Isn't this dangerous?

[mmckenna]

Fire folk usually seem pretty radio savvy and won't hesitate to switch to direct when needed. At least, that's been my experience.

Good point, that's been my experience, too.
They seem to be more knowledgeable than most PD.

 

[MysterAitch]

How easy would it be to have vehicle-based cross-band repeaters that output on both uhf/800 (to ground crews) and vhf (to the standard fixed repeaters)?

How far apart would the antennas need to be to not desensitise? Fire trucks aren't particularly short so would e.g. one at each end be far apart enough?

If there are multiple vehicles and this causes problems, then just turn them all off except one nominated as being the comms truck?

Perhaps I'm being naive in bringing computer/IT networking ideas into the RF space, but this sounds like an easy (if perhaps slightly naive) solution and allows users on the ground to toggle between the two as needed?

 

[mmckenna]

How easy would it be to have vehicle-based cross-band repeaters that output on both uhf/800 (to ground crews) and vhf (to the standard fixed repeaters)?

It would be easy. Not cheap, but easy.

How far apart would the antennas need to be to not desensitise? Fire trucks aren't particularly short so would e.g. one at each end be far apart enough?

Depends on the frequency, but not far. Even at VHF, a couple of feet and good filtering will work. Running different bands, and they can be closer.

If there are multiple vehicles and this causes problems, then just turn them all off except one nominated as being the comms truck?

Good systems out there will negotiate and shut down mobile repeaters on their own.

Perhaps I'm being naive in bringing computer/IT networking ideas into the RF space, but this sounds like an easy (if perhaps slightly naive) solution and allows users on the ground to toggle between the two as needed?

It is an easy solution. It's also a commercially available, off the shelf solution.

However, it can be an expensive solution to a problem that may not exist. Not every agency wants or needs to record fire ground. Not every agency needs to have dispatch listening in on it.
But some do, and there are some solutions.

 

[zz0468]

Not every agency wants or needs to record fire ground. Not every agency needs to have dispatch listening in on it. But some do, and there are some solutions.

And the cheapest and easiest solution is a trunked talk group where it works, and direct where it doesn't.

 

[Voyager]

When they want to justify something, they’ll say “NFPA requires it”. When they don’t want to do something, they’ll say “NFPA is only a guideline “.

Guidelines not followed become liability/negligence in court cases.

 

[Voyager]

False information, NFPA does not require you to use a simplex channel for fire ground use. The NFPA requirement is that there be a analog simplex frequency available, there is no requirement to use it on the fire ground.

I’m not saying I agree for the record, I’m all for simplex fire ground channels.

How does having something available make you more safe if you don't use it?

I'm not saying you are wrong - only that having a radio channel available has to have a reason tied to it, and if there is a benefit tied to it that is not used that benefit is lost.

 

[iceman382]

Which specific NFPA rule?

Lots of areas do this despite the fact it is against NFPA rules.

Which specific NFPA rule?

 

[belvdr]

How does having something available make you more safe if you don't use it?

I'm not saying you are wrong - only that having a radio channel available has to have a reason tied to it, and if there is a benefit tied to it that is not used that benefit is lost.

It doesn't make it any safer by itself, but if for some reason, the repeater network is unavailable, simplex should work. It only requires the radios be within receiving distance, which on a typical fireground should be the case.

 

[mmckenna]

Which specific NFPA rule?

2010 Edition. There are newer versions...
NFPA 1221 9.3.1.3 A communications radio channel, separate from the radio dispatch channel, shall be provided for on-scene tactical communications.

NFPA 1221 9.3.1.4 A tactical communications channel shall be capable of operating in analog simplex mode.

There's a bunch of other stuff that I'm not going to type out that some might find interesting.

 

[kruser]

So a fire department in Elizabeth, NJ uses their trunked p25 talk group for fireground isn't that awfully dangerous? I can't imagine being in a basement of a fire and calling for help only to get an "out of range" error.

