New Baltimore County P-25 System

[Dispatcher308]

Seems that Baltimore County's P-25 system is online but only from a couple of tower sites. I found 858.1125 System ID: 0389h-101. I found 858.1125 licensed to Baltimore County WQNX 465 & WNAS500.

[2wayfreq]

The systems control channels are probably "Turned on" for optimization purposes. Not necessarily in service yet.

[pratzert]

Originally Posted by Dispatcher308

Seems that Baltimore County's P-25 system is online but only from a couple of tower sites. I found 858.1125 System ID: 0389h-101. I found 858.1125 licensed to Baltimore County WQNX 465 & WNAS500.

P25 System ?

I haven't kept up as I should. I recall mention of a new system, but I thought it was still at least a year away.

But now that you mention it.... the reception of the Balt.Co systme "seems" to be coming in stronger recently on my Pro-96. I wonder if it has something to do with the implementation of this new system ?

[troymail]

If it's anything like the recent switch/upgrade of the BCity system, you may expect reception to ultimately get worse (!!!) - keep you fingers crossed.....

[pratzert]

Originally Posted by troymail

If it's anything like the recent switch/upgrade of the BCity system, you may expect reception to ultimately get worse (!!!) - keep you fingers crossed.....

I hope not.

I can live with sketchy reception for Balt.City, but I will not be a happy camper if Balt. County ends up the same.

[CqDx]

Baltimore County is a big county, if they go low power or directional antennas, you probably would need a lot of fill in transmitters through the county to cover the terrain.

Time will tell my friend

[pratzert]

Originally Posted by CqDx

Baltimore County is a big county, if they go low power or directional antennas, you probably would need a lot of fill in transmitters through the county to cover the terrain.

Time will tell my friend

I'll be keeping my fingers crossed.

[troymail]

Originally Posted by CqDx

Baltimore County is a big county, if they go low power or directional antennas, you probably would need a lot of fill in transmitters through the county to cover the terrain.

Time will tell my friend

It's not so much a low power thing (although that's exactly what it seemed like at first). It's more about the new simulcast modulation scheme Motorola seems to be deploying these days.

[ocguard]

Originally Posted by troymail

It's not so much a low power thing (although that's exactly what it seemed like at first). It's more about the new simulcast modulation scheme Motorola seems to be deploying these days.

Linear Simulcast CQPSK is all Motorola will install with P25 anymore. At least two of Baltimore County's NEW sites (for the P25 upgrade, not yet in service) employ directional Tx antennas. Scanning Baltimore County post-upgrade will sadly be disastrous.

Originally Posted by CqDx

Baltimore County is a big county, if they go low power or directional antennas, you probably would need a lot of fill in transmitters through the county to cover the terrain.

Time will tell my friend

Doubling the towers, lowering the Tx antennas on all towers, some directional

Originally Posted by pratzert

But now that you mention it.... the reception of the Balt.Co systme "seems" to be coming in stronger recently on my Pro-96. I wonder if it has something to do with the implementation of this new system ?

Seems unlikely, probably coincidence

[troymail]

Originally Posted by ocguard

Linear Simulcast CQPSK is all Motorola will install with P25 anymore. At least two of Baltimore County's NEW sites (for the P25 upgrade, not yet in service) employ directional Tx antennas. Scanning Baltimore County post-upgrade will sadly be disastrous.

Uh-oh......

[ocguard]

Originally Posted by troymail

Uh-oh......

Maybe there's hope that one of the scanner manufactures will address and tweak the issue. HOWEVER, I just got back from Dare County, NC (forced out in a rush) and they have a new Moto P25 system that has LSM, and even some of their Moto portables have trouble handling the multipath.

[pratzert]

Originally Posted by ocguard

Maybe there's hope that one of the scanner manufactures will address and tweak the issue. HOWEVER, I just got back from Dare County, NC (forced out in a rush) and they have a new Moto P25 system that has LSM, and even some of their Moto portables have trouble handling the multipath.

We can hope that the scanner Mfgs can come up with some sort of tweak to improve the reception of these systems.

I wonder why Balt.County is setting up "directional" TX towers when I would think they would want more of a 360 degree reception around the tower to allow for greater coverage and not less.

