DIGTIAL SITES

[PanJurekMrJerry]

:arrow: I am curious. I notice that with DIGITAL, each site seems to transmit audio that needs to be adjusted on the Uniden scanners but NOT on the GRE scanners. This part I understand. What I do NOT understand is why is that DIGTIAL sites have this problem(?) but ANALOG sites do not.
Also, is this just limited to the 800 Megacycle band or is this something that DIGITAL Sites do through out the spectrum? Also, why do they do that and NOT the ANALOG sites?[/b]

Also I noticed that on the Pro-96, there is a PERCENTAGE indicator that indicates how much DATA(?) is being transmitted from the site that the scanner is currently scanning. How low can this PERCENTAGE be before the site can NO longer make the public safety radios and / or radio scanners do trunking?

 

[LarrySC]

This week I PGM'ed 4- PRO-96's and 3- BC-796's and 1- BC-296. I find the audio on the Uniden units to be almost perfect with good base. Really impressed with BC. GRE, however, has that little echo. Whats being transmitted thru the air with digital is high speed computer data. This is very critical and requires a strong signal in order to decode. In my area the data % is usually 80 to 100.

 

[jimsokol]

:arrow: Also I noticed that on the Pro-96, there is a PERCENTAGE indicator that indicates how much DATA(?) is being transmitted from the site that the scanner is currently scanning. How low can this PERCENTAGE be before the site can NO longer make the public safety radios and / or radio scanners do trunking?

The percentage indicator is not how much data is being transmitted from the site. It is the receive percentage the scanner is successfully receiving the control channel data. The lower the number gets the worst chance you have of hearing or following anything. If it's a smartzone system, however, like in Michigan or Colorado for example, the radio will switch to another control channel when it gets too bad, provided you have other control channels programmed in, of course.

...jim

 

[PanJurekMrJerry]

Well I have heard, that here in OHIO, they use repeaters based on affiliation and voting.

 

[jimsokol]

Don't know about the voting part, but all of the systems we have mentioned (even MICHIGAN and COLORADO) use affiliation. If the radio doesn't affiliate, then it doesn't communicate on the system. Also, if no radios are affiliated to a given talkgroup on the tower you are monitoring, it won't be broadcast on that tower unless coded to always be carried on that tower.

....jim

 

[PanJurekMrJerry]

I believe that voting towers work like this:
IF a system users is near a tower and tha ttower is NOT recieving the signal well enough it will be routed to another tower based on signal strength.

 

[jimsokol]

Thanks, Jerry. It is interesting that it is used on a trunked system like MARCS.

...jim

 

[N_Jay]

I believe that voting towers work like this:
IF a system users is near a tower and tha ttower is NOT recieving the signal well enough it will be routed to another tower based on signal strength.

Voting is the use of more than one receiver site (tower) to enhance portable talkback in the range of a single transmitter site (or in a simlucast area).

The signals from all the receiver sites are brought back to a common point where they are summed together or selected (depending on the manufacturer and/or technology). This composit signal is used by the system just like any other received signal.

The system only knows where you are by the signal it recieves, so the idea that "system users is near a tower and that tower is NOT recieving the signal well enough it will be routed to another tower " does not make sense.

Voting has been around long before trunking, digital, or even simulcast.