More LTR Passport questions

snoopyII · #1 (**permalink**) 01-19-2008, 04:08 PM

I've come across a local 900 mhz LTR, it contains 7 frequencies according to FCC data. Here is the part I dont get, ALL of the voice can be heard on 1 specific frequency, i.e. if you park the scanner on that one channel, you can hear BOTH sides of the conversation. That channel has never changed either. Is this the "home repeater"? I have heard nothing but the data bursts on any of the other frequencies. Usually about 3 sec. apart, but somtimes as long a 7 to 8 sec. apart. Also, if you set the scanner (785D) to scan it like a LTR it displays the TG but I get no audio, If you change the format to conventional, I get the audio. Now, Im pretty sure the channels are in the wrong order, because I just entered them in ascending order, (I dont have a tapped scanner, nor do I have a PC currently operating some type of software like LTR Analyzer.) So, is this a really a Passport system? or is it impossible to tell based on my observations?

KD4YGG · #2 (**permalink**) 01-19-2008, 06:48 PM

Certainly sounds like a LTR Passport system and sounds like you've identified the home repeater.

Does the home repeater key up every 3 seconds when it is NOT busy with voice?

snoopyII · #3 (**permalink**) 01-20-2008, 12:18 AM

I would say no, This is the American Medical Response system in Denver, here's how I have it set up (eventhough I know its not right yet.)

936.175 as F1
936.750 as F2
937.175 as F3
937.750 as F4
938.750 as F5
939.150 as F6
939.750 as F7

I have idenentified two TG's so far as 0-07-002 and 003. All of the voice is on F4, when the scanner is running in conventional mode, the data bursts seem to alternate on F5 and F7 most frequently. Ocassionaly on F2 and F4. When parked on F4, data bursts are nowhere near 3 seconds apart, sometimes several minutes apart. So, if the voice is always on F4, assuming its the home repeater in this case the 07. Now for the really newbie questions, This LTR Analyzer sounds like an intersting program, will it identfy the proper LCN order for a passport system? I saw threads regarding programs called LTRdump and LTRTrunk, is Analyzer an easier to use upgrade to these?

KD4YGG · #4 (**permalink**) 01-20-2008, 06:54 AM

Quote:

Originally Posted by snoopyII

I would say no, This is the American Medical Response system in Denver, here's how I have it set up (eventhough I know its not right yet.)

936.175 as F1
936.750 as F2
937.175 as F3
937.750 as F4
938.750 as F5
939.150 as F6
939.750 as F7

I have idenentified two TG's so far as 0-07-002 and 003. All of the voice is on F4, when the scanner is running in conventional mode, the data bursts seem to alternate on F5 and F7 most frequently. Ocassionaly on F2 and F4. When parked on F4, data bursts are nowhere near 3 seconds apart, sometimes several minutes apart. So, if the voice is always on F4, assuming its the home repeater in this case the 07. Now for the really newbie questions, This LTR Analyzer sounds like an intersting program, will it identfy the proper LCN order for a passport system? I saw threads regarding programs called LTRdump and LTRTrunk, is Analyzer an easier to use upgrade to these?

This may be a mixed LTR Regular/LTR Passport system - they do exist.

Have you tried programming in F4 into a new LTR system in you scanner as home repeater 07? This might work.

I haven't yet used Analyzer, but it should be as easy as the other two.

N1GTL · #5 (**permalink**) 01-20-2008, 05:04 PM

If a Passport sytem has XX repeaters, the system will use the first repeater. Only if that repeater is in use will it move to repeater 2. If 1 and 2 are in use, it will use 3, and so on. It is possible that the last repeater is never used. Passport will not just move around and use different repeaters every time the repeater drops.

fwradio · #6 (**permalink**) 01-20-2008, 05:14 PM

Quote:

Originally Posted by N1GTL

If a Passport sytem has XX repeaters, the system will use the first repeater. Only if that repeater is in use will it move to repeater 2. If 1 and 2 are in use, it will use 3, and so on. It is possible that the last repeater is never used. Passport will not just move around and use different repeaters every time the repeater drops.

Passport reports all available free repeaters. If the transmission is long enough you will be able to get a list of every frequency at the site. It is up to the radio to pick out of the free list when the home channel is being used, just like LTR.