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Old 03-24-2017, 4:28 PM
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Default How to improve airband reception?

Hi there,

I am finding myself wanting to listening to the "local" airports more and more.

My problem is I can barely receive the towers.

I live 20 miles from SFO and 10 miles from SJC.

I can receive both towers but they are very weak. SFO actually comes in just slightly better than SJC.

Right now I'm using a discone antenna along with a notch filter for the FM band. Before that filter I couldn't receive either tower.

I tried an inline amplifier. It really didn't make much difference.

I'm wonder if a dedicated antenna tuned to the airband frequencies would be a good move.

Anyone have any thoughts on that?

Thanks!

Charlie
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Old 03-24-2017, 5:40 PM
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I bought a j-pole tuned for the aviation frequencies from KB9VBR and boy did it ever make a difference.

I am 9 kms from the airport and my st-2 just couldn't do it. Now I get 5 bars and so crystal clear, I started a feed.

And I just ordered another j-pole from him.

Good luck
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Old 03-24-2017, 5:54 PM
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An antenna tuned to the frequency range you want to receive will always work better.
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Old 03-24-2017, 6:17 PM
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A typical scanner Discone works similar and maybe a tiny bit less than a 1/4 wave ground plane on the VHF air band. A J-pol properly made and tuned would be slightly better buy not drastic. A J-pole is not very wide band and at band edges the Discone might even work better over the J-pole.

How high is your existing antenna? Raising it 10ft or more can make a very noticeable difference, especially if its currently below nearby roof lines, etc.
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Old 03-24-2017, 6:18 PM
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Keep in mind that most towers are not using big antennas or lots of power. It's not unheard of to have their comms routed to a remote site for better coverage. In either case, you shouldn't expect to hear the tower more than a couple of miles away, if that, given open terrain and no real obstacles. A better antenna will certainly help, as will height above ground; just temper your expectations with the reality of how those comms work. The aircraft, on the other hand, are quite a different matter. You should hear lots from the approach and departures, depending on the size of the airport, and with a good antenna, from a good distance away

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Old 03-24-2017, 7:31 PM
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Hi Charlie i am using an Icom-AH7000 discone hooked up to a Stridsberg 4 Port MCA204M active multicoupler got 8 radios running reception is excellent on all my receivers coax is RG213 also my commercial airband antennas using RG 58 coax cable to RG213 makes a big difference.The higher the antenna the better the reception.

Regards Lino.
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Old 03-24-2017, 8:13 PM
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Man! How are you getting AM airband from airports 10-20 miles away. At the CLT airport, both my scanner and ICOM Aircraft Radio with a handheld and antenna on the roof of my truck can barely get the towers sometimes at the other end of the runway. After a few miles away from the airport, all my signals go down for the tower. Only traffic I get that far away are the airplanes
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Old 03-24-2017, 8:18 PM
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I am about 8 miles from the tower of our local airport with a ridge in between. I have a folded dipole cut down to the aero band from an old TV antenna which receives the tower and Atis better than the discone mounted above it on the mast. Both are only about 15feet up.
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Old 03-24-2017, 9:44 PM
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I live about 20mi line of site to LAX but there is most of an 1,100ft tall hill between me and the airport. I can't hear the tower on a handheld but it comes in great with various antennas I have up about 35ft on a tower. My house is about 350ft altitude on the opposite side of the hill. I can also pick up many other airports and ATIS from a good 100mi away like San Diego.

Years ago I did some distance testing with a cooperative aircraft that did many flights going east from my location where there is a couple of mountain ranges about 50mi and 100mi from me and along the route. At that time I had a commercial VHF/UHF Discone used by some airports and a TACO brand Yagi that covered our aircraft frequency with 11dBd gain.

The maximum distance I could get in the direction of the mountain range was 200mi before the aircraft abruptly went silent and it was the exact same spot using the Discone or the Yagi. The signals were very slightly stronger on the Yagi but not really any noise on the signal until the final few mi where it went silent.

