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Went to the monster truck show last night in the Tri-Cities. The sport that killed one a couple weeks ago hurt another last night during the quad races. Anyways, there was an ambulance company there that took him out. I though AMR was in the Tri-Cities? What freq. are they on down there?

Wish I had looked up Frequencies for the TRAC and J and J Security before we went. Anybody? Looks like we need to do some database work for down there.

On a side note, one which I thought was pretty cool, each truck had a receiver in it and there was a guy out on the ground in front of the truck holding what looked like a CP200. He'd hit the PTT button and the truck would be dead in the water. DTMF or tone encoding kind of thing im assuming? Anybody ever heard of this before?

Side note x2, traded in my last batwing product for a Kenwood. The reception I'm getting is remarkable over that CP150 batwing product.

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Interoperability is an attitude, not a technology.

AMR and Mid Columbia. I think AMR is in the process of a freq change. I recall 152 or 157 mhz previously. I don't know anything about Mid-Columbia.

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"I was installing un-programmed radios"

It could be accomplished as simply as a CTCS / DCS decoder on board, or like you say a DTMF or tone signaling sequence. For that matter it could even be accomplished with MDC1200 or Fleetsync.

The game is, to discover what it is they use.
Problem is - it sounds like rather hazardous duty to do so!

In looking over the VHF fire list for Benton County I saw no mention of an ambulance frequency. I found that odd since most other fire radios have the local ambulance channels programmed in.

On a side note I spent several hours in the Tri-Cities Friday afternoon/evening. Took the TK-290 along to see what I could hear. I did not monitor the 800mhz system. The busiest channels: Franklin County Sheriff (155.910) and Se-Comm (154.175).

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You won't find them in any radio list. I don't know if they have SECOMM or Franklin Co freqs in their radios.

Here is an article from several years ago explaining the role of private ambulance in the Tri Cities. A+ was purchased by AMR
http://news.google.com/newspapers?id=Fl ... alls&hl=en

The Tri Cities is not like other areas that have joint response with private ambulance. The fire depts have done all the emergency runs since 1968 when the standards changed and the funeral homes turned it over to the cities. http://news.google.com/newspapers?id=iV ... alls&hl=en

The private ambulances are not toned out on the EMS calls. I think AMR uses a lot of Nextel and Mid Columbia may be similar. You should hear them on HEAR as the fire depts still use that with the different PL tones. Walla Walla Fire is the only one I know of that does both emergency and convalescent runs over there.

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"I was installing un-programmed radios"

I've got Mid-Columbia as being on a simplex channel...somewhere...

It was AMR at the show. They use 155.220 here, but they run with every fire department here too. That makes sense why they wouldn't need radios and would be able to do Nextel because they don't run nearly as much as they do in Yakima County.

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Interoperability is an attitude, not a technology.

A couple years ago, [Commstar] reported that AMR in Spokane was using a 152/157 repeated pair that they apparently were leasing from Day Wireless I believe. They moved away from it as there was to much interference from paging systems nearby on the hill. They have gone back to their primary frequency of 155.175. When I lived there, I used to listen to them all the time and had their freq programmed in with the Fire channels in my scanner. The funny thing was, for some reason the cars were transmitting with one tone and the base was transmitting with another tone. There was this one time when a car out of Seattle came into Spokane for a transport and was trying to call Spokane dispatch and they couldn't hear them but one of the cars could. So the Spokane car relayed the Seattle cars traffic back to dispatch. Obviously the Spokane car was receiving in CSQ because as I remember, the Seattle cars tone was totally different.

The reason for this is likely the same reason many Taxis work a non-repeated duplex operation. This arrangement allows the mobiles to transmit to the base, without other mobiles hearing them.

In Taxi-World it is almost a neccessity, as you certainly do not want the "fares" riding in Taxis to hear the other hacks - hacking away on the radio.

In this case, all mobiles hear base, and base hears all mobiles, but mobiles do not hear other mobiles - and it is all accomplished on one freq.

Overall pretty efficient.

Makes me wonder though, if they have busy-channel lockout programmed in the mobiles to prevent them from walking on each other. That or a hookswitch-unmute operation...

A friend of mine is a taxi driver and also a ham. He owns his own cab but uses a shared dispatch service which they have enabled DTMF signaling plus busy channel lockout.

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Pre AMR, A+ had a cab service as well in the Dry Cities.

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"I was installing un-programmed radios"

Probably both, although the second is required by law. But when was the last time you saw someone monitoring before they transmitted?