DFW Airport

[TXFirefighter112]

I just moved to Irving, I'm literally half a mile south of Runway 17L/35R and want to listen to the aircraft coming and going. I only programmed in Tower East 17/35 L & C 126.5500mHz for the time being. I am able to hear the aircraft clear as day regardless where they are. But the tower is hardly coming through at all. It's strong enough for my scanner to recognize there's a signal but the static over powers the transmission.

My first thought was that it might be a line of sight issue, the aircraft are up in the air and have nothing obstructing their transmissions. But then I would hear the tower giving instructions to planes on the ground as well. They're told to take certain taxi ways, line up, take off, and given an altitude and heading before contacting departure. All that is horribly distorted under the static. Then the aircraft reads the instructions back and it's perfectly clear. So that eliminates line of sight as the cause. Any LOS issue causing poor reception of tower vs aircraft in the sky would also cause poor reception of aircraft on the ground vs flying.

My next thought is the tower's just transmitting on such low power that their transmissions aren't going much further than the border of the airport. But that's not possible as they're acknowledging aircraft intercepting the ILS from as far south as Midlothian and giving them instructions.

So any ideas on how to improve the tower reception?

And is there something more interesting to listen to here? I have Uniden BCT15 (in use now) and BCD996P2 (still packed up from moving) stock antennas on both.

Thanks!!

 

[w8prr]

What are you using for an antenna? Even that close, an inside antenna on the back of a scanner is questionable. Try to get an outside antenna, most any VHF high band antenna will work, a simple ground plane for most any frequency between 120 and 160 will work. Yes, I know some will start saying that it must be an air band antenna, but try anything you have, better a ground plane than a gain antenna at an off frequency, Use good coax and you will be amazed what you will hear.

 

[dlwtrunked]

What are you using for an antenna? Even that close, an inside antenna on the back of a scanner is questionable. Try to get an outside antenna, most any VHF high band antenna will work, a simple ground plane for most any frequency between 120 and 160 will work. Yes, I know some will start saying that it must be an air band antenna, but try anything you have, better a ground plane than a gain antenna at an off frequency, Use good coax and you will be amazed what you will hear.

And I am sure you meant to add-get it up in the air--like on the roof.

 

[w8prr]

True, when I said outside I guess I assumed up in the air, we all know what that makes us.!

 

[dlwtrunked]

...

My first thought was that it might be a line of sight issue, the aircraft are up in the air and have nothing obstructing their transmissions. But then I would hear the tower giving instructions to planes on the ground as well. They're told to take certain taxi ways, line up, take off, and given an altitude and heading before contacting departure. All that is horribly distorted under the static. Then the aircraft reads the instructions back and it's perfectly clear. So that eliminates line of sight as the cause....

Almost certainly a line of sight problem. The aircraft is sitting out there in the open with the "tower" antenna somewhere else (not likely atop the tower) and surrounded by who knows what. Be aware that aircraft talk to the tower until in the air and then given directions to talk to departure.

 

[KE5MC]

I've spent many hours at Founder's Plaza at the North end, West side of the airport listening to tower traffic. Typically East tower has a better signal than West tower. Most and always risky to say always, transmissions from aircraft are better from that location from ground or airborne planes than the tower. West tower is the one I listen to the most because of the side of the airport the plaza is located.

Generally I would characterize tower transmissions as reasonable signal strength with low audio compared to aircraft, so I'm thinking tower transmissions are under modulated.

Radio's used were Yaesu FTM400 or 100, Icom-51A, Uniden 436 or SDS100. All radios sounded the same as outlined in the previous paragraph only differing slightly in audio quality.

Off hand I would say a better antenna would be helpful up to a point as the West tower does not appear to be operating at it's peak. From my location at the plaza, line of sight to any point of the airport, tower reception is disappointing. Admittedly I have no idea where the tower antennas are located.

Likely an FCC search would establish transmitter/antenna location and power levels.

Good Luck,
Mike

 

[n0iop]

I don't fly much anymore but used to.

Not sure how DFW is set up but usually the tower, ATIS, clearance, and ground control antennas are co-located in the vicinity of the runways or atop the tower itself. They will design and adjust the system for coverage in the ramp, taxiway, runup, and runway areas. Tower's authority extends out 5 miles so a great deal of power is not used.

It is exactly the opposite of the situation where concrete trucks are talking to dispatch 20 miles away over the hill on low band and running 100 watts.

