Plymouth PD P25

[murphcc1]

Hi, heard that this coming week Plymouth PD will be going to P25, 12th I think they said (FB, so, consider the source!)
I imagine they'd keep the same frequency, what might the NAC be?
Some of the other towns that just went P25 like Hanson, Hanover, Plympton, kept the same freq and all had the NAC of 270.
Might Plymouth have that same NAC 270?

[Mark SNE Moderator]

Not surprising. I was actually thinking about this the other day when I had to go up to the South Shore. Kingston and Plymouth are the only ones left in that immediate area still analog. Don't be surprised if Kingston follows suit right behind Plymouth.

[W1KNE]

Moved to the Southeastern Mass Forum.

The towns who have an NAC of 270 have Industrial Communications as their radio vendor.
Cybercomm and All Comm use the city exchanges for theirs.
Other vendors will use random codes or have some sort of internal codes.
Marcus Communications typically has letters in their NAC codes. (i.e. 1AD, etc)

[AJ1L]

Kingston is scheduled to make the switch on Tuesday. Could someone have mixed up Kingston and Plymouth?

[murphcc1]

Could be, got this news from farcebook.........
We'll see in a few days then.......

[ecps92]

451.2750 will be converted to P25 and use the NAC of 73B , over Tue and Wed

Hi, heard that this coming week Plymouth PD will be going to P25, 12th I think they said (FB, so, consider the source!)
I imagine they'd keep the same frequency, what might the NAC be?
Some of the other towns that just went P25 like Hanson, Hanover, Plympton, kept the same freq and all had the NAC of 270.
Might Plymouth have that same NAC 270?

[AJ1L]

Very odd freq for public safety…

[ecps92]

true, but with 453/460 well occupied......

Looks like the Sewer and Water don't need it anymore if they are giving it to the PD

Very odd freq for public safety…

[AJ1L]

true, but with 453/460 well occupied......

Looks like the Sewer and Water don't need it anymore if they are giving it to the PD

Makes me wonder if there’s another piece to the puzzle here… The normal thing to do is just use the same freq as you have always been on analog.

[W1KNE]

true, but with 453/460 well occupied......

Looks like the Sewer and Water don't need it anymore if they are giving it to the PD

There shouldn't be a need for a new frequency. Especially if they have the 482.6625 infrastructure (filters, antennas) in place. Unsure why the change from the T Band to biz band frequency.

I suspect the plan to switch to channel 2 , is because channel 2 isn't changing, they will use that while everything gets switched.

The whole thing is unusual, all the way down to the somewhat unusual NAC as well.

[astro]

There shouldn't be a need for a new frequency. Especially if they have the 482.6625 infrastructure (filters, antennas) in place. Unsure why the change from the T Band to biz band frquency.

The likely explanation is T-Band give back. While I didn't dig for call sign information as to the where/when/who my guess is this is a plan a few years in the making. If they had one channel maybe this is their expansion to two channels. A lot of departments also want a fall back plan, so, they could be leaving the analog channel in play while they migrate and test the p25 channel for their operations. Again, I'm guessing, but, this is likely a plan coming together that's been in play for a couple of years. Regardless of T-Band being unfrozen and no more give back - it doesn't mean the licenses gained are no good.

[AJ1L]

Just wait until some hotel, school, etc in the same town also gets licensed on the same freq…

[TheCoolMatrix]

There shouldn't be a need for a new frequency. Especially if they have the 482.6625 infrastructure (filters, antennas) in place. Unsure why the change from the T Band to biz band frequency.

I suspect the plan to switch to channel 2 , is because channel 2 isn't changing, they will use that while everything gets switched.

The whole thing is unusual, all the way down to the somewhat unusual NAC as well.

After reviewing their FCC license for 482.6625 and the speculated 451.2750 frequency, it appears that they may be upgrading 482.6625, as the P25 emission designators appear on that license, whereas the 451.275 has DMR emission designators. I know that there are departments that don't have the proper emission designators, but it may be a clue.

[AJ1L]

First test transmissions have been heard on 451.275 NAC 73B

[Lynskey 85]

Moved to the Southeastern Mass Forum.

The towns who have an NAC of 270 have Industrial Communications as their radio vendor.
Cybercomm and All Comm use the city exchanges for theirs.
Other vendors will use random codes or have some sort of internal codes.
Marcus Communications typically has letters in their NAC codes. (i.e. 1AD, etc)

You could also do what I did...

PL94.8 became a NAC of 094
DPL 371 a NAC of 371
PL 100.0 a NAC of 100 (two channels)
PL179.9 a NAC of 179
PL 127.3 a NAC of 127

Why you ask? Why not. Local radio techs and shops have likely memorized the PL/DPL as they have been place for 20+ years so figured I'd make it easy to remember.

[Mark SNE Moderator]

Confirmed just now:

Kingston PD on 482.4625 NAC270.

[W1KNE]

You could also do what I did...

PL94.8 became a NAC of 094

I've seen this in other areas too.

I've also seen call sign numbers become NAC codes. (i.e. WNPQ629 has a NAC of "629").

Around here, of course we have some common ones like 270 or city exchanges.

[W1KNE]

Confirmed just now:

Kingston PD on 482.4625 NAC270.

I caught this as well here.

[Mark SNE Moderator]

Tonight I have not heard a peep from Plymouth PD on their "Channel 2", 482.8375. I have it set to search CTCSS/DCS but have not heard anything. Won't matter by tomorrow.

[W1KNE]

Tonight I have not heard a peep from Plymouth PD on their "Channel 2", 482.8375. I have it set to search CTCSS/DCS but have not heard anything. Won't matter by tomorrow.

Repeater failure overnight. They switched to BAPERN S/E for the time being.

[Scott]

Watching 451.275 with my IC-R8600. I've seen a few key-ups this morning but no voice. As confirmed already NAC showing as 73B. It is interesting that it is right next door to some pretty strong Eversource DMR signals.

[Mark SNE Moderator]

Hearing Plymouth PD now on 451.275 NAC 73B. P-25 sounds kind of garbled from my location.

[Scott]

My $2300 Icom IC-R8600 is not receiving P25 from this system. However, I have a signal that is more than adequate for decoding. My center tuning is spot-on. Even in analog mode I'm not hearing digital noise. I am however seeing the 8600's pop-up window display the NAC, talkgroup (1), and radio ID's.

Additionally, I have better, yet very poor, decoding using my SDS200 and Airspy running FMPA. I've tried attenuation as well. First thought was that they are off-frequency somehow but I trust the center tuning of the 8600 impeccably. Very unusual.

[Mark SNE Moderator]

Kingston was coming in well here last night, they are quiet so far tonight. Plymouth is there, but it's a somewhat garbled audio sound. I should hear them without issue from here, probably even better now that they are P-25.

[Scott]

It's not a signal strength issue to be certain. I tuned in 100 kHz steps to either side of 451.275 and started getting a little decode at 451.274 on the 8600. With the 8600 it is surely not an issue of adjacent channel interference as this receiver has incredible performance in that regard.