XTS5000 and narrowband

[dasuriano]

My agency finally decided to narrowband last week and I've noticed a definite drop in range and quality. I've also noticed that several local agencies are all silent even though the frequency and PL is correct, unless I program my radio to RX CSQ. And my QCII tones no longer alert, and they are the correct tones. I am wondering if since everything has narrowbanded, if my radio needs to be retuned to work properly on narrowband or is this how things are going to be now?

[MTS2000des]

IF the radio is tuned and aligned, it should work just as good on 2.5 as it did on wideband. This is ASSUMING the system is running correct narrow deviation, PL deviation adjusted accordingly. The XTS2500/5000/XTL's are VERY sensitive to tolerances, and will reject off freq carriers or overdriven PL/DPL tones on an RX carrier. I've seen this myself.

I know of one VHF conventional user in middle GA who, after narrowbanding, no XTS radio or APX would properly RX. Turned out the dealer who narrowbanded never bothered to do proper alignment on the repeater/base stations on narrowband, and just changed the b/w settings in the programming software. After looking at the carriers on a service monitor, they were way off frequency by almost 200Hz and PL deviation was way overdriven. Lower quality radios didn't seem to mind, but higher tier ones did.

[Bill_G]

200hz is not that far off. Shoulda worked. But, overall that is my experience as well. The system worked. Techs roll through with laptops narrowbanding everything. System quit working as well as it had. Now, the pressure is on to do five years of maintenance catch-up in just a few days. Usually the deviation is too high so it sounds crunchy in a receiver. But, we ferret out the bad spkr mics, bad antennas, and all the usual suspects until it gets dialed in again. In other words - it didn't really work well before. Oy vey.

[SteveC0625]

200hz is not that far off. Shoulda worked. But, overall that is my experience as well. The system worked. Techs roll through with laptops narrowbanding everything. System quit working as well as it had. Now, the pressure is on to do five years of maintenance catch-up in just a few days. Usually the deviation is too high so it sounds crunchy in a receiver. But, we ferret out the bad spkr mics, bad antennas, and all the usual suspects until it gets dialed in again. In other words - it didn't really work well before. Oy vey.

We are bumping into the exact same issues here. I sat in on a conversation with the county EMA (who controls all the county's radios) and I presented these exact issues to him. And I made the point that until he could assure us that the repeater that serves our area is 100% within NB spec, I will not start sending my agency's gear out for alignment. Please note that all of our equipment is less than two years old with the exception of the CDM1550's in the ambulance which are working OK so far anyway.

[Bill_G]

200hz is not that far off. Shoulda worked. But, overall that is my experience as well. The system worked. Techs roll through with laptops narrowbanding everything. System quit working as well as it had. Now, the pressure is on to do five years of maintenance catch-up in just a few days. Usually the deviation is too high so it sounds crunchy in a receiver. But, we ferret out the bad spkr mics, bad antennas, and all the usual suspects until it gets dialed in again. In other words - it didn't really work well before. Oy vey.

We are bumping into the exact same issues here. I sat in on a conversation with the county EMA (who controls all the county's radios) and I presented these exact issues to him. And I made the point that until he could assure us that the repeater that serves our area is 100% within NB spec, I will not start sending my agency's gear out for alignment. Please note that all of our equipment is less than two years old with the exception of the CDM1550's in the ambulance which are working OK so far anyway.

Are you having audio quality issues after a county wide effort to NB, or are you guys preparing for the process?

I'm of the opinion it is best to do the base stations and repeaters first. The date is announced. I NB the transmitters, but where possible I leave the receiver WB so that overall quality remains the same. They get the full tech treatment to find problems before we move forward. Then, after all the fleets are touched, and we have a reasonable assurance that everything is still working like it is supposed to, then I touch the base and rptrs again to NB their rcvrs. That's when we find the individual radios that need a little TLC. We'll have one or two radios that don't receive well with reduced PL, and a handful that need their mic gain / dev touched. But, overall it is a painless and transparent process.

[dasuriano]

Same here. We have CDM1250s and HT1250s at work. This is my personal radio that I am having issues with. All the work radios work fine, just had to be repogrammed to NFM, but no other noticable differences. My XTS still has better Rx than the HT1250s, but doesn't unmute unless the NFM channels are set for CSQ. And I've noticed it only is a few of them, so it could very well be the systems having the issues rather than my radio.

[SteveC0625]

Are you having audio quality issues after a county wide effort to NB, or are you guys preparing for the process?

I'm of the opinion it is best to do the base stations and repeaters first. The date is announced. I NB the transmitters, but where possible I leave the receiver WB so that overall quality remains the same. They get the full tech treatment to find problems before we move forward. Then, after all the fleets are touched, and we have a reasonable assurance that everything is still working like it is supposed to, then I touch the base and rptrs again to NB their rcvrs. That's when we find the individual radios that need a little TLC. We'll have one or two radios that don't receive well with reduced PL, and a handful that need their mic gain / dev touched. But, overall it is a painless and transparent process.

