Rebanding and Montgomery county

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ka3jjz

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Some traffic on Scan-DC suggests that rebanding should start sometime in the next week or two.

The current database listing is below...

Montgomery County MD Trunking System, Montgomery County, Maryland - Scanner Frequencies

As was mentioned on Scan-DC, you will need to drop all the freqs by 15 mhz; and you will need to put in a custom table to trunk this system when it happens. The Uniden 250 and 785 won't be able to follow this system completely due to the fact that neither radio can be modified, and some of the channels have a 0 in the 4th position.

Section 7 of the rebanding wiki article has the particulars - note that you can just click on the section name in the table of contents, and you'll be taken there...

Rebanding - The RadioReference Wiki

Home Patrol and PSR-800 users won't have to wait for a db unload to put in the new system; there are procedures for both linked in this article. So far, no one has come up with a similar procedure for the baby brother to the 800, the PRO-18.

Mike
 

m-town

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Montgomery Country hit go on the re-banding TODAY, 3/27/2012.

The procedure to enable rebanding on my PSR-800 worked fine. But I was hearing traffic even without changing anything.
 

ka3jjz

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As I understand it from traffic on Scan-DC it appears that at least when the messages appeared, that Mont is simulcasting on both the rebanded and non-rebanded channels. How long/if this is going to last (or it's even happening now) I haven't a clue - I'm down in a hole here and no way I'm going to hear Montgomery...Mike
 

m-town

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Update... Using the re-band function didn't work. I don't hear jack. Using the "old-banding" still works perfectly fine. Not sure what's up. They've been telling everyone to switch to re-banded all afternoon.
 

dwlipp

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Rebanding Status

MC has hit a snag in the rebanding process. As the techs started the frequency realignment process (the actual act of rebanding the system) they noticed significantly degraded performance on some of the new frequencies at some sites. Further investigation determined that there are filters on the tower top amplifiers on some sites that are significantly degrading performance on some of the new frequencies. As a result of this discovery the channels that had been realigned have been moved back to their old assignments until a solution to the filter issue can be implemented.

All of that said, Fire/Rescue has moved from the legacy zones in the radios (zones marked with an "*") to the rebanded zones (no "*"). The reason we have made this change is that concurrent with the rebanding of the system we had to transition from our existing VRSs (Vehicular Repeater Systems) to new DVRSs (Digital Vehicular Repeater Systems). The old VRSs would not support the new frequency assignment so we had to install new DVRSs that would support the frequency.

We could not roll back (nor would we want to roll back even if we could) the VRS/DVRS transition when the system rebanding hit the snag. As a result once the majority of the DVRSs had been installed we advised our users to start using the "non-*" zones on the radios all of which have the new DVRS frequencies programmed; by doing this we ensure that our users can continue to use the DVRSs to enhance coverage when needed.

What this means to those scanning the system is that the old frequency assignments are still in use and will be for some time to be determined (a resolution plan is being developed today). That said, as a result of the VRS/DVRS transition MCFRS will be operating exclusively on the "non-*" (post-rebanding) zones from this point forward. On the trunked side of the rebanding equation the talkgroups work regardless of what frequency is in use or where the talkgroup is selected in the radio (* or non-* zones in MCFRS radios). What impacts the users are the conventional channels embedded in each zone; those have to match or stuff doesn't work.

For those that are not familiar the DVRSs (or previously VRSs) are conventional repeaters that are interfaced to the trunked radio system. This allows a user who is out of range of the trunked system to switch to a conventional channel and continue to communicate with users on the trunked system and vise versa.

In addition to the DVRSs using the new channel assignments, the conventional channel that we use exclusively as a simplex talk-around channel (7 Oscar) has also moved to the new channel assignment in the "non-*" zones.

Hope this helps to unscramble some of the understandable confusion.
 
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m-town

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Great update LT. That explains why I thought I heard traffic on the re-banded frequencies for a short while and then it disappeared.

Further investigation determined that there are filters on the tower top amplifiers on some sites
Oh that should be fun to fix. Whoops :p
 

jkahn

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there are filters on the tower top amplifiers on some sites that are significantly degrading performance on some of the new frequencies. As a result of this discovery the channels that had been realigned have been moved back to their old assignments until a solution to the filter issue can be implemented.[/QUOTE said:
Good time to change the lightbulbs on the tower tops while they remove or change the filters!

Do you know what the newly added talkgroup IDs are for 7N & 7O? or do they just change the radio to simplex on the DVRS frquency?

I have read somewhere that there are some new IDs for both FRS and PD but I cannot locate that msg again.

JK :)
 

dwlipp

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Do you know what the newly added talkgroup IDs are for 7N & 7O? or do they just change the radio to simplex on the DVRS frquency?
7O and 7N are conventional frequencies (Oscar is a simplex frequency, November is the DVRS repeater pair) using analog modulation so there are no IDs, talkgroup or otherwise.
 

dmi

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Where would I find the post re-banded system frequencies and programming instructions for PRO-106?

j
 

ka3jjz

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When it happens - we don't know anything about that yet - you will need to subtract 15 mhz from the current frequencies. In addition a custom table will be required. If you have the software, it appears to be pretty easy to set up the table. The instructions for ARC500 and Win500 are in their respective user guides - and they're linked at the bottom of;

Programming Your Radio Shack Scanner - The RadioReference Wiki

I'm pretty sure PSREdit500 would work in a similar manner.

It would also be wise to have the latest firmware (I think the 106 is rebanding ready out of the box) - and that can be pulled from the RS website;

RadioShack® PRO-106 39,000-Channel Digital Handheld Scanner - RadioShack.com

Click on the 'PRODUCT SUPPORT' tab underneath 'YOU MIGHT ALSO WANT'

HTH...Mike
 

redburgundy

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Where would I find the post re-banded system frequencies and programming instructions for PRO-106?
If you're using Win500, you can go in today and add the four System Frequencies 853.xxxx where the xxxx are the same digits as now appear for the four 868 MHz frequencies (no need to delete the 868 frequencies). Then select Trunking Tables and pull down the arrow under "Standard" band plans and select 800 MHz "rebanded".
That's it.
 

dmi

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If you're using Win500, you can go in today and add the four System Frequencies 853.xxxx where the xxxx are the same digits as now appear for the four 868 MHz frequencies (no need to delete the 868 frequencies). Then select Trunking Tables and pull down the arrow under "Standard" band plans and select 800 MHz "rebanded".
That's it.
Thanks! Still not hearing anything on 853.* rebanded system freqs from Montgomery County..

j
 

ka3jjz

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I suspect it will be several months, regardless of any FCC deadlines, before this happens. Just the sheer amount of work that will be needed to identify the bad filters, getting the contracts together with bids to replace them or correct the filter tuning is going to take a long time. And I haven't even thought about bids for physically doing the work.....

I wouldn't hold my breath about seeing this done anytime soon...Mike
 
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