Originally Posted by mkewman
what is this freq? it's 417.45 with a pl of 144.8
The 144.8 CTCSS tone is not a standard or "sine wave" tone. It is also very close to the standard tone of 146.2, close enough that the two tones might not be distinguishable for many commercial grade radios. Are you sure this is the tone you received?
gmclam said:
Well "Sacramento traffic" may be analog, but it seems there is federal stuff which is not. I receive digital transmissions on 162.300, 163.200 & 164.600 - US Marshall. There is a lot of USFS transmissions +/- 170 MHz, and some is digital; but I am not sure if it is data or voice (I believe data).
Are you hearing the digital USFS traffic on 170.525? That is the USFS Region 5 or Pacific Southwest Region data frequency. It is used for packet communications and for a system very much similar to the amateur radio APRS or Automated Position Reporting System. Fire apparatus and law enforcement vehicles are equipped with this system.
If I'm correct the former radio tech on the Inyo National Forest is the one who pioneered the use of packet and APRS on this frequency, which was later adopted for region wide use. He is a ham and was quite innovative in his approach to solving the communications problems the Inyo had. I worked on the Inyo for the last 11 years of my career and prior to that worked on a Ranger District on the Toiyabe National Forest for 7 years that bordered the Inyo on the north. I followed what he did for 18 years. The Inyo's trail crews often had a great deal of radio traffic as they would set up camp for many weeks and needed to relay personal logistical traffic as well as long supply lists and it would tie up the Forest Net for half hour periods or more. So the radio tech set up a packet system to keep this traffic off of the Forest net. The Inyo has a lot of very large wilderness areas.
He also set up the APRS and computers in dispatch for obvious reasons. When we replaced the old Motorola crystal handhelds, he placed them in surplus military ammo boxes for use as portable extenders to solve coverage problems in areas that were blind to any of the mountain top repeaters. Some of these extenders were put in every year in the same places and some where put in when a large trail maintenance project was going to be done in a blind area.
He rarely surplussed out any radios or parts and his solutions to some of our communications needs cost almost nothing. He was also very good with computers and obtained quite a few of them from the surplus stock of the military and used them for specific applications for the Forest's communications system. Obtaining the military surplus radio parts and computers only cost us his travel time to the Bay Area to pick it up. He probably saved us enough to pay his annual salary most years. What was his reward for doing this for 32 years? The current presidential administration "outsourced" all radio system maintenance the contractor cannot even tell anyone what frequencies the Forest uses and has not been able to get the Forest's Administrative Net working after three years, which had only been partially completed, but had all the components purchased, at the time of the Forest Service radio tech's forced retirement. This due to the wisdom of the administration of the village idiot from Texas!
