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Author Topic: High gain base station antenna recommendations?  (Read 13936 times)
TomCat4680
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« on: January 05, 2012, 07:02:25 PM »

I'm looking for a high gain VHF/UHF outdoor base station antenna so I can hear loud and clear both sided conversations of as many air traffic control (Tower, TRACON, and ARTCC RCAG) communications as possible with very little or no static. I'm mostly interested in the civilian band, but military would be good too. I'm even looking at 2m/70 cm ham radio antennas and can't figure out which one to buy since they have a lot of mixed reviews.

I've given up on Radio Shack base station antennas after several negative experiences, and recently put up a Diamond D-130J, and my airband RX is better but still very weak and mostly static. I have a 30' AGL outdoor chimney mount  (2 story flat roof plus 10 foot fence pole) with commercial grade RG-11. My airband capable scanners are a Pro 106, Pro 96 and Maycom AR-108. Also I'm well aware that "higher is better" (I've been listening to scanners for 13 years), but my chimney is over 100 years old and the guy who sold me the mount said with brick chimneys that old, anything over 10 feet will make them topple, so more height is NOT an option unless I were to install a new freestanding tower. (I also have 2 TV antennas on the same mount btw). Also I'm well aware of the "line of site" rule.

Per Google Maps, I'm about 15 miles from KFNT, about 45 miles from KMBS, about 65 miles from KLAN, about 75 miles from KMTC, and about 85 miles from KDTW. I'd like to be able to receive strong both sided communications from all of them and possibly more.

So which antenna should I get? Would a high gain base station antenna alone even fulfill my wishes or would I also need an airband preamp?

I'd appreciate any recommendations and tips.

Tom
Mt. Morris, MI
« Last Edit: January 05, 2012, 11:19:08 PM by TomCat4680 » Logged

Scanners: Radio Shack Pro 106, Radio Shack Pro 96, Maycom AR-108AE

Antennas: Diamond D-130J mounted 30' AGL (base), Waters & Stanton WSM-225 (mobile),
Diamond RH77CA (handheld)
K5PAT
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« Reply #1 on: January 05, 2012, 10:53:54 PM »

Tom,
    First of all, for a good gain antenna to work well, all three airports should be in the same direction from your location.  Gain antennas only supply max gain in one direction, with a beamwidth of about 30 degrees.  Unless your three stations are in line with each other, a beam antenna will not do much good; especially the ones 65 and 75 miles away.
    I am confused from your post that your antenna is on the 92nd?? floor, but you say your chimney is 30'AGL.  92 floors equates to about 750 feet high. Assuming the airport ATC transmitters are around 50' high, at 750' your line of site distance from antenna to antenna is only about 47 miles.  Hearing the two farthest airports would be marginal at best, even under the best conditions.
     
    If I were you, I would concentrate on aiming your antenna at the 15 mile station and from 750' you should receive ATC and planes on the ground pretty well.  If your antenna is on the chimney at 30-40', you should be able to receive ATC fairly well, but planes on the ground will be weak at best.
     Naturally, all of this only applies to the ground stations.  The airborne transmissions should be no trouble to receive within 100-150 miles.

     RG-11 cable is 75ohm impedance and most antennas and good quality scanners are matched to 50ohm cable, so you are going to lose several db of signal with the 75ohm cable.

     An RF preamp will also help, unless you are close to a high power FM transmitter.

Hope this helps.
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TomCat4680
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« Reply #2 on: January 05, 2012, 11:20:48 PM »

Tom,
    First of all, for a good gain antenna to work well, all three airports should be in the same direction from your location.  Gain antennas only supply max gain in one direction, with a beamwidth of about 30 degrees.  Unless your three stations are in line with each other, a beam antenna will not do much good; especially the ones 65 and 75 miles away.
   I am confused from your post that your antenna is on the 92nd?? floor, but you say your chimney is 30'AGL.  92 floors equates to about 750 feet high. Assuming the airport ATC transmitters are around 50' high, at 750' your line of site distance from antenna to antenna is only about 47 miles.  Hearing the two farthest airports would be marginal at best, even under the best conditions.
    
