Loudoun County's new radio system

[mike_s104]

The Fire/EMS shift has begun

2872 - Fire/EMS Dispatch
2873 - 6B

2897 - Loudoun Hospital Patch
2899 - Cornwall Patch
2875 - fire/ems, not sure what channel

 

[byrddog27]

loudoun county new radio

do we put this number in your scanner

 

[j2brown]

Based on the above and what I posted here

Loudoun County (VA) - The RadioReference Wiki

my guess for LCFR talkgroups is:

2872 - 6A
2873 - 6B
2874 - 6C
2875 - 6D
...etc...

Also, I'm wondering if we're still hearing so much traffic because the unit/mobile radios are the old ones and can't do the "Motorola flavored almost TDMA". Not sure what will happen with MWAA/Fairfax running mutual aid. Perhaps we'll get to hear some fo those calls.

Tomorrow is my first night with the new radios. We'll see how it goes.

jeff
sdg

 

[freqhopping]

Based on the above and what I posted here

Loudoun County (VA) - The RadioReference Wiki

my guess for LCFR talkgroups is:

2872 - 6A
2873 - 6B
2874 - 6C
2875 - 6D
...etc...

No need to guess, I've been listening all afternoon and can confirm. Mike is right about the hospital channels too.

 

[mike_s104]

Tomorrow is my first night with the new radios. We'll see how it goes.

Can you get us a few of the radios if they can monitor the LCSO? Just kidding.

No need to guess, I've been listening all afternoon and can confirm. Mike is right about the hospital channels too.

At first I was thinking that I'd not be able to hear anything, but after a few hours listening today I was hearing almost as much as I did on the old system. BUT, I think over the next few weeks, this will change.

 

[j2brown]

Can you get us a few of the radios if they can monitor the LCSO? Just kidding.

I don't recall seeing any LCSO zones or channels in the LCFR radios during training, but that doesn't mean they're not in there. However, I've heard that some in the LCSO are less than thrilled with their first week with the new system, so perhaps they can be more easily persuaded to part with some.

jeff
sdg

 

[rfburns]

The problem it poses is having enough coverage outside the county such as for moving surveillances or for Deputies who have take home cars and live out west around Stephens City. So the question is, will they keep a 3 or 4 channel high power zone with fewer sites (such as Bull Run Mtn) to provide the out of county coverage.

So far I see no sign that they have kept a couple of high power channels.

 

[mike_s104]

I don't recall seeing any LCSO zones or channels in the LCFR radios during training, but that doesn't mean they're not in there. However, I've heard that some in the LCSO are less than thrilled with their first week with the new system, so perhaps they can be more easily persuaded to part with some.

jeff
sdg

or better yet, switch back to the old until the issues are worked out in about 4 years and by then maybe there will be a scanner ready for it. If you have any "found" units, I'm sure they'll be disabled.

 

[j2brown]

If you have any "found" units, I'm sure they'll be disabled.

That, and they'll make an attempt to use the built in GPS to recover them.

jeff
sdg

 

[fireradio]

It is 14 conversations, since the control channel is not slotted.
One control and seven 2-slot traffic channels.

Duh -- you caught me posting prior to drinking an adequate amount of coffee! You're right -- that's what I was going for!

 

[jeffmulter]

Loudoun is operating a Motorola proprietary implementation of TDMA that is similar to P25 Phase II. The real P25 Phase II has not been released yet. ...

As others have said, a talkgroup will work in TDMA mode as long as no FDMA (or "regular") radios are affiliated. As soon as an FDMA radio affiliates, the talkgroup reverts to FDMA. This is why you can hear traffic on some talkgroups some of the time, but not all of the time.

Will the "proprietary" aspect of this project / system upgrade be something that will impede Uniden or GRE from making a scanner compatible with Motorola P25 phase 2 in the future ? Could it add to the current licensing requirements for P25 scanners ... specifically the vocoder ?

According to the RadioReference database, the old Loudoun TRS is 3600 baud, so a specific dispatch talkgroup on the old system would have a different hex value than the "same" dispatch talkgroup on the new system. Does the system controller identify that the two hex values are the same, or is that something done at the dispatch consoles ?

Thanks to those of you who listened to and commented on the new system since its startup. At some point, many more hobbyists will experience similar transitions in their listening areas. I appreciate the education.

A couple of follow-ups to previous comments ...

The Scout 40, as well as most of the hobby-grade frequency counters of its generation, was not capable of detecting digital signals. Opto Electronics made a separate digital version of the Scout for that purpose.

Loudoun County was licensed under an STA (special temporary authority) for conventional (non-trunked) frequencies in the 700 MHz band earlier this year. The license was returned because the frequencies had not been co-ordinated through the regional 700 band committee.

The FCC database reflects 4 licenses for Loudoun County's 800 trunking. Only two of the licenses ... WQKP620 and WQKP620 ... provide an appropriate emission designator for a P25 / 9600 baud system. Both of those licenses are STAs, and expire at the end of January.

 

[N_Jay]

Will the "proprietary" aspect of this project / system upgrade be something that will impede Uniden or GRE from making a scanner compatible with Motorola P25 phase 2 in the future ? Could it add to the current licensing requirements for P25 scanners ... specifically the vocoder ?

