Ch Hi/Ch Lo

[rananthony04]

Can anyone help me figure out the Ch Hi/Ch Lo settings in the extended/multi table section in Win 96? I would like to put Pomona, Glendale and Burbank all in one bank, or is that even possible using a Pro-96? Would I need a seperate bank for each? I input the extended tables (as shown in the ICIS page for Glendale, Burbank, Pomona) but still get nowhere. I've looked for specific topics regarding the Ch Hi/Lo settings but to no avail. ANY help would be appreciated. Thank You in advance.

-Robert

 

[mike_webb59]

Holy cow, I think I figgered it out.

In the Win96 Help file there is this nasty formula when discussing Extended Trunking Tables: Voice Frequency = Base + [(channel – Offset) x Step]

This same formula is used in this most excellent but mind-numbing Wiki:
http://wiki.radioreference.com/index.php/Determining_Base/Step/Offset_for_VHF/UHF_Motorola_Systems

It seems that Lo and Hi are pertaining to the "channel numbers" in a system. The Wiki describes that 0-379 are dedicated for 'receive' and '380 -759' are for transmit. So it starts with 380 and can't go past 759, IMHO. Also something about the channels cannot overlap


I created a spreadsheet for the formula: Base + Channel + Offset = Frequency.

480.5000 + Some Number + .0125 = 482.0875 (your first channel)

I started with 380 and I worked up from there.

I found that

480.5000 + 507 + .0125 = 482.0875 (first channel)
through eventually where
480.5000 + 681 + .0125 = 484.2625 (last channel)

I think that solves Glendale, Monetbello, & Oat Mountain.

For Burbank I programmed in
470.0125 + Some Number + .0125 = 470.0625 (first channel)
and right away I found that
470.0125 + 384 + .0125 = 470.0625 (first channel)
through
470.0125 + 402 + .0125 = 470.2875 (last channel)

So you'd create a Customized Fleet Map as follows:

Lo: 384 || Hi: 402 || Base 470.0125 || Offset 380 || Step 12.5
Lo: 507 || Hi: 681 || Base 480.5000 || Offset 380 || Step 12.5

Again, w/o Trunker S/W, this is just a good guess. And you are on your own for Pomona.

HTH, Mike

 

[fmon]

The system should be in two tables as Mike indicates, however, the second table Offset needs to be the same as the Ch Lo for that table and should be 1 channel above the Ch Hi of the first table.

If the base does start (we don't know without the hex value) at 407.0125 and the step is 12.5, then the last channel in the 470 MHz freq range is channel 402.
470.2875 - 470.0125 = .275 / .0125 = 22 channels. The next channel (403) is the base channel of the second group, 480.500 (assuming it's hex is correct). Using the same math as in the previous table, then 484.2625 - 480.500 = 3.7625 /.0125 = 301 channels. 301 channels + 22 channels = 322 channels which falls within the range for Motorola tables. Thus all 5 sites are covered.

Lo: 380 || Hi: 402 || Base 470.0125 || Offset 380 || Step 12.5
Lo: 403 || Hi: 759 || Base 480.5000 || Offset 759 || Step 12.5

And of course, if the coverage is from 380 to 759, the second table Ch Hi should be 759.

My 2 cents.

 

[rananthony04]

Thank You Frank and Mike for your help, I am still a little stuck, however, with your guys' information, I am able to study it more in depth, and will get the hang of it.
Thanks again

-Robert