Rebanding has begun on Motorola trunked systems

[loumaag]

The city of Opelika, Al. just went thru a rebanding last week. Can anyone tell me the best way to find the new frequencies? I am hearing that they moved to the 900Mhz range. Any help would be greatly appreciated.

Rebanding has nothing to do with 900 MHz or 700 MHz. Check the license issued to the entitiy on the FCC site for the old system, get the FRN and then re-search using the FRN as the search argument; review the results.

 

[Steve]

No rebanding activity showing at the FCC website (using Opelika's FRN).
Yesterday and earlier today, I did hear Opelika "control channels" and they were the same frequencies as before. Only 2 systems in Alabama that have rebanded so for are Albertville and Tallapoosa County (that I know of). And only Albertville is active. Tallapoosa County's is currently operating on 1 frequency (with beeping in the background).
kennethj215 contact me by PM or e-mail (tayl91@bellsouth.net) and maybe we figure out what has happen (if you would like to).

Steve
KD4LCY
KAF9087

 

[DonS]

*EDACS and OpenSky are M/A Com proprietary 9600 bps control channel trunking products.

Except when they're not (i.e. "narrowband EDACS", which has a 4800 bps control channel).

Although, you are technically correct, pointing out that APCO 25 has a 9600bps symbol rate, but only effectively uses 4800 bits of data because it is a 4-level signal

It has a 9600 bps (bits per second) data rate. The symbol rate ("baud") is 4800. 4800 symbols per second at 2 bits per symbol (4-level) = 9600 bits per second.

 

[AlanTilles]

You are missing the whole issue. The Colorado system is a true P25 system so tracking is not an issue. It is the analog or mix-mode systems that will require firmware updates. That is really what this thread is about. True P25 systems will track without any radio changes.

Actually, as counsel to the State of Colorado for rebanding, I'm not missing anything at all (except to the extent that my teenaged daughter tells me that I'm not hip anymore). This thread was titled " Rebanding has begun on Motorola trunked systems," with the first post saying "at least two systems have been discovered to be using newly rebanded frequencies and no longer are being trunk scanned correctly using the current trunking scanners." I reported that other licensees had indeed begun using their new frequencies, and that included the State of Colorado (although Colorado won't be finished until June). And, in Colorado's case, every one of their more than 28,000 radios did indeed need to be "touched" at least once for a software upgrade.

 

[loumaag]

Actually, as counsel to the State of Colorado for rebanding, I'm not missing anything at all (except to the extent that my teenaged daughter tells me that I'm not hip anymore). This thread was titled " Rebanding has begun on Motorola trunked systems," with the first post saying "at least two systems have been discovered to be using newly rebanded frequencies and no longer are being trunk scanned correctly using the current trunking scanners." I reported that other licensees had indeed begun using their new frequencies, and that included the State of Colorado (although Colorado won't be finished until June). And, in Colorado's case, every one of their more than 28,000 radios did indeed need to be "touched" at least once for a software upgrade.

Alan,

I think the point that was trying to be made is that this thread is about Motorola systems; the state of Colorado's statewide system is not a Motorola system, it is a Project 25 system. They are not the same thing and don't suffer from the same rebanding problems. Any software upgrade that may have been necessary for any radio used on the CO system had nothing to do with the CO system itself.

 

[WayneH]

Alan,

I think the point that was trying to be made is that this thread is about Motorola systems; the state of Colorado's statewide system is not a Motorola system, it is a Project 25 system.

Exactly. Any trunking topics in this forum are specifically for 3600 systems using the old Type I and II signaling formats. APCO-25 Trunking (i.e., 9600 bps CC rate) systems have their own forum.

The specific reason for this thread was to highlight the change in format for frequency/channel identifier codes used over the 3600 control channel. Nothing is changing for 9600 systems.

Hopefully that clears things up.

 

[AlanTilles]

Alan,

I think the point that was trying to be made is that this thread is about Motorola systems; the state of Colorado's statewide system is not a Motorola system, it is a Project 25 system. They are not the same thing and don't suffer from the same rebanding problems. Any software upgrade that may have been necessary for any radio used on the CO system had nothing to do with the CO system itself.

OK, now you've really got me confused. The system is indeed manufactured by Motorola. Now, if you mean that its not a "simple" Smartnet or Smartzone system, ok I can buy that. However, your statement that they "don't suffer from the same rebanding problems," you lose me. Perhaps you can elaborate on what a rebanding "problems" that a Smartzone or Smartnet (or LTR for that matter) radio suffers, that a P25 radio does not.

