It's kind of vague and ambiguous without context. If I'm reading right what you wrote, you are receiving site 044-001 with control channel 160.59 which is LCN #00-1958. Site 044-001 has "neighbours" of 044-002, 050-184, 044-022, and etc. You have a TON of neighboring sites you might be able to find. Each one of those sites will have its own control channel. Some of them may be in reach of you - but some may not, they may be far up the coast, or even into the interior. Just because the site is listed as a "neighbor" doesn't mean it's necessarily nearby, but often they are.
The second control channel/LCN also helps out because it helps us understand the "band plan". A radio doesn't get a message that says "go to 154.77", it says "go to channel 00-0794". There is a data table inside the radio that knows what channel is what from its Logical Channel Numbering (LCN). (This isn't exactly the right name except for certain trunk systems, but it'll do for now). So when Unitrunker gets a request for a voice channel from the trunk control channel, you might see extra/other channels pop up in the listing but with 000.0000 as the frequency. (If you're really lucky, Unitrunker will fill it in by itself, because it is going to do these math calculations on its own.) Using a little bit of simple math, and assuming that the band plans are the same for all the sites, we can figure out what frequency each LCN represents.
From what you posted, we know 160.59 = channel 1958, and 154.77 = channel 794. (We'll skip the "00-" bit for now.) 160.59 minus 154.77 equals 5.82. 1958 minus 794 equals 1164. 5.82 divided by 1164 equals 0.005, which is the
step size. That means, every channel number you go up, is 0.005 MHz higher than the previous one. So channel 795 would be 154.775 for example.
Using that, we can tell that the
base value for this trunk system is ... 154.77 minus (794 * 0.005) = 150.80. That means that 150.8 is channel 00-0000. This also means that you shouldn't have a frequency lower than this in the system.
So... let's say Unitrunker now shows you a channel "00-1004" with no frequency data (000.0000). 1004*0.005 = 5.02. 150.8 plus 5.02 = 155.82. There's the frequency value for channel 1004.
Conversely, if you find a frequency of 160.2 and don't know its LCN, you can figure it out this way: 160.2 minus 150.8 is 9.4. 9.4 divided by 0.005 is 1880. There's your channel number for 160.2 - 00-1880.
This, to me, is what makes finding a new trunk system so damn
fun. Figuring out all this stuff, picking up the talkgroups and trying to determine who they are/what they belong to, and all that.
Quick favor to ask - when you're running Unitrunker, please provide the info on the top of the "Site" window. You'll see probably "Site 044-001", and right below that, beside the colored "graph" that shows how strong your signal is, you will see "APCO P25 #####-XXX". Please please post the #####-XXX part!
