It can't be skip.....but why is it happening ?

Hoofy · #1 (**permalink**) 04-13-2006, 01:26 PM

I have discovered an amazing coincidence.

I went back through my notes and logs of my earlier situations where I believed that skip was coming thru on 800mhz trunking. I received enough info after those posts to come to the conclusion that receiving a skip signal was not possible.

What I found was that where I had kept notes or a log of the traffic and scanner info I found that in every case, and there were a number of them, that the out of area traffic showed up on the pro 2096 display as a local voice channel on a local tower. But then I found that the area within the state that the traffic originated from had a tower with the exact same control channels and voice channels as one of the local towers I had heard the traffic on. I don't believe in coincidence's. Anyone know what's happening??

seamusg · #2 (**permalink**) 04-13-2006, 02:38 PM

Quote:

Originally Posted by Hoofy

I have discovered an amazing coincidence.

I went back through my notes and logs of my earlier situations where I believed that skip was coming thru on 800mhz trunking. I received enough info after those posts to come to the conclusion that receiving a skip signal was not possible.

What I found was that where I had kept notes or a log of the traffic and scanner info I found that in every case, and there were a number of them, that the out of area traffic showed up on the pro 2096 display as a local voice channel on a local tower. But then I found that the area within the state that the traffic originated from had a tower with the exact same control channels and voice channels as one of the local towers I had heard the traffic on. I don't believe in coincidence's. Anyone know what's happening??

I've heard Keweenaw traffic on the Mt. Clemens tower a few times and it was all USCG, because a radio either at Shores CG station or Air Station Detroit was on that TG. That's how the system is designed to work

safetyobc · #3 (**permalink**) 04-13-2006, 02:49 PM

Possibly ducting?

http://home.cogeco.ca/~dxinfo/tropo.html

rdale · #4 (**permalink**) 04-13-2006, 02:53 PM

If you pressed hold on the control channel and saw your local tower - it is coming from your local tower. Plain and simple.

Hoofy · #5 (**permalink**) 04-13-2006, 09:20 PM

In the case today I heard a Chippewa County tg which is located on the east end of the U.P. coming in on the Centennial Heights tower just a couple of miles from me. What baffles me is that to affiliate with this tower a radio would have to be within a 10 mile or so radius of the tower. To get within range of the tower they would have had to go by at least 4 other towers which they should have affilliated with yet I heard nothing on any tower but the one. Even if they would have flown in for some reason they would have been closer to another tower.

I don't question that it came thru the local tower just trying to figure how it got there. I'm going to check with the two sheriffs dept tomorrow to see if they know about anyone in the area.

If you were familiar with this area you might understand why I question the affilliation part. Especially with this tower which from the top you could easily see Lake Superior on both sides of the peninsula. West to Minnesota and east to the Soo.

seamusg · #6 (**permalink**) 04-13-2006, 11:15 PM

Quote:

Originally Posted by Hoofy

In the case today I heard a Chippewa County tg which is located on the east end of the U.P. coming in on the Centennial Heights tower just a couple of miles from me. What baffles me is that to affiliate with this tower a radio would have to be within a 10 mile or so radius of the tower. To get within range of the tower they would have had to go by at least 4 other towers which they should have affilliated with yet I heard nothing on any tower but the one. Even if they would have flown in for some reason they would have been closer to another tower.

I don't question that it came thru the local tower just trying to figure how it got there. I'm going to check with the two sheriffs dept tomorrow to see if they know about anyone in the area.

If you were familiar with this area you might understand why I question the affilliation part. Especially with this tower which from the top you could easily see Lake Superior on both sides of the peninsula. West to Minnesota and east to the Soo.

How do you know there was not another radio affiliated with that tower on that talk group- are you using two digital scanners with one running WIN96COM and you know all the radio's that are affiliated with that tower and know what channel grants were given on that tower- to find most of the radio's on a tower you would have to run WIN96COM for at least 72 hours and you will not see a base station affiliate unless it changes TG's - your log are useless since they are what you want them to be..

