railtrailbiker
Member
First Glen Rock, now Edgewater.
https://www.northjersey.com/story/n...aking-sure-cop-radios-work-indoors/690249002/
https://www.northjersey.com/story/n...aking-sure-cop-radios-work-indoors/690249002/
Edgewater (Bergen County) Public Safety Radios
- Thread starter railtrailbiker
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wtp
Member
in the article
it sounds like radio waves can't penetrate cement.
"unable to place radio calls through cement walls"
if i remember the problem was that the fireground frequency (154.1) was overwhelmed.
everybody was on the same frequency and all talking at once.
the main reason they were killed was the roof was a metal bow truss roof and they twist and bend when heated.
the men should have never gone in and only fought it from the outside.
i was living in bergen county at the time.
charges were brought against a commander a short time later.
it sounds like radio waves can't penetrate cement.
"unable to place radio calls through cement walls"
if i remember the problem was that the fireground frequency (154.1) was overwhelmed.
everybody was on the same frequency and all talking at once.
the main reason they were killed was the roof was a metal bow truss roof and they twist and bend when heated.
the men should have never gone in and only fought it from the outside.
i was living in bergen county at the time.
charges were brought against a commander a short time later.
902
Member
There seems to be a conflation of a few of issues -
1) Hackensack - Fireground operations were conducted through the repeater system. The repeater had console priority, which is a standard implementation configuration. If I recall, the repeater system had been keyed by dispatch at the time of the collapse, which meant that the field units were muted by dispatch traffic. New York City's radio system configuration allows break-in communication which prevents that, however, the most efficient and reliable method of fireground communication is simplex. A few of us (myself included) had fireground simplex operations codified into NFPA 1221 and 1802. There was a lawsuit against Motorola with respect to Hackensack. I don't exactly recall all of the outcomes, but the inclusion of an off-network simplex fireground frequency (153.8300) was one of them.
2) VHF in East Bergen - VHF everywhere is a garbage heap of systems piled on top of other systems. It's the reason why Cliffside Park left VHF as its primary, and contributed to other communities' decisions to move to UHF. The interference threshold of a VHF system is fairly high, and is worse the higher an antenna is placed. You might not hear anything on a scanner and think a frequency is clear, but at 300 ft. up, on top of a 300 ft. cliff using a professional grade receiver, you can hear many, many things that you couldn't on a consumer device. This noise creates a plateau that has to be overcome by local signals. Those signals are attenuated through high rise construction.
3) System configuration - I don't know what Edgewater's configuration is, but some of its neighbors have multiple voting receivers located throughout their jurisdiction and in neighboring jurisdictions just to have portable coverage. They STILL experience attenuation. It's impossible for one site to cover everything, particularly when this attenuation is factored in.
4) I'm not sure Glen Rock's system configuration is a similar solution to what Edgewater requires. Their school system may be using small campus repeaters, rather than a central site with a high noise floor. Someone else might be better able to speak to that.
So, with all that in mind, "signal boosters" ("bi-directional amplifiers" are a better term) are usually necessary to get in-building coverage for repeaterized systems. But let's go back to NFPA 1221 for a minute - unless you're in a Faraday cage (and you might be if you're in a hospital, or in a vault), your most reliable path to help is SIMPLEX.
Bi-directional amplifiers with distributed antenna systems are written into NFPA standards. There require careful selection of materials and calculation of battery life in case of power failure. But they're also maintenance intensive and cannot be set-and-forget. A poorly installed BDA ("signal booster") will break into oscillation and will destroy communication more than help it.
This is going to be important as responders move on to Radio over LTE. It will shift everything to network dependency. Coverage enhancement might be through fiber to 5G gNodeBs (IT-speak for "base station"). We go back to fire codes for materials, placement, and power backup.
Finally, a caveat: Edgewater spec'ing infrastructure-dependent in-building solutions might be problematic for mutual aid operations, particularly when Fort Lee (T-band trunking) and Cliffside (T-band conventional) respond. Unless they've done something extraordinary, their system will only work on their VHF frequencies.
