasn’t picking up any activity. I held on the CC getting the correct System ID and showing active talkgroups. I go back to search – nothing.

I check over the programming and find the System Band Plan blank. I load it again with FreeSCAN. It won’t take the band plan, it stays blank. OK what gives?

I try to enter it manually. A problem arises when entering the band plan:

Edit Band Plan
Select Band Plan
Custom (only other options are 800/900 Standard & 800 Splinter)
Select Plan
Band Plan 1
Set Base Freq
Input Lower: 507.0125
Input Upper:516.4875 – upon pressing enter it says “Out of Band, Press Any Key”

I even try entering the Step and Offset first before the Inputs but it’s the same “Out of Band” message.

I then go to my trusty 396T (which doesn’t ask for an Upper Input) and enter the same Lower, Step and Offset and presto, working fine, picking up all talkgroups clearly (except for the ENC of course).

Any ideas on what the problem is here? And why do we now need an “Upper Input” and a “Polarity” in the XT when we appeared to be doing fine without it. And if somebody could explain the polarity, that would be great, (the manual’s shortcoming is that it doesn’t explain anything new).

Thanks in advance for you help.

TAS

 

[W2SJW]

Using FreeScan, I imported the data I used to have from ARC396. Monroe came out as this:

507.0125 - 511.7500 - 25.0 - 380

And she's working OK the last time I checked...

 

[robbinsj2]

It looks like this high frequency value is a different way of specifying the same limit that GRE handles through Channel High. Uniden skipped GRE's Channel Low since, as far as I know, it is always the applicable offset value/base frequency.

Ready for some math? On Motorola systems the lowest repeater offset is 380 and the highest is 759 (inputs run from 0 to 379). That leaves 759-379=380 possible repeater channels. If channel spacing ("step") is 25kHz and there is only one base used then the bandwidth is 380*0.025=9.500MHz. TAS, it looks like FreeScan took that 9.500 and added it to the base frequency of 507.0125 to get 516.4875, which the scanner rejected because it is out-of-band and untunable. (Note that the system maximum bandwidth starts with and includes 507.0125, so it ends with 516.4875; if it ended with 516.5125 then it would be 9.525MHz of bandwidth and 381 channels.)

Scott, it looks like your FreeScan used a step of 12.5, for reasons I can't explain, to get a bandwidth of 4.7375 and an upper limit of 511.75. While that should and does appear to work, naturally there would be no repeaters to hear between 509 and 511.75 unless the FCC makes some drastic changes.

TAS, try 511.75, or 509.000, or really anything between the highest system frequency (508.7875) and the scanner's UHF-T limit.

This morning I did verify the basic system settings (base/offset/step) with my Pro-106. Do note that Monroe PD is now encrypted so unless there is a fire or EMS call there may not be much to hear late at night. Maybe the talkgroup activity you saw while sitting on the control channel were those encrypted talkgroups (48xxx range), which were skipped during scanning.

Jim

 

[W2SJW]

Yeah, I'm not sure why my old 396 had Monroe as a 12.5k step, but it did work in the old scanner!

Quite upset to hear about the PD going encrypted

Did they upgrade to an ASTRO mixed-mode system?

 

[TAS]

Monroe TRS

Thanks to everyone who responded. The Upper of 511.750 appeared to work correctly in the XT. I monitored the T and XT side by side for a period of time and they tracked the system without variation. I wonder what happened with the FreeScan that in this one case it gave an incorrect upper. Thanks again.

TAS

 

[W2SJW]

I updated the database to show that the system is now a mix-mode capable Type-II (I saw the digital 'LNK\ENC' show up when I was getting hits on the new PD dispatch channel).