As with so many things, height and a directional antenna are your friend here.

 

[TXFirefighter112]

What are you using for an antenna?

I am using the stock antenna that came with the scanner itself.

And I am sure you meant to add-get it up in the air--like on the roof.

Unfortunately I am on the bottom floor of a two story apartment. So roof mounting is absolutely out and any sort of other outdoor mounting at all may not be allowed. Running cable through walls is certainly out.

Typically East tower has a better signal than West tower.

If east has better signal than west at Founder's Plaza, the exact opposite corner of the airport from me, I wonder if West would have better reception where I'm at? Stranger things have happened with radio signals. But alas, as I type this I have tried it and west is actually worse than east at my location.

Something else I have just tried as I type this, I've experimented with antenna positioning. Laying the antenna directly flat so it points straight out the back of the scanner and aimed roughly in the direction of the tower has improved the signal to 5/5 from both tower and aircraft. Was not expecting that result, otherwise I would have done it sooner!

Are aviation transmissions typically polarized horizontally?

 

[nd5y]

Are aviation transmissions typically polarized horizontally?

All aviation base antennas I have seen are vertically polarized. Aircraft antennas are usually not perfectly vertical. Base stations can be anywhere from 10 to 55 watts. Civilian aircraft radios can be up to 25 watts.

There is no telling what the polarization might be by the time the signals get inside your building and reflect off of all the nearby conductive surfaces. in the mid 1990s I lived in an apartment in Euless just W of there and never had any problems picking up anything at DFW. If you go outside away from the building how well can you receive?

 

[TXFirefighter112]

All aviation base antennas I have seen are vertically polarized. Aircraft antennas are usually not perfectly vertical. Base stations can be anywhere from 10 to 55 watts. Civilian aircraft radios can be up to 25 watts.

There is no telling what the polarization might be by the time the signals get inside your building and reflect off of all the nearby conductive surfaces. in the mid 1990s I lived in an apartment in Euless just W of there and never had any problems picking up anything at DFW. If you go outside away from the building how well can you receive?

I can't receive at all. Unplugging the scanner to from the wall appears to have an adverse effect on its power.

 

[n0jy]

I am pretty sure that the tower and ground are lower power relative to enroute and planes because ground only need cover the 2 mile radius or so of the airport and tower has everyone either in that same 2 miles or in the air. In the air a watt can go a very long way. For example, as can be seen in the AMSAT Fox-1 amateur radio satellites, their 600 mW output can be heard on a handheld radio with a rubber duck hundreds of miles away because it's line of sight. So you and tower both hear the planes fine, for you they are either in the air or on the ground but they have higher output power than tower.
I listen to the ATC on my mobile when I go to the airport to pick someone up, and I can't hear tower until I'm within 5 miles (antenna on top of the car).
I lived in apartments many years, I would suggest things such as having the scanner/antenna near an outside wall on the airport side, or using a mag-mount antenna up on a shelf, and also making sure the radio/antenna are not near your PC, TV, coffeemaker, all that stuff the puts out noise. You might be able to receive the signal, but it's below the noise, so you can't hear it.

Jerry
N0JY

 

[billpritjr]

these are your freqs

http://dtpp.myairplane.com/pdfs/SC-2/06039IL17L.PDF

you need a higher and/or external antenna

you can try a magnet mount 2M ham mobile, with magnet on a barbell plate, and place it on a high bookshelf or similar location and you will get huge improvement

-Tech Class Ham and Professional Pilot

 

[KE5MC]

these are your freqs

http://dtpp.myairplane.com/pdfs/SC-2/06039IL17L.PDF

you need a higher and/or external antenna

you can try a magnet mount 2M ham mobile, with magnet on a barbell plate, and place it on a high bookshelf or similar location and you will get huge improvement

-Tech Class Ham and Professional Pilot

Thanks for posting the PDF file. I have an AirPort layout showing runways, but I've not seen anything that lays out the frequency position/time line.

I always wanted to change favorite's list to group frequencies better. This looks like a great resource document.

Mikke

 

[billpritjr]

Is the original poster on a 2nd floor at all ? Does he have visual (his own eyes) on the DFW skyline ?

EDIT: OK I see he is on bottom level. He may be suffering from RF/Static from appliances or stuff in other apartments. The best thing would be to get an external antenna set up somehow.