1. #1
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    Default Legality and Safety of Repeaters

    The 'Radio Guy' in my District is convinced that using a high band repeater for the fireground frequency is both 'illegal' and 'dangerous'

    He claims that its 'illegal' from OSHA - I checked with them and they have no such rules. The NFPA might have something to say about it, and Im waiting for my NFPA book to be delivered. Does anyone know anything about this?

    As far as dangerous, he claims that if the repeater dies, then teams 10feet from each other cant talk on the radio. Again, I beleive that with redundant repeaters its not a problem. The pro side of it is that communications are clear across the fireground.

    Any thought on either of these?

    Thanks.

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    I know of no NFPA or FCC reg prohibiting the use of repeaters on fireground. Both local and fed depts do so.

    Failure of the repeater should not be a problem if the radios have a talkaround capability. This allows the radios to work in a non repeater mode. This is the same as a non repeated frequency. You would be limited to "line of sight" capability. It would also be a a reduced power, especially the handhelds.

    If your handhelds are transmitting at 5 watts throught a repeater, the repeater will boost the power to 25-100 watts depending upon the repeater. When you lose the repeater, you lose the power boost which will decrease range depending upon the terrain, bldg construction, etc.

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    Fireground tactical communications -- for most firegrounds -- should be simplex.

    Don't rely on a repeater in an apparatus or on a tower miles away when you only need to reach a few hundred feet.

    Why spend many times more money building a redundant network, with just as good coverage, that you can do just as reliably for less money by using simplex?

    The radio signal has a much, much better chance of reaching 10' than it does hundreds or thousands or tens of thousands of feet to a repeater, then coming back and being heard as well.

    If you'd like to use a mobile repeater so Dispatch can listen in too, and that works for your system, that's not necessarily a bad idea. Just to throw out a frequency (don't know if it's a valid combination/use off-hand), you may talk-around on the fireground on 465.000 in simplex mode...but there's a repeater that repeats it to 460.000 so dispatch can listen in and talk direct to units if neccessary (mayday calls, etc).

    There are going to be places repeaters make sense -- certain very large buildings for instance where simplex simply can't reach everyone you need to reach.

    Repeater systems have their place -- for apparatus responding, and for command & control nets. They shouldn't be relied on for the fireground.

    Just my humble opinion
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    There is an NFPA standard requiring availability of simplex channels (read talkaround)for trunked systems.
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    We used a repeater for a while on the fireground. It failed while 3 of us were inside a building. Never heard the evacuation orders. Repeater has since gone bye-bye and ain't coming back.
    "This thread is being closed as it is off-topic and not related to the fire industry." - Isn't that what the Off Duty forum was for?

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    We use a repeater to convert our high-band system back to low band to reach dispatch. Otherwise, on scene communication is radio-radio no repeater necessary. If the repeater fails we have the option of going to a dispatch monitored tactical channel to maintain a link back to a dispatcher.

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    it is NOT illegal as long as you are licnesed on said frequency ........where is nmfire ?
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    Your "radio guy" has been putting his head a little too close to the transmitters....
    ‎"The education of a firefighter and the continued education of a firefighter is what makes "real" firefighters. Continuous skill development is the core of progressive firefighting. We learn by doing and doing it again and again, both on the training ground and the fireground."
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    Originally posted by Weruj1
    it is NOT illegal as long as you are licnesed on said frequency ........where is nmfire ?
    Have no fear, I am here and armed with NFPA 1221

    First order of buisness, your "Radio Guy" is on something, possibly PCP or LSD. Either way, he is hallucinating.

    Now, when you say you want to use a "high band repeater on the fireground", are you talking about a vehicle repeater that would, for example, link your high-band portable radios to a low band dispatch channel?

    If that is the case, then he is totally out of whack. Those things work on a single frequency so your portables are all talking to eachother anyway. You are talking to other people on scene directly. This is an illustration I made for a radio training presentation here:



    As you can see, if you remove the truck repeater, you can still talk portable-to-portable on scene AS LONG AS EVERYONE IS USING THOSE PORTABLES! If you have some people using the "high band" portables and some people using "low band portables" and you lose the repeater, yes you will lose the link between the two. This is usually not the way it works though. Usually, everyone is using the common portable channel.

    The only thing NFPA has to say that is remotely close is the following, translated to english:

    A simplex channel shall be provided for on scene tactical communications (it doesn't say you have to use it).

    A trunking talkgroup shall not be used to fullfill the above requirement.

    Portable radios shall be of a multi-channel nature to allow the above.