1) Hackensack - Fireground operations were conducted through the repeater system. The repeater had console priority, which is a standard implementation configuration. If I recall, the repeater system had been keyed by dispatch at the time of the collapse, which meant that the field units were muted by dispatch traffic. New York City's radio system configuration allows break-in communication which prevents that, however, the most efficient and reliable method of fireground communication is simplex. A few of us (myself included) had fireground simplex operations codified into NFPA 1221 and 1802. There was a lawsuit against Motorola with respect to Hackensack. I don't exactly recall all of the outcomes, but the inclusion of an off-network simplex fireground frequency (153.8300) was one of them.
2) VHF in East Bergen - VHF everywhere is a garbage heap of systems piled on top of other systems. It's the reason why Cliffside Park left VHF as its primary, and contributed to other communities' decisions to move to UHF. The interference threshold of a VHF system is fairly high, and is worse the higher an antenna is placed. You might not hear anything on a scanner and think a frequency is clear, but at 300 ft. up, on top of a 300 ft. cliff using a professional grade receiver, you can hear many, many things that you couldn't on a consumer device. This noise creates a plateau that has to be overcome by local signals. Those signals are attenuated through high rise construction.
3) System configuration - I don't know what Edgewater's configuration is, but some of its neighbors have multiple voting receivers located throughout their jurisdiction and in neighboring jurisdictions just to have portable coverage. They STILL experience attenuation. It's impossible for one site to cover everything, particularly when this attenuation is factored in.
4) I'm not sure Glen Rock's system configuration is a similar solution to what Edgewater requires. Their school system may be using small campus repeaters, rather than a central site with a high noise floor. Someone else might be better able to speak to that.
So, with all that in mind, "signal boosters" ("bi-directional amplifiers" are a better term) are usually necessary to get in-building coverage for repeaterized systems. But let's go back to NFPA 1221 for a minute - unless you're in a Faraday cage (and you might be if you're in a hospital, or in a vault), your most reliable path to help is SIMPLEX.
Bi-directional amplifiers with distributed antenna systems are written into NFPA standards. There require careful selection of materials and calculation of battery life in case of power failure. But they're also maintenance intensive and cannot be set-and-forget. A poorly installed BDA ("signal booster") will break into oscillation and will destroy communication more than help it.
This is going to be important as responders move on to Radio over LTE. It will shift everything to network dependency. Coverage enhancement might be through fiber to 5G gNodeBs (IT-speak for "base station"). We go back to fire codes for materials, placement, and power backup.
Finally, a caveat: Edgewater spec'ing infrastructure-dependent in-building solutions might be problematic for mutual aid operations, particularly when Fort Lee (T-band trunking) and Cliffside (T-band conventional) respond. Unless they've done something extraordinary, their system will only work on their VHF frequencies.
radioman2001
Member
Basically this is old news, has been a problem for years. Municipalities are just now catching up to the fact that if you rely on a trunked or repeater system for a fire ground of PD operations you will have problems.
Channel loading may have been a contributing factor to the Hackensack tragedy but using a repeater with it's receiver miles away in never a good thing. Fire operations should ALWAYS be conventional and analog. PD should learn this too, and stop being secret squirell about everything. If you are worrying about someone hearing you in a tacticle operation use proper OPSEC. Even the Feds when there is an emergency switches everything to clear.
BDA's while good are not always the best answer as too many closely spaced can actually cause interference, and the issue of multiple bands can also be a problem. IMO using multiple bands or even frequencies on a Fire ground is dangerous, unless a preplan has been created to prevent loosing someone on a frequency no one is listening to. A VHF BDA with a channel separation of less than a few MHZ is a disaster waiting to happen, as it can actually interfere with receiving itself.
I think that including a plan for communications equipment in the building phase is a good idea, but I see this as going to be haphazard unless a true RF engineer is included.
A note about VHF the most common frequency band around. It has some really weird properties where you can actually see someone and shout to them but no radio reception. I have seen this first hand in tunnels, subways and even large veranda's. Just think about a schools hallway as a tunnel and you get the idea.