Alan

 

[UPMan]

He is referring to the effect on scanners that rebanding has. P25 systems (regardless of manufacturer) do not require any changes to the control channel handling method, so all P25 capable scanners work the same on rebanded or non-rebanded systems (except for the change in frequencies).

Motorola "proprietary" systems (i.e. not P25 systems built by Motorola, but rather Motorolas systems that conform to their own 3600 bps control channel protocol) will not work on most trunked scanners post-rebanding. Some scanners will require a firmware update, if possible, to track such systems after they reband.

 

[AlanTilles]

OK, now you've really got me confused. The system is indeed manufactured by Motorola. Now, if you mean that its not a "simple" Smartnet or Smartzone system, ok I can buy that. However, your statement that they "don't suffer from the same rebanding problems," you lose me. Perhaps you can elaborate on what a rebanding "problems" that a Smartzone or Smartnet (or LTR for that matter) radio suffers, that a P25 radio does not.

Alan

OK, I wrote that before I saw Wayne's post, which I guess answers the question. In either event, I can go back to my original post, there are over 100 systems that have completed their NPSPAC reband, and these systems include Motorola Smartzone and/or Smartnet systems.

Also, to answer the questions earlier on with regard to licensing, the status of licensing (old vs. new) doesn't always tell you where the licensee is in regard to its rebanding progress. To be specific, an application is not filed with the FCC until the licensee is ready to reband their infrastructure. So, if you see a license that only has old frequencies on it, that means: (1) the licensee has not reached an agreement with Nextel; or (2) the licensee has reached an agreement, and is in the process of flashing or replacing their subscriber units, and isn't ready for infrastructure work. If the license shows both old and new frequencies, the licensee: (1) is in the process of rebanding infrastructure; or (2) has completed their infrastructure rebanding, and hasn't gotten to the point in the process yet where a 2nd set of applications is filed to remove the old channels. In addition, please note that the licensee may utilize so-called "back-to-back" repeaters for the mutual aid channels, and will operate on both old and new channels, for quite a period of time (perhaps over a year), until other area licensees who the first licensee has interoperability with has completed their retune(s).

Hope that was understandable.

Alan

 

[DonS]

To add to the confusion...

He is referring to the effect on scanners that rebanding has. P25 systems (regardless of manufacturer) do not require any changes to the control channel handling method, so all P25 capable scanners work the same on rebanded or non-rebanded systems (except for the change in frequencies).

Not all P25-capable scanners. Those that handle the P25 CC messages that contain channel->frequency mapping (i.e. the IDEN_UP message) will require only a modification to the CC frequencies (e.g. PSR-500/600, some Unidens); those that don't handle IDEN_UP will require some additional form of user re-programming (e.g. the "tables" on a PRO-96).

Motorola "proprietary" systems (i.e. not P25 systems built by Motorola, but rather Motorolas systems that conform to their own 3600 bps control channel protocol) will not work on most trunked scanners post-rebanding. Some scanners will require a firmware update, if possible, to track such systems after they reband.

For purposes of discussing "rebanding" on Mot 3600 systems, scanners probably fall into three rough categories: 1) those that cannot track a rebanded system at all (e.g. PRO-93, BC250D?), 2) those that might be updated via a "firmware" upgrade to handle rebanding (e.g. PSR-300, PRO-164, or BCD396T?), and 3) those that can handle rebanding via user re-programming of the channel->frequency tables (e.g. PRO-96, PSR-500).

 

[UPMan]

there are over 100 systems that have completed their NPSPAC reband, and these systems include Motorola Smartzone and/or Smartnet systems.

However, until just a few weeks ago, no public safety system had actually changed onto any of the "split" channels created by the new rebanded band plan. The "rebanded" licenses were made up of systems that were already operating on the lower channels (so needed no change to even their infrastructure...for example the city of Denton, TX shows as rebanded but nothing changed other than paperwork to get its YE (rebanded) status).

 

[AlanTilles]

However, until just a few weeks ago, no public safety system had actually changed onto any of the "split" channels created by the new rebanded band plan. The "rebanded" licenses were made up of systems that were already operating on the lower channels (so needed no change to even their infrastructure...for example the city of Denton, TX shows as rebanded but nothing changed other than paperwork to get its YE (rebanded) status).

