Beale AFB P25 system off the air.

[b52hbuff]

a simple repeater swap and site controller reprogramming didn't seem like the most likely explanation. That would have been entirely too logical!

I wonder how this approach plays into the base/offset programming? If Beale had one base/offset, I wonder if they carried this concept into the new system?

Would it be possible to revive or at least document the base/offset settings for the old system until the new system is totally figure out?

 

[avtarsingh]

beale is working for me using 138.000 lower 142.7375 upper step 12.5 offset 380

for trunk freqs i have all of the freqs listed previously in this thread
except that 137 freq

the signal is 50% better for me than the uhf was - 722 on the LCARS signal meter in freescan

 

[milcom_chaser]

I'm getting it just barely at home in SJ County. CC is on 138.0375 and is announcing that as $17F. That equates to a base of 138.0000, spacing of 12.5 and offset of 380. I think I got a voice channel on $212 which would be 139.8750 if the base stays the same and the data decode was correct.

And no, no site #.

So on the 396XT do you HAVE to enter the upper frequency when it asks for it in the custom band plan menu? I know on the Pro-197 it calculates the upper automatically...

 

[jimvm]

Beale VHF P25 system

Thanks all for your help. I have it working now using my BCD996T.
There are a few unknown group id's using id search.

Lots of ATC on UHF and VHF air frequencies. A new one is 'Cougar' MC-12 Liberty.

jim vm

 

[avtarsingh]

im not sure about entering manually - i ALWAYS use freescan

its the only way to fly in freescan all u have to do is enter in low freq and it calculates the upper for you

done

once the database is updated on here - u can import it right from freescan into the scanner and never touch anything

gonna check on travis and see if they changed over

my guess is this changeover was prompted by crappy uhf on a hilly base and i would not rule out pave paws

if they make 150 rptr owners turn off their rptrs or lower power .. might not be that far off

esp when u have a contractor put in a dsp system which raises the noise floor.. and then dont know how to notch local vs over the horizon

evidently theres a bigger threat now than when the soviet union had everything aimed at us


there's a freq or 2 still missing - the control channel just switched to a new one and i cant hear anything

if anybody is closer to beale than i am - can you please scan 135-139.99 in 5khz steps see if you can find the missing data channel

thanks

 

[kma371]

Thanks all for your help. I have it working now using my BCD996T.
There are a few unknown group id's using id search.

Lots of ATC on UHF and VHF air frequencies. A new one is 'Cougar' MC-12 Liberty.

jim vm

Please submit all the freqs if you haven't already.

Thanks.


Sent from my iPhone 4 using Tapatalk

 

[b52hbuff]

I'm getting it just barely at home in SJ County. CC is on 138.0375 and is announcing that as $17F. That equates to a base of 138.0000, spacing of 12.5 and offset of 380. I think I got a voice channel on $212 which would be 139.8750 if the base stays the same and the data decode was correct.

And no, no site #.

Thanks for showing the math. I verified your work and duplicated it on the GGNRA at home with my HP-1. I can confirm that the HP-1 in 'data dump' mode advertises the LCN in the log for a TGID grant. It doesn't seem to advertise the LCN for the currently active control channel. It does show the site number in the log.

For my education, what is the significance of no site number?

Is there anything other than guessing and experience to get the base? It seems to be the edge of the band. Is there anything in the data stream that gives a hint on the base?

The offset seems to be pretty easy to guess based on the found voice channels....

Anyway, I may make a trip up there in the near future and scout things out. I'll submit a report when I get back.

 

[WayneH]

Would it be possible to revive or at least document the base/offset settings for the old system until the new system is totally figure out?

"Other Band Trunking" (OBT) systems are each unique. There is no connection between one system's table and another's. Travis and I think Atwater FCI are two that have really weird multiple lined tables when they aren't needed. Some systems like Marin, San Mateo, need them since one range does not span enough spectrum which is really why you use more than one line/range. Ultimately it is Motorola who defines them. If they want to go wild, they can and evidently have.

I'll have to split this up to answer each question...

It doesn't seem to advertise the LCN for the currently active control channel. It does show the site number in the log.

I'm not familiar with the Uniden data that is dumped. I know it sucks. But, the system ID announcement in the CC data stream includes the CC's "LCN". That's how I was able to initially figure out Beale so quickly.

For my education, what is the significance of no site number?

It's not a networked (aka SmartZone) system. It could still be Simulcast or have multiple receiver sites.

Is there anything other than guessing and experience to get the base? It seems to be the edge of the band. Is there anything in the data stream that gives a hint on the base?

Like I mentioned since the CC LCN is announced with the system ID (every three seconds) you have an instant sample for at least one range for the system. I use a spreadsheet to speed the process up. [link] You'll want to use the Base Calculation tab. The light blue area is where you enter your known values (freq and hex code). If you have the decimal version then you need to swap the formulas around. Then you have to make a guess as to what the spacing will be. The calculation will tell you which are valid. Now, in most cases, it will be 12.5kHz or smaller to support narrowband. Ideally you want more than one freq and hex code so you can look for a common similarity.

Once you have a known base, spacing and offset you can use the Print All Frequencies tab (with supplied data that's entered in to cells O4[spacing], P4[base] and N7[offset]) to do cross-references. Input freqs have channel assignments between 0-379 and outputs are 380-759.

If someone isn't familiar with spreadsheets then I would suggest getting out your scientific calculator. And read this also.