Summit County Ski Areas - Park City Trunked?

[K4AAQ]

For the past several years, the Park City Mountain Resort ski patrol was using 462.950, with 162.2 tone, as listed in the RR database. This year (2012), I heard a little traffic, but nothing like I had come to expect from previous years. I also noticed that 162.2 tone wasn't working. This was a problem because something on frequency was keying up for about a second, about every 10 seconds. Very annoying kerchunks (at least my wife thought so when we were on the ski lift together. I was using a speaker-mic to monitor, not earphones). But with 162.2 decode on, I heard nothing.

Kind of hard to play with the radio and ski at the same time, so at lunch, I investigated. I tried a tone scan, both analog and digital. No luck - nothing 'pinged.' By the way, I'm using a Kenwood TH-F6 ham radio handheld, not a scanner that might give me instant readout of any tone in use (why can't the ham manufacturers do a better job on this, but I digress).

Next, I listened to some of the other listed channels to see if the resort maybe swapped things around.

First thing I noticed was that the every-ten-second kerchunk was on all the channels. And it seemed to be the Park City repeaters. No kerchunk on any adjacent channels, and they faded out as I drove out of town, just as repeater traffic faded out. And same signal strength.

Finally, on ski day #2, I found a LOT of activity on one channel - 461.4750 - the "grooming" channel. I heard ski patrol, ski school, lift maintenance and other stuff I couldn't quickly identify (parking lot?).

Paying more attention, I noticed that ongoing conversations were occasionally interrupted by other, totally unrelated conversations.

My analysis: the system is now trunked. Same freqs., but the traffic seems to be distributed among the 5 repeaters by some form of trunking. And it seems that everything starts on 461.475 (at least it did today), and things only move when a second, simultaneous conversation begins.

I didn't bring a 'real' scanner, just the Kenwood F6, so I couldn't investigate real trunking.

I put this into a Wiki for Summit County Ski Areas. Anybody watching Summit County scanning?

73,
Gary KN4AQ

 

[n0nhp]

I don't know the system, however you have perfectly described an LTR trunking system. The "kerchunk" is the controller telling the radios that home on that channel what channels are in use and which are open. It sounds like everyone was "homed" on one channel and bumped off when a second group grabbed the channel.
Having set up an LTR system, this is not the most efficient setup. However if the radio shop that set it up has previously set up a Motorola type trunk, it is the way they were trained.
Your non-trunking hand-held is not going to be as useful on the mountain anymore. Most of the modern trunking scanners will track this type of system. You will have to do some investigative monitoring so you can figure out the LCN for each channel and their order. Then the IDs of the users you are interested in. After that you might have half a day left to slide down the mountain out of your ski weekend.

Bruce

 

[K4AAQ]

Thanks, Bruce - sounds like you've nailed it.

I do have a trunking scanner, but didn't bring it with me on that trip (back home in North Carolina now).

As it turns out, the way they had the system configured was pretty good for me, since I was just eavesdropping on the radio activity of the resort. I got to hear pretty much everything, since they were not really that busy, and most of their traffic was pretty short. So they "scanned" themselves for me while I was listening on just one channel.

Next year I'll probably bring the scanner, though it's bigger and harder to carry than the Kenwood F6, and requires an earphone.

73,
Gary KN4AQ