I'm sorry, you have confused 800 MHz REBANDING with 150/450 MHz NARROWBANDING. There are NO "split" channels created in rebanding in the 800 MHz band. Rather, former General Category (851-854 MHz) licensees moved up into the interleaved band (854-860 MHz), and NPSPAC (866-869 MHz) moved exactly 15 MHz down to the 851-854 MHz band. Every licensee maintains their current occupied bandwidth.

In contrast, all 150/450 MHz radio systems must reduce their occupied bandwidth from 25 kHz to 12.5 kHz by 2013 (I have simplified the process for this purpose). That is narrowbanding.

While there are no "split" channels created by rebanding, there will be additional spectrum made available to public safety at the end of rebanding, by virtual of the excess interleaved channels (854-859 MHz) that Nextel vacates and are not needed for rebanding.

With regard to the City of Denton, their NPSPAC infrastructure has not been rebanded (meaning that they continue to operate on their old channels). As counsel to DFW Airport, I attended the Transition Administrator's Implementation Planning Session in Dallas in March for that region. According to the rebanding schedule that I have (which was developed at that session with input of all of the licensees), Denton has only now began touching their mobile units, and they expect to complete that first touch by December 2008. Because of Denton's dependencies on other area licensees to get their mobile units touched, Denton does not currently plan on rebanding its infrastructure until July 2010 (yes, 2010).

Alan Tilles

 

[loumaag]

I'm sorry, you have confused 800 MHz REBANDING with 150/450 MHz NARROWBANDING. There are NO "split" channels created in rebanding in the 800 MHz band. Rather, former General Category (851-854 MHz) licensees moved up into the interleaved band (854-860 MHz), and NPSPAC (866-869 MHz) moved exactly 15 MHz down to the 851-854 MHz band. Every licensee maintains their current occupied bandwidth.

In contrast, all 150/450 MHz radio systems must reduce their occupied bandwidth from 25 kHz to 12.5 kHz by 2013 (I have simplified the process for this purpose). That is narrowbanding.

While there are no "split" channels created by rebanding, there will be additional spectrum made available to public safety at the end of rebanding, by virtual of the excess interleaved channels (854-859 MHz) that Nextel vacates and are not needed for rebanding.

With regard to the City of Denton, their NPSPAC infrastructure has not been rebanded (meaning that they continue to operate on their old channels). As counsel to DFW Airport, I attended the Transition Administrator's Implementation Planning Session in Dallas in March for that region. According to the rebanding schedule that I have (which was developed at that session with input of all of the licensees), Denton has only now began touching their mobile units, and they expect to complete that first touch by December 2008. Because of Denton's dependencies on other area licensees to get their mobile units touched, Denton does not currently plan on rebanding its infrastructure until July 2010 (yes, 2010).

Alan Tilles

Alan,

Trust us, we do know what we are talking about. The entire rebanding problem for the scanner world is indeed the "new" channels formed due to the process the FCC/Nextel took to move the PS to the lower part of the band. Those channels did not exist in the "old" Motorola predefined channel lineups (the LCN's). No one is confusing rebanding with narrow banding of the VHF/UHF spectrum although it is related. You are coming to this "clam bake" pretty late and uninformed. Please read the fine explanation of what the problem is/was presented on our Wiki. Speaking of that Wiki article, would someone be so kind as to update the bottom on "Latest Updates" with the ones we have discovered and the LCN changes needed to continue to monitor. (How about it Wayne?)

 

[AlanTilles]

Alan,

Trust us, we do know what we are talking about. The entire rebanding problem for the scanner world is indeed the "new" channels formed due to the process the FCC/Nextel took to move the PS to the lower part of the band. Those channels did not exist in the "old" Motorola predefined channel lineups (the LCN's). No one is confusing rebanding with narrow banding of the VHF/UHF spectrum although it is related. You are coming to this "clam bake" pretty late and uninformed. Please read the fine explanation of what the problem is/was presented on our Wiki. Speaking of that Wiki article, would someone be so kind as to update the bottom on "Latest Updates" with the ones we have discovered and the LCN changes needed to continue to monitor. (How about it Wayne?)

OK, I'll sign off now. Kind of interesting, as the person who helped write the rebanding rules, and representing a couple of hundred licensees in rebanding, first time that anyone's ever told me that I was "uninformed". And, you might note that there are quite a number of licensees who have completed their reband who operate on what you are calling "new" channels.

Enjoy.

Alan Tilles

 

[loumaag]

OK, I'll sign off now. Kind of interesting, as the person who helped write the rebanding rules, and representing a couple of hundred licensees in rebanding, first time that anyone's ever told me that I was "uninformed". And, you might note that there are quite a number of licensees who have completed their reband who operate on what you are calling "new" channels.

