Rebanding: What will Motorola will do to their control channel
- Thread starter Tugboats
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FPO703
Member
Motorola won't do anything. Rebanding is just changing (re-programming) the repeaters.
902
Member
My impression is that the repeaters will be reprogrammed or re-crystalled (although most agenicies do not want to retain equipment that goes back to the crystal era because of "mileage"), combiners and filters need to be realigned, tables in the site controllers need to be changed - and much of that equipment in 70's - 90's vintage controllers has obsoleted, with the chip manufacturers no longer making much of the components.
The newer subscriber units got flashed with new firmware that allows 8 control channels and not 4. The four original CCHs and the new 4 CCHs 15 MHz lower. This allows for the system to be cut-over with minimal interruption and no additional reprogramming of subscriber units.
Many legacy subscriber units will not do 12.5 kHz channelspacing on the new NPSPAC range. The manufacturers were going to replace those with 'lite' versions of current equipment that may have masked capabilities - like an XTS-1500 with SP firmware that excludes 700 MHz (after all, you didn't PAY for that value-added feature).
800 rebanding has turned into a quagmire. Imagine if we were re-aligning VHF to 12.5 kHz channelspacing and setting standard inputs and outputs!
The newer subscriber units got flashed with new firmware that allows 8 control channels and not 4. The four original CCHs and the new 4 CCHs 15 MHz lower. This allows for the system to be cut-over with minimal interruption and no additional reprogramming of subscriber units.
Many legacy subscriber units will not do 12.5 kHz channelspacing on the new NPSPAC range. The manufacturers were going to replace those with 'lite' versions of current equipment that may have masked capabilities - like an XTS-1500 with SP firmware that excludes 700 MHz (after all, you didn't PAY for that value-added feature).
800 rebanding has turned into a quagmire. Imagine if we were re-aligning VHF to 12.5 kHz channelspacing and setting standard inputs and outputs!
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N_Jay
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The 15 MHz drop in Chanel assignments is ONLY for NPSPAC systems. Others can have different channel assignment changes.
MMIC
Member
The control channel will, in fact change. There will be an extra bit transmitted over the control channel once a site is rebanded to indicate to the portable and mobile radios that the site is using the rebanded channel plan. This will cause the radio to use the rebanded channel plan programmed into it when listening for channel assignments, hence allow the end user to have zero intervention when transitioning between rebanded and non-rebanded sites. This is particularily important in SmartZone systems where some sites may be rebanded, while others are not. The radio will be able to automatically adapt between the rebanded and non-rebanded sites because of that bit.
On a related note, there is a feature that Motorola is selling called the "shuffled band plan". This will allow system owners to use a non-standard and/or customized channel plan assignment on their system. So frequency 851.xxxx may have a hex value of 100 on the control channel per the "standard" plan, but they have the option to change that to be another arbitrary number with the shuffled band plan.
The shuffled band plan option is not a standard implementation on systems after rebanding, but Motorola is making a run on selling it to go with rebanding since all subscribers will be touched anyway. If a system is P-25, they will need to have 100% Motorola radios on the system to support the proprietary feature.
On a related note, there is a feature that Motorola is selling called the "shuffled band plan". This will allow system owners to use a non-standard and/or customized channel plan assignment on their system. So frequency 851.xxxx may have a hex value of 100 on the control channel per the "standard" plan, but they have the option to change that to be another arbitrary number with the shuffled band plan.
The shuffled band plan option is not a standard implementation on systems after rebanding, but Motorola is making a run on selling it to go with rebanding since all subscribers will be touched anyway. If a system is P-25, they will need to have 100% Motorola radios on the system to support the proprietary feature.
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DonS
Member
If it's a P25 control channel, won't the IDEN_UP messages take care of it? Wouldn't deviation from that part of the P25 'spec' make it a non-P25 system?MMIC said:
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N_Jay
Guest
car2back said:
The specification allows for proprietary extensions.
The buyer needs to make sure he is informed about the advantages and disadvantages of the options they select.
(Just like just about every system procurement):roll:
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N_Jay
Guest
DonS said:
No, because the P25 specification is designed to allow extensions and enhancements.
DonS
Member
Extensions and enhancements, yes, but something that defeats another part of the P25 specification? (Presuming IDEN_UP is actually required by the P25 spec).N_Jay said:
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N_Jay
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DonS said:
If you would phrase your question without your poor attempt at humor it might be understandable enough to answer.
DonS
Member
No attempt at humor was made.N_Jay said:
I'll rephrase, though:
Presumption 1: IDEN_UP with accurate information is required by the "P25 specification"
Presumption 2: Motorola plans on adding an "extension" or "enhancment" to their implementation of a P25 system, as permitted by the P25 specification.
Presumption 3: Motorola's extension/enhancment conflicts with the [presumed] required information in the IDEN_UP messages, based on the earlier post that said "If a system is P-25, they will need to have 100% Motorola radios on the system to support the proprietary feature" in regard to a "shuffled band plan".
Question: If all three presumptions are true, is a system with Motorola's extension/enhancement still a "P25 system", given that it no longer includes accurate information in the required IDEN_UP message?
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DonS
Member
It does appear that the IDEN_UP message, with accurate channel -> frequency mapping, is required. TIA/EIA-102.AABC-2000 Annex F.
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N_Jay
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DonS said:
I am fairly sure that "shuffled band plan" is only on Motorola (3600) control channels.
I misread your reference to the IDEN_UP command as an "iDENed Up" (as in F-cked Up) command. Sorry
Since it is 3600 bps only it has no impact on P25 systems or standards.
DonS
Member
I attempted to clarify that in my initial post (#7) on this thread, where I qualified my question with "If it's a P25 control channel". I was trying to determine what was meant by "P-25 system" in the statement "If a system is P-25, they will need to have 100% Motorola radios on the system to support the proprietary feature".N_Jay said:
902
Member
This seems to be a common thread with them, coming up with nice, proprietary "enhancements" that rob the standardization and competitive procurement element of P25 - like their "wide pulse" mode or ADP encryption.MMIC said:
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N_Jay
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902 said:
Or offer products to market to meet the needs.
Glass 1/2 full or 1/2 empty?
EDIT: Just to be clear, this entire branch of the thread is based on a mistaken statement about the shuffled band plan feature.
The only control channel changes are to occur on 3600 control channels. And there's more than just a bit to signify rebanding/retuning in the changes or additions. The channel plan for a partial range will be changed.
902
Member
I understand the discussion predicated on a misconstrued statement. My comment is about meeting needs, which probably deserves its own thread, but I don't really intend on going further with it once I get this out -N_Jay said:
Those features marketed are merely hooks that are intended to deviate from a standards-based system (indicated by a consensus of public safety constituents). True, public safety in general has failed to completely embrace standards-based digital systems and there could be a strong argument that these so-called "standards" were a fabrication of industry, themselves, and not really public safety. It seems that this failure to take root has dragged into the period of time the Commission was looking to implementing 6.25 kHz solutions and the technology for this 12.5 kHz solution has already been obsoleted even though many noisy-environment vocoding issues (i.e., wind noise and fireground ambient noise levels) and implementation training issues (i.e., doubling is destructive) haven't been worked through.
Still... if we don't commit to supporting the standards even if it's simply for the sake of being able to buy through competitive bidding, then the only thing we're doing is going off in separate directions. If that's the case, I don't need all this P25 stuff (phase 1 or 2), I can just put in an MPT1327 system, since it's APCO-16 compliant and open source, for significantly less money and we're done. I see it as pretty much the same thing doing that as implementing ADP or wide pulse.
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