Rebanding in Maryland

[ka3jjz]

With rebanding starting to pick up steam, I thought it might be a good idea to get some simple tips and straighten out some misconceptions about rebanding

First, rebanding has nothing to do with the 700 Mhz migration, nor with narrowbanding. This procedure applies only to 800 Mhz systems, and the special procedures that we talk about when we mention custom tables apply only to Motorola systems. EDACS and LTR systems that reband simply need to be reprogrammed with the new frequencies to continue to trunk properly.

As a good general rule, if any of the Motorola system frequencies have a 0 in the fourth position, a custom table will be required to trunk this system correctly if the system type is what we loosely refer to as 'mixed mode' - in the database, these are shown as Analog and APCO-25 Common Air Interface as the System Voice. It also applies to any Motorola systems that are analog only.

Systems that show up with a System Voice of Project 25 Phase I (FDMA) and a System Type of APCO-25 Common Air Interface Exclusive would not require a table as the necessary information is calculated from the data in the control channel.

This may involve a firmware fix (as it would, for example, for a Uniden BC396T with old firmware) and/or modifications to the programming (for example, a PRO-96 or 2096, which requires software to perform the necessary change to rebanding).

The following threads in this forum mention rebanding for the indicated counties;

http://forums.radioreference.com/ma...forum/236646-rebanding-montgomery-county.html

http://forums.radioreference.com/maryland-radio-discussion-forum/245734-howard-county-rebanding.html

http://forums.radioreference.com/ma...on-forum/239925-harford-county-rebanding.html

To find the rebanded frequencies for a system, take all the frequencies and subtract 15 Mhz. One thing to keep in mind is that sometimes new frequencies will be added to the system as control channels, or frequencies previously dedicated to voice only are moved into service as a control channel. Folks running trunking utilities such as UniTrunker will have the leg up on identifying these changes.

These tips are only a summary. There's a great deal of other details that are covered in our wiki. Section 7 of the rebanding wiki has a list of all the links needed for the various scanners and rebanding. A tip here; just click on the topic in the table of contents, and you'll be taken directly to it.

Rebanding - The RadioReference Wiki

Mike

 

[Kumba]

Any news on Charles' rebanding? They've had the frequencies for at least two years now [1], but I think they picked a fight with Sprint and the FCC over Sprint's costs for the rebanding, which forced the FCC to change its rules (I think, but don't quote me on that) [2]. I suspect this delayed things a bit, but, while I haven't probed the rebanded frequencies too much lately, they seem to have stayed rather quiet.

I'm half-hoping that w/ the reband, I'll get better reception at home because I've got a tower with cell and microwave about 200ft away from my neighborhood which seems to mangle the control channel's signal pretty good (since it's right up against the tail-end of the public safety spectrum anyways).

Thoughts? Considered actually e-mailing someone in the county government to see if they'll say anything.

 

[ka3jjz]

While it's possible, the real issue here is that you're too close - you're getting swamped by all that RF. Frequency separation might help somewhat, but that's not the real answer

Mike

 

[Kumba]

While it's possible, the real issue here is that you're too close - you're getting swamped by all that RF. Frequency separation might help somewhat, but that's not the real answer

Mike

Yeah, kinda stuck here for a few more years, though. Housing market is getting better, but it's still not ripe enough to sell this one and move to something with less RF interference. I pegged the local fire department about it when they came around for donations, and they noted it's an issue they're aware of. I think the 1.10.00 firmware is helping (BCD396XT), but I figured a drop in 15MHz would help even more. Can't find any kind of statuses on Charles' rebanding, though. Not sure if they're still waiting on something.