I always thought fireground should be analog and simplex with an incident commander controlling the scene. Even P25 conventional simplex makes me feel uneasy for fireground.

Your thoughts? Any FD's near you using trunked talk groups for fireground operations? How do they make out?

They have about 30 TAC channels here used for Response. I find they also use them often for fireground. I do not know if they still have analog fireground channels for use as all incidents have been out of my range for the old analog channels since they went P25 quite some time ago.

 

[hill]

All the local jurisdictions in this area are using a trunked radio talkgroup for fireground, including Baltimore City and Baltimore County. Most are now P25, Anne Arundel County is the last analog trunked system in my local area. They have using a talkgroups for fireground going all the way back to late 1980's in Baltimore County on the analog TRS.

 

[KB7MIB]

The Phoenix Fire Department Regional Dispatch Center maintains a 15 channel analog conventional VHF simplex system, which they utilize for fire and hazmat incidents, and they use one of the regional 700 MHz P25 simulcast trunked systems for EMS and any other calls not involving a hazard zone.
The Phoenix Valley is ringed by mountains, and has mountains running through the center of it, and this is where the VHF sites are advantageously located, giving them excellent simplex coverage on the order of 2,000+ square miles, covering 26 different jurisdictions. (Several intelli-repeater high sites for the trunked system are co-located on these mountaintop sites as well.) This allows a tactical radio operator to monitor the simplex fireground communications, as well as communicate with the IC as needed on a single channel, and I believe it is all recorded as well.

This is because of lessons learned from past firefighter LODD's. (They have several SOP's that are a direct result of past LODD's. Assigning multiple battalion and deputy chiefs, as well as safety captains to fire and hazmat incidents is another.)

The Mesa Fire Department RDC uses the other regional simulcast system for all incidents, but is in the process of re-establishing an at least 4 channel analog conventional VHF simplex system, similar to what they had prior to the simulcast system, and will probably split incidents like the Phoenix FD RDC does. Curently, the VHF dispatch channel is the only channel up and running.

The Phoenix FD has become very safety concious, and using two seperate radio systems is one result of this.

John
Peoria, AZ

 

[lmrtek]

That's the same stupidity that killed alot of good men on 9-11.
............
One repeater goes down and everybody on fire ground is back to using hand signals.
..............
No REAL radio tech would ever advise such a risky procedure.

 

[riccom]

The Phoenix Fire Department Regional Dispatch Center maintains a 15 channel analog conventional VHF simplex system, which they utilize for fire and hazmat incidents, and they use one of the regional 700 MHz P25 simulcast trunked systems for EMS and any other calls not involving a hazard zone.
The Phoenix Valley is ringed by mountains, and has mountains running through the center of it, and this is where the VHF sites are advantageously located, giving them excellent simplex coverage on the order of 2,000+ square miles, covering 26 different jurisdictions. (Several intelli-repeater high sites for the trunked system are co-located on these mountaintop sites as well.) This allows a tactical radio operator to monitor the simplex fireground communications, as well as communicate with the IC as needed on a single channel, and I believe it is all recorded as well.

This is because of lessons learned from past firefighter LODD's. (They have several SOP's that are a direct result of past LODD's. Assigning multiple battalion and deputy chiefs, as well as safety captains to fire and hazmat incidents is another.)



The Mesa Fire Department RDC uses the other regional simulcast system for all incidents, but is in the process of re-establishing an at least 4 channel analog conventional VHF simplex system, similar to what they had prior to the simulcast system, and will probably split incidents like the Phoenix FD RDC does. Curently, the VHF dispatch channel is the only channel up and running.

The Phoenix FD has become very safety concious, and using two seperate radio systems is one result of this.

John
Peoria, AZ

John I remember this, they held off going to the digital system cause of that fact, they and the ntsi was doing a study about this as well if my memory is correct, I am glad they held to the vhf side of the system, that is a 50 year old voting system that had never failed.

