Half the Convo

[Treabhar]

Hi Ladies and Gents,

I have a Motorola Trunktracker III base scanner... very nice unit... but I have a question.

When just general scanning... I get things like Toronto Center and Cinncinatti Center. The problem is I can only hear the aircraft calling but not the replies from the tower. Any assistance would be appreciated.

Thanks,
Treabhar

 

[edweirdFL]

You are probably not close enough to the ground based transmitters to hear them, but can easily hear the planes that are in the air, since your antenna can "see" them line of sight.

Assuming there's no issue with your scanners programming (delay) or squelch setting, a better antenna mounted higher might help you hear the ground stations, depending on location.

 

[w0fg]

You'll find you can easily hear aircraft 200 or more miles away, but you'll need to be within 10 or 15 miles of the center's transmitter to hear it. Nothing unusual there if you think about it..the difference in hearing a signal from an antenna that's 7 miles in the air vs. one that's 17 feet in the air.

 

[Treabhar]

I assumed this was the reason but just wanted to verify. I very much appreciate your help.

- Treabhar

 

[eorange]

You'll find you can easily hear aircraft 200 or more miles away, but you'll need to be within 10 or 15 miles of the center's transmitter to hear it. Nothing unusual there if you think about it..the difference in hearing a signal from an antenna that's 7 miles in the air vs. one that's 17 feet in the air.

Would it be possible to hear the VHF ground-based comms with a yagi if you're 20-30 miles away? Terrain is generally flat between me and the airport.

Has anyone done this?

 

[Lexxx]

Would it be possible to hear the VHF ground-based comms with a yagi if you're 20-30 miles away? Terrain is generally flat between me and the airport.

Has anyone done this?

This guy http://www.radioreference.com/forums/showthread.php?t=59135&highlight=military was getting ground transmissions from 75 miles away, if that helps

Lexx
www.ykf.ca

 

[trainman111]

20-30 miles ground side shouldn't be too much of problem in flat terrain. I'm about 22 miles or so from KRIC and I pickup tower, ground, and APP just fine. I'm using a discone about 25 feet up and between me and the airport is part of the City of Richmond.

 

[eorange]

I forgot about that mil yagi thread...

I am about the same, less than 20 miles from the airport with a discone about 20-25 feet up, and no way can I hear the tower side. I am thinking about slapping together a VHF beam and going up on the roof next to the discone with a scanner and see if I can hear it.

I wouldn't say the terrain is totally flat, not like an open plain. There's some topo variation between me and the airport. But there's certainly no hills or mountains in NE Ohio!

 

[w0fg]

Terrain makes all the difference. I'm about 25-30 miles from the airport and cannot receive ground transmissions with an omni antenna at the top of my 65' tower, but I can receive them on a rubber duck at 20 miles once I get up on higher terrain.

 

[Comint]

Range also depends on the transmitter power being used. Some airports only use 10 watts, others use 100 watts, or more.

 

[chgomonitor]

Aircraft Ground Transmitter Antennas

-Also depends on the type of antenna in use at the ground site and where it is mounted. Many antennas used by ground transmit sites are designed to throw their signals skywards. The exception is supposed to be (obviously) anything for ground, clearance, etc. This maximizes the aeronautical range and lessens the distance at which another ground transmitter can operate on the same frequency.