Delaware County Pa New System

captaincab

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This was sent to all users of the Delaware County police and fire system as well as Posted on the county council

Over the past few weeks, First Responders in Delaware County have experienced emergency communication radio issues that are being caused by Troposphere Propagation, commonly referred to as ducting. The ducting prevents First Responders from communicating with the 911 Center. Police Departments from across the County have reported problems with radio communications during the month of July and there have also been reports of radio problems due to ducting over the past few years.
First Responders throughout the county and members of Delaware County Emergency Services have expressed concerns of the current radio system for several years, citing examples which have put first responders and the community in danger. The current Council began addressing these concerns immediately after being sworn into office.
In January, Council invited members of the public safety community and residents to attend a presentation on the findings of the "Delaware County Emergency Radio System Assessment and Conceptual Design" report. The VComm Telecommunications Engineering firm provided the results of their comprehensive evaluation of Delaware County’s emergency communications network and a framework to modernize the County’s public safety capabilities.
Following the presentation, Council voted to approve the purchase of a comprehensive emergency communications radio system and network infrastructure. The installation and implementation of the new system is expected to take approximately three years.
In order to address the immediate and critical need to allow First Responders to communicate, the County is piloting a cellular extension of its Land Mobile Radio System that will operate outside of the T-Band ducting area. While ducting can also occur in the cellular spectrum, we do not believe that it is as pronounced as it is in the T-band spectrum. The immediate response plan has been put into place to ensure the safety of all First Responders and the community.
“The safety of our First Responders and the public are our top priority,” said Delaware County Council Chairman Brian Zidek. “We are doing everything we can to address the safety concerns that the current systems presents.”
The County is aggressively pursuing a new radio system and is meeting this week with potential project engineers to define their scope of work. The new radio system will move emergency communications out of frequency bands that are shared with digital television stations. The system will also add security features that prevent unauthorized use of the system and provide advanced safety features. The new system will also replace legacy equipment that has reached end of life and no longer meets the growing demand of first responders.
As the County awaits the completion of the new upgraded system:
• The County is requesting that the FCC investigate the dramatic interference occurring on County licensed radio frequencies.
• The County is requesting that all authorized agencies submit proof of certification of effectiveness of their portable and mobile radios equipment.
• The County is studying the operational condition and appropriateness of its current radio infrastructure antennas and receivers to confirm reception capabilities and if possible, reduce ducting interference.
• Specific to fire communications, the County is encouraging the use of simplex channels for incidents. Delaware County Emergency Services is working with the Fire Chief’s Association to encourage a dedicated member to monitor a specific fire-ground channel allowing for the Incident Commander to remain on the primary fire channel. A meeting with the County Fire Chief’s is planned to discuss operation changes.
 

2IR473

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I don’t listen to Delco much, but I haven’t heard any issues with ducting or skip while listening. Can someone tell me if they have heard this ? and has it caused an issue with communications as stated in the post above ?

When I worked in a Montgomery Co municipality back in the early 90’s, we were on VHF low band, and we didn’t experience any issues with skip that I recall (and low band propagation was strong back then).

Years later, when we went to 800 mHz (analog), I can recall maybe two or three times when I heard a transmission come through that was obviously skip or ducting. It didn’t create a hazard to communications, and only lasted one or two transmission and was gone. I am curious if the issue in Delco is as prevalent as they make it sound.

Also, wouldn’t the PL tone on the input generally keep these distant signals out of the repeaters ? Do the distant signals have the same PL tone that allow the repeaters to open ? I am just confused as to how this is “preventing First Responders from communicating with 911 center” ? I have friends that have worked as dispatchers, and they say they used to drop the PL tone on their console so they could hear distant signals during quiet overnight shifts, so if they had to drop the PL on their console, wouldn’t that mean the PL tone was in fact keeping the distant signal out of the repeater?

