ARMER coverage/ reception question

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blue5011

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Technical question here, as I am trying to "fine tune" my talkgroups/ tower sites.

So I am wondering if all State Trooper calls for the Mankato district go out on all tower sites (in the district), OR do the calls ONLY go out on the tower sites where Trooper cars are located (since the system should know who is where)?

In other words, if I only listened to the Blue Earth tower, would I still hear each and every State Trooper call in the district? Or would I only hear calls that are w/ in the BE tower site coverage area?

I have already taken my outdoor antenna down (which I was able to receive 8-10 different tower sites), and now I am only using a 18" 2mtr/440 rubber duck on the back of my 996XT.
 

mmtstc

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State patrol talkgroups (in my understanding) are forced on to all state owned sites in their jurisdiction. Locally owned enhancement sites are often (again, in my understanding) at the discretion of the owner.


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blue5011

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State patrol talkgroups (in my understanding) are forced on to all state owned sites in their jurisdiction. Locally owned enhancement sites are often (again, in my understanding) at the discretion of the owner.

The Blue Earth tower IS a state tower to my knowledge.

So it stands to reason then I will still hear ST James MNDoT snowplows also on the BE site regardless that they are 25-35 miles away? Because surely MNDoT vehicles are "forced" on all sites too?
 

mmtstc

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There is no reason to force mndot talkgroups. No system user really scans mndot.
State patrol forces because many police and sheriff units scan their talkgroups.


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blue5011

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There is no reason to force mndot talkgroups. No system user really scans mndot.
State patrol forces because many police and sheriff units scan their talkgroups.

Blue Earth ARMER tower is 4 miles away. So you are saying I should only hear MNDoT snowplows that are w/ in range of the BE tower? And if I do hear a ST James truck it is because it is w/ in range of the BE tower? Provided I am only scanning on the Blue Earth tower...

Normal signal strength from the BE tower is 650-750, Mapleton 350-550, Fairmont 350-500, Truman 250-400, and Walters 300-500. I don't quite understand why the signal strength changes, unless what is being reported is the strength of the "incoming" signal to the tower... In other words, the further vehicle *A* is from any tower, the lower the signal.

I have a 2mtr Ham repeater w/ in a mile of me. Generally that signal strength is 800+.
 

johnmoe1

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Blue Earth ARMER tower is 4 miles away. So you are saying I should only hear MNDoT snowplows that are w/ in range of the BE tower? And if I do hear a ST James truck it is because it is w/ in range of the BE tower? Provided I am only scanning on the Blue Earth tower...

If there is any radio using* the Blue Earth tower that is tuned to talkgroup xxxx, anything said on talkgroup xxxx anywhere in the state will be broadcast over the Blue Earth tower.

I don't know what those signal strengths mean, but I can't imagine any way it could be related to signal strength inbound to the tower. (These towers are nothing like simple repeaters. The outbound signal does not even use the same modulation as the inbound. LSM/CQPSK vs C4FM.)

* I don't mean currently talking. I mean has gone through the little handshake that goes sort of like: "Hi Blue Earth Tower, I am Radio #xxxxxx and I would like to listen to tg xxxx. Hi Radio #xxxxxx, you can listen to tg xxxx and should also monitor the broadcast tg yyyy."
 
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davef3138

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The dot emergency talkgroups seem to be forced to all sites in each district...

This has been my observation as well. I regularly hear 511 road updates and crash reports from MnDOT plow operators all over southern Minnesota on the McLeod simulcast site.

As far as I know, the main State Patrol and the MnDOT<-->State Patrol talkgroups are forced to all sites in the district so that the scan function can be leveraged in the radio. "Scanning" in the subscriber radios doesn't pull the talkgroup audio to the site, it has to be either forced to the site that the scanning radio is affiliated to or another radio has to have that talkgroup manually selected.

In the operation & tech committee minutes, there's often requests by counties to have certain talkgroups of theirs forced to neighboring sites for the same reason. Often times, a county's radio will affiliate to a neighboring county's site, but will miss calls if a talkgroup they're scanning isn't present on that site.

-Dave
 

blue5011

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If there is any radio using* the Blue Earth tower that is tuned to talkgroup xxxx, anything said on talkgroup xxxx anywhere in the state will be broadcast over the Blue Earth tower.

I don't know what those signal strengths mean, but I can't imagine any way it could be related to signal strength inbound to the tower. (These towers are nothing like simple repeaters. The outbound signal does not even use the same modulation as the inbound. LSM/CQPSK vs C4FM.)
Well why does the signal strength vary so much? I am using the signal strength as logged from Freescan.

The 2mtr repeater signal is consistently 821-830 (9 points difference). Signals from the BE ARMER tower are sometimes as low as 423, usually in the 600-700 range. I don't under stand why the signal strength varies, since the tower does not move and my place of residence does not move.

Does it matter whether the signal is "regular" FM or "LSM/CQPSK vs C4FM" digital?
 

NDRADIONUT

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Yep... 800 gets absorbed by a lot of things and bounced around a lot more than vhf... Uhf has a similar behavior but not as bad as 800...
 
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