Motorala System Questions

[millam]

I have attached 2 files with screens of a system I am trying to find the base and offset for.
If anyone can help please do. 410.4 meg sid A81A

Mil

 

[SCPD]

I presume 410.4 is frequency for control channel 2C8. If so, please go ahead and fill that out for the program. Use [F]ind -> [C]hannel ... type in 2C8 and press Enter. Tab over to the frequency field and type in the frequency there. Type [Alt], to save.

Next step is to identify the frequency of at least one more channel. You'll have the scan the portion of the band where you think you might find the other frequencies.

The lazy approach is to wait a day or so for the system to roll over to a different control channel. You'll stop hearing the CC noise on 2C8. Since it is a control channel, it will be easy to identify since Unitrunker will display the system ID.

The more aggressive approach is to scan for a voice channel while there is an active voice call. Using a second radio that can sweep a range of frequencies - makes this much easier. If you only have one radio - the "lazy" wait-for-control-channel-to-change trick is worth a try.

With one channel known - we can guess the base frequency and offset. With a known second frequency, we can make a guess as to the spacing or step size. You will want to verify each computed voice channel to be sure (a) one of the frequencies isn't a repeater input and (b) the system does not require multiple base/offset/step table entries.

 

[millam]

motorala question reply

I have attached a file with 406.2125 meg sid A81A which I assume is the second control freq that you said I should look for. I am old and seem to be slowing down in the thinking department. I just can't get a handle on this trunking math. I do though enjoy listening to different ststems to pass the day and appreciate you helping me.

Mil

 

[millam]

motorola question reply no 2

I have attached another picture. You misread 2CB to read 2C8 I think. My trifocals picked that up. I have entered the 2 freqs, I think in the right place.

 

[SCPD]

I see you also cleaned out the repeater input channels.

Next step is to create a band plan entry.

nsert -> and ... and select the [W]izard option. This will (hopefully) fill out the entry for you. [Alt] to save.

If not ... the math works out to ...

Base 406.2125 Mhz
Offset 380
Step 12.5 khz

 

[millam]

motorola question

I am confused, quit often, can the base freq (406.2125) be the same as the control freq (406.2125)? Right now the system I listen to is dead. I can receive it when the conditions are right which is about 2-3 hours every day or two. Also is there more logging I can do besides the one on the (O)ptions menu?

Mil

 

[SCPD]

can the base freq (406.2125) be the same as the control freq (406.2125)?

380 is the lowest possible channel number for the type of system you are monitoring.

Also is there more logging I can do besides the one on the (O)ptions menu?

The [V]iew -> [A]ffs and the [V]iew -> [P]atches screens will show non-call activity. The logging enabled under the [O]ptions menu - which logs to a file - is primarily useful for chasing down decoding issues but it does provide a kind of history of control channel activity; but not nearly as readable as the other displays.

 

[millam]

Motorala System Question

I finnally have the math, with Excel's help, but I have one question left. What about the channels below 17C? In the photo I have 3 or 4 below 17Ch or 380d, what do I do with these.

Mil

 

[SCPD]

I finnally have the math, with Excel's help, but I have one question left. What about the channels below 17C? In the photo I have 3 or 4 below 17Ch or 380d, what do I do with these.

Delete them. Low numbered channels are valid for 800/900 mhz trunking but not for this system.

To remove them ... [F]ind -> [C]hannel ... type in the channel #, press enter. Select [Del]ete from the menu. Repeat for each low numbered channel.

 

[millam]

Thanks for all the help. This is the last question, maybe. I am using a BCD-996T scanner. There is no way to get the radio id that Unitrunker shows to appear in the 996 display is there?

Mil

 

[SCPD]

Don't know. Please try the Uniden forum ...

 

[Jay911]

millam - Unfortunately, it seems that Uniden only shows radio IDs during I-calls. I wish I knew why. The data is obviously there, and I'm sure people want to see it. I have it on my actual issue radio for my city's trunk system, and I use it for lots of things.

I think it's a firmware upgrade away from happening, but we have to convince Uniden that it's worth putting in.