TRBO on Hold

[RCS2-way]

When will the 90 day hold on licenses over 10 watts for Trbo expire? Has a docket been filed with the FCC to extend? Is Motorola looking for a fix. There is a lot of interference a lot of investment and a lot of short tempers in the Public Safety Arena. Two Motorola Service Reps have told me that Trbo was never designed to be a Public Safety System. Has anyone else heard this?

 

[inigo88]

I assume you're talking about this? http://www.info4u.us/PSCC Letter.pdf

TRBO is based on a European digital standard called DMR, which was designed exclusively for BUSINESS users. It was NEVER intended for use by public safety, but Motorola has irresponsibly sold these systems to public safety users (no doubt championing the features like two TDMA voice slots per frequency, text messaging or GPS AVL - all directed at a business audience). These users are now at a severe disadvantage because TRBO is NOT interoperable in disasters and emergencies where these agencies might require outside mutual aid assistance, and last I checked as far as Homeland Security is concerned P25 (Phase I or II) is still the only accepted public safety digital interoperability standard.

 

[mmckenna]

MotoTrbo radios will interoperate just fine with other radios on analog. The government insisting that everyone use P25 is a waste of money. Analog, the original interoperability mode!

Too bad about MotoTrbo, we did a trial with it at work and it sounded pretty good. Ended up choosing Kenwood NexEdge for a few different reasons. Glad we did now.
Public Safety or not, this interferes with business band stuff as well. It's just a lot more critical when public safety is involved. Not sure why Motorola didn't figure this out before.

 

[inigo88]

How exactly is it interfering? Just users on the same frequency (due to the TDMA frame false triggering the CTCSS code) or adjacent ones as well? I've been chasing a few TRBO repeaters in the 409 MHz - 413 MHz Federal range, which may simply be harmonics of something down in VHF, or intermod from something nearby. This may be bad news for UCSD, which chose to put all non-public safety users on a campus-wide MotoTRBO Capacity Plus trunking system last year. However with so many users having already made the switch to TRBO I believe it has become "too big to fail" and Motorola will likely just throw money at the FCC until they decide to de-legalize CTCSS tones or something similarly ridiculous.

 

[16b]

How exactly is it interfering?

The primary issue is that, as the letter indicates, many TRBO repeaters that have been implemented are operating at close to 100% duty cycle, whereas the analog systems they replaced were closer to 10%. As far as I know, this is due to the use of GPS location services on the channel, where the radios automatically transmit their GPS coordinates at regular intervals. With enough radios on the channel, this could cause the repeater to stay keyed most of the time. An easy way to mitigate the issue would be to tell shared-frequency users to stop using GPS location services, but of course that would cause those users to lose an important feature of their new radio system.

As far as the CTCSS thing goes, I guess I'm not sure why that's even a concern of the FCC. They don't license CTCSS tones.

 

[N2ICV]

As far as the CTCSS thing goes, I guess I'm not sure why that's even a concern of the FCC. They don't license CTCSS tones.

Dont give them any ideas

 

[RCS2-way]

Thanks for the response. We also opted for NEXEDGE but have customers suffering the results of the interference. They are all analog customers and the interference seems to really get out there, much more than a coverage map would show. We have also had reports that MotoTrbo looses existing range when installed. This seems counter-intutive but that what several users have said after purchasing Trbo from different vendors. Could it be that they are still using analog?

 

[srftr]

Trbo was and is not designed for public safety.... the main reason for P25.

 

[wuzafuzz]

MotoTrbo radios will interoperate just fine with other radios on analog. The government insisting that everyone use P25 is a waste of money. Analog, the original interoperability mode!

Not only that, but I'd wager that gateways can make DMR / TRBO talk to P25 just fine. I know the Denver CO area has gateways that bridge P25 and EDACS users. It's doable with $$!

 

[JRayfield]

If a user loses range when moving from analog FM to MOTOTRBO, then something has been done wrong in the 'setup' of the MOTOTRBO system. Consistently, MOTOTRBO has provided considerably more range than analog FM, when all other factors (antennas, power output, etc.) are equal.