 

[ka3jjz]

Actually that's not the answer I was considering. A Yagi pointed AWAY from that tower toward the next nearest tower for that system might be worth trying. At freqs like these, a Yagi is very tiny, so it's not likely to make the neighbors nervous...Mike

 

[Kumba]

Actually that's not the answer I was considering. A Yagi pointed AWAY from that tower toward the next nearest tower for that system might be worth trying. At freqs like these, a Yagi is very tiny, so it's not likely to make the neighbors nervous...Mike

I've thought of mounting a small discone in the attaic on one of the support beams. Not sure about roof-mounting something, though. I am in an HOA, though they've been mysteriously quiet for the last two years. Also not sure about grounding anything on the roof from storms.

Probably a project for the next house. Still reading up on HAM stuff so I can eventually go try for a license. All I have right now are mobile scanners anyways, and drilling holes and running coax through the house for one of those is probably more work than would be gained. Have to see if the rebanding helps at all, first. Though, I should tune to other frequencies near the rebanded range and see if I get the same "static wind" I get on the main control channel.

 

[ka3jjz]

A discone is basically unidirectional, so it wouldn't help. A yagi has some attenuation toward the back end of the beam, and this would amount to a de facto 'attenuator' for any of the RF coming from that nearby tower.

As mentioned before, Yagis on these freqs are tiny - I know of more than one person who put them in a nearby closet that happens to point in the right direction. And keeping it low with respect to the tower might gain you some additional attenuation, depending on the construction of your home and whether the adjoining walls face the tower (which you should likely avoid).

You'll learn more about Yagis that way - hams use them (and their cousins) quite frequently....Mike

 

[W2NJS]

Uni vs. omni...

Didn't you mean to say that a discone is OMNIdirectional?

 

[ka3jjz]

Absolutely correct - omni is what I meant to say...Mike

 

[ka3jjz]

With Harford, Howard and now Montgomery counties having undergone rebanding, I'm wondering when Anne Arundel will jump on this wagon. Anyone know?

Mike

 

[Kumba]

With Harford, Howard and now Montgomery counties having undergone rebanding, I'm wondering when Anne Arundel will jump on this wagon. Anyone know?

Mike

Don't know about AA, but for Charles, I've been directed to someone to ask about rebanding so hopefully I'll get some info on their plans within the next few days.

 

[dpm797]

other than the VRS/DVRS units that are being replaced Anne Arundel should be done.....they were the first to reband in 2004 when they went from the old 800 Mhz system to the new 800 Mhz system.....The new CMARC/NIPS Pac frequencies are programmed in the portable radios. Have to re program the mobiles for new CMARC and other jurisdictions.

 

[Kumba]

Looks like Charles just rebanded either tonight or last night. All four control channels are dead, and I'm picking up what sounds like a control channel on the rebanded frequencies. Gotta setup that custom table mess, though, it looks. I'll post more later.

 

[Kumba]

Looks like Charles just rebanded either tonight or last night. All four control channels are dead, and I'm picking up what sounds like a control channel on the rebanded frequencies. Gotta setup that custom table mess, though, it looks. I'll post more later.

Everything works. I thought all of the frequencies got rebanded, though, not just the control channels? Or is that next?

 

[ka3jjz]

Usually - but I'm betting, like Dave said in the Charles County rebanding thread, that it's not complete as yet.

It's also possible that they're dropping some of the old frequencies - an examination of the FCC records would show what is going on...Mike

 

[ThePhotoGuy]

An Anne Arundel County Police supervisor requested a couple officers today to come to the station to get their radios rebanded.

Anyone have any additional information on this?

 

[Grondoline]

AA County Police Rebanding

See attached

 

[ThePhotoGuy]

See attached

Thanks!

Are they just rebanding or are they also changing any of the talkgroups (more encrpytion, etc)?

 

[Grondoline]

Thanks!

Are they just rebanding or are they also changing any of the talkgroups (more encrpytion, etc)?

I'll let you know after I get mine done.

 

[ka3jjz]

Why would AA county need rebanding? All of their frequencies are well below the 866 Mhz limit.

I suspect we're about to see some new TGs - not actual rebanding...

???

Mike