 

[fredva]

In the county where I reside, fireground channels on the trunked system are the primary means of radio communication at fire scenes. They want the dispatchers to monitor radio traffic at the scene, and the dispatchers are relied upon to send out emergency evacuation tones if needed and to prompt for periodic PAR checks. They may also be extra ears to listen for a mayday. If the radios start cutting out, the on-scene commander will order a switch to a simplex channel.

Where I grew up, much of the at-scene communication is in talkaround (simplex) mode as the norm.

 

[Voyager]

2010 Edition. There are newer versions...
NFPA 1221 9.3.1.3 A communications radio channel, separate from the radio dispatch channel, shall be provided for on-scene tactical communications.

NFPA 1221 9.3.1.4 A tactical communications channel shall be capable of operating in analog simplex mode.

I know of no TG on any system type that can operate in simplex analog mode. Therefore the original assertion that trunked is against NFPA rules is accurate (for fireground channels).

On-scene cannot be on the dispatch channel, and must be capable of analog simplex. The only grey area is the use of a repeater, as a button can make it analog simplex and even when on repeater can hear analog simplex transmissions provided the CTCSS/CDCSS is the same or is not used at all.

Note that it says the channel must be capable of analog simplex, and not the radio as a whole.

The reasoning is simple. IF the trunked system does down while in the middle of operations, you just lost your communications. That is the WORST thing that can happen to persons in dangerous situations. The same is true for a repeater. You might be able to hear others who have switched to simplex, but not talk back. And they want FFs focused on the job and not at trying to make the radio work again. When you break it down like this it really is the safest choice.

While the arguments about more ears are true, that will not save you in the system goes down either. And if there is a collapse, the odds of a local simplex signal being completely lost (from all other radios) are much lower than losing a signal from a tower that may be miles away. Better to have many receivers on-site than an eggs-all-in-one-basket receiver elsewhere.

 

[Danny37]

Like someone else mentioned any good radio tech would know a trunked fireground talk group is way too dangerous. There's absolutely no way for techs to test to make sure every single building or house will have coverage for the talk group. Simplex analog will not give you an error or make you miss a repeater that may be miles away.

As far monitoring by dispatchers and recording, this easily be done with a vehicle repeater rebroadcasting to a tower.

Too risky for me. As others have stated Fire personel tend to be more radio savy compared to PD I'm sure the idea has been pitched numerous times.

A fire department in upstate New York running a mutual aid run was using their repeater as fireground, their mayday calls weren't heard because the repeater couldn't pick up their signal. I doubt anybody monitors their input frequency at the fireground. Could've easily been prevented using a simplex frequency.

 

[crazyboy]

2010 Edition. There are newer versions...
NFPA 1221 9.3.1.3 A communications radio channel, separate from the radio dispatch channel, shall be provided for on-scene tactical communications.

NFPA 1221 9.3.1.4 A tactical communications channel shall be capable of operating in analog simplex mode.

There's a bunch of other stuff that I'm not going to type out that some might find interesting.

From the 2016 Text
9.3.1.3* A communications radio channel, separate from the
radio dispatch channel, shall be provided for on-scene tactical
communications.
9.3.1.4* At a minimum, the tactical communications channel
identified in 9.3.1.3 shall be capable of operating in analog
simplex mode.
9.3.1.5* Trunked system talk groups shall be permitted to be
used to provide on-scene tactical communications if desired by
the AHJ, and the provisions of9.3.1.3 and 9.3.1.4 shall still
apply.

Special Attention to 9.3.1.5

 

[mule1075]

Have to remember technically they are not rules. They are recommended standards many places do not go by what the NFPA says or recommends.

 

[crazyboy]

Have to remember technically they are not rules. They are recommended standards many places do not go by what the NFPA says or recommends.

Correct, they are standards, but I guarantee they will come up in NIOSH reports and more importantly in court if they are not followed.