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Author Topic: High gain base station antenna recommendations?  (Read 31560 times)
K5PAT
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« Reply #25 on: January 11, 2012, 11:01:19 AM »

Tom,
     Just to give you a point of reference:

     At my KMSY feed I am approx. 6 miles from KMSY. The antenna is a KB9VBR J-pole mounted on a 30' push-up pole. Coax is about 70' of LMR-240 cable (mini-RG/8).  NO PREAMP.  Receiver is an old radio Shack PRO-2006.
    Ground is flat- Louisiana flat. I probably have line-of-site with the ATC antennas.
I am able to receive 98% of the ground vehicles and planes on the ground, plus 100% of ATC and planes airborne.

     With your location 15 miles from the airport, I  would concentrate on raising my antenna to maybe 50' in order to get the
most height. Height is going to be your most important element in receiving anything on the ground. All the amplification in
the world won't help if you don't have a signal to amplify.  If there are any tall buildings or hills between you and the airport, that will reduce the signals even further.

     My suggestion is to work it in stages. 
First get a good antenna (yagi, if possible), ground-plane or J-pole if yagi is not available. Put it up as high as possible and put some good coax on it.
Second, see what you can and cannot hear and if the ground signals are scratchy, but you can hear them, then try the preamp. (20 db)

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TomCat4680
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« Reply #26 on: January 11, 2012, 11:30:38 AM »

Tom,
     Just to give you a point of reference:

     At my KMSY feed I am approx. 6 miles from KMSY. The antenna is a KB9VBR J-pole mounted on a 30' push-up pole. Coax is about 70' of LMR-240 cable (mini-RG/8).  NO PREAMP.  Receiver is an old radio Shack PRO-2006.
    Ground is flat- Louisiana flat. I probably have line-of-site with the ATC antennas.
I am able to receive 98% of the ground vehicles and planes on the ground, plus 100% of ATC and planes airborne.

     With your location 15 miles from the airport, I  would concentrate on raising my antenna to maybe 50' in order to get the
most height. Height is going to be your most important element in receiving anything on the ground. All the amplification in
the world won't help if you don't have a signal to amplify.  If there are any tall buildings or hills between you and the airport, that will reduce the signals even further.

     My suggestion is to work it in stages.  
First get a good antenna (yagi, if possible), ground-plane or J-pole if yagi is not available. Put it up as high as possible and put some good coax on it.
Second, see what you can and cannot hear and if the ground signals are scratchy, but you can hear them, then try the preamp. (20 db)



I don't think 50' is possible unless I can talk my landlord into letting me put up a new freestanding tower. Also the only tall buildings around here are in downtown Flint which is to the south of me; which is nowhere near KFNT, which is to to the southwest of me. It's pretty flat here too. In fact they call the entire region (probably a 20-30 square mile radius) Genesee Valley. Also with my D-130J the signals already ARE "scratchy but I can hear them"; so more height probably isn't even necessary.
« Last Edit: January 11, 2012, 10:12:46 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 #27 on: January 11, 2012, 11:45:39 AM »

Tom,
    I re-read your original post and I guess I was hoping for too much out of your situation.
Since you say you are hearing ground stations weak and scratchy, I would purchase the best preamp available (20db) and try it with your present equipment.  If that improves reception, then you could try changing to better coax, LMR-400 or similar. That may give you 3-4 more db of gain.
   A Yagi antenna may be too much for your chimney pole mount, but I have seen home-made ones on this forum which are light, cheap and easily made.
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TomCat4680
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« Reply #28 on: January 11, 2012, 11:49:38 AM »

Tom,
    I re-read your original post and I guess I was hoping for too much out of your situation.
Since you say you are hearing ground stations weak and scratchy, I would purchase the best preamp available (20db) and try it with your present equipment.  If that improves reception, then you could try changing to better coax, LMR-400 or similar. That may give you 3-4 more db of gain.
   A Yagi antenna may be too much for your chimney pole mount, but I have seen home-made ones on this forum which are light, cheap and easily made.

Well Flint Approach/Departure and Cleveland Center Flint RCAG come in weak and scratchy, Flint Tower/Ground are even weaker and scratchier. LMR-400 is equivalent to RG-8. My cable run is about 70 feet so wouldn't LMR-240 (RG-8X) be better; the manual to the Pro 106 (page 16) specifically says you should use RG-8X for runs between 50' and 100'; and plain RG-8 for 100' or more.
« Last Edit: January 11, 2012, 11:52:27 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 #29 on: January 11, 2012, 12:25:27 PM »