Hoofy · #7 (**permalink**) 04-14-2006, 11:10 AM

Why didn't it affiliate with any other towers?????? T061A is an isolated tower. I can hear all the towers north and east of it and 4 or 5 towers south of it.

No matter how they came into this area, either by ground or air, they would have to come by other towers to get into the area.

I'm just trying to understand.

mikey60 · #8 (**permalink**) 04-14-2006, 11:31 AM

Quote:

Originally Posted by Hoofy

Why didn't it affiliate with any other towers?????? T061A is an isolated tower. I can hear all the towers north and east of it and 4 or 5 towers south of it.

No matter how they came into this area, either by ground or air, they would have to come by other towers to get into the area.

I'm just trying to understand.

A radio can be affiliated to only one tower at a time. Predicting exactly which towers the radio would affiliate with while in transit is difficult at best, especially if it is an airborne unit of some kind.

Should you have heard it on another tower? Maybe but there are so many factors present in a system the size of the MPSCS that there is never a guarantee you'll hear every transmission.

Mike

seamusg · #9 (**permalink**) 04-14-2006, 11:33 AM

Quote:

Originally Posted by Hoofy

Why didn't it affiliate with any other towers?????? T061A is an isolated tower. I can hear all the towers north and east of it and 4 or 5 towers south of it.

No matter how they came into this area, either by ground or air, they would have to come by other towers to get into the area.

I'm just trying to understand.

how do you know it did not affiliate with another before affiliating with this tower? The condition for a radio to affiliate with a tower are:
1. turn on
2. change TG
3. move from one tower to another.
hearing a tower does not tell you if a radio affiliates with a tower, unless you run PRO96COM. Affiliating is done over the control channel not a voice channel, Also do you know the RADIO ID of this radio (RADIO ID's are a number like ZCCRRRR where Z is it's home zone, CC is the county number and RRRR is the radio number).

zeus_msp · #10 (**permalink**) 04-14-2006, 04:16 PM

Who says there is no skip on 800??? We get it all the time. If 2 cars are talking on the same channel on 2 different towers at the same time, and if there is skip (ducting) between those areas, then when one car unkeys his radio the other car will continue to come through on that distant tower because the system sees it as a continuation of the same transmission. The distant radio will not key the distant tower, but most certainly can come through on anothers tail. We have been experiencing that since the system went on the air, especially during spring and fall skip seasons.

seamusg · #11 (**permalink**) 04-14-2006, 05:02 PM

Quote:

Originally Posted by zeus_msp

Who says there is no skip on 800??? We get it all the time. If 2 cars are talking on the same channel on 2 different towers at the same time, and if there is skip (ducting) between those areas, then when one car unkeys his radio the other car will continue to come through on that distant tower because the system sees it as a continuation of the same transmission. The distant radio will not key the distant tower, but most certainly can come through on anothers tail. We have been experiencing that since the system went on the air, especially during spring and fall skip seasons.

You can't have skip on the Control Channel. His claim is he is getting TG's from a distant tower. TG. ID's come from the CC. not the VC. If you had skip on the CC the scanner would not be able to detect anything.

zeus_msp · #12 (**permalink**) 04-14-2006, 06:05 PM

Read what he said again, he is hearing out of area traffic THROUGH the local tower, not the control channel.

seamusg · #13 (**permalink**) 04-14-2006, 08:01 PM

Quote:

Originally Posted by zeus_msp

Read what he said again, he is hearing out of area traffic THROUGH the local tower, not the control channel.

Read all his previous postings on this. He's getting TG's from the other side of the bridge and it's not the 'BIG MAC'- You've got it.

rdale · #14 (**permalink**) 04-14-2006, 11:38 PM

"The distant radio will not key the distant tower"

He is saying the distant radio is keying the distant tower... If it were ducting of the voice channel, it wouldn't affect the control channel and he says it is.

Hoofy · #15 (**permalink**) 04-15-2006, 02:13 PM

1) On an average day I receive 10 different towers with a capture rate of 94% or greater.