Not trying to cause a controversy here, just trying to understand why this is happening to Delco when it seems the technology to prevent it has existed for decades. If this is just a B.S. excuse to spend tens of millions of dollars of tax payer money, well then I get that, but if I read what they are posting as legit, I am trying to understand the problem, and the real solution.
 

GTR8000

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They don’t seem to understand that they are subject to ducting on any band and at 800mhz it’s usually worse at times.
Except that 700/800 ducting doesn't involve a full 6 MHz wide carrier like a T-Band TV signal occupies. A couple of random 12.5-20.0 kHz 700/800 frequencies ducting that may or may not be in use locally, vs the entire 506-512 block getting hammered with one TV carrier signal, wiping out all public safety frequencies within that block at once. Apples and oranges.
 

phillydjdan

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I don’t listen to Delco much, but I haven’t heard any issues with ducting or skip while listening. Can someone tell me if they have heard this ? and has it caused an issue with communications as stated in the post above ?
The problem isn't that anyone is "hearing" anything. The issue is the DTV signal blocks the Delco unit's signal getting into the repeater. So really, the issue is we AREN'T hearing anything when we should be.
 

phillydjdan

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I'll add this: it certainly doesn't help that most police departments opted to spend twice the money on cool low profile "puck" style antennas. They only stick up about 1/2", which does not help the signal get out. They are essentially transmitting into a paint can for all those antennas are worth. They could probably solve most of the mobile ducting issues by simply installing 3db gain low-profile antennas or even standard 6" whips. Just my 2 cents, what do I know? lol
 

GTR8000

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Even if the mobile antennas were +3 dB gain whips, you'd still have issues with the portables getting into the repeaters, drastically reducing in-building coverage most of all. And of course that 6 MHz of DTV signal affects both the inputs and outputs, so a unit on portable on the fringe of coverage might not even hear the repeater, to say nothing of not being able to get inbound.

Morris County, NJ experiences this issue, where their entire 11 channel 477-478 P25 TRS gets taken out by a DTV station down in Virginia. It's a pretty awful thing to deal with. At least on 700/800, those slices of the spectrum are dedicated to public safety, and so the interference/ducting issue is greatly mitigated. As I said, you may experience one or two individual frequencies ducted into your area from elsewhere, but it's certainly better to have one or two channels knocked out vs an entire TRS or network of conventional frequencies that fall within the same block.
 

saber2k5

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What Delco should do is apply to the FCC for STA frequencies in the 460 Mhz range. No DTV interference there. They can use existing equipment, as in most cases it is in 450-512 Mhz range.
 

philacop

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Another idea is to go after some 453 MHz frequencies that were abandoned by Philly or just piggyback off the states p25 system??
Burlington will be off the T band stuff now so they and SEPTA will be the only real T band in the Del Val besides a few freqs in Salem co
 

HM1529

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What the hell is a "cellular extension"? Are they telling cops to pull out their cellphones when they need help??
Maybe integrating Zello Work or another cell app with the consoles as an alternate way to get to the dispatcher from the field? If the radio doesn't make it, use the app which still has the dispatch traffic coming across? How does ZelloWork differ from the free Zello app?
 

captaincab

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You can blame a certain radio shop in the southern end of Delaware County for most of those crappy puck antennas the fire and ems vehicles don’t have as many issues with their mobiles but they usually have a real antenna.

I'll add this: it certainly doesn't help that most police departments opted to spend twice the money on cool low profile "puck" style antennas. They only stick up about 1/2", which does not help the signal get out. They are essentially transmitting into a paint can for all those antennas are worth. They could probably solve most of the mobile ducting issues by simply installing 3db gain low-profile antennas or even standard 6" whips. Just my 2 cents, what do I know? lol
 

phillydjdan

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Na Montco is 800. Burlington County NJ is phasing out their 500mhz system
Phased. Past tense now. Everyone is off UHF except Salem County, Mercer County and SEPTA now in this region.

And, wasn't it Gloucester County that went from 500 to 460 before switching to 700?
 
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