    If I were you, I would concentrate on aiming your antenna at the 15 mile station and from 750' you should receive ATC and planes on the ground pretty well.  If your antenna is on the chimney at 30-40', you should be able to receive ATC fairly well, but planes on the ground will be weak at best.
     Naturally, all of this only applies to the ground stations.  The airborne transmissions should be no trouble to receive within 100-150 miles.

     RG-11 cable is 75ohm impedance and most antennas and good quality scanners are matched to 50ohm cable, so you are going to lose several db of signal with the 75ohm cable.

     An RF preamp will also help, unless you are close to a high power FM transmitter.

Hope this helps.

Typo, I meant (2 story flat roof plus 10 foot fence pole) I WISH I was on the 92nd floor, if I was I would only need a paperclip. Freudian slip I suppose.  grin

Thanks for the tips. The RG-11 was free so I guess I got what I paid for.   angry
« Last Edit: January 06, 2012, 12:16:20 AM by TomCat4680 » Logged

Scanners: Radio Shack Pro 106, Radio Shack Pro 96, Maycom AR-108AE

Antennas: Diamond D-130J mounted 30' AGL (base), Waters & Stanton WSM-225 (mobile),
Diamond RH77CA (handheld)
K5PAT
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« Reply #3 on: January 06, 2012, 12:30:10 AM »

   Here are some sites which sell good aviation band antennas, but they are not cheap.  Search the archives in this forum for homemade Yagi antennas and you should find a few.

http://www.dpdproductions.com/page_vhf_air.html#vhfairout DPD even sells a combo VHF/UHF aviation antenna.
http://www.ab9il.net/aviation/airband-antenna1.html
http://www.arrowantennas.com/gp/gp146.html
http://www.jpole-antenna.com/
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TomCat4680
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« Reply #4 on: January 06, 2012, 12:56:56 AM »

  Here are some sites which sell good aviation band antennas, but they are not cheap.  Search the archives in this forum for homemade Yagi antennas and you should find a few.

http://www.dpdproductions.com/page_vhf_air.html#vhfairout DPD even sells a combo VHF/UHF aviation antenna.
http://www.ab9il.net/aviation/airband-antenna1.html
http://www.arrowantennas.com/gp/gp146.html
http://www.jpole-antenna.com/

Thanks for the links. Smiley

Do you recommend a certain model though? Which one(s) do you use?
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Scanners: Radio Shack Pro 106, Radio Shack Pro 96, Maycom AR-108AE

Antennas: Diamond D-130J mounted 30' AGL (base), Waters & Stanton WSM-225 (mobile),
Diamond RH77CA (handheld)
dave
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« Reply #5 on: January 07, 2012, 08:38:33 PM »

We've used a lot of the Arrow Antennas GP126, and at $41 they represent great value.  The DPD antennas are nice, but fairly expensive.  I've measured the performance of many of the available antennas - as I said, the Arrow Antennas GP126 represents great value.

If you want an inexpensive Yagi, get one custom made from Arrow Antennas - and get the mounting clamp (not included in the handheld Yagi antennas they ship).
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bugalou
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« Reply #6 on: January 08, 2012, 12:05:30 AM »

We've used a lot of the Arrow Antennas GP126, and at $41 they represent great value.  The DPD antennas are nice, but fairly expensive.  I've measured the performance of many of the available antennas - as I said, the Arrow Antennas GP126 represents great value.

If you want an inexpensive Yagi, get one custom made from Arrow Antennas - and get the mounting clamp (not included in the handheld Yagi antennas they ship).


Dave suggested the Arrow Yagi setup for me and the Memphis feed and I am quite pleased with its design and performance.
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Squawk 7700
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« Reply #7 on: January 08, 2012, 12:19:53 AM »

I use both the DPD VHF Air Vertical Outdoor Model Antenna and Arrow GP126 on my feeds. They both perform equally well. The Arrow GP126 is a great value and built well.
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TomCat4680
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« Reply #8 on: January 08, 2012, 12:22:07 AM »

Thanks for the suggestions, I'll look into them. Smiley
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Scanners: Radio Shack Pro 106, Radio Shack Pro 96, Maycom AR-108AE

Antennas: Diamond D-130J mounted 30' AGL (base), Waters & Stanton WSM-225 (mobile),
Diamond RH77CA (handheld)
TomCat4680
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« Reply #9 on: January 09, 2012, 06:15:26 PM »