2) Some days there is little traffic on any of these towers.

3) On several occassions I have heard distant tg.

4) On several occassions my scanner shows that it is receiving the distant tg from a local tower.

5) On several occassions, when I had taken notes, I discovered that when I was receiving a distant tg, the tower the tg was originating from shared the same cc and vc as one of the local towers.

6) In one case a Post 24 (Richmond) car was talking on the Flat Rock tower on the Post tg. The Flat Rock tower shares cc and vc with the local Houghton tower which is where my scanner said it was coming from. In another case a Chippewa County tg from the east end of the U.P. was coming in on the Centenial Heights tower, according to my scanner. Centenial Heights shares cc and vc with the Soo tower.

What zeus_msp says makes the most sense to me.

Take a look on the MPSCS tower map and see where I live on the Keweenaw peninsula. http://radiowurx.com/mpscs/

I'm 2 miles south of the Centenial Heights tower. I hear Copper Harbor, Eagle Harbor, Phoenix, Cent. Heights, Houghton, Baraga, Donken, L'anse, Skanee, and Donken every day. Sometimes US141, Champion, Marquette-3, Negaunee.

Atmospheric conditions have to impact on the system somehow. Yesterday a trooper from L'Anse checked into service with Negaunee on her portable and it came thru the L'Anse tower about 10 miles south. About 15 seconds later she checked in again using her mobile and came thru the Houghton tower which is 20+miles north. The Houghton pd cars were coming thru the Eagle Harbor tower 20+ miles away rather than the local Houghton tower and 2 MSP-90 cars checked out at the post and came thru the Eagle Harbor tower and there are 2 towers closer that they usually come thru.

seamusg · #16 (**permalink**) 04-15-2006, 02:38 PM

Quote:

Originally Posted by Hoofy

6) In one case a Post 24 (Richmond) car was talking on the Flat Rock tower on the Post tg. The Flat Rock tower shares cc and vc with the local Houghton tower which is where my scanner said it was coming from. In another case a Chippewa County tg from the east end of the U.P. was coming in on the Centenial Heights tower, according to my scanner. Centenial Heights shares cc and vc with the Soo tower.

It would be very rare for a post 24 car to be on the Flat Rock tower since they don't usually go that far south. Their area ends at 21 Mile. Unless the car was on TG 2005 (district 2 statewide) or there was a patch up on the system.

Hoofy · #17 (**permalink**) 04-15-2006, 05:01 PM

I had the Flat Rock tower in my notes so I must have heard a reference to it. It was mostly one patrol car just going from car off the road to car off the road. On the express way some place. As soon he cleared from one the dispatcher would say as long as you're in the area here's another.

Freezing rain I think.

seamusg · #18 (**permalink**) 04-15-2006, 07:27 PM

Quote:

Originally Posted by Hoofy

I had the Flat Rock tower in my notes so I must have heard a reference to it. It was mostly one patrol car just going from car off the road to car off the road. On the express way some place. As soon he cleared from one the dispatcher would say as long as you're in the area here's another.

Freezing rain I think.

If it was freezing rain, it would take over 3 hours or more to get from Richmonds area to Flat Rock's area.
I would realy suggest you try running PRO96COM on your towers to see what is realy getting a channel grant. Maybe someone has a rogue radio in your area.

jimsokol · #19 (**permalink**) 04-15-2006, 11:19 PM

Hoofy,
If the Chippewa county unit was in your area picking up or dropping off a prisoner, or otherwise visiting, and left his radio on the Chippewa County talkgroup you would hear it off your local tower.
Happens in my area all the time in my area.

...jim

Hoofy · #20 (**permalink**) 04-16-2006, 06:44 PM

I took a look at the pro96com program directions and I don't see where it would work for anything I need. If I understand it correctly when you connect to the scanner with the program then it reads one cc at a time and I wouldn't be hearing anything on the scanner. It would take 2 scanners to monitor the situation and have any idea of what I was seeing on the computer. I think the radio numbers would be of no value unless I knew who they were assigned to. I'll just keep listening and wondering.