On another test from the from near the top of the 1,100ft hill and in the direction of Hawaii over the pacific ocean, I personally got 388.96 statute mi to an aircraft using a 5w aircraft handheld with 1/4 wave vehicle antenna. Bottom line is height above ground and minimizing obstructions is key to getting the best distance.
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Quote:
Originally Posted by drayd48 View Post
Man! How are you getting AM airband from airports 10-20 miles away. At the CLT airport, both my scanner and ICOM Aircraft Radio with a handheld and antenna on the roof of my truck can barely get the towers sometimes at the other end of the runway. After a few miles away from the airport, all my signals go down for the tower. Only traffic I get that far away are the airplanes
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Old 03-26-2017, 1:44 PM
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I guess I have the opposite of the problem reported by the original poster. Our local airport is only 2 miles from here, and I'm in an apartment on the 3rd (top) floor of our building. My Uniden BC75XLT receives the tower loud and clear using just the rubber ducky antenna. I can sometimes even see the runway lights from my living room window at night, since the tower is in that direction. However, the approaching and departing planes are often behind the building, so the building itself is an obstruction, even though it's not a steel frame building. Plus I get an effect similar to picket fencing as the aircraft move between other obstructions.

It would help if the audio on the pilots' transmissions were clearer. This scanner has excellent audio, but it often sounds like the pilot's mike is either too far away from his mouth, or he's muttering, and the background sounds in his cockpit dominate. Even so, the controller has no difficulty copying him. I've tried opening the squelch fully, but the scanner's circuit noise is too loud during pauses in communications.

Now, the surprising thing is that if I connect my indoor longwire shortwave antenna with its coax lead-in to the scanner via an SO-239 to BNC adapter it improves airband reception dramatically, even though that antenna is far too long for those frequencies. In fact, it even improves reception on the other VHF bands.
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Old 03-26-2017, 1:57 PM
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Quote:
Originally Posted by GB46 View Post
I guess I have the opposite of the problem reported by the original poster. Our local airport is only 2 miles from here, and I'm in an apartment on the 3rd (top) floor of our building. My Uniden BC75XLT receives the tower loud and clear using just the rubber ducky antenna. I can sometimes even see the runway lights from my living room window at night, since the tower is in that direction. However, the approaching and departing planes are often behind the building, so the building itself is an obstruction, even though it's not a steel frame building. Plus I get an effect similar to picket fencing as the aircraft move between other obstructions.

It would help if the audio on the pilots' transmissions were clearer. This scanner has excellent audio, but it often sounds like the pilot's mike is either too far away from his mouth, or he's muttering, and the background sounds in his cockpit dominate. Even so, the controller has no difficulty copying him. I've tried opening the squelch fully, but the scanner's circuit noise is too loud during pauses in communications.

Now, the surprising thing is that if I connect my indoor longwire shortwave antenna with its coax lead-in to the scanner via an SO-239 to BNC adapter it improves airband reception dramatically, even though that antenna is far too long for those frequencies. In fact, it even improves reception on the other VHF bands.
The reason you can't hear them well is because aircraft operate in AM mode. AM mode on scanners sound really quiet and hard to hear at times. That problem can be fixed if you get an aircraft radio made for the transmission. Another reason the tower hear the panes better than you do is because you are inside a building. VHF AM AIR does not go through building real well. The tower aso has a lot better antennas than you do so they can hear the planes better
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Old 03-26-2017, 4:59 PM
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Yes, I knew that about being inside a building. Fortunately it's a wood-frame building. Reception is a lot better on the higher VHF bands, but of course I'm hearing most of those stations through their repeaters, whereas the tower and planes are using simplex mode. The biggest disadvantage I have is antenna restrictions. At this height, an outside antenna would work wonders, but that's not likely to be possible any time soon. Still, I expected an overly long antenna to make matters worse on VHF, when it actually improves reception.

Regarding VHF AM, by the way, back in the sixties when I was a licensed ham for a few years, I worked 2 meters AM exclusively. There were no repeaters available, and my transmitter ran only 18 watts input, from which I was lucky if I got 10 out. Despite that, I was often able to reach stations 3 or 4 hundred miles away on 145 mHz. The reason: An 11-element beam on the roof, and frequent temperature inversions, during which there were usually band openings.
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Old 03-26-2017, 8:27 PM
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Hey Charlie,

I have problems as well hearing tower transmissions when I'm terra firma. I live about 5 miles from our airport, and really will only catch aircraft transmissions when they're using a particular runway. Isn't AM simplex fun?

Heck, sometimes (when propagation is poor, and my aircraft is RF-rich), I'll be flying back to the field and the ATIS will be hit or miss from just ten miles out.