Tom,
    You are trying to squeeze out the maximum signal strength at your location, so the lower loss in your cable, the better.
LMR-240 is equivalent to "Mini RG/8" and has higher loss than LMR-400 or RG-8.  Be careful where you buy the RG/8. Some sources sell inferior cable.  LMR-400 is much higher quality cable and costs a little more, but may be worth the price in your situation.
     The Pro-106 manual was merely suggesting that you can "get away with" smaller cable if your length is less than 100', but if you are  seeking max performance, stay with the lower loss cable.
    I ran across this thread from a few years ago which has lots of good info from Dave on antennas.
http://www.liveatc.net/forums/listener-forum/airband-yagi-antenna-designs/
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TomCat4680
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« Reply #30 on: January 11, 2012, 09:00:40 PM »

Tom,
    You are trying to squeeze out the maximum signal strength at your location, so the lower loss in your cable, the better.
LMR-240 is equivalent to "Mini RG/8" and has higher loss than LMR-400 or RG-8.  Be careful where you buy the RG/8. Some sources sell inferior cable.  LMR-400 is much higher quality cable and costs a little more, but may be worth the price in your situation.
     The Pro-106 manual was merely suggesting that you can "get away with" smaller cable if your length is less than 100', but if you are  seeking max performance, stay with the lower loss cable.
    I ran across this thread from a few years ago which has lots of good info from Dave on antennas.
http://www.liveatc.net/forums/listener-forum/airband-yagi-antenna-designs/

Thanks for the tips. I need to quit trusting Radio Shack. tongue
« Last Edit: January 11, 2012, 09:03:19 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)
Squawk 7700
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« Reply #31 on: January 12, 2012, 12:17:28 AM »

Aside from using an efficient antenna and low loss cable, the single item that most improved reception like night and day was this filter. http://www.scannermaster.com/HPN_30118_Combined_Notch_Filter_p/24-531024.htm

My receivers are in the San Francisco Bay Area and there is heavy RF everywhere. This filter really improved my reception amazingly on the airband frequencies.

Hope we can all help out?  smiley
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Feeder:
KHWD Ground/Tower
KOAK Del/Gnd/Twr
KSFO NORCAL App Rwy 28L/R
KSFO Tower/Ground
NORCAL Approach (KOAK)
NORCAL Departure (KSFO/KOAK)
KSJC NORCAL Approach #2
ZOA Oakland Center (35/40/41)


RJTT App/Dep
RJTT Tokyo Control
RJTT Twr/TCA
Solent Radar
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« Reply #32 on: January 19, 2012, 10:52:25 AM »

Newbie alert ! Hi everyone from southern UK Smiley

As stated, filters in the fed line can remove FM radio hash and pager interference .

I use an FM bandpass filter to remove the effects of an FM broadcast transmitter 1 mile away line of sight, and a fixed notch filter plus variable notch filter to remove 4 pager transmitters 1mile away line of sight . Both transmissions would mix together to cause de-sencing of my RX. All of the filters were placed antenna end , then fed into low noise amplifiers to boost the signal down the feeder cable.

Remember, an amplifier at the receiver end , may not work as well as if placed at the antenna end.
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Casper87
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« Reply #33 on: January 19, 2012, 03:45:28 PM »

Mr Radar,

You seem to know your tech  smiley

Close to enough to HI to pick up both Solent & Southampton Radar clearly?

C
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Solent Radar
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« Reply #34 on: January 20, 2012, 05:36:58 AM »

No not close enough to HI Sad (oops , busted Wink )

2 ways from from the following; HH, HA, DM Radar, DY Radar, plus the usual London Control feeds and and Brest Control (yet to determine transmitter location of the latter).

To clarify the filter makes used in my above post (and to avoid an off topic happening Wink ).

Par Notch filters 3 off . Various spot frequencies in the 153 MHz pager TX range.

SSE (Solid State Electronics) UK VHF Airband Band Pass filter - stops local FM Broadcast radio.

SSE (Solid State Electronics) Variable notch filter.

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sstokes
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« Reply #35 on: April 09, 2015, 06:44:11 PM »

Hi Tom,

I think I may have addressed another one of your posts similar to this topic elsewhere on this forum. However, I am going to address this topic as well. I have been scanning public safety and aircraft communications for 25 years now. I have tried many different types of antennas from many different manufacturers in that time. The absolute best airband antenna I have used and still use is the Centerfire VHF Airband Base Station Scanner Antenna. I use mine all of the time. For more specifics, you can see my personal review of the antenna I just wrote clicking the link below to my website.

I really do not know why I did not write that review sooner. I have owned my Centerfire antenna for about 15 years and the thing is still in awesome shape and works as well as the day I first installed it. I would recommend that particular antenna to anyone who is into picking up aircraft transmissions with the highest gain. I routinely pick up ground control communications at an airport more than 18 miles away! It is an awesome antenna to say the least. Again, you can read my review of it at the site listed below, if you are interested. I also provide a link on my site letting you know where to get it for the cheapest price as well.

Steve
http://howtobuyapolicescanner.com/best-performing-vhf-airband-antenna-an-antenna-i-use-frequently/
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