Tetra interference

[WB3DYE]

The MTA plans to move city bus radio transmissions into the same bandwidth as that of the Fire Department and EMS, despite a federal order that warns about possible interference with first responders, the Daily News has learned.

A recently approved $202 million contract with Parsons Transportation relies on a type of radio system the Federal Communications Commission bans from use on the so-called “public safety” bandwidth.

The FCC found that the technology that Parsons uses — called TETRA — could potentially interfere with public-safety radio calls



MTA to change bus radio transmissions, raising safety fears - NY Daily News

 

[Spec]

TETRA NYC MTA

Just saw this tidbit in the Daily News.
http://www.nydailynews.com/new-york...ssions-raising-safety-fears-article-1.2549643

 

[Darkstar350]

So this will supposedly replace the 900mhz bus system?
I did hear rumors that the MTA will eventually build a 700mhz system - but i imagine that would be P25...

Personally i am not a fan of these new digital voice formats such as MotoTRBO - makes way too much noise floor and if nothing else i think it is definitely inappropriate for public safety use...

 

[902]

So this will supposedly replace the 900mhz bus system?
I did hear rumors that the MTA will eventually build a 700mhz system - but i imagine that would be P25...

Personally i am not a fan of these new digital voice formats such as MotoTRBO - makes way too much noise floor and if nothing else i think it is definitely inappropriate for public safety use...

Nothing says you have to make a 700 MHz system P25. Only the interop channels "have to" be P25, and in the age of software defined radios, that's just another waveform. Aside from that, TETRA, OpenSky, DMR, is all potentially acceptable if Region 8 approves the submission. The submission is analyzed more on how the signal is contained within the defined area that needs to be covered, and not necessarily on the protocol used.

 

[Spec]

Correct me if I'm wrong...I was under the belief 700 systems had to be TDMA after 2017.

 

[Darkstar350]

Nothing says you have to make a 700 MHz system P25. Only the interop channels "have to" be P25, and in the age of software defined radios, that's just another waveform. Aside from that, TETRA, OpenSky, DMR, is all potentially acceptable if Region 8 approves the submission. The submission is analyzed more on how the signal is contained within the defined area that needs to be covered, and not necessarily on the protocol used.

True i suppose - but if the MTA does decide to use Tetra then that would be very unusual and somewhat counter productive because for one - Tetra is mainly a european thing and second if anything wouldnt switching to Kenwood DMR be in the MTA's best interest? because i think that is the plan in the long run for mass transit...

here are some of the MTA 700mhz licenses-
ULS License - Trunked Public Safety 700 MHz License - WQOZ581 - METROPOLITAN TRANSPORTATION AUTHORITY POLICE DEPARTMENT (MTA-PD)
ULS License - Trunked Public Safety 700 MHz License - WQOZ549 - METROPOLITAN TRANSPORTATION AUTHORITY POLICE DEPARTMENT (MTA-PD)
ULS License - Trunked Public Safety 700 MHz License - WQOZ552 - METROPOLITAN TRANSPORTATION AUTHORITY POLICE DEPARTMENT (MTA-PD)
ULS License - Trunked Public Safety 700 MHz License - WQOZ551 - METROPOLITAN TRANSPORTATION AUTHORITY POLICE DEPARTMENT (MTA-PD)
ULS License - Trunked Public Safety 700 MHz License - WQOZ585 - METROPOLITAN TRANSPORTATION AUTHORITY POLICE DEPARTMENT (MTA-PD)

 

[Thunderknight]

Correct me if I'm wrong...I was under the belief 700 systems had to be TDMA after 2017.

The FCC did away with the 6.25 on 700 requirement a few years ago.

here are some of the MTA 700mhz licenses-

Those are licensed for MTA Police, not the MTA bus operations. Look at some of the locations too, way outside NYC.

 

[Darkstar350]

So if i am understanding this correctly - the plan for the Tetra system would actually be operated by a private contractor exclusively for bus operations?
I could understand that - because it does seem that MTA buses always operated on a trunk system whereas the rest of the MTA/train operations were always on conventional
For example - here in Nassau county the buses always operated on the county wide 800mhz system(just a few years ago a private company actually took over the bus operations but they still use the trunk system)...

