Motorola M1225 Narrow Band

[KB3WIR]

My Dad has a Motorola M1225 in his truck with receive chester county high band pager frequencies in it and his ham frequencies in it. Chester county went to narrow band about a month ago now and we got our new Minitor 5 pagers. I reprogrammed the 1225 for narrow band and ever since the radio sounds like absolute crap, it's all gargled and I've tried everything to see if it would help. When I put my pager on the fire operations channel and the radio on the same channel my pager is as clear as day and the radio sounds like junk. If anyone can help me or can give me any input it would be greatly appreciated!

[W2NJS]

Are you aware that there is no FCC requirement for pagers to go narrowband? Might it be that they did not narrowband your paging channel?

[KB3WIR]

I was told that it was, the radio has the same frequency's as the pager. I've been super busy and haven't had a chance to read my pager on the programmer to see if it is set for narrow band to narrow that down.

[Wyandotte]

I agree with NJS. The paging freq isn't narrowband. Set it back to wideband, should be all set.

[FFPM571]

Check to make sure the Xpand setting in the CPS is set to off..

[jim202]

Originally Posted by W2NJS

Are you aware that there is no FCC requirement for pagers to go narrowband? Might it be that they did not narrowband your paging channel?

There might be some confusion on the way you worded this. Let me see if I can lend a little more clarity here. A receiver has no requirement to be narrow banded. As such a pager does not need to be changed. However, if the transmitter being used to send the paging signal is narrow banded, then the recovered audio on the pager will be low.

There is a possibility that the transmitter has not been narrow banded yet and that is why the M1225 set to the narrow band mode sounds like crap. The modulation from the transmitter is too wide for the receiver in the narrow band mode and is clipping, breaking up and what ever else you want to call it. A receiver set to narrow band mode trying to listen to wide mode modulation isn't going to sound very nice.

Unless you know for a fact the transmitter has been set to narrow band, I would leave the M1225 in the wide band mode till the word comes out from the department.

[Mtnrider]

Out of boredom i did a quick look at the FCC info for 160.185 Chester voice pagers NO PL at this time license has 3 emissions it can use 11K3F1D,11K3F3E,20K0F3E For 3 bases and 1560 mobiles.....so at this time yeah it all could be half done...so what jim202 said....turn it back and wait...

[Pat]

Just FYI we have several M1225s that we use for control stations at our county dispatch center and after our system was switched to narrowband a couple of them had really poor audio on receive. It turned out that for whatever reason the radios drifted off frequency quite a bit after reprogramming and needed to be realigned. I'm not sure why it only affected a few of the radios and not all of them though.

Pat

[jeatock]

The problem with the FCC database is that it sometimes reflects a fantasy world. License holders will have narrowband emissions modified on their licence, but may not have actually reprogrammed their equipment (or are keeping their wideband equipment and don't plan on doing so, hoping that nobody will notice).

There are four ways to tell for sure:
-read the codeplug from the transmitter and look at both the channel width and transmitter alignment (not a likely possibility)
-look at the transmitter's output with a spectrum analyzer (Easy if you have one, but expensive to get. That is what the FCC - it's only taxpayer dollars - will possibly start doing as they drive around.)
-use a receiver that shows audio deviation: 3~4 KHz is wide, less than 2 is probably narrow. (Not foolproof, but easier to do.)
-change back to wide on that channel and see if that fixes things- just don't transmit wide after the first of the year!