Since even some of the Motorola units are having difficulty coping with the system, perhaps Motorola will do some tweaking of their own which will help our scanners receive the signals.

[ocguard]

Originally Posted by pratzert

We can hope that the scanner Mfgs can come up with some sort of tweak to improve the reception of these systems.

I wonder why Balt.County is setting up "directional" TX towers when I would think they would want more of a 360 degree reception around the tower to allow for greater coverage and not less.

Since even some of the Motorola units are having difficulty coping with the system, perhaps Motorola will do some tweaking of their own which will help our scanners receive the signals.

Directionality and lower profiling are mandated by the FCC now to reduce co-channel interference (a near-by system using the same frequencies). Since everyone and their brother wants 20 or 30 800mhz channel pairs, they run out quick in metro areas. Using directional tx antennas and lowering them on the towers makes it possible to "re-use" the system's frequencies closer-by. When Baltimore County built their original 800mhz system in the late 80s, they built 300' and 600' towers, put the transmit antennas at the very top, and let the power flow. Not acceptable anymore.

[pratzert]

Originally Posted by ocguard

Directionality and lower profiling are mandated by the FCC now to reduce co-channel interference (a near-by system using the same frequencies). Since everyone and their brother wants 20 or 30 800mhz channel pairs, they run out quick in metro areas. Using directional tx antennas and lowering them on the towers makes it possible to "re-use" the system's frequencies closer-by. When Baltimore County built their original 800mhz system in the late 80s, they built 300' and 600' towers, put the transmit antennas at the very top, and let the power flow. Not acceptable anymore.

OCGUARD,

You are quick and accurate with your response... as usual.

Thanks for sharing your knowledge with us. I really do appreciate it.

What you explained makes sense.... but in the case of emergency response and puplic protective services, I still think it make sense to be able to radiate the communcations over a broader area.

But I gotta try to understand the reasoning. I guess overall, it makes sense.

[ocguard]

Originally Posted by pratzert

OCGUARD,

You are quick and accurate with your response... as usual.

Thanks for sharing your knowledge with us. I really do appreciate it.

What you explained makes sense.... but in the case of emergency response and puplic protective services, I still think it make sense to be able to radiate the communcations over a broader area.

But I gotta try to understand the reasoning. I guess overall, it makes sense.

I understand what you mean, but, if our radiated power interferes with another system, it affects their public safety and law enforcement communications, and vice versa. I can tell you that when I worked at Baltimore County 911 in 2001-04, there were times when 3 or 4 of the 20 repeaters had to be taken out of rotation because of co-channel interference on the input side.

This is why the number of transmission sites was more than doubled in planning for the new system; less power but more saturation, keeps the signal within the intended coverage footprint.

[pratzert]

Originally Posted by ocguard

I understand what you mean, but, if our radiated power interferes with another system, it affects their public safety and law enforcement communications, and vice versa. I can tell you that when I worked at Baltimore County 911 in 2001-04, there were times when 3 or 4 of the 20 repeaters had to be taken out of rotation because of co-channel interference on the input side.

This is why the number of transmission sites was more than doubled in planning for the new system; less power but more saturation, keeps the signal within the intended coverage footprint.

Hopefully if they put up more towers for more saturation the reception with scanners will improve.

Thanks again.

[ocguard]

Managed to get a CC dump on one of the frequencies listed under the licenses Nate noted. Signal was weak from Hampden, so not sure which site is making the RF. An adjacent site is listed by the CC data, so it appears that the two-zone rumor for Baltimore County's new system will be accurate.

[JRoCc]

So if one was contemplating a new PSR-800 should they wait? I'm only interested in listening to Baltimore County PD primarily. I'd like to purchase it soon but if it's going to be a waste for me I'll pass. Thx.

[troymail]

Originally Posted by JRoCc

So if one was contemplating a new PSR-800 should they wait? I'm only interested in listening to Baltimore County PD primarily. I'd like to purchase it soon but if it's going to be a waste for me I'll pass. Thx.

When AA County "was" going digital years ago, I bought several radios to prepare -- and they are still only partially digital.

It's a personal preference/decision -- if you need it, get it - otherwise, you don't know what else will appear (new radios) between now and the time the digital switch actually occurs....

[JRoCc]

Yeah...that makes sense. Thanks Troy