jaymatt1978
Member
Here we go again:
abc13.com/478586/
abc13.com/478586/
Houston Fire Department radio system plagued with problems HFD radio system plagued
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APX8000
Sarcastic Member
I'm going to go out on a limb here and guess they are using a trunked digital talkgroup while conducting interior operations based upon the radio checks in the video. How about complying with NFPA standards and using SIMPLEX and ANALOG !!!!!
Redneck0410
Member
My local fire department conducts radio checks every morning at 0715. The toneouts occur on both the VHF channels and the p25 talkgroup, but the responses from personnel occur strictly on p25. Has been this way for quite some time.
NewsGuy1
Member
What are the chances the encryption used on the tactical channels is causing the problem, or maybe partially to blame ?
Thoughts anyone ?
Thoughts anyone ?
K1STBDENIS
Member
tone outs on p25
I heard from a radio guy that tone outs are done on analog as P25 does not handle the tones very well ??
does anyone have anything about tone outs on p25 ?
thanks have a great day
I heard from a radio guy that tone outs are done on analog as P25 does not handle the tones very well ??
does anyone have anything about tone outs on p25 ?
thanks have a great day
I heard tones on p25 before and it didn't impress me. No surprise here another multi million system with problems. Sounds like El paso counties new county fire system phase1/2 mix. Problems with it but they hide it since it's all enc. Big bucks spent on these and nothing but problems.
That's correct. All of their operations are on their Phase II P25 system. The reason they switched to this system was because their aging UHF conventional system was starting to fail. In fact, they were forced to switch to the new system slightly earlier than planned because the UHF system suddenly quit working on April 25, 2013.
The news story seems to be pointing out a fault in coverage and not the radios themselves, per se. Also, the Motorola spokesman hit the nail on the head about the Southwest Inn fire issues. The state report primarily found that it was a breakdown in training and incident communications protocol, not coverage, that caused most of the problems there. However, coverage issues with the system do exist, and began cropping up soon after the April 2013 switchover, despite over six months of extensive and thorough coverage testing using a handheld.
iamhere300
Member
So how does the system work for the other users? PD? PW? Etc?
Substantiated reports please, not just "A guy who uses the system that lives next to my nephews baby sitter, and their dog told them"
I mean, they all go into the same kind of places.
Substantiated reports please, not just "A guy who uses the system that lives next to my nephews baby sitter, and their dog told them"
I mean, they all go into the same kind of places.
szron
Member
This is all that has to be said. For God sakes there are channels allocated on each band for that purpose.
Because that is not what the 1221 standard requires. It says "shall be capable of operating in analog simplex mode", which I believe this channel fulfills "HFD AC10 Spx". Perhaps they should expand on that with more simplex channels being available, which would be a "best practice"- but not a "standard".
troymail
Silent Key
Encryption appears to be in use but is not likely the problem.
Digital is binary encoding of analog voice which can then be thought of as a data stream (vs. analog voice).
Encryption of that "data" stream simply modifies the bits in the data using a key that requires the process to be reverse on the receiving side (decryption/decode) to get back to the voice.
Either way - it's just data and loss of more than a certain amount of bits in that data stream will result in the decryption/decoding process failing.
If encryption were a problem, the receiver wouldn't be able to decrypt/decode/hear anything except possibly digital noise. There would not be "partial" reception - it's all or nothing.
It's more likely that the problem is poor connectivity to the towers/repeater sites.
Assuming they are using the trunked system and it's towers/repeaters for operations, the signal must make it out of the structure or other operational area to the tower/repeater and then received back by other radios.
Most of the acceptance testing that can heard when a system is first deployed is "on street" testing. Occasionally, there is some "in building" coverage testing -- but I'm guessing that varies from system to system.
I believe the Maryland State P25 P2 system is designed for "on street" coverage. However, some special testing was done for some "in building" coverage for some areas.