It is not a vocoder issue.
P25 Phase 2 and Motorola's pre-phase 2 TDMA use (or are proposed to use) the same vocoder.

It is a modulation difference, channel rate difference and channel coding difference.

 

[mike_s104]

The Scout 40, as well as most of the hobby-grade frequency counters of its generation, was not capable of detecting digital signals. Opto Electronics made a separate digital version of the Scout for that purpose.

Thanks. I'm glad someone got what I was saying.

 

[fireradio]

According to the RadioReference database, the old Loudoun TRS is 3600 baud, so a specific dispatch talkgroup on the old system would have a different hex value than the "same" dispatch talkgroup on the new system. Does the system controller identify that the two hex values are the same, or is that something done at the dispatch consoles ?

I'm not 100% sure I'm following the question you're asking, but in Loudoun's case, there are two completely independent controllers at work right now. The controller for the old system, and the controller for the new system. The two of them aren't talking together. Once the transistion is complete (they won't be leaving the old system turned on very long), there will only be one controller. I'm not sure what they're doing for dispatch consoles, but it is possible that they are using their old consoles, which would be able to simultaneously communicate with the old system and the new system via a SmartX interface.

 

[jeffmulter]

It is not a vocoder issue.
P25 Phase 2 and Motorola's pre-phase 2 TDMA use (or are proposed to use) the same vocoder.

It is a modulation difference, channel rate difference and channel coding difference.

Hi, N_Jay, and thanks for responding. I understand the basics of analog vs digital FM vs TDMA ( and FDMA ). It was the term "proprietary" that "Fireradio" used that threw me, since there is a set of standards applicable to P25.

Although I understand that a Motorola top-to-bottom P25 system will have some features that a Harris P25-compatible radio may not be able to access (as an example), I wonder if the proprietary aspect of Loudoun County's new system might have an impact on Uniden's and GRE's ability to offer a scanner in the future that will decode the system ?

(edit)

Sorry, Fireradio - I was replyng to N_Jay as you posted your reply. Thanks for helping me understand what was occurring with the talkgroups.

 

[freqhopping]

I'm not 100% sure I'm following the question you're asking, but in Loudoun's case, there are two completely independent controllers at work right now. The controller for the old system, and the controller for the new system. The two of them aren't talking together. Once the transistion is complete (they won't be leaving the old system turned on very long), there will only be one controller. I'm not sure what they're doing for dispatch consoles, but it is possible that they are using their old consoles, which would be able to simultaneously communicate with the old system and the new system via a SmartX interface.

The old system is no longer online now. All the radio IDs are different now. They used to be 7##### (6 digit). Now they are 3###### (7digits), except for the Leesburg PD dispatch consoles which are 1301 to 1304.

 

[N_Jay]

Hi, N_Jay, and thanks for responding. I understand the basics of analog vs digital FM vs TDMA ( and FDMA ). It was the term "proprietary" that "Fireradio" used that threw me, since there is a set of standards applicable to P25.

Although I understand that a Motorola top-to-bottom P25 system will have some features that a Harris P25-compatible radio may not be able to access (as an example), I wonder if the proprietary aspect of Loudoun County's new system might have an impact on Uniden's and GRE's ability to offer a scanner in the future that will decode the system ?

The issue is that THIS system is currently being implemented using a MOTOROLA PROPRIETARY protocol that provides TDMA using much of the existing P25 Phase 1 standards as its base.

The eventual system will be a P25 Phase 2 standards based system.
The fact that the transition started from the Motorola system should have no impact on the final design.

I would bet (if I was a betting man) that the scanner companies will not bother designing for the Motorola protocol due to the market size and the fact that these systems should be rater short lived.

Of course I could be wrong, and they may implement the Motorola TDMA along with the standard TDMA if it is not a significant effort, and they feel it is required by the market.

 

[gcgrotz]

The issue is that THIS system is currently being implemented using a MOTOROLA PROPRIETARY protocol that provides TDMA using much of the existing P25 Phase 1 standards as its base.

The eventual system will be a P25 Phase 2 standards based system.
The fact that the transition started from the Motorola system should have no impact on the final design.

I would bet (if I was a betting man) that the scanner companies will not bother designing for the Motorola protocol due to the market size and the fact that these systems should be rater short lived.

Of course I could be wrong, and they may implement the Motorola TDMA along with the standard TDMA if it is not a significant effort, and they feel it is required by the market.

Well said N_Jay, but I would make an educated guess that being "MOTOROLA PROPRIETARY" there will be no way that they will license it to scanner users, the same way OpenSky is done. Their customers will be assured that no one not authorized will be listening.

OTOH, when P25 Phase2 is final, that will be a public standard just like Phase1 is now.

 

[freqhopping]

I've been hearing Leesburg PD this afternoon. This will give me a chance to label RIDs. Sure would be nice if Animal Control, Jail and the Court could be heard at least once.

 

[N_Jay]

Well said N_Jay, but I would make an educated guess that being "MOTOROLA PROPRIETARY" there will be no way that they will license it to scanner users, the same way OpenSky is done. Their customers will be assured that no one not authorized will be listening.

OTOH, when P25 Phase2 is final, that will be a public standard just like Phase1 is now.

Except, the Moto Proprietary solution is just about timing. (Customers wanted a system before the standard was finished)

It is already fairly public since it was essentially their suggested solution to P25 Phase 2.