01/23/19 13:47:28 UTC
225.875 MHz
BYRON, GA
Couple of pilots talking
 
01/19/19 18:49:59 UTC
385.55 MHz
WEST PALM BEACH, FL
Lucky 21 heading to W-168 on ZMA Discrete
 
01/18/19 02:32:40 UTC
343.500 MHz
MOLINE, IL
Refueler on AR16 Primary. “I’ll take your tail number”
 
01/17/19 15:12:39 UTC
343.000 MHz
BYRON, GA
Couple of pilots talking
 
01/15/19 13:32:19 UTC
339.500 MHz
BYRON, GA
Go for Defense 986 and another pilot in communications.
 

01/20/19 20:17:16 UTC
337.3000 MHz
E-4 Data Link
 
01/13/19 15:29:30 UTC
60.1000 MHz
Calling in strikes against ground targets at Avon Park
 
01/07/19 20:39:46 UTC
254.400 MHz
?
 
01/07/19 20:21:34 UTC
317.525 MHz
?
 
01/07/19 18:46:13 UTC
350.200 MHz
?
 
01/07/19 17:37:23 UTC
262.760 MHz
sells range
 
01/07/19 14:13:41 UTC
143.425 MHz
Night Watch Reporting System
 



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Build your own ADSB Mode S Antenna for about $7.00

In October 2013 I had purchased a cheap TV Dongle to use as an ADSB Mode-S radar system. You can read the original "how to" article by Clicking Here.

Since putting together the system I've been using a cheap scanner antenna in my attic. No more than 18' above ground level. It was enought to provide hours of fun. At any one time I could see around 30 (40 on busy days) aircraft's Mode-S data. Usually I would have 3-5 aircraft being plotted on the map via ADS-B.

I found an article on how to build a better ADS-B Mode-S antenna, I'm not going to go into the construction process here. I will provide a link to the article on building the antenna at the bottom of this article. In his contruction article he provides a video, please watch his video prior to building yours. His video will be of great help.

The antenna is called a Coaxial Collinear Antenna. His construction article will show you how to build a '4 Section' collinear. I started with the '4 Section', gave it a try and was impressed. The great thing with Coaxial Collinear Antennas is that you can made as many sections as you want. After seeing how 4 sections worked, I added another 4 sections, creating an 8 section antenna, and again saw a slight improvement (about 3dB over a 4 section).

The pictures below are of my 4 section antenna. For my first test I just hung the antenna in the window, top of the antenna was no more than 6' above ground level. While doing an "A/B" comparison between the attic scanner antenna and the new collinear antenna the difference was like night and day! Attic antenna at the time was only tracking 28 planes, my new collinear antenna was consistenly tracking about 10 more aircraft (remember new antenna not as high off the ground!).

Here is what I used to build my antenna. I just bought a 6' length of cable TV jumper cable and started by cutting off 1 of the F connectors. I let the other F connect attached, used a barrel connector to later connect the finished antenna to a length of RG-6 already in the attic leading to my shack. Not bad for only spending about $7.00!

Check for Full Size Picture




After finishing the 8 section antenna and mounting it in the attic I was in for a surprise. Preformance was terriable, I first thought I had lost all of my gain in the 50' section of RG-6 I was using to feed the Dongle. After scratching my head I decided to go back to the attic and move the antenna do a different location in the attic. WOW, what a difference. You need to remember that at 1090 MHz many things around the house or in your attic can act as a reflector causing strange things to have at the very high frequencies we're dealing with.

After moving the antenna about 4' that made all the difference in the world. Now I'm picking up an average of 60-70 planes at any one time on Mode-S. Usually plotting 10+ on the map display in ADS-B mode. On the original scanner antenna in the attic the best I could do is seeing planes about 60-65 miles out on ADS-B. In the picture below I'm now getting planes as far as 126 miles! Its now rare to have less than 10 on the ADS-B map. Before building the new antenna I never seen planes on ADS-B over the Gulf of Mexico, as you can see in the image below I can.

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In summary this antenna took me about an hour to build including testing and installing. It only cost about $7.00 in parts. It nearly doubled the amount of aircraft as well as the distance I was seeing aircraft. While an everyday scanner antenna in the attic did a fine job, this experiment proves that an antenna built for 1090 MHz will do a far better job!

To view the original construction article for this antenna please Click Here

I hope you've enjoyed this article.