The JNCR System

[Chris52]

I’ll check the sites I have enabled but I believe I have them all enabled. I do see at times that I get talk groups that are from Ft. Polk site (that’s no where near me). I would also figure that due to it being summer that tropospheric ducting would come into play meaning the service area from a VHF or UHF radio transmitter extends to just beyond the optical horizon, at which point signals start to rapidly reduce in strength. Viewers living in such a "deep fringe" reception area will notice that during certain conditions, weak signals normally masked by noise increase in signal strength to allow quality reception. Such conditions are related to the current state of the troposphere.

 

[Chris52]

I saw your posting in the VA forums - hopefully you will get more insight there. If you are experiencing RSSI issues at your home, remember that you are over 10 miles from that base. A typical multicast site for a military installation is likely not to be mounted on a 100m tower; it's more likely installed on a water tank or BANT. The site is not designed to provide coverage over a wide area like typical simulcast systems, hence the shorter towers. The good thing for you is there is a large expanse of water between you and Dahlgren, thus less interfering land features. I'd also expect the site was designed to support range control activities out on the river adjacent to and south of the base. Perhaps weather / temperature inversions are affecting your coverage (it is the summer still.)

It seems doubtful but hopefully someone with some sense will come along.

 

[maus92]

I’ll check the sites I have enabled but I believe I have them all enabled. I do see at times that I get talk groups that are from Ft. Polk site (that’s no where near me). I would also figure that due to it being summer that tropospheric ducting would come into play meaning the service area from a VHF or UHF radio transmitter extends to just beyond the optical horizon, at which point signals start to rapidly reduce in strength. Viewers living in such a "deep fringe" reception area will notice that during certain conditions, weak signals normally masked by noise increase in signal strength to allow quality reception. Such conditions are related to the current state of the troposphere.

What I'm asking you to do is disable all sites except Dahlgren. That would ensure that you are receiving / locked on Dalgren's control channel, and any frequencies assigned to that site. Then monitor the RSSI for fluctuations in strength, noting the time of day, weather etc. Also, ducting *can* cause far away signals to interfere with the local site frequencies that you normally receive with no issues. It might take a while work through all the variables.

 

[Chris52]

What I'm asking you to do is disable all sites except Dahlgren. That would ensure that you are receiving / locked on Dalgren's control channel, and any frequencies assigned to that site. Then monitor the RSSI for fluctuations in strength, noting the time of day, weather etc. Also, ducting *can* cause far away signals to interfere with the local site frequencies that you normally receive with no issues. It might take a while work through all the variables.

Understood, I’ll work on that tonight. A cat nap lasted a lot longer today lol so I’m wide awake

 

[maus92]

@Chris52 I was in SoMD today and monitored the Dahlgren site from 6 areas: just outside the base gate; Glasva; Swan Point; Morgantown / Cedar Point; Cobb Island; and Coilton Point. All those areas produced 100% decodes and acceptable RSSI; Colton Point was ~ -80dbm in the museum parking lot. I'm not sure why you are having intermittent reception problems other than your programming *might* include neighboring sites (Indian Head, Pax River / Webster Field) that carry similar tgs, and are sometimes (barely) receivable depending on atmospherics. BTW, Dahlgren does have an actual tower site vs a tank or building mounted antenna - saw it today when crossing the bridge, lol.

 

[Chris52]

@Chris52 I was in SoMD today and monitored the Dahlgren site from 6 areas: just outside the base gate; Glasva; Swan Point; Morgantown / Cedar Point; Cobb Island; and Coilton Point. All those areas produced 100% decodes and acceptable RSSI; Colton Point was ~ -80dbm in the museum parking lot. I'm not sure why you are having intermittent reception problems other than your programming *might* include neighboring sites (Indian Head, Pax River / Webster Field) that carry similar tgs, and are sometimes (barely) receivable depending on atmospherics. BTW, Dahlgren does have an actual tower site vs a tank or building mounted antenna - saw it today when crossing the bridge, lol.

