I would suggest programming them with the 4C9 NAC and see if the SDS decodes them. If so, then that is the correct NAC. It's certainly possible that they are not using the same NAC across all channels, but I really don't see the point of doing so except to add complication to the programming.
Ocean County 700MHZ Fire Ground channels (Simplex)
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Will do.
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Sounds good, thanks.
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edisonfire
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Question re: Ocean County fire operations. I use the Unication to monitor. I obviously hear the dispatch, some response/operations. Are all FG operations on simplex? I hear the zone traffic (west/east etc) I generally don't hear the Tactical channels. Am I missing something?
Tactical channels aren’t regularly used unless there’s a major incident going on or multiple calls on the ops channels. County has moved away from the zone naming on 700 MHz.
Correct me if I am wrong, but doesn't the NFPA state that fire ground frequencies are supposed to be used on analog simplex only? Especially for interior operations, because of issues with being able to hear digital radio transmissions in that type of environment.
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If that's true, there is a lot of places not abiding by that guideline.
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Generally speaking NJ has only adopted portions of NFPA guidelines. NJ is governed by PEOSHA and adopts via Chapter Law what it is interested in. Enforced by NJ Dept of Labor.
As far as I know the guidelines on radio communications have not been adopted.
Interesting to note that these guidelines are often cited in accident reports even though they have not been adopted.
While Simplex may be used the last time I looked, it was suggested that FG operations be monitored by someone off the FG and not the IC. Re Digital I do not recall.
RBFD415
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I know this was discussed prior, r60 is essentially correct on all points. I would add that the International Association of Fire Chiefs ("I" Chiefs) also adopted a position paper to the same effect, fireground ops should be on legacy simplex, (non digital) analog radios. The aspects of whether its been adopted by NJ as law may not be as significant as you would suspect. The fact it was already accepted and is a consensus standard (nationally) will weigh heavily in civil litigation across the board.
As for the final point on local fireground being monitored, I have noted more than a few departments arrive on scene and then inform county they were switching to local fireground and off the monitored response channel. Do they have staff standing by in the station monitoring? Unknown?
As for the final point on local fireground being monitored, I have noted more than a few departments arrive on scene and then inform county they were switching to local fireground and off the monitored response channel. Do they have staff standing by in the station monitoring? Unknown?
I am curious to know how well 700mhz vs 450mhz, on analog simplex, works on the fire ground, especially inside large metal buildings or something like a multi story or high rise type building?
Another issue on fire ground frequencies, especially on UHF, is that many agencies have their FG channels programmed at high power in the mobile radios. When I was a member of my FD, it was very common to have Chief's cars & apparatus pushing anywhere between 25-100 watts on UHF FG channels, instead of having them programmed for low power. On numerous occasions, during an interior fire attack, you had FFs trying to communicate with each other or the officer assigned to "Operations" and you had an engine doing water supply operations, transmitting some nonsense message, at high power, on the same FG channel, which totally "covered" the radio transmissions from inside the fire. If one of the FFs were in trouble and tried to call a "MAYDAY", it would not have been heard by the IC or the Operations Officer.
We have Career "Class 1" Department's that still do this in CT... sounds like they are just waiting for their own LODD before they change
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I would suggest searching the web for "UHF vs 700 propagation" and "UHF vs 700 in-building penetration", where you will find no shortage of answers. You'll get even more results if you search on 800 instead of 700, however the same principles apply since the two bands share nearly identical characteristics, which is why it's not uncommon for some trunked sites to have a mixture of 700 and 800 frequencies. They are treated as a single band when it comes to the majority of infrastructure and subscriber equipment, and it would be pretty rare for you to find any hardware these days that is purely 700 or 800, but rather 700/800.
As to whether analog vs digital affects how far a signal travels or how well a signal penetrates in-building, the simple answer is "no". RF is RF. There are differences when it comes to how well that RF will be received based on the strength of the signal. Analog gets noisy to the point where it's nearly impossible to recover anything intelligible, and you'll just hear static. Digital tends to be "all or nothing", although it's not uncommon to have some words drop out due to intermittent bit error.
There are some who swear by analog because even when the signal fades a bit, you can still generally make out what is being said through the noise. Others swear by digital as the transmissions are devoid of noise due to a weaker signal. As long as the vocoder can recover the majority of the bits, the transmission will be clear on the receiving end.
I've always been a proponent of KISS...analog simplex is pretty foolproof when it comes to fireground comms. It just works, and has for decades. There is a reason why the FCC allows for low power analog operation on some 700 MHz frequencies, because they acknowledge that there are going to be agencies that want to follow the NFPA recommendations, however they also need to operate in the 700 MHz band.
That being said, the P25 vocoder has come a long way since the early days. The ABME+2 vocoder does a much better job dealing with loud background noise (common on the fireground), and improvements to that technology are continuously being made. It wouldn't be entirely fair to judge digital based on reports from 20+ years ago, which unfortunately many are quick to do.
While I would personally stick with analog simplex, I also acknowledge that digital has improved, and so it's nowhere near the epic fail it once was.
Oh and as to your original question...the issue with digital aren't that you can't "hear it" well, but rather that the encoding of clear voice can suffer when there is loud background noise. If you've ever had an APX with a 3w speaker on full volume listening to the Rockland or Orange systems, you'd know that it's plenty loud.
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