Possible New Region 5 (USFS) Air Guard Down Link

Status
Not open for further replies.

SCPD

QRT
Joined
Feb 24, 2001
Messages
0
Location
Virginia
Before narrow banding many National Forests, if not most or all, in California used 415.550 as the down link from the Forest's National Air Guard remote base. Typically there was one remote base per Forest. With narrow banding there have been changes made to UHF linking frequencies and traffic on 415.550 disappeared for the Silver Peak remote base on the Inyo National Forest. Since the new spread between the up and down links is now 9 MHz and the down link is the lower of the two frequencies, I have tried monitoring 406.550 with no results.

Today I copied a signal on 406.325 that may have originated from the Silver Peak Air Guard remote base. If the Forest Service is using this frequency to replace 415.550, then you might be able to copy it if you are within receiving range of a National Forest main remote base. I request that anyone who is monitor 406.325 for a few days to see if this frequency is in widespread in California.

The rest of the link frequencies from the Silver Peak remote base stations for the Inyo NF's Forest and Admin nets have been changed within the last 3-5 months. I would suggest that everyone who is interested in hearing their nearby National Forests links on UHF (many Forests use microwave instead of UHF for linking) place their scanners on a search from 406.1125 to 410.9875. The new link frequencies may show up as a result.
 

SLOweather

Member
Premium Subscriber
Joined
Jun 28, 2006
Messages
117
Location
San Luis Obispo, CA
I've punched this into my R-7100 and will listen as I can over the weekend.

Not being familiar with this channel, if it's in use, what are the chances that the LPNF will be using it this weekend? Is it a much-used one, or a once-in-a-great-while one?
 

SCPD

QRT
Joined
Feb 24, 2001
Messages
0
Location
Virginia
Traffic on National Air Guard is for emergencies only or for initial contact when doing so on other frequencies has been unsuccessful. So it will be very infrequent. Unless you are within range of the Los Padres NF hub remote base, which is probably located on Santa Ynez Peak or La Cumbre (sp?), north of Santa Barbara, it will be difficult to receive this down link. The Los Padres is so spread out, that it might be one of those Forests with more than one Air Guard remote base. If it does have a second one, it would probably be located somewhere on the Monterrey Ranger District. Since the Los Padres uses microwave to link its remote bases on Forest Net, it is possible that the Air Guard remote bases on this Forest are also linked with microwave.
 

DPD1

Member
Joined
Jul 24, 2005
Messages
1,994
I tried searching that block for a good amount of time the other day, during a particularly busy time in the ANF that I heard on VHF... I didn't hear anything on UHF. At least not from my location in the SF Valley. I would love it if there was some way to hear both sides of all traffic for the ANF, if not through the forest service itself, then at least one of the other services like LA Co. FD or CHP, just so you can hear what's going on. You can get some of the basic traffic on the north fire response channel, but most is on the simplex tacs. I've also searched for CHP repeated traffic for that sector, but not found any. Due to all the bike wrecks and other stuff, there's usually something going on up there, but no real way to hear it well down here.

Dave
www.DPDProductions.com
Antennas & Accessories for the RF Professional & Radio Hobbyist
 

SCPD

QRT
Joined
Feb 24, 2001
Messages
0
Location
Virginia
The Angeles uses microwave for linking. It is actually better to be somewhat far away from the Forest with a very good antenna. You can pick up more of the simplex traffic when you can see more of the Forest. I know what you mean about only hearing one side of the conversation though, I would rather have a Forest use repeaters than use microwave linked remote bases.
 

JayMojave

Member
Joined
Dec 13, 2007
Messages
685
Location
Mojave Ca
Hello Exsmokey and DPD1:

I am in Lancaster Ca, and have a reasonable view into Angles NF. I am not sure this will help but I;ll give it a shot.

I hear Angles on 172.375 and a few other of the VHF frequencies that I have not written down as I have been chasing the Air Attack Tankers on the fires north of me.

But I do hear the Angles crowd on 172.225 172.375 406.225 406.425 415.225 415.425
Hope this is a help. I am sure the posted USFS Angles frequencies are also a help. But again one needs a scanner to scan the known frequencies and another scanner to search the unknown used frequencies.