    Portable radios shall not require the use of RF amplifiers (like a CB linear amp) to communicate within it's dispatch area. And RF amplifier is not a repeater.

    If this "Radio Guy" is refering to a base repeater on a radio tower, the same applies, the difference is you can not talk portable-to-portable without putting it on direct or simplex. Talking through a base station repeater is totally different and if you are out of range or the repeater dies, no one will hear you. There are contingencies for this, like I said you can switch to direct or operate on another simplex channel. This brings me to my next poit that I always say... interior fire attack should NEVER be on a base repeater. It should always be simplex (either the direct mode or another tactical channel).
    Even the burger-flippers at McDonald's probably have some McWackers.

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    Hello,

    Your radio guy is on the right track..... You should not be using a repeater for fireground operations (there may be some special needs for one in certain types of buildings and should only be used than in those cases since having no communications would be worse).

    There are some standards by the NFPA. (yes I am aware they are not law and are recommendations)

    NFPA 1221
    Installation, Maintenance, and Use of Emergency Services Communications Systems

    6-3.1.3: A simplex radio channel shall be provided for on-scene tactical communications.

    and yes as it was pointed out there is also something about trunked system, but that is not what is being discussed here

    6-3.4.1.26: Trunked radio system talkgroups shall not be used to fulfill the requirement for the provision of a simplex radio channel for on-scene tactical communications.



    But it is just common sense. Sure you can switch to a simplex freq...... But if your in trouble and in a building the last thing you need to be doing is trying to figure out what freq you need to be on to get your mayday out. In general a repeater should never be use for fireground ops and I believe most good radio techs would back that up.


    Gary
    Last edited by captain247; 12-23-2004 at 10:13 PM.

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    Captain247- The main thing we need to establish here is what kind of repeater he is asking about. If it is just a vehicle repeater to link their fireground radios to dispatch, there is nothing there to inhibit fireground communications.

    Like I said in the end of mine, if it is a true semi-duplex base station repeater, that is a horse of a different color. In that case, communucations would be inhibited hence the common sense rule of using simplex for interior operations. There is nothing to get in the way.
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    Hello again.....

    NM I was getting ready to write something back and deleted it with your second post..... I think you are 100% correct and that more info is needed.... However I would not want the original poster to think that his radio guy is on somethingand should not take his advice based on those comments.

    I believe his radio guy agrees with both of us (if I understand your post correctly) and that is that the "fireground communications" (which is what the original post states)should be simplex and that a repeater should not be used to communicate between firefighters at the scene.

    Gary

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    I am a radio tech and a volly FF...so I have input from two directions. I have worked with vehicular repeaters a fair amount. Their main operational theory is to provide portable radio coverage in areas that a five watt handheld can not communicate with the base/repeater or other units at a distance. I have never worked on or used one that gave me that "warm fuzzy feeling". They are a "band-aid" solution to a radio system that does not totally meet your needs.

    However, I have worked with tactical "on-scene" repeaters that have worked well. The only application that I have seen them in is wildland fires that may extend over several miles and better portable coverage is needed.

    As for the concern of failure of the repeater. The repeater should be the last component of the system that you should be concerned about failing...however, they do at times. Most are housed in "ideal" enviroments with many back-ups.

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    I personally am not a huge fan of vehicle repeaters either. I would much prefer a base infrastructure adequate enough to not need them. We do NOT use them for tacitcal on scene work, it is only to link our portables back to low band for dispatch which not a life-or-death thing.

    The one thing I think we can all agree on for sure is there is no "law" against the use of repeaters. They have their uses, you just need to make sure your life-or-death inteior attack is not relying on them for communications with people outside the building who are going to come save your ***.
    Last edited by nmfire; 12-24-2004 at 01:29 PM.
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    I think that radio communications is a very technical subject that does not lend itself to blanket statements.

    Sometimes, simplex (aka 'direct') communications are not adequate in large buildings. Page 10 of Volume III, 2004 of the Line Copy Newsletter from Fairfax County VA Fire and Rescue Dept chronicles one of these situations. Units were operating in a 5 story building, and neither their trunked channels nor their simplex channel would afford them adequate comms within the building. When mobile repeaters were brought to the scene, communications were adequate. If the building had a 'built in repeater system' then radio comms probably would have been perfect.

    Boston MA FD has been using repeaters on the fireground for the last ?20 years. When they cannot hit the repeater, they switch over to simplex comms.

    AFAIK - most of the big city FDs that operate on trunked radio systems stay on the repeaters until they find themselves in dead spots or problem buildings.

    Note - repeaters typically use 2 frequencies - a 'input' frequency and a 'output' frequency. It takes a little bit of study to understand how repeaters work.