The issues are hit and miss complicated by the fact that dispatch has to manually select which transmitter site they use to talk with the various agencies. Some dispatchers use the right towers, some don't. They don't work for EMA which complicates the whole mess. When we get what sounds like a crappy dispatch, we can't know for sure if it's the radio or the short between the headphones that's the cause.

We're theoretically done with the initial narrowbanding process and now are looking at the results. EMS here is a unique situation as there's no clear management like there is for fire and law enforcement radio systems. The powers that be will take all the credit when things go right, but they're the first to say "Not my job!" when there's a problem.

We didn't have any control over the NB process for the repeaters and base stations. The county did it without even informing us of the plan or the schedule. I tried for two years to get them to get everyone to the table and work out a plan so we'd all be on the same page. But that was a no go. Instead we got a phone call saying, "Oh, by the way, we narrowbanded everything last week."

When I started converting our portables and mobiles, I found a couple that initially would not access our primary EMS repeater. That's when my Chief and I sent an email to the EMA outlining our concerns and requesting that the tech go back to the repeater and check all the deviations, power, on freq, etc. before we'd start sending our gear into the shop. We're waiting for that to happen now.

I did find one or two programming errors so the number of radios that might need to go to the shop is down to one. FWIW, I have a mouse for my PC that has a roller between the left and right buttons, and if I accidentally touch that when setting a PL frequency, the freq can change without me seeing that it happened. I am learning to be very precise about tabbing out of the PL or DPL freq fields before going on to the next personality.

[Bill_G]

That is truly unfortunate Steve.

[dasuriano]

Just an update on the situation. The techs were out on the tower yesterday. Seems the problem might have been the fact that they decided to narrowband all the field radios but never thought to narrowband the towers. True geniuses at work there. I have to change around a few settings in my radio again, but I am hoping that that fixed the problems I was having with PL tones. I am still having issues with QCII tones decoding. I have maybe 7 or 8 sets of tones in my radio, all on different channels, yet since the agencies all switched over to NFM, none of the tones work properly. If it was one agency, I would say that the issue was on them, but the fact that none of them will alert leads me to believe I have something wrong on my end. Before the NFM switch, the tones could be covered in static, yet the radio would still alert. Now, when I can hear the tones going off fully, with no static at all, the radio will not alert at all. The main channel that I use the pager function on is a CSQ channel too, so I know that PL is not an issue there. I really want to get this fixed, since I use the radio as a pager as well. Anyone have any thoughts?

[AEC]

Just an update on the situation. The techs were out on the tower yesterday. Seems the problem might have been the fact that they decided to narrowband all the field radios but never thought to narrowband the towers. True geniuses at work there. I have to change around a few settings in my radio again, but I am hoping that that fixed the problems I was having with PL tones. I am still having issues with QCII tones decoding. I have maybe 7 or 8 sets of tones in my radio, all on different channels, yet since the agencies all switched over to NFM, none of the tones work properly. If it was one agency, I would say that the issue was on them, but the fact that none of them will alert leads me to believe I have something wrong on my end. Before the NFM switch, the tones could be covered in static, yet the radio would still alert. Now, when I can hear the tones going off fully, with no static at all, the radio will not alert at all. The main channel that I use the pager function on is a CSQ channel too, so I know that PL is not an issue there. I really want to get this fixed, since I use the radio as a pager as well. Anyone have any thoughts?

Check out the lag time from transmit to receive. QCII tones that are activated on transmit should have a pre time so the transmitters have time to stabilize before sending a QCII tone.
I had the same problem with decoding QCII when my Transmit signal would start, the QCII tone pair began at the same time, causing reception issues by not decoding the tones. Once I inserted a wait time(pretime) I decode the tones, the receivers unaquelch and the world is fine once more.

Poor signal areas can wreak havoc with any tone signaling system. You get shadows, multipath and worse. Time of arrival creates interference to your own tone signaling, making your receivers deaf.

If you have a short string, such as A, long B, and you are in an area with severe multipath, you can end up with two A long B strings and a receiver that can not handle this and decide which is legit and which isn't. Either the receiver opens, or it remains quiet. Low signal levels will also cause issues, strong beginning tone sequence, and last one weak, weak enough to not be heard or decoded. Like going from +90dBm, to -120 dBm in a microsecond. Very strong to ultra weak. No receiver is built to work with such differing levels and perform properly.

Given that even a NB system still has a bandwidth that can 'hear' midband signals, an error of 200 Hz. should never be a problem. You might also check the squelch alignment, or the squelch adders just to be certain.

Adjust your service monitor to transmit your tone sequence to the affected receivers, note the level at which they always activate, as well as the level they should activate.
The degradation may be in the receivers, 2nd oscillators, or even the I.F stages.