Tower & frequency understanding

[hotrod501]

My radio is a 396T I have 1 tower program into it the radio the tower 1-035 is 6 miles from my home its for dist 16 talk groups for dist 16 & dist 1 are program in my questions are.

1. do i need all the frequency for the tower in radio I took out all but the primary control channel and alternet channel seems to have less audio drop off without them but am I missing calls without those other frequency in radio.

2. why does dist 16 audio fall off alot more then Dist 1 when they are comming off the same tower.

[RADIOGUY2002]

More Information required for processing-

Wattage, height differences even at the same tower, loss in line feeds, etc

Could you be more speciffic on whats systems your listening to?

[hotrod501]

Starcom for isp the only 2 frequency i put in are 851.16250 & 853.0625 wattage and height no clue on them. just dont understand why there less audio fall off for sterling state dist 1 then rockford state dist 16 being the tower is in pecatonica 6 miles from me. I did not enter frequency 851.4625 & 852.4625 they were in black and not controls channels but without them i have less audio drop off but if they should be program in i will

[N9JIG]

On current scanners like yours the only freqs you MUST have programmed for StarCom21 and other P25 systems is the current Control Data channel. The radio will find the voice channels automatically and they do not need to already be in your scanner.

P25 systems usually have up to 3 assigned data channels per site, the active one is designated as "Control" and the others are designated as "Alternate". If you know all three of these channels then you are all set. If not then it is a good idea to include any frequency that you know is used at that site so that if the control channel changes you will likely have it in your radio.

The presence or lack of presence of other channels programmed into the same System on your scanner will have no affect whatsoever as to the intelligibility or voice quality. The P25 settings may affect this however, so you may want to try to tweak those settings.

[RADIOGUY2002]

The other note issue is multi site systems as oppose to single site systems. We have a discussion going on this already in the Chicago metro thread. But, like Rich said you only need control channels to follow these systems (data burst-grrrrrr channel) with the type of scanner your using. The other frequencies that rich talks about are back up's (alternates) to the main (grrr channel). A master computer control is on in link with these grrr channels that assigned a direct frequency and talk group path. (handshaking) with players involved. Utilize the frequencies( control channel or CC) that best support your listening. I was unaware that the two state police districts utilize the same tower, for district coverage, I am however aware that with multit site systems have several locations that all broadcast on the set of frequencies for a district, Looking in the carma files on starcom 21 references this.

This is a multi cast system as it has several locations that supply a radio connection, to improve radio coverage, thus meaning you can get a signal from anyone of these towers and shift in between them. Their are more on this tower / site location / system, but this servers as in example.

102A Westchester Cook Toll Plaza 35 41.8533 87.9178
102B Chicago Cook CFD Shops 41.8386 87.7022
102C Chicago Cook CPD Zone 8 41.6925 87.6031

District 16 Sites- aka District Rockford-this is known as a muliti cast system, for some reason the 396T is getting (as designed in scanner world) to rx radio signals from mutiple locations, the problem is that one of these sites may be strong then the other. Which is causing drop out and fade off as it getting signals from multiple locations. The newer xt models seemed to decode these individuals sites improving audio quality and drop out you speak off.

111ARockford East Winnebago Tollway M7 42.2728 88.9625
111B Rockford North Winnebago TV Ch 51 42.3232 88.9987
111C Rockford West Winnebago American Tower Co 42.2906 89.1642
111D Rockford South Winnebago Midwest Tower Co 42.2281 89.0197

Where as District 1, which serves the following counties (Carroll,Lee,Ogle,Whiteside) appears to have all single site based systems.

Please read the starcom 21 profile located on Carma website under profiles as Rich and few others have explained this. We have been trying to figure out the radio logic on why the drop out occurs more on simulcast system as oppose to single site systems.

[jblake76]

So from what I am getting from this is just input the control channels and not the alternates? I am using the pro-106.

[cheld18]

BTW Does anybody know what the optimal settings would be for a BCD-396T for...
P25 Waiting Time (400 ms Default)
P25 Adjust Mode (3 Default)
P25 Adjust Level (50 Default?)

[RADIOGUY2002]

So from what I am getting from this is just input the control channels and not the alternates? I am using the pro-106.

If the scanner operates in Control Channel Mode, you only need the the main CC Channel and it is a wise idea as well to have the secondaries if the main fails or is switched. The other frequencies are not needed, I can not commment on the exact steps as I'm not familiar with the model you mention.

[RADIOGUY2002]

"BTW Does anybody know what the optimal settings would be for a BCD-396T for...
P25 Waiting Time (400 ms Default)
P25 Adjust Mode (3 Default)
P25 Adjust Level (50 Default?)"

Every system is different, and that another issue in itself. Conditions on where your scanning can even effect this.