Some Detroit site signals break up

[dnoyeb]

I am wondering why I hear some of the signals from Wayne county loud and clear, and others break up terribly. Yet the person they are speaking with seems to hear them fine.

This seems to imply the audio I hear is coming from the given radio, and not from the tower itself. is that true? Does the tower not repeat the audio for all to hear? Or does the tower just instruct on which frequency the group should listen, but itself does not broadcast the audio?

 

[Citywide173]

I'm going to assume that you are physically outside the City of Detroit, trying to listen to Detroit talkgroups.

The Detroit system is very unique, in that the majority of the repeater sites are on the outskirts of the city, and pointed in toward the center with directional antennas....at least this is how it was explained to me. The reasoning, again as explained to me, was to avoid interference on co-allocated frequencies in the neighboring sections of Canada.

Basically, they designed a system that works in the City, on the lowest power possible to provide coverage, which is the way that every system should be designed, but thankfully for those monitoring, the systems usually have more power than necessary, and can be monitored for a greater distance than necessary for adequate coverage.

You are not hearing the radios on the input frequencies (unless you're monitoring 45 mhz below the published frequencies, and even then I'm not sure a P25 radio would decode a trunked system properly), you're just hearing a weak signal.

 

[dnoyeb]

OK, that's very helpful. I am actually about 1/2 mi from the Southfield/Oakland County tower. So I am indeed on the outside of the city. I am 1 mile outside of Detroit. I get OK reception. Probably much better if I had a real antenna instead of the handheld.

So it sounds like Detroit does not have just 1 antenna like the database shows, but several antennas pointed inward?

Anyway, I think I'm getting the hang of this.

 

[gpp10x]

I forget the exact number but there are 10 or 12 tower sites that broadcast (simulcast) the same radio transmissions thru out the city.

 

[a29zuk]

Simulcast digital distortion - The RadioReference Wiki

Detroit City is a simulcast system. Simulcast systems play havoc with scanners. Go to the above link in the wiki for a better explanation.

 

[dnoyeb]

Interesting. Is there anyway to know the location of the antennas in Detroit?

 

[UPMan]

In the DB, click on the site name (Simulcast, in this case) then click on the License.

FCC Callsign WNAJ346 Details

EDIT: Oops, same instructions, different system. See below.

 

[gpp10x]

Interesting. Is there anyway to know the location of the antennas in Detroit?

If you go to the database & click on the Detroit simulcast site it will bring up the information page. There are 10 sites. Click on the site license on the right side of the page or click on the links below.

RadioReference.com - Scanner Frequencies and Radio Frequency Reference Database

FCC Callsign WQBJ564 Details

FCC Callsign WQBK909 Details

 

[dnoyeb]

Fascinating! I guess simulcast site means multiple antennas? I found the one closest to me. I used to live 1/2 mile away from that. Its interesting to finally know what these towers are for. This tower (#6) is on Grand River, right inside the Fire Department station. The Police station is right behind it as well. Sadly, that police station is closed. Along with the high school right in front of it... I bet the fire station is not closed since the tower is there.

I'm going to drive over there and see what I can pick up.

 

[UPMan]

Simulcast = multiple antenna sites all transmitting the same signals on the same frequencies.

Simulcast - The RadioReference Wiki

 

[gpp10x]

Even if DFD closed the fire station the antenna tower would remain. If you are in close proximity to that antenna site you should have terrific reception. Also be sure to read the 2 wiki links posted here if you haven't done so. It will help explain things.

 

[dnoyeb]

Yes I read the wikis.
If the fire station closed there would be trouble protecting the tower.
Anyway, I get very choppy reception in the city.much better outside of it. Hope I can figure something out. Seems like a mobil scanner will be tough in Detroit

 

[gpp10x]

If the fire station closed there would be trouble protecting the tower.

The FD has no responsibility in protecting or maintaining the radio towers.

 

[dnoyeb]

The FD has no responsibility in protecting or maintaining the radio towers.

I doubt if anyone will mess with the tower being next to a station that is manned 24-7. Next to an abandoned station is another story. So I would expect there to have been some consideration. The most unprotected area in the city has to be the location of former police stations.

 

[Rexem]

Detroits system is kind of funny sometimes. I was sitting outside of the communications building and Detroit EMS was still breaking up every so often.

 

[OsloViking1975]

The only place I can pick up Detroit is my bathroom

 

[dman9377]

iam 1/2 mile from tower on grand river and my scanner is choppy 24/7 any suggestion to get better reception