Channel loading may have been a contributing factor to the Hackensack tragedy but using a repeater with it's receiver miles away in never a good thing. Fire operations should ALWAYS be conventional and analog. PD should learn this too, and stop being secret squirell about everything. If you are worrying about someone hearing you in a tacticle operation use proper OPSEC. Even the Feds when there is an emergency switches everything to clear.
BDA's while good are not always the best answer as too many closely spaced can actually cause interference, and the issue of multiple bands can also be a problem. IMO using multiple bands or even frequencies on a Fire ground is dangerous, unless a preplan has been created to prevent loosing someone on a frequency no one is listening to. A VHF BDA with a channel separation of less than a few MHZ is a disaster waiting to happen, as it can actually interfere with receiving itself.
I think that including a plan for communications equipment in the building phase is a good idea, but I see this as going to be haphazard unless a true RF engineer is included.
A note about VHF the most common frequency band around. It has some really weird properties where you can actually see someone and shout to them but no radio reception. I have seen this first hand in tunnels, subways and even large veranda's. Just think about a schools hallway as a tunnel and you get the idea.
902
Member
This industry has a lot of quacks and hacks. Some of them can't tell the difference between a radio and a toaster oven, but they have a smooth line. It's probably one of the reasons why "radiomen" never developed their domain in a scientific environment, like "IT" people did. But it's a self-solving problem because most of the ITheads are enamored with LTE.
I've seen the tunnel phenomenon, too. There's no good way to cover a lengthy tunnel, unless it's leaky coax. (I've experienced the really old Motorola pre-SpectraTAC stuff with twinlead, too, in one of the popular tunnels in the area.) Some materials detune antennas, or, the tunnels can be like a waveguide and have areas where there is a very high VSWR or phase cancellation. One of the reasons why some places that used low band migrated higher. Just like Edgewater, my hometown started on 33.86, then migrated to 154.445 when high rises were built. The stories from the old-timers went that they could be inside, see the engine, and not be able to communicate with it on low band. Then VHF got jam packed, first with Pike County, PA, Bayonne, Cranford, and Long Island. At that point, it was easier to go to UHF, except now that's threatened, too. Edgewater had the same problem with their base being on top of a 32 story building on top of the cliff. They might have done better coverage-wise with a heavy mechanical downtilt.
North Carolina??? Did you finally retire???
wtp
Member
fireground
hackensack dispatched on 154.385 repeater
fireground was either 154.1 or 154.28 simplex.
i just remember that i could not hear the on the scene stuff unless i was in town and close to the fire.
hackensack dispatched on 154.385 repeater
fireground was either 154.1 or 154.28 simplex.
i just remember that i could not hear the on the scene stuff unless i was in town and close to the fire.
radioman2001
Member
New York City Transit used to have twinax as it was called. Nothing but 2 #10 wires in Teflon sheath that looked like extra large 300ohm TV wire. There were miles of it, and I think it was replaced in the late 80's with Radiax. We found that if the clean up train didn't spray off the steel dust at least once a year signal quality would suffer and the SWR would go up. It was kinda spooky when you could see the other person on the opposite platform and couldn't talk to them direct.
Quote"
North Carolina??? Did you finally retire???
2 years to go and counting (710 days), unless I decide to stay another 2 to pay off the other house. Do spend a lot of time down south when I can.
Quote"
North Carolina??? Did you finally retire???
2 years to go and counting (710 days), unless I decide to stay another 2 to pay off the other house. Do spend a lot of time down south when I can.
Last edited:
902
Member
Got to love "train dust." We had Mitrek consolettes in trays past the edge of platforms and the Mitrek radios would go intermittent. Blast them with compressed air and they'd start working again. Those were combined by a big washing machine sized enclosed combiner and eventually went to Radiax. The outsides were voted, the tunnels were summed audio... except for one platform that had to be voted. But that was 25 years ago.
Those other tunnels, the sprayers used to get hung up in the cables and pull them down, or water would end up in the CCTV camera enclosures and it would look like a fish tank.
Two years is a good number for me, too, if I can hit it. By then, 3 out of the 4 kids should be completed with college, training, apprenticeship, etc. and we can probably leave down south and go back to the Midwest.
All the best!
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