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Wondering if companys new bus radio system is causing my interference?

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Old 07-13-2004, 09:21 PM
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Kmot
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Default Wondering if companys new bus radio system is causing my interference?

My employer, Los Angeles Metro, has a new radio system made by Orbital Sciences. We use their systems they describe here: http://www.tms-online.com/products_transit_index.html

Among the many systems we now have on our buses, some of them transmit data whenever they are parked in the maintenance yard. Here is a brief description:


Both voice and data messages are transmitted by the new radio system. The old radio system relied solely on voice and status button changes to provide communication with bus operators. Because every MTA bus will have a Mobile Data Terminal (MDT), it is possible to handle routine communications, such as general announcements, by displaying them on the screen. The combination of using MDTs for routine communications and advances in wireless technology gives MTA’s radio system the capacity to handle bus communications according to the actual "on-street" need for real time communication.

ATMS utilizes three separate radio systems, a wide-area trunked simulcast radio for voice (Voice Radio System), a wide-area data radio for real-time data (Bus Data Radio System), and a wireless LAN (WAN) for batch data transfers (Bus Division Data Radio System


The voice radio is a trunked simulcast system. This will allow for efficient use of the existing radio channels. It will support communication from bus operators to radio dispatchers, operations supervisors, and police. It operates on 508 MHz channels.

The Bus Data Radio, known in the radio industry as a Mobile Data Radio System, has the same coverage area as the voice radio. It operates on 900 MHz channels. The default mode of TRS is data. Although the primary use of the data radio is to transmit system related data, it is also used to send text messages to vehicle MDTs.

The Bus Division Data Radio System is known in the radio industry as a Wireless Local Area Network(WAN). Data transfers to and from buses and supervisor vehicles will take place at each division using the WAN. Current schedule, stop, and other data will be loaded to the onboard data system to be used for the TRS, AVA, APC, and other systems. Data collected during vehicle operation will be downloaded using the same system. The data will be transferred to or from the MTA’s enterprise network. Buses will be polled while they are parked in the yard. The WAN will have a data transfer rate of at least 10 Mb/sec and will conform to IEEE Standard 802.11b for wireless Ethernet.


From what I can tell, there is radio freq of 500-900 Mhz going on in my bus yard. Very far away from the 75Mhz AM I am operating on.

Here's the situation.... up to one year ago myself and a few buddies ran our r/c cars/trucks at lunch break. We operate on 27 and 75 AM freq's. A year ago I got injured and was off work for 11 months. When I got back the new TMS system was installed and operating. Now, we have started running our r/c's again and the 27 band is unaffected but the 75 band is glitching so heavily it is literally impossible to use. Myself and one other user are on 75.

Although the new bus systems are on 500-900 Mhz is it possible that due to the large number of buses with trasnmitting radios going that it could cause a cross-frequency or whatever hostile environment for the 75Mhz AM band?

BTW, I have not tried my 75FM yet but will be attemting it to see if it also is affected.

This is really puzzling us!
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