John Rayfield, Jr. CETma

Thanks for the response. We also opted for NEXEDGE but have customers suffering the results of the interference. They are all analog customers and the interference seems to really get out there, much more than a coverage map would show. We have also had reports that MotoTrbo looses existing range when installed. This seems counter-intutive but that what several users have said after purchasing Trbo from different vendors. Could it be that they are still using analog?

 

[JRayfield]

So, you list out TDMA, GPS AVL, and text messaging as being "directed at a business audience". Interesting, since P25 Phase 2 is also 2-slot TDMA, and offers GPS/AVL and other data services just like MOTOTRBO. Oh, I guess that must mean that P25 Phase 2 is "directed at a business audience", too.

Yes, you're correct, the U.S. Office of Homeland Security considers P25 (Phase 1 or Phase 2) as the only "public safety interoperable digital standard". Of course, they fail to point out that P25 conventional is not 'interoperable' with P25 trunking, without some kind of 'gateway' interface between the two 'systems'. And I thought they knew everything about communications.

John Rayfield, Jr. CETma

I assume you're talking about this? http://www.info4u.us/PSCC Letter.pdf

TRBO is based on a European digital standard called DMR, which was designed exclusively for BUSINESS users. It was NEVER intended for use by public safety, but Motorola has irresponsibly sold these systems to public safety users (no doubt championing the features like two TDMA voice slots per frequency, text messaging or GPS AVL - all directed at a business audience). These users are now at a severe disadvantage because TRBO is NOT interoperable in disasters and emergencies where these agencies might require outside mutual aid assistance, and last I checked as far as Homeland Security is concerned P25 (Phase I or II) is still the only accepted public safety digital interoperability standard.

 

[JRayfield]

You're 100% correct, and it's doable with not a lot of money, either. I know - I sell one of them.

John Rayfield, Jr. CETma

Not only that, but I'd wager that gateways can make DMR / TRBO talk to P25 just fine. I know the Denver CO area has gateways that bridge P25 and EDACS users. It's doable with $$!

 

[JRayfield]

You're correct about the GPS being part of the problem. This is made worse when a system is set up with units transmitting their GPS data too often, and when the 'hang time' on the repeaters are too long.

Those who are 'against' MOTOTRBO (especially for public safety) will, of course, latch on to something like this and use it to try to 'backup' their opinion of MOTOTRBO. But, such ones aren't thinking about the fact that if an analog FM system was setup with GPS/AVL (such as that sold by Pyramid Communications) and it was configured the same as these 'interfering' MOTOTRBO systems, there would be nearly, if not just, as much interference from them as from the MOTOTRBO systems. Shared channels are just that - shared - and users can't 'monopolize' a shared channel, no matter what type of system it is that they're using.

As to interference with 'falsing' CTCSS.... I had to change a customer's CTCSS to a different tone, not too long ago, because I happened to choose the 'wrong' tone - the same tone as a user only about 45 miles away. Hearing other stations that have the same PL tone, in the VHF public safety band, has been a 'problem' for a long time now, and just keeps getting worse. The problem with 'falsing CTCSS' from MOTOTRBO, is that the user doesn't hear voice - they hear the digital signal, which can be quite 'irritating' to listen to, as compared to hearing voice.

John Rayfield, Jr. CETma

The primary issue is that, as the letter indicates, many TRBO repeaters that have been implemented are operating at close to 100% duty cycle, whereas the analog systems they replaced were closer to 10%. As far as I know, this is due to the use of GPS location services on the channel, where the radios automatically transmit their GPS coordinates at regular intervals. With enough radios on the channel, this could cause the repeater to stay keyed most of the time. An easy way to mitigate the issue would be to tell shared-frequency users to stop using GPS location services, but of course that would cause those users to lose an important feature of their new radio system.

As far as the CTCSS thing goes, I guess I'm not sure why that's even a concern of the FCC. They don't license CTCSS tones.