Anybody got a more thorough specs sheet (gain, SWR, etc.) on the Arrow GP126? I found their website and its user's manual but they don't really tell me anything about it except the price and how to install it.
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Scanners: Radio Shack Pro 106, Radio Shack Pro 96, Maycom AR-108AE

Antennas: Diamond D-130J mounted 30' AGL (base), Waters & Stanton WSM-225 (mobile),
Diamond RH77CA (handheld)
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« Reply #10 on: January 09, 2012, 06:44:41 PM »

The GP126 is a classic quarter-wave ground plane antenna.  Ideally its gain would be 5 dBi (dB over an isotropic radiator).  I don't have an antenna range so I have never measured this.

It presents an acceptable SWR across the aviation band.
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dave
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« Reply #11 on: January 09, 2012, 06:53:05 PM »

I never got a chance to reply to your original post.  For the limitations you have placed on your installation, you can forget hearing both sides of anything beyond 15-20 miles.  You will hear the airborne traffic, but nothing on the ground, including the controllers. I can look at the terrain between you and the airports beyond that distance, but you won't likely hear anything at all on the ground at those places.

VHF isn't *strictly* line of sight, but you need to have a reasonable radio horizon between you and the transmitting ground stations.  Magic doesn't happen - the laws of physics don't change just because we want a certain result.  smiley

No amount of achievable antenna gain will overcome the physical path loss you are facing on those longer paths.  Not trying to discourage you, just telling it like it is, in hopes that you won't waste time and money thinking you will achieve a certain result and then don't.

Dave
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TomCat4680
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« Reply #12 on: January 09, 2012, 08:40:14 PM »

I never got a chance to reply to your original post.  For the limitations you have placed on your installation, you can forget hearing both sides of anything beyond 15-20 miles.  You will hear the airborne traffic, but nothing on the ground, including the controllers. I can look at the terrain between you and the airports beyond that distance, but you won't likely hear anything at all on the ground at those places.

VHF isn't *strictly* line of sight, but you need to have a reasonable radio horizon between you and the transmitting ground stations.  Magic doesn't happen - the laws of physics don't change just because we want a certain result.  smiley

No amount of achievable antenna gain will overcome the physical path loss you are facing on those longer paths.  Not trying to discourage you, just telling it like it is, in hopes that you won't waste time and money thinking you will achieve a certain result and then don't.

Dave

You make a lot of sense. Good thing I don't even have a lot of money to waste too. I'm most interested in KFNT anyway, and at least I've learned that RG-11 isn't made for scanners and I need to replace it with RG-8.
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Scanners: Radio Shack Pro 106, Radio Shack Pro 96, Maycom AR-108AE

Antennas: Diamond D-130J mounted 30' AGL (base), Waters & Stanton WSM-225 (mobile),
Diamond RH77CA (handheld)
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« Reply #13 on: January 10, 2012, 01:23:12 PM »

Hi Tom,

If I can pop in my .02 - the Pro-106 and Pro-96 typically get just fair reception on VHF airband. The GRE based scanners typically suffer front end overload from 108-174 MHz and must be attenuated. I use both the PSR-500 and PRO-197 and the problem gets worse on high-gain antennas.

Mike
« Last Edit: January 10, 2012, 01:34:27 PM by datainmotion » Logged

TomCat4680
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« Reply #14 on: January 10, 2012, 02:36:17 PM »

Hi Tom,

If I can pop in my .02 - the Pro-106 and Pro-96 typically get just fair reception on VHF airband. The GRE based scanners typically suffer front end overload from 108-174 MHz and must be attenuated. I use both the PSR-500 and PRO-197 and the problem gets worse on high-gain antennas.

Mike

Okay well which scanner(s) do you suggest for better home base airband reception? What do you use on your ATC feeds?
« Last Edit: January 10, 2012, 02:37:52 PM by TomCat4680 » Logged

Scanners: Radio Shack Pro 106, Radio Shack Pro 96, Maycom AR-108AE

Antennas: Diamond D-130J mounted 30' AGL (base), Waters & Stanton WSM-225 (mobile),
Diamond RH77CA (handheld)
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