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Thread: Making an inexpensive 1090MHz ADS-B collinear antenna

  1. #1
    Captain fungus's Avatar
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    Making an inexpensive 1090MHz ADS-B collinear antenna

    I hope this isnt a duplicate post as I've searched to see if it is posted elsewhere to no avail and I've no real knowledge of antenna theory, nor can I vouch for this antenna but I found it on the net recently and thought it may be of use to some one. The guy in the vid makes it look very simple.

    I do have a small amount of the RG6 cable being used in the vid (he could do with a good kleenex tissue for his nose too so I hope the antenna performs better than his snoz) and I'm thinking I may try to make one of these antennas just to see if I can. I'll do a follow up on this in the following weeks;

    http://www.youtube.com/watch?v=TkUYdCPFXXs

    The following may also help anyone wishing to make this 'home brew' antenna;

    http://www.balarad.net/
    http://www.balarad.net/comparisonM50.htm

    Perhaps some one with a little more knowledge than I have may wish to comment on the vid before I (or anyone else) wastes any time attempting to make or use it.

    Regards,
    Gregg
    Last edited by fungus; 2013-09-28 at 10:30.

  2. #2
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    It's what I'm using for my radar

    Rather than putting a resistor at the top, I'd put a 68mm spike (1/4 wave) - then since the antenna is open circuit you can use one of these in line amplifiers http://www.ebay.com.au/itm/Satellite...a54c1fc&_uhb=1 ... and a power inserter like one of these http://www.amazon.com/PCT-Inserter-M.../dp/B005Y12UH6

    They require about 15v dc up the wire and pass the voltage up the line ... if there was a resistor at the top it would make it toasty.

  3. #3
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    Colinear with good performance almost for free

    Here is the performance graph of my almost costless colinear 10 element antenna made from RG59 cable ends.The cable setting is occupied in a leftover 3/4 inch PVC water pipe and my device is a RTL 1090 DVB-T dongle from China.The RG59 cable costs about 1 $.The two ends of the pipe are sealed with epoxi.
    The antenna is held in place by a "tripod" made from two leftover 1 inch PE pipes and one 3/4 PVC electrical conduit.Each end of a pipe has a PVC T-piece,glued with epoxi to the pipes.Roof anchors are 6 Tek screws with welded rings on top made of 5mm GI wire.The T-pieces fit between two rings.To give a hold 6 short pcs.of PVC pipes are sticked through the GI rings into each end of a T-piece.And thats it.
    RTL 1090 @PP_coverage 3@1740_2.10.13 by colinear.png
    The lucky ones live longer

  4. #4
    Captain fungus's Avatar
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    One word (or two) on the above antenna (or any other type for that matter requiring external protection) which I've partly made and does seem easy to make and does work. I have yet though to test it outdoors or do comparison tests.

    If you are making these types of antennas and using electrical conduit for the external 'tubing' (the external physical protection for your antenna) or any other pvc tubing bear in mind it isnt necessarily UV protected (PVC electrical conduit in Australia isnt) so you'll likely need to paint it or something to protect it from the elements, depending on how long you want it to last.

    Another thing, and there are a number of points of view on this topic but in my view if you are mounting a metal mast to attach your antenna to externally, dont earth it (that's the mast) or you'll turn it into a lightning arrestor- basically a lightning rod which is MORE likely to attract lightning and do unimaginable damage.

    In my years within the electrical industry I have seen a great deal of damage done by lightning strikes and we dont want to make our house (or whatever building we use) any more attractive to it.

    And dont even think about connecting it up to, or in any way interfering with, the earthing system of your house. It was done by a member a while ago and was so dangerous the post (including pictures) was removed for reasons of safety.

    It's one thing to experiment with various types of antenna, it's another whole different ball game to interfere with your electrical installation beyond plugging something into a General Purpose Outlet (or power point