Yet I can hear Delta XYZ at 20,000 feet as clear as day.

God speed!
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Old 03-27-2017, 12:21 AM
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Being at a higher elevation than a lot of the surrounding terrain, I don't really have a problem hearing local towers. What I seem to have problems is hearing the RCO's used by Los Angeles Center for the high altitude routes, which for me is much more interesting to listen to.

I've found two things help - an air band filter followed by a low noise preamp, and I've also found that many tower and center transmissions are simulcast on both a VHF and a UHF airband frequency. I frequently find I hear ATC on the UHF channel best, while the VHF frequency hears the aircraft the best. Bonus when the aircraft is on UHF.

I use a dedicated antenna, filter, and preamp for each band.
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Old 03-27-2017, 9:47 AM
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Hey CD-

If you are receiving these stations, but weak on your Discone antenna, Id look to your antenna. A discone has no gain, and is about as minimalist an antenna as they come.
.
You asked if a dedicated antenna(s) for these two airports would be a good idea-- more than good, thats an excellent suggestion.
.
Id suggest you get a length of pine strip, and a coil of heavy aluminum wire- and make yourself an experimental beam. 3 elements will give you about 7 dbs over your Omni antenna. The numbers go up from there as it gets bigger, though 7-8 dbs will be a big improvement, especially- as I suspect, your Discone is actually at less than unity (ie: its has a negative gain compared to a ground plane.) While experimenting, also play with the polarization- you may be surprised at the results. As far as designs go, look to the myriad antenna books, online sites- for beam antennas- and scale them for the Air Band.
.
If everything works, reconstruct it as a better model out of aluminum tubing (etc) for regular outdoor use.
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Good Luck!
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Old 03-27-2017, 10:07 AM
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It's kind of surprising that you're having trouble with monitoring those airports. I'd think you'd be line of site over water to SFO. (I'm just south of OAK). A change in antennas sounds like the way to go. CF offered a good suggestion with a homebrew yagi.
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Old 03-29-2017, 7:18 AM
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I agree on the yagi suggestion. If your not into making one, Arrow Antennas has a cheap hand held 5
element VHF airband yagi that worked quite well for me. You can order a bracket for it to mast mount it.
Currently I'm using a 7.5' long 10 element VHF airband yagi from InnovAntennas. It's mounted 35' up, below
it is a UHF airband log periodic yagi. I use band pass filters, FM traps, pre-amps, lighting protection etc. and LMR-400 coax on both. Here in flat South Florida, I can hear ATC transmissions 25 to 40 miles away.

Good Luck

Kel
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Old 03-29-2017, 11:32 AM
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These are the antennas

Last edited by captkel; 03-29-2017 at 11:34 AM.. Reason: picture size is to large
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Old 03-29-2017, 11:43 AM
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trying again...My Antennas
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Old 04-02-2017, 7:25 PM
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"Right now I'm using a discone antenna along with a notch filter for the FM band..."

Hello Charlie!

You haven't mentioned where you live; i.e. in an apartment, condo or a conventional residence. Others have mentioned antennas, coax and so on. However, I don't believe that anyone mentioned HF aero monitoring...nor did you.

I was an apartment dweller for 26 years and lived about 5 miles from San Diego's Lindbergh Field and the Navy's North Island. As you can imagine listening was great, but I was never more thrilled until I got a gently used ICOM R71-A and began monitoring worldwide, HF aero transmissions.

My bedroom was about 10' X 10'. The landlord permitted no outdoor masts, flag poles...nothing. So, I began to wire the ceiling in my room with over 100' of copper wire. My greatest "DX" [distance reception] was a brand new, 747 being delivered from Boeing, in Seattle to Rio de Janeiro, in Brazil.

The flight left Seattle early on a weekday afternoon. I followed the flight across the USA. I had to stop listening as it crossed into the Atlantic Ocean, because I had to go to sleep and wake up in the AM for work.

The point of my post is that if you have the where-with-all, do NOT neglect global aero monitoring! Most of the transmissions are in upper sideband, so you will need a shortwave radio with USB capabilities. The radio I used [and still own] comes highly recommended.

I'm sure that others will respond and fill you in with other information.

Have fun and let us know how you get on with VHF, and if you chose, HF aero.
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