Enjoy.

Alan Tilles

So Alan, if you wrote those rules (I suspect again you are talking about the DTRS and how to reassign frequencies) how come you don't know that the channel numbers are now only 12.5 KHz apart instead of the previous 25 KHz? (Once again referring to the analog channel plan.)

The DTRS in Colorado is not affected since the channel spacing on a P25 system is 6.25 KHz to begin with and has not changed with rebanding.

 

[WayneH]

Alan, what this thread about is how the underlying control of channel assignments has changed with these systems. You could have been involved with everything and would have never touched on how Motorola changed the internal code used by the control channel. It is not relevant to your involvement in the process. Motorola has not shared what they changed with scanner manufacturers hence why this is such a big deal.

Previously frequencies between 851.0125 and 854 were assigned in 25kHz increments; we know this. Therefore when Motorola designed the control channel freq assignments they basically went in sequential order following 25kHz spacing. Since rebanding changes the spacing to 12.5kHz Motorola had to reuse frequency channel assignments from somewhere else in the 800MHz band. The control channel does not follow FCC channel designations.

The customer, consultant, etc do not need to know this information. It does not concern them. Whomever programs the system's radios simply has to check that the system is a rebanded system and let the radio do the work. Our scanners are not the same; we needed to determine what has changed.

 

[AlanTilles]

So Alan, if you wrote those rules (I suspect again you are talking about the DTRS and how to reassign frequencies) how come you don't know that the channel numbers are now only 12.5 KHz apart instead of the previous 25 KHz? (Once again referring to the analog channel plan.)

The DTRS in Colorado is not affected since the channel spacing on a P25 system is 6.25 KHz to begin with and has not changed with rebanding.

Of course I know about channel assignments. That's the whole reason that Motorola had to re-write software (and M/A-Com didn't). In Motorola's system, frequencies were assigned by channel number, not frequency. Therefore, 851.0125 was Channel 1, 851.0375 was Channel 2. In the NPSPAC band, such channel numbers already corresponded to the fact that the NPSPAC frequencies are spaced every 12.5 kHz (even though the equipment is not narrowband, requiring geographic separation). Going forward, in the Motorola scheme, Channel 1 is still 851.0125, but Channel 2 will be 851.0250, which required software to be written for the new numbering scheme. Motorola radios which did not have enough memory for the new software, or where the code was so old no one was around that could still write it, will be replaced. Since M/A-Com radios don't use channel numbering, but instead use the actual frequency, there was no need to write new software for those radios (but some had to be replaced for other reasons).

Motorola radios bought after the band plan was re-written (about the past two years) already come with the new band plan (the software detects whether the site is "new" or "old" trunked frequencies, and adjusts accordingly). The very latest iteration of Motorola's P25 equipment (although not ALL of it) doesn't use the channel numbering scheme at all, from what I was told the other day.

With regard to your last comment, the mis-communication between us I see as two-fold: (1) I was referring to the FCC's Rules (where there are no 6.25 channels assigned), while you are referring to how the system allocates resources (by dividing channels by frequency in FDMA, time in TDMA, etc.); and (2) when the term "new" channels were used, I believed the reference to be to new, previously unused spectrum, and not to channel assignment schemes.

Alan Tilles

 

[AlanTilles]

Alan, what this thread about is how the underlying control of channel assignments has changed with these systems. You could have been involved with everything and would have never touched on how Motorola changed the internal code used by the control channel. It is not relevant to your involvement in the process. Motorola has not shared what they changed with scanner manufacturers hence why this is such a big deal.

Previously frequencies between 851.0125 and 854 were assigned in 25kHz increments; we know this. Therefore when Motorola designed the control channel freq assignments they basically went in sequential order following 25kHz spacing. Since rebanding changes the spacing to 12.5kHz Motorola had to reuse frequency channel assignments from somewhere else in the 800MHz band. The control channel does not follow FCC channel designations.

The customer, consultant, etc do not need to know this information. It does not concern them. Whomever programs the system's radios simply has to check that the system is a rebanded system and let the radio do the work. Our scanners are not the same; we needed to determine what has changed.