From what I've read, the cost of "on street" performance vs. "in building" coverage is vastly different (I'm no expert but -- double, triple the cost?). However, it does appears from what I can see that there are as many as 10-11 sites providing coverage for Houston (below report says 48 antennas!). Perhaps the issue is digital simulcast performance problems given the signal distortion from operating inside buildings.... It's impossible to test for proper performance under all conditions and many times these are exposed through operational use.
Many local (county) systems in my area use both legacy digital as well as the latest P25 P2 systems. Operational procedures vary but in some cases, simplex (local radio to radio comms) might be used), the use of vehicle repeaters are applied (like a mini tower/repeater built into the fire apparatus, etc.).
My county is one a very few in the central Maryland area that has long refused to switch to digital for fire department operational use (although there is some very limited use by command staff). This is due mostly to in building coverage issues. The fire department regularly uses vehicle repeaters for operational (also analog) due to poor in building coverage of the old Motorola system being used. They also have simplex channels that can but are rarely used. In contrast, the police department uses the same exact system but have been using digital for many years.
The article the OP posted didn't go into too much detail on the actual problems being reported so I'm wondering what the specifics are (and under what conditions where) the radios and/or system is failing -- are are they now doing daily radio tests under those conditions... Other departments (such as public works, etc.) are on the street most times and are also far less sensitive to radio issues.
See page 97 and beyond: http://dig.abclocal.go.com/ktrk/PICS/SEPTEMBER14/090114-ktrk-hfd-deadly-fire-report.pdf
Other things this report points out are the differences between older analog system characteristics and trunked systems... most notably that unlike analog systems, only one user can get the channel/talkgroup at at given time, there is a delay between pushing the transmit/PTT button on digital that doesn't exist on analog systems, etc. It takes time for users to adjust to these things when that type of transition occurs but could be seen as a problem by the users of the systems.
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The MD FIRST system is designed for on street coverage in it's entire footprint, and has added towers in areas where local jurisdictions require in building coverage (Kent Co).
PG has been using Phase-2 (and X2 before that) in building longer than anyone in the US.
AACoFD hasn't switched to digital because no towers have been added to support it. It's a big coverage loss going from analog wideband smartnet to digital narrowband smartzone. They won't have a choice very soon when legacy parts are NLA.
I hope to see the detailed report on the communications situation in Houston very soon to clarify some of the statements made in the media.
troymail
Silent Key
Understood - same with Baltimore City and County (P25 Phase 1). Any idea if PG or other systems what is nay issues are being reported? I have no knowledge of special procedures or simplex being used (although I do believe PG has a "talkgroup" in each zone that is simplex if I'm not mistaken).
That's the way I understand it as well. Hopefully there will be sufficient coverage planning and acceptance testing to ensure good in building comms. One of the things that always comes up is how many sites/towers/antennas are required to provide the required coverage -- and that typically leads to price tags that people balk at....
There are numerous observations/recommendations in the report I previously posted (http://api.viglink.com/api/click?fo...ig.abclocal.go.com/ktrk/PICS...ire-report.pdf). Is there another report out/due?
box23
Member
As troymail mentioned encryption by itself isn't the problem. Using infrastructure to talk to someone feet away when neither of you can reliably reach that infrastructure much much greater than feet away is the problem.
Even digital on a fireground can work well. You just have to have the right equipment and someone who has the knowledge to set up that equipment properly, including the use of simplex when needed.
Encryption, in terms of system coverage, is a moot point because it adds no more complexity than the normal digital signal. Now if a radio loses its key(s) that's a whole other story.
The problem the use of encryption does reveal, however, is the egos and politics at play regarding the system.
NIOSH independent review
Sometime back in 2012, the Houston Chronicle did a story about the techs testing the system. Apparently, the testing was EXTREMELY thorough. They conducted signal tests throughout the city and in hundreds of buildings using APX7000 handhelds. From what I recall, it took several months to complete this. Going back to the Southwest Inn fire, reception wasn't a big issue. The issue there was traffic load and too many people monitoring and transmitting on the same channel. There was a section in the State Fire Marshal report discussing how firefighters complained of repeatedly getting "bumped" when trying to transmit. For all those wondering, HFD uses the trunked system for all operations, including fireground.
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