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Old 07-19-2008, 6:42 AM
Kendrick10423 Kendrick10423 is offline
Join Date: Dec 2002
Posts: 7,039

I have not received the dispatcher on 173.800 at all. When I have it in my scanner I keep getting repeater input traffic for mobile units in the local area and some very marginal signals from more distant mobile units. The scanner locks onto these weak and noisy signals, which can be received more clearly on the repeater output and the Silver Peak down link. I think the lack of dispatcher traffic might be the result of the north/south split nets on the linking frequencies. At one time the remote base for the south net was at the Lone Pine Ranger Station and the remote base for the north net was located at the Mammoth Airport. Since I'm so close to the Mammoth Airport I would think that I would receive the 173.800 input for the northern repeaters coming from that base. In addition, I would think I could receive the linking frequencies for this remote base, but I don't receive anything other than the 409.1875 signal. The north net was supposed to be linked to Silver Peak with 400 MHz frequencies. The remote base at the Lone Pine Ranger Station was supposed to be linked to Mazourka Peak with 400 MHz frequencies and then down to Bishop from there on 400 MHz frequencies as well.

I receive all of the northern repeaters on 409.1875 along with Silver Peak on tone 8 and Mazourka Peak on tone 4. This is what leads me to think that this is a Silver Peak down link, but I can't be positive. I don't hear Cerro Gordo on tone 5, Olancha Peak on tone 6, or Piper Peak (east of the Whites) on tone 7 on this frequency at all. It used to be simple to listen to the entire Inyo National Forest as the 415.475 Forest Net down link used to receive all of the repeaters, simplex traffic on 168.125, and the up link as well. I could monitor the entire Forest by just listening to this one 415 MHz frequency.

There has been a lot of change to the linking frequencies this year due to the new allocations and directions contained in the NTIA Redbook. Something you heard only a couple of months ago is subject to change. I've been hearing traffic from radio techs this last week so some work is being done on the system. So far I've only heard them call in when they are out of service in Bishop, so their communications do not help decipher what type of work is being done.

Another possible explanation for what you heard on 406.275 and 406.250 is that they are Mazourka Peak to Bishop down links for the southern net. I need to travel around a bit while searching the 406 to 411 MHz range to get this sorted out.

In the case of Susanville, you are located far enough away from the mobile units in northern California that you probably don't hear them, but are close enough to Susanville to hear the repeater input coming from the dispatch center there. You might pick up some repeater input traffic from mobiles when they are in the southern portion of the District, but I would bet topography blocks them out most of the time. The result is pretty advantageous for you. The only way I could duplicate this is to live in Bishop and hear both the up and down links from both the north and south nets. Even though Bishop is only 45 miles away from me, the location is down in a hole created by the Owens Valley, and I cannot hear very much traffic on simplex from there. What I do hear is fire department base traffic and the power must be 50 watts or more. I would bet the UHF up link traffic from the Inyo NF dispatch center is at 10 watts or less.

The BLM seems to have disappeared from 166.875 and are not back on 166.4875 either. I'm not sure what is going on, perhaps with the BLM and Forest Service fire organizations being merged on the Inyo National Forest it did not justify the maintenance of a separate net for the BLM. I always thought that the Forest could really use a Forest Net, an Admin Net, and one more net for fire command or to split the fires on the Forest into two nets due to the large amount of traffic generated when there were multiple fire starts during lightning activity. The BLM net would have served well as this third net.

In any case, I will be taking advantage of the logging function of my new PSR-600 radios (one base and one mobile) in trying to sort out all of this.

Last edited by Kendrick10423; 07-19-2008 at 6:52 AM..
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