Subaudible data question

[dstew67]

Are there some cases where subaudible data is transmitted on some channels, and not others in the same system?

There are two systems I'm monitoring, both with 5 freqs each, where the subaudible data is transmitted on only 4 of the five channels. Futher, it seems like that fifth freq is not even being used on either system. So, I'm wondering if the frequency is simply not in use, or is there some other purpose for this one freq not transmitting the subaudible.

Any thoughts?

 

[pro92b]

Active frequencies in an LTR system must transmit subaudible data. There is no other way to control radios on the system. If you hear transmissions on these frequencies and there is never any subaudible data, they are being used as conventional repeaters.

Why do you believe the frequencies should be part of the LTR system?

How are you determining that the subaudible data is absent?

 

[dstew67]

In both cases, the fifth frequency is listed under the same license and site as the other four. This is what makes me think they should be part of the system.

I'm using a PRO-97. The radio easily picks up the HRXX for the other four freqs, and hears audio. I have not heard any audio on these two "fifth" frequencies, and it doesn't seem to make a difference whether that fifth freq is a part of the bank or not. This is why I think that in both cases, the frequency is not being used.

 

[pro92b]

If you program the two fifth frequencies in conventional FM mode and hear nothing, then the frequencies are not in service. It may be possible to use software to record those frequencies for a day or two to see if there is ever any activity.

The absence of an idle burst does not mean that the frequency is not part of the LTR system. If no users are homed to that frequency, there is no need for an idle burst and it may be turned off. Systems with low activity may seldom use the overflow channel and you might not hear it activate.

 

[dstew67]

OK. That makes sense. I don't know why I've never had an interest in LTR, so I'm not very knowledgeable in this area. I feel like an idiot, trying to figure this out...

 

[cg]

if someone in your area has built the LTR data slicer and uses the LTR Dumper program, you will be able to tell if there are 4 or 5 active freqs.


chris

 

[DaveH]

if someone in your area has built the LTR data slicer and uses the LTR Dumper program, you will be able to tell if there are 4 or 5 active freqs.
chris

Yes, if you monitor each channel individually when running LTRTrunk, or even scan them, the fifth would eventually show up as a GOTO or FREE repeater; or you could monitor only the suspected frequency over time to see if its repeater number shows up.

Dave