 

[radioman2001]

Another whiney response from Mother M, NYCTA has from my information been playing with the Tetra system for years in test. Now comes the money to replace their 800 mhz analog Type I system built in 1990 when they left low band. Tetra is used in the EU, Asia, and it works. M doesn't like it and has tried for years to keep it out of the US with it's claims of interference and violation of it's copyrights (which I believe were unfounded),and since it really is a vendor neutral protocol, it runs against the grain of M's business plan to keep all it's customers tied up with their product.The radios I heard NJ Transit were going to were PowerTrunk, and I didn't know NYCTA was going with Kenwood. I was supposed to go to a briefing for my agency (also a Transit) by Power trunk to see if it would do anything for us but didn't make for various reasons.

Nassau's trunk system has always been owned by the County, and was supposed to take over all the non emergency radio systems the county had (buses, highway etc), and I wonder what they are going to do when the support for EDACS ends soon.

 

[Darkstar350]

PDV Wireless, which is a multi state MotoTRBO system operating in the 900mhz band now has service here in New York so i suppose that could be another option for Bus operations - if they wanted to go that route...

My stance on Tetra/DMR is nothing more then my opinion and if its cost effective, dosent cause interference and it works decent then why not use it - more power to them...

However it was/is in the works for Kenwood DMR to be the standard for Railroad/Transit authorities nationwide - i am not sure if that is due to a grant/contract type deal or what but i do know that the MTA/LIRR does use a mix of Kenwood as well as Motorola radios - obviously operating in analog at the moment
Most of their licenses also have a DMR emission on them (4K00F1E)
The LIRR radio system has excellent coverage and seems to work well so no need to tamper with that quite yet...

As far as what Nassau county is going to do with their radio systems - thats a whole other ball game

 

[dave3825]

MTA/LIRR does use a mix of Kenwood as well as Motorola radios - obviously operating in analog at the moment Most of their licenses also have a DMR emission on them (4K00F1E) The LIRR radio system has excellent coverage and seems to work well so no need to tamper with that quite yet.../QUOTE]

I am in East Islip and rarely hear any train activity. Occasionally I will hear marked unit when they are out here. I struggle to get there HQ to come in. I wish they would upgrade to something better..

 

[Darkstar350]

Also i would say from a technical standpoint that any type of train/rail work operations or anyone who would be working on or near a lot of sensitive electrical equipment would generally want to stay away from the higher bands because when you are talking 8/900mhz at a considerable transmit power that could definitely disrupt certain sensors,etc and possibly become a safety hazard
That being said i guess that gives something such as Bus operations more lee way as far as spectrum is concerned...

I can see there being some dead spots in areas such as the East end
In Nassau i can generally hear the dispatch towers/"204" just fine but i am not always able to hear the mobile side of the convo i suppose if its a rather distant train...

 

[Septa3371CSX1]

The railroads are going to Kenwood's NXDN, not DMR. Typically when one says DMR they mean something like MotoTRBO. NXDN was the standard the railroads decided on for digital voice.

 

[Kitn1mcc]

I wonder how well that old low band system worked.


There 800mhz were SP i belive and were set up to interface into the buses PA system and a bunch of other things. I do not think they really talked on it much

 

[radioman2001]

A few things, first TETRA is a base heavy infrastructure system, meaning many bases to work with very low power sets. More cell phone like that 2-way.

Next buses are not railroad so they don't have to meet any expectation of using some one else's roads.

Hearing rail traffic over any long distance is not how the system is designed in the Metro NYC area.There are multiple simplex transmitters assigned to multiple desks who are responsible for a particular territory.

As far as listening to MTA PD when and if they finish the 700/800 system, they have plans of going encrypted so for now be happy with what you get.