Actually, we do very much have to be involved with the control channel issue. Whether the control channel is being rebanded is one of the most important issues in a Motorola system, because it almost entirely determines the complexity of reband. A system where only one of the (typically four) control channels are being rebanded is much simpler for the user and vendor than one where all four are being rebanded. Thus, in some cases, where one of the four control channels was an Expansion Band channel (860 MHz), and the licensee had a choice whether to reband that channel or keep it, the licensee has elected to keep it. In other cases, the licensee has elected to keep it and, to keep the reband simpler, has agreed to go to only three control channels during the course of rebanding, and going back to four at the end of rebanding.

Alan Tilles

 

[DonS]

Of course I know about channel assignments. That's the whole reason that Motorola had to re-write software (and M/A-Com didn't). In Motorola's system, frequencies were assigned by channel number, not frequency. Therefore, 851.0125 was Channel 1, 851.0375 was Channel 2. In the NPSPAC band, such channel numbers already corresponded to the fact that the NPSPAC frequencies are spaced every 12.5 kHz (even though the equipment is not narrowband, requiring geographic separation). Going forward, in the Motorola scheme, Channel 1 is still 851.0125, but Channel 2 will be 851.0250

Not quite. Note that we, as scanner users, are always referring to Motorola's channel numbers, as they appear in the 3600 bps control channel messages. Any other channel numbering scheme (e.g. "channel 2 will be 851.0250") is irrelevant for our purposes, and discussing it only confuses things.

Motorola 3600 CCs send a 10-bit channel number that ranges from 0 to 1023, with some "holes" of unused channels.

Pre-rebanding, channels 0-719 are assigned to 851.0125 - 868.9875 on 25 kHz steps. To handle "rebanding", channels 440-559 are moved from 862.0125 down to 851.0250, still on 25 kHz steps, but now interleaved with channels 0-119 - for a resulting 12.5 kHz spacing.

The result is:
Channel 000: 851.0125
Channel 440: 851.0250
Channel 001: 851.0375
Channel 441: 851.0500
...

Or:
Channels 000-439: 851.0125 - 861.9875 on 25.000 kHz steps
Channels 440-559: 851.0250 - 854.0000 on 25.000 kHz steps
Channels 560-719: 865.0125 - 868.9875 on 25.000 kHz steps
Chanenls 720-759: 866.0000 - 866.9750 on 25.000 kHz steps
...

(Whether any given channel number is actually used on a rebanded system is also irrelevant for our purposes; all we're concerned with is the "shifting" of channels 440-559).

This behavior has been confirmed by people monitoring "rebanded" Mot 3600 systems. Using scanners that support it, people have "remapped" channels 440-559 in their scanners, changed the control channel frequencies if required, and the rebanded systems are monitorable again.

 

[AlanTilles]

Not quite. Note that we, as scanner users, are always referring to Motorola's channel numbers, as they appear in the 3600 bps control channel messages. Any other channel numbering scheme (e.g. "channel 2 will be 851.0250") is irrelevant for our purposes, and discussing it only confuses things.

Motorola 3600 CCs send a 10-bit channel number that ranges from 0 to 1023, with some "holes" of unused channels.

Pre-rebanding, channels 0-719 are assigned to 851.0125 - 868.9875 on 25 kHz steps. To handle "rebanding", channels 440-559 are moved from 862.0125 down to 851.0250, still on 25 kHz steps, but now interleaved with channels 0-119 - for a resulting 12.5 kHz spacing.

The result is:
Channel 000: 851.0125
Channel 440: 851.0250
Channel 001: 851.0375
Channel 441: 851.0500
...

Or:
Channels 000-439: 851.0125 - 861.9875 on 25.000 kHz steps
Channels 440-559: 851.0250 - 854.0000 on 25.000 kHz steps
Channels 560-719: 865.0125 - 868.9875 on 25.000 kHz steps
Chanenls 720-759: 866.0000 - 866.9750 on 25.000 kHz steps
...

(Whether any given channel number is actually used on a rebanded system is also irrelevant for our purposes; all we're concerned with is the "shifting" of channels 440-559).

This behavior has been confirmed by people monitoring "rebanded" Mot 3600 systems. Using scanners that support it, people have "remapped" channels 440-559 in their scanners, changed the control channel frequencies if required, and the rebanded systems are monitorable again.

There is on typo on what you wrote. 862.0125 does not move down to 851.0250. First, the 862 MHz band is the ESMR band, and does not move. I believe that you were referring to 866.0125, the first NPSPAC channel, which would indeed move down to the 851 MHz band. Second, the move down is 15 MHz directly, thus 866.0125 MHz would move down to 851.0125, not 0250. As I said, I assume that it was just a typo.

Alan