Well you are right, it was the “neighboring sites” that were enabled that has caused all of this. I went into EZ Scan and disabled all of them except the Dahlgren site and have had a strong signal ever since. Now I just need to remember to enable the other sites back for when I travel.

I was wondering if you could explain this ? The Dahlgren site has always been enabled, I also didn’t run into this receiving issue until later on, why not earlier in ? With only this site enabled, will I now miss out on some parts of the system from other bases ? I’m glad the signal has changed but now concerned on what I may miss in other areas.

Again, thank you to all who has helped and chimed in

 

[GTR8000]

I was wondering if you could explain this ? The Dahlgren site has always been enabled, I also didn’t run into this receiving issue until later on, why not earlier in ?

You were focused on what you thought was a diminished signal from Dahlgren, when in fact it may've been an enhanced signal from a different site that your scanner was picking up. The first step in the process of figuring out what was going on would've been to disable all other sites and to make sure that you were receiving only the one site you were focused on. We've now arrived at that step and have determined what the issue was.

With only this site enabled, will I now miss out on some parts of the system from other bases ? I’m glad the signal has changed but now concerned on what I may miss in other areas.

If there was activity on other sites you were receiving, then you will naturally miss that activity scanning only one site. You're only going to receive the activity at whatever site you're scanning, nothing else.

 

[Chris52]

Thank you and my apologies for all the questions.

 

[GTR8000]

No worries, if you don't ask, you won't know!

 

[Chris52]

@maus92 Do you think I should narrow it down to my closest site for MD First and just scan only that site ? I know it’s not fully active but same principle?

 

[maus92]

It will depend on what you want to hear, what tgs the sites actually carry, and how well you can receive the sites from your location. Did you test the reception of the control channels when the sites were up? In my case, I can receive the AACo cell and the Greenbury Point ASR (and *sometimes* Traceys Landing ASR on a good day). Greenbury Point only carries a subset of traffic that the AACo cell carries, so I only monitor the AACo cell. Same for the Traceys Landing, but that *might* change when the Calvert cell comes online. I would guess that you will be able to receive the Charles and St. Mary's cells from your location, plus the Nice Bridge ASR, and *maybe* the Bethune ASR. You'll have to wait to see how each site is configured wrt the tgs they will carry.

 

[fredva]

In the case of the JNCR, with Navy regional dispatching, several of the talkgroups are now carried on multiple sites. So you may not miss a whole lot by enabling only Dahlgren, since traffic from a couple of other bases is coming across the Dahlgren site.

 

[maus92]

Tg 10301 was identifying as "Control" this morning for an exercise. Not sure if this is permanent radio designation for JB Anacostia - Bolling Police Dispatch.

Tg 25500 was identifying as "Command Post" and talking about airfield ramp closures - could be Pax River or JBA.

 

[Chris52]

Tg 10301 was identifying as "Control" this morning for an exercise. Not sure if this is permanent radio designation for JB Anacostia - Bolling Police Dispatch.

Tg 25500 was identifying as "Command Post" and talking about airfield ramp closures - could be Pax River or JBA.

It was a drill at Bolling

 

[spanner]

10301 is JBAB PD Dispatch and I "believe" 25500 is Andrews Command Post.

 

[maus92]

I received a list of new talk groups for law enforcement for NDW South - my source monitored from the Dahlgren site. Since I cannot directly hear these, can someone confirm them?

South LE - DISP 23240
South LE - TAC1 23241
South LE - TAC2 23242
South LE - TAC3 23243

He also had info on NDW North:

NORTH LAW

North LE - DISP 23236
North LE - TAC1 23237
North LE - TAC2 23238
North LE - TAC3 23239

Apparently, NDW is having staffing issues (like everyone else) and is consolidating dispatch operations.

 

[maus92]

Although I cannot see the NDW South tgs off the USNA site, I can see older (e.g. 943x) tgs patched to the NDW North tgs. Back on October 1 (probably the last time I logged onto the site,) the NDW South tgs were at least patched, but never had any users affiliated with them on the USNA site.

 

[BM82557]

I received a list of new talk groups for law enforcement for NDW South - my source monitored from the Dahlgren site. Since I cannot directly hear these, can someone confirm them?