The old low band system for the buses work fine, just the razor back antennas were a problem. NYC ran their transmitters at 350 watt so it did cover the city quite well. The 800 mhz system is called METRO-COMM, the buses have a SP head that the driver loads his route into, has many sensors throughout the bus (oil pressure, water temp, etc) and I think the first gen GPS interface for location and staging. There is also alarms on the coin box(if they still have them) and panic alarm for the driver. The driver if he/she wants to talk to control hits a request to transmit button. The driver hears nothing unless the control wants them to. Also if it's similar to the old Westchester County Bee Line system has capability of control making PA anouncements.

 

[Darkstar350]

MTA Buses on low band? Must have been the radios that Ralph Camden used

This "Metro-Comm" system - are we talking the current 900mhz system? Or is that the stillborn 800mhz system that was supposed to have repeaters at almost every railroad station which now has a bunch of cancelled licenses?
ULS License - PubSafty/SpecEmer/PubSaftyNtlPlan,806-817/851-862MHz,Trunked License - WQEC816 - New York, State of
ULS License - PubSafty/SpecEmer/PubSaftyNtlPlan,806-817/851-862MHz,Trunked License - WQEC766 - New York, State of
ULS License - PubSafty/SpecEmer/PubSaftyNtlPlan,806-817/851-862MHz,Trunked License - WQED375 - New York, State of

Whatever system they decide to go with - as with any bus operation - hopefully it will be reliable, accessible and have decent coverage because bus ops in general can have A LOT of radio activity
Though in this era and due to the nature of the job it wouldnt suprise me if more bus companies decide to go the way of a Quallcomm/computer-aided type dispatch...

 

[Kitn1mcc]

metro comm is like a trade name . if you have ever played with the Spectra RSS there is all kinds of odd things for metro comm that will not work in a standard spectra


if you watch the Bronx Tail. the bus had a ball whip antenna on it. Low Band works guys

 

[radioman2001]

All my discussion was for NYC Transit bus operations. The only 900 system I know of was owned by Queens Transit until they were bought up by NYC after going bankrupt in the early 90's MTA TA Surface system was on 800 was built in the mid to late 80's to replace the low band.

There were multiple versions of the METRO-COMM transit radio system in the NYC metro area. The first was actually built and tested in 1977 for NJ Transit. It used pole location transmitters on a RR channel at 300 mw that sent out a steady stream of data giving a location that was picked up by the bus and relayed by the bus radio back to the console giving the time and location. It basically was a poor mans GPS which BTW didn't exist in 1977.

Westchester County Bee Line run by Liberty Lines Bus had one on 450. The first channel was all data, the second was the RTT channel and the third channel was for supervisors, which was all included and controlled by the METRO-COMM radio package control head. I maintained the Westchester one for years and it did work, the weakest link were the pole transmitters that would die when hit with power surges and lightning. The mobile radios used were Syntors, Syntor X and Spectra mobile radios.

 

[kayn1n32008]

However it was/is in the works for Kenwood DMR to be the standard for Railroad/Transit authorities nationwide - i am not sure if that is due to a grant/contract type deal or what but i do know that the MTA/LIRR does use a mix of Kenwood as well as Motorola radios - obviously operating in analog at the moment.

Most of their licenses also have a DMR emission on them (4K00F1E)
The LIRR radio system has excellent coverage and seems to work well so no need to tamper with that quite yet...

The rail industry is eventually going to migrate, maybe, to very narrow NXDN.

4K00F1E is not DMR, that is very narrow (6.25KHz channel) NXDN, DMR emission is 7K60FXE.


Sent from my iPad using Tapatalk

 

[Darkstar350]

Okay - i stand corrected i guess
I was under the impression that "DMR" was kind of a blanket term for any of these non-P25 digital voice formats such as Nexedge,MotoTrbo,etc

I receive the 900mhz Bus system so-so(the control channel is 935.4625 i think)
There is also a NYC bus company that is quite active on this 470mhz LTR system - Atlantic Telecommunications Trunking System, New York, New York - Scanner Frequencies
I am not sure if they handle school bus operations exclusively or what but i am pretty sure they operate anywhere from manhattan/si/bronx all the way to the queens border...