    Peter Sz - I am not a firefighter - I am not a radio engineer - but I do know a thing or two about radio systems.

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    Default Repeaters

    Well, Im back.

    2 items got me to post this. First off, his 'all knowing' use of the work illegal struck me as crazy.

    We have a 2 radio system. Low band to dispatch, high band simplex for tactical. Because our Chiefs REFUSE to act like adults and run command from the back of their trucks (which are all set up for command post ops), repeaters were put in their trucks so that on Chan1, they can talk with thier high band portables to Dispatch.

    This causes 2 problems. First 80% of the time they forget to switch from repeater to tactical, so commo is always messed up. Second, having high band in the trucks means that people invariably try to use high band instead of low band when they are not on scene. We regularly have Chiefs yelling into high band to give orders which go unacknowledged b/c the trucks are more than 1/4mile away.

    So yes, the technology works, but the people dont.

    I then heard about PG county where a setup is used so that tactical transmits on the repeaters outgoing freq, and command transmits on the incoming freq, which means that nobody has to switch.

    We have been trying for 10yrs to get the Chiefs to learn.

    Thoughts?

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    So let me make sure I have this right.

    You have VHF vehicle repeaters connected to the low band radio in the truck. The chief's portable has channel 1 as the repeater channel and maybe channel 2 as the tactical channel? Am I on the right track?

    What you are describing in the second thought is a normal semi-duplex base station repeater. The guys are using direct for their operations. Everyone on scene can hear them and they are not going through a repeater. Command is on the repeater so he can talk to everyone. He isn't inside the structure so he isn't worried about not hitting the repeater from where he stands.

    These are two very different animals.
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    Radio tech here also. Volunteer FF, and Fire Service Instructor. Couple thought about the previous posts.

    As toddman?? (I think) said, he hasn't seen a vehicular repeater that gave him a warm fuzzy feeling. Me either! Yes they work, but it's not the best situation, they are somewhat clumsy for the average joe to use, causes more clipping of transmissions as its one more step in the process of having to wait for a transmitter to power up, and a reciever to unsquelch - takes time, although just a bit...none the less - clipped transmissions - the beginning of transmission will get cut off, no matter how many times you train your people to wait before they start talking. It's also one more step in the process to #E^%@ up the audio quality...they just don't sound all that good.

    I am a firm believer that all tactical fireground communications should be on a simplex channel, unless special circumstances warrant the required use of a local repeater due to building size etc...

    The only other exception would be if your communications system(s) were engineered from the get-go to provide you with 100% in building coverage for your jurisdiciton. If that wasn't a design consideration, and it hasn't been tested to that standard - plan on your repeater (system) not working in building. Most often repeater (trunked systems fall in this category also) systems or not designed for in building penetration for 100% of the area, simply due to cost issues (some are, but as a rule not). Yes it will work in some building, even alot of buildings, but not the one your gonna need it in!!!!!! There are buildings that will have good coverage; someone has to live close to the repeater tower site right? but plan on most not, especially if you are required to operate below ground level! Test coverage before you need it! And don't just walk into a building lobby and do the "CAN YOU HEAR ME NOW" thing... Try it in several places on several floors, basements, elevators, bathrooms. Also be aware that there are buildings constructed of materials specifically designed to reject the penetration of radio frequencies - thats handy huh? Also, any place that does radiological imaging is going to have lead lined sheetrock in at least a portion of the building.

    Simplex for tactical is IMO most often the way to go. There are systems for local repeater coverage of an incident, put it on your ladder truck etc...and then the repeater is right there on scene - this is an option, but I havn't been able to "test" these as of yet. Only problems I see are what if lader gets reassigned or goes out of service ... just to damn easy to drive away with the repeater...
    Rick Gustad - Chief
    Platte Volunteer Fire Department
    www.plattevfd.com

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    Our handie talkies are on a non repeated channel. We speak HT to HT.

    There are only two times I can think of that we use repeaters to assist in communications.

    1. Highrises, we have a portable repeater that we can use however since most of you don't have 70+ story buildings I doubt anyone else out there needs one.

    2. There is a new transit repeater, also something that doesn't apply to anyone else.

    PS-I've also seen some local buildings that have installed boosting systems for our radios that are activated by a key we carry but that also doesn't apply to the rest of the world.

    Otherwise all commuincations are HT to HT. Most situations it is benefictial not to have to hit a repeater.

    Something to consider is setting up a procedure for a relay if a problem occurs in a large structure. Have locations, distances and assignments figured out if possible before hand to aliviate confusion.

    FTM-PTB

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