South LE - DISP 23240
South LE - TAC1 23241
South LE - TAC2 23242
South LE - TAC3 23243

He also had info on NDW North:

NORTH LAW

North LE - DISP 23236
North LE - TAC1 23237
North LE - TAC2 23238
North LE - TAC3 23239

Apparently, NDW is having staffing issues (like everyone else) and is consolidating dispatch operations.

The four North LE tgs show up as additional patch subgroups on 580A0-015 Site 8.8 Camp David

 

[BM82557]

This has been the typical patch configuration for Site 8.8, Camp David, lately --

2021/12/01 20:20:57 Freq=389.175000 NAC=06B Current site: 8.8
2021/12/01 20:20:57 Freq=389.175000 NAC=06B Current network: 580A0.015 JNCR Sysid 015
2021/12/01 20:20:58 Freq=389.175000 NAC=06B Patch Supergroup: TG=9427 [Patch]
2021/12/01 20:20:58 Freq=389.175000 NAC=06B Patch Subgroup: TG=22782 [Washington Naval Yard Police Tac 1]
2021/12/01 20:20:58 Freq=389.175000 NAC=06B Patch Supergroup: TG=9427 [Patch]
2021/12/01 20:20:58 Freq=389.175000 NAC=06B Patch Subgroup: TG=23237 [Naval District Washington North PD Tac 1]
2021/12/01 20:20:58 Freq=389.175000 NAC=06B Patch Supergroup: TG=9427 [Patch]
2021/12/01 20:20:58 Freq=389.175000 NAC=06B Patch Subgroup: TG=22441 [Walter Reed Medical Center Police Tac 1]
2021/12/01 20:20:58 Freq=389.175000 NAC=06B Patch Supergroup: TG=9427 [Patch]
2021/12/01 20:20:58 Freq=389.175000 NAC=06B Patch Subgroup: TG=22502 [US Naval Academy Police Tac 1]
2021/12/01 20:20:58 Freq=389.175000 NAC=06B Patch Supergroup: TG=9428 [Patch]
2021/12/01 20:20:58 Freq=389.175000 NAC=06B Patch Subgroup: TG=22444 [Walter Reed Medical Center Police Tac 2]
2021/12/01 20:20:58 Freq=389.175000 NAC=06B Patch Supergroup: TG=9428 [Patch]
2021/12/01 20:20:58 Freq=389.175000 NAC=06B Patch Subgroup: TG=22783 [Washington Naval Yard Police Tac 2]
2021/12/01 20:20:58 Freq=389.175000 NAC=06B Patch Supergroup: TG=9428 [Patch]
2021/12/01 20:20:58 Freq=389.175000 NAC=06B Patch Subgroup: TG=22503 [US Naval Academy Police Tac 2]
2021/12/01 20:20:58 Freq=389.175000 NAC=06B Current site: 580A0.015-8.8 Camp David Frederick County
2021/12/01 20:20:58 Freq=389.175000 NAC=06B Patch Supergroup: TG=9428 [Patch]
2021/12/01 20:20:58 Freq=389.175000 NAC=06B Patch Subgroup: TG=23238 [Naval District Washington North PD Tac 2]
2021/12/01 20:20:58 Freq=389.175000 NAC=06B Patch Supergroup: TG=9429 [Patch]
2021/12/01 20:20:58 Freq=389.175000 NAC=06B Patch Subgroup: TG=22525 [US Naval Academy Police Tac 3]
2021/12/01 20:20:58 Freq=389.175000 NAC=06B Patch Supergroup: TG=9429 [Patch]
2021/12/01 20:20:58 Freq=389.175000 NAC=06B Patch Subgroup: TG=22786 [Washington Naval Yard Police Tac 3]
2021/12/01 20:20:58 Freq=389.175000 NAC=06B Patch Supergroup: TG=9429 [Patch]
2021/12/01 20:20:58 Freq=389.175000 NAC=06B Patch Subgroup: TG=22445 [Walter Reed Medical Center Police Tac 3]
2021/12/01 20:20:58 Freq=389.175000 NAC=06B Patch Supergroup: TG=9429 [Patch]
2021/12/01 20:20:58 Freq=389.175000 NAC=06B Patch Subgroup: TG=23239 [Naval District Washington North PD Tac 3]
2021/12/01 20:20:58 Freq=389.175000 NAC=06B Patch Supergroup: TG=9432 [Patch]
2021/12/01 20:20:58 Freq=389.175000 NAC=06B Patch Subgroup: TG=22440 [Walter Reed Medical Center Police Disp]
2021/12/01 20:20:59 Freq=389.175000 NAC=06B Patch Supergroup: TG=9432 [Patch]
2021/12/01 20:20:59 Freq=389.175000 NAC=06B Patch Subgroup: TG=22501 [US Naval Academy Police Disp]
2021/12/01 20:20:59 Freq=389.175000 NAC=06B Patch Supergroup: TG=9432 [Patch]
2021/12/01 20:20:59 Freq=389.175000 NAC=06B Patch Subgroup: TG=23236 [Naval District Washington North PD Dispatch]
2021/12/01 20:20:59 Freq=389.175000 NAC=06B Patch Supergroup: TG=9432 [Patch]
2021/12/01 20:20:59 Freq=389.175000 NAC=06B Patch Subgroup: TG=22780 [Washington Naval Yard Police Disp]
2021/12/01 20:20:59 Freq=389.175000 NAC=06B Patch Supergroup: TG=9427 [Patch]
2021/12/01 20:20:59 Freq=389.175000 NAC=06B Patch Subgroup: TG=22782 [Washington Naval Yard Police Tac 1]
2021/12/01 20:20:59 Freq=389.175000 NAC=06B Patch Supergroup: TG=9427 [Patch]
2021/12/01 20:20:59 Freq=389.175000 NAC=06B Patch Subgroup: TG=23237 [Naval District Washington North PD Tac 1]
2021/12/01 20:20:59 Freq=389.175000 NAC=06B Patch Supergroup: TG=9427 [Patch]
2021/12/01 20:20:59 Freq=389.175000 NAC=06B Patch Subgroup: TG=22441 [Walter Reed Medical Center Police Tac 1]
2021/12/01 20:20:59 Freq=389.175000 NAC=06B 580A0.015-8.8 neighbor: Site 580A0.005-4.4; CC=0-543 386.7875 JNCR Sysid 005 Mt Quirauk Washington County
2021/12/01 20:20:59 Freq=389.175000 NAC=06B Patch Supergroup: TG=9427 [Patch]
2021/12/01 20:20:59 Freq=389.175000 NAC=06B Patch Subgroup: TG=22502 [US Naval Academy Police Tac 1]
2021/12/01 20:20:59 Freq=389.175000 NAC=06B Patch Supergroup: TG=9428 [Patch]
2021/12/01 20:20:59 Freq=389.175000 NAC=06B Patch Subgroup: TG=22444 [Walter Reed Medical Center Police Tac 2]
2021/12/01 20:20:59 Freq=389.175000 NAC=06B Patch Supergroup: TG=9428 [Patch]
2021/12/01 20:20:59 Freq=389.175000 NAC=06B Patch Subgroup: TG=22783 [Washington Naval Yard Police Tac 2]
2021/12/01 20:20:59 Freq=389.175000 NAC=06B Patch Supergroup: TG=9428 [Patch]
2021/12/01 20:20:59 Freq=389.175000 NAC=06B Patch Subgroup: TG=22503 [US Naval Academy Police Tac 2]
2021/12/01 20:21:00 Freq=389.175000 NAC=06B 580A0.015-8.8 neighbor: Site 580A0.006-1.1; CC=0-464 JNCR Sysid 006 Fort Detrick Frederick County
2021/12/01 20:21:00 Freq=389.175000 NAC=06B 580A0.015-8.8 neighbor: Site 580A0.005-1.1; CC=0-477 385.9625 JNCR Sysid 005 Raven Rock/Site R Adams County

 

[maus92]

These are the patches I see off the NSA Annapolis / Nava Academy site: