BCD996XT: Radio Programming Question - P25 Trunked Systems - Okay To Use Multiple Antenna Sites?

[Wthom100]

Hello RR Community,

Wanted to get experienced opinions regarding the following: is it a good scanner programming practice to load multiple antenna sites for a single P25 (phase I) trunked system? Will loading multiple antenna locations that cover my home geographic scanner location improve ability to pull in strong signals into the scanner? Or is loading multiple antennas overkill and potentially confusing the scanner programming (e.g. making the scanner work harder than necessary vs. just loading 1 antenna site)?

Some background: I live in AZ PHX metro (Maricopa County). I have 996XT scanner and using Freescan. Using the TOPAZ P25 phase I trunked system as an example, I loaded all the antenna sites that had control channels that were in Maricopa County that covered my geographic scanner location (using Radio Reference Database map data - it is about 4 antenna sites). I notice my 996XT scanner scans all the antenna sites for the TOPAZ trunked system (the antenna sites show-up in the scanner display). I get good signals from the edges of the PHX Metro. But would I still get good talkgroup signals if I just loaded the 1 antenna site closest to me (in this case: Thompson Peak)? Just wanted to make sure my scanner was working efficiently.

Your comments are welcomed!. Thx

 

[dave3825]

The more sites your scanner is scanning, the more you miss listening to. If your using the scanner at home as a base, the best signal you will get will be the site closest to you. Adding more sites will not make a signal stronger. If you do not travel with the scanner, there is no need for a bunch of sites.

 

[Mex]

In my opinion, it all depends on what you wanna hear.

For example, I listen to 3 local sites and one that is about 40 miles away. 1st local site carries traffic from the surrounding counties, 2nd carries my sheriff's department and, the 3rd site is a state police dispatch site, which happens to carry most of the local state police and statewide interop talk groups.
But like @dave3825 mentioned the more sites you scan the higher the chance of missing other traffic.

 

[Dog]

Hello RR Community,

Wanted to get experienced opinions regarding the following: is it a good scanner programming practice to load multiple antenna sites for a single P25 (phase I) trunked system? Will loading multiple antenna locations that cover my home geographic scanner location improve ability to pull in strong signals into the scanner? Or is loading multiple antennas overkill and potentially confusing the scanner programming (e.g. making the scanner work harder than necessary vs. just loading 1 antenna site)?

Some background: I live in AZ PHX metro (Maricopa County). I have 996XT scanner and using Freescan. Using the TOPAZ P25 phase I trunked system as an example, I loaded all the antenna sites that had control channels that were in Maricopa County that covered my geographic scanner location (using Radio Reference Database map data - I loaded 4 antenna sites). I notice my 996XT scanner scans all the antenna sites for the TOPAZ trunked system (the antenna sites show-up in the scanner display). I get good signals from the edges of the PHX Metro. But would I still get good signals if I just loaded the 1 antenna site closest to me (in this case: Thompson Peak)? Just wanted to make sure my scanner was working efficiently.

Your comments are welcomed!. Thx

It is my experience that scanning more sites than you need slows scanning down. If you have a strong signal from a site then there is no need to scan more sites and it will only slow things down.

 

[Wthom100]

Thanks guys for the quick replies. Dave - I see your point about the more sites you monitor the more you might miss. I am trying to make sure I understand the concepts of how this programming works. Here is an example:

I live at point X. The closet trunk system antenna site is 5 miles north of me (antenna “A”). The signal I have programmed (among many over a wide geographic area) I want to listen to is 40 miles south of me (point Z). There is a system antenna (antenna “B”) between my base scanner and the point Z. I would think I would want to program in that antenna “B” location as it is closer to the signal origin (point Z). I do not think the closest antenna to me (antenna “A”) would pull in a quality signal from 40+ miles away. Am I thinking about this the right way?

Mex - it sounds like you are saying split-up the coverage area into multiple groups (‘quick keys” - each with their own antenna site).

 

[nessnet]

Thanks guys for the quick replies. Dave - I see your point about the more sites you monitor the more you might miss. I am trying to make sure I understand the concepts of how this programming works. Here is an example:

I live at point X. The closet trunk system antenna site is 5 miles north of me (antenna “A”). The signal I have programmed (among many over a wide geographic area) I want to listen to is 40 miles south of me (point Z). There is a system antenna (antenna “B”) between my base scanner and the point Z. I would think I would want to program in that antenna “B” location as it is closer to the signal origin (point Z). I do not think the closest antenna to me (antenna “A”) would pull in a quality signal from 40+ miles away. Am I thinking about this the right way?

Mex - it sounds like you are saying split-up the coverage area into multiple groups (‘quick keys” - each with their own antenna site).

Frankly, no you are not "thinking about this the right way".

Here is what you ask.....
Does each of these sites carry different (unique to it) traffic?
Or, are they all part of the same system, with the SAME traffic?
If different, scan different sites to pick up what each carries.
If the same, only scan the nearest (or strongest/best signal) site.

Where the dept you want to listen to is physically located does not make any difference if the sites are all putting out the same traffic.
Remember, the sites are all connected to the system via data circuits, not radio signals.

Remember, there is only ONE tuner in the radio.
It will only be listening to ONE site at a time.

 

[Wthom100]

Ok - well clarified. They are all part of the same system. So I will just load the closest antenna to me and see if everything comes in with good signal quality. The “connected via data circuits” vs. “radio signals” brought it home for me.

Thanks!

 

[rrobinso84]

All very interesting, but don't forget that traveling mobile and portable radios can "affiliate" with disregard sites within a system (P25, for example). So I would say listen to whatever sites you know you can receive.

My experience thus far is that I hear local affiliate traffic at my local site much more often than I hear more distant precincts/ divisions. The only exception is for "major incident" traffic which I have a hunch that they widen the affiliation on purpose to provide more area access in the larger incidents.

Anybody know the deeper details?

 

[tvengr]

For example, I listen to 3 local sites and one that is about 40 miles away. 1st local site carries traffic from the surrounding counties, 2nd carries my sheriff's department and, the 3rd site is a state police dispatch site, which happens to carry most of the local state police and statewide interop talk groups.

Are you using 3 sites or systems? I don't understand why the sheriff would not be using the same local site unless it is on a different system.

 

[tvengr]

Your comments are welcomed!. Thx

You can easily select the systems, sites, and groups you want to scan by using quick keys. Here is a PDF file which will answer all of your questions about using quick keys:

 

[Mex]

Are you using 3 sites or systems? I don't understand why the sheriff would not be using the same local site unless it is on a different system.

3 sites same system. The affliations are very weird, sheriff only affliates to the local tower maybe once a day if I'm lucky.

 

[RMason]

You may want to log the traffic on each site and compare the results to see what talk groups are carried on each site. You will want to compare the number of hits on each tg in addition to what talk groups are seen.

Once you know what traffic is seen on each site, then you can make better decisions about what sites you should scan.

 

[W8HDU]

The more sites your scanner is scanning, the more you miss listening to. If your using the scanner at home as a base, the best signal you will get will be the site closest to you. Adding more sites will not make a signal stronger. If you do not travel with the scanner, there is no need for a bunch of sites.

In the case of myself, living in Allen County (OH), if I want to listen to Mercer County, or Van Wert County, they don't come through the Allen County tower, do they? For each county I add to my scanner I have to add a tower residing in that county, don't I?

 

[dave3825]

It all depends on what talk groups affiliate with what sites. Simple test would be add the tg's from Mercer County and Van Wert County and then sit on the sites from Allen County. Lima and Bluffton. If you get those tg's, then they affiliate. If not, then you would need to add/enable the sites for Mercer and Van Wert.

 

[nessnet]

In the case of myself, living in Allen County (OH), if I want to listen to Mercer County, or Van Wert County, they don't come through the Allen County tower, do they? For each county I add to my scanner I have to add a tower residing in that county, don't I?

Are they all on the same system?
Or, on completely different ones?

If the same system, they both could have traffic from each other on them...

 

[W8HDU]

Are they all on the same system?
Or, on completely different ones?

If the same system, they both could have traffic from each other on them...

That's a good question. I'm not familiar with the way MARCS works to offer an educated answer.

However, the seller of the scanner stated, "You must put in the tower which resides in the county of the agency you're monitoring." To me that indicates you want to monitor agencies in your county, and six others, then you have to enter seven counties.

Where I started to doubt this is when setting up the scanner, and have Hancock County (OH) in it, and when O.S.P. comes in sometimes I'm hearing Turnpike action, or Williams, Fulton, or Lucas Counties. FYI, I'm in Allen County (OH) which is pretty far away from the previously mentioned three counties.

 

[nessnet]

.... the way MARCS works....

...the seller of the scanner stated, "You must put in the tower which resides in the county of the agency you're monitoring."

So, it is a common system (MARCS).
Chances are, the majority of the dispatch traffic on both sites is common.
Possible that some traffic, such as tac for the locals may be on one or the other - than, maybe not....

As to what the seller told you. I would classify that as bad advice. You FIRST need to know the various affiliations used on that system - what TGs may be used in each area, or possibly everything is on every site.

 

[W8HDU]

As to what the seller told you. I would classify that as bad advice. You FIRST need to know the various affiliations used on that system - what TGs may be used in each area, or possibly everything is on every site.

And how does one find out this information? Is it documented or more word of mouth from scanner enthusiasts?

 

[nessnet]

And how does one find out this information? Is it documented or more word of mouth from scanner enthusiasts?

It could be "word of mouth" or maybe ask questions in your area's forum, here on RR.

Many of us did it by simply monitoring and taking notes.
Then, adjusting what sites we scan accordingly.

Does the 996 have the ability to ID search?

 

[dave3825]

And how does one find out this information?

If you're lucky enough to know someone managing the system, that's a plus. Other wise its program, watch and compare. Using dongles makes it clearer, faster. You can program different sites into software like DSDPlus or Unitrunker and watch activity on each site. Or program different sites in a scanner and monitor a different one each day and take notes.

My counties system, not a State system, has most entities, cops, local towns, transit etc all using an 800mhz site in phase 1. Fire depts are said to be, in the end, using the 700mhz side that runs phase 2.

The MTA out here by me has tg's from areas no where near me (4 counties away) broadcasting on the site local to me.

Its all about how its set up..