Hope this is a help.

Jay in the Mojave
 

DPD1

Member
Joined
Jul 24, 2005
Messages
1,994
On the 406.425 one I get some sort of constant data. Nothing on the other UHF so far. You must be in a better position on that side.

Dave
www.DPDProductions.com
Antennas & Accessories for the RF Professional & Radio Hobbyist
 

SCPD

QRT
Joined
Feb 24, 2001
Messages
0
Location
Virginia
The Forest Service Region 5 VHF data channel is 170.525. The 406.425 downlink you are hearing Dave, might be the remote base downlink for 170.525. The data channel has two purposes. First, most of the fire apparatus and law enforcement vehicles have something that resembles the ham radio APRS (Automatic Positioning Radio System is the translation I believe) system. It has its own VHF antenna on the roof of the vehicles for this use. Second, backcountry trail crews and wilderness rangers can carry a very small keyboard and screen, about the size of a small laptop, but thinner and not as heavy. They use the data channel to send text messages for health and welfare traffic as well as logistical traffic. In the past trail crews that stayed in the backcountry for a month at a time would have to tie up Forest Net for up to an hour with supply requests and other messages for crew members. The Forest Service was using text messaging long before it became available in commercial cell phones so that Forest Net did not have to be tied up for so long.

Jay, you are hearing both the up link, which is the higher of the two frequencies, and the down link, at 9 MHz lower in frequency. I would bet that both of the links you are picking up are linking Fox Field , where the dispatch office is located for he Angeles, to the Forest's radio system on the mountain. I would have thought it is linked via microwave as the old office location in Arcadia, at the Forest Supervisor's Office, was linked in that manner. Try listening to both the Forest and Admin nets on VHF and see if the 400 MHz pairs are carrying the same traffic.

When you figure out the linking system for a National Forest or National Park, should it be on 400 MHz, you may lock out the VHF frequencies, as you can often hear the whole Forest or Park in the same manner as the dispatcher does at their console. In my Mammoth Lakes location I used to listen to the down link coming off of Silver Peak to the dispatch office in Bishop. It was set up so that the down link repeated the up link so I just permanently locked out the VHF Forest Net frequency as I could hear the whole Forest by monitoring the down link from the hub remote base on Silver Peak. I could even hear car to car traffic from as far away as Lone Pine, 100 miles to my south, by listening in on the 400 MHz link.

Many people don't know to search 400 MHz and 72 MHz frequencies to find links that can open up a whole new world of monitoring they previously didn't hear. It is right there ready to grab if you know where to look. I listen to the down links used by Mono County to link the hub site on Conway Summit, located about 45-50 miles to my north. I can hear some more northern repeaters that even a amplified antenna can only pick up with a lot of noise on VHF, but are clear as they can be on the 453.000 down links. What is interesting is that the 453 MHz links are carried on vertically polarized antennas that are pointed nearly 180 degrees from my location. I'm actually picking up the small amount of signal that is coming off the back side of the antenna from a location nearly 50 miles away. To have that happen I have to use LMR-400 coax and replace it about every 3-4 years, as my roof can be covered in snow 7-8 months of the year, which is hard on coax.

I'm writing files for my PSR-600 mobile for all the northern Nevada counties and I do a licensee search for each county to see if they are linking their repeaters with 450 MHz frequencies. I then program in those frequencies in addition to the VHF frequencies that almost every Nevada county uses.

There are some remote base and repeater sites on State of California radio systems, especially the CHP and Caltrans, that are not linked via microwave. These two agencies often use 72 MHz links to those sites and if you know what to listen for you can often pick up traffic you would otherwise not be able to hear.

I hope that this thread will result in some folks searching the UHF band and the 72 MHz area to find those wonderful links that are just waiting to be monitored. In addition, I hope we might be able to figure out if a new USFS Region 5 Air Guard linking frequency pair has been allocated. I used to have 415.550 programmed into my mobile scanners and could often hear very interesting traffic from some very distant locations while driving around in the Central Valley. The fun of listening to linking frequencies is that you have all the advantages of being at a remote base location on some mountaintop at the end of a bad dirt road, while in your home or your car down in the flatlands.
 
Status
Not open for further replies.
Top