 

[inigo88]

Besides the GPS/AVL data, another thing to consider is that the TRBO trunking variants are not very efficient with their use of frequencies and generate a lot of data as well. If you elect to purchase Connect Plus you'll need a dedicated control channel frequency which will be active 100% of the time. On the other hand, Capacity Plus has no dedicated control channel and operates similar to an LTR system. With Capacity Plus, idle radios are constantly told by the system to switch to the "rest channel" (usually identifiable by a 3 second beacon data burst), which dynamically shifts between all the system frequencies every time the current rest channel goes in use with voice traffic. In addition to the current channel, the system often sends out reminder data messages on the other frequencies to tell radios the current voice call activity LCNs and the current LCN for the rest channel for any other idle radios that have yet to move there.

What this translates to, to the layperson with a scanner, is a digital radio system that makes an awful lot of noise while nobody is talking.

(Compared with say, an old LTR system which could accomplish the same features with a voice channel on one talkgroup and Kenwood Fleetsync GPS/AVL data on another.)

 

[jparks29]

Dont give them any ideas

Related (and unrelated) story about CTCSS..

Ericsson/Ma/Com/Harris engineers.......heh....

In making some of the recent portables and mobiles, they needed to cut down on some space, and remove features that were deemed to be no longer needed, in order to create space for more advanced programming capabilities and remove potential conflicts...

So they said... T99 (two tone decode), ChannelGuard (PL/CTCSS), Mon (disable squelch), and 'scan' were on the chopping block..

It took a few guys to lean into the engineers for them to realize that the engineers didn't know WTF they were talking about, because all they were focusing on was digital, completely ignoring the fact that you NEED CTCSS, two tone, etc etc for analog ops. and who needs to 'scan' channels? They can just put the knob on the channel they want!.....

L O L

 

[62Truck]

I think Trbo needs some tweaking. I use Trbo where I work and every so often we will miss a "call" some one will call on the radio and one radio will hear and the other one wont and when it starts you only get the tail end of what was said. It happens all the time I go to call in to dispatch and they'll answer but all I will get is hiss sometimes, and when they do come through you can hear the pulsing, which sounds to me the vendor never installed the radio in the dispatch console right.

 

[PACNWDude]

MotoTrbo has worked well for me.

Where I work, we have many tree covered hills and need to communicate from ships within 20 miles of land and shore based locations spread around three states. We replaced older Motorola MSF5000 repeater with XPR8400's and kept our range. We have seen no decrease in range, and the audio is a lot better. This is in analog only mode, using the same antennas and feed-line as before. However, unlike many places, we use UHF repeaters as most everyone else uses VHF. I hear a lot of complaints about VHF interference, and have yet to experience it as well. We also do not use GPS.
The push for MotoTrbo was due to Motorola ending support for CDM mobiles and several models of handheld radios we were using.

 

[rapidcharger]

As to interference with 'falsing' CTCSS.... I had to change a customer's CTCSS to a different tone, not too long ago, because I happened to choose the 'wrong' tone - the same tone as a user only about 45 miles away.

I'm getting falsing on a radio using DPL.
I know that must sound impossible but its happening.

Have you heard of that happening with dpl before?

 

[TampaTyron]

I have it here in Tampa (falsing on DPL). I have had to migrate several customers away from TRBO users. It stinks when a users has been on the channel a long time, then get a TRBO user coordinated over the top of them. However, it turns out a low power Connect Plus control channel on their frequency kills the offending TRBO batteries very quickly due to the portable radio consuming battery power to determine if it should open squelch. Even faster if it is on the same color code....... TT

 

[12dbsinad]

I'm getting falsing on a radio using DPL.
I know that must sound impossible but its happening.

Have you heard of that happening with dpl before?

I've had to change many PL's due to falsing. I haven't run across DPL doing it however. Usually DPL is what the user will go to to avoid falsing.

More and more of interference service calls are from new TRBO systems either on freq or adjacent channel. I've noted a lot of them with VERY spurious transmitters, which makes things even worse. When I look at the spectrum analyzer it reminds me of those cheap SCADA radios that put out more garbage than one would like to imagine. It amazes me how they obtained FCC certification. I always enjoy stories my dad tells me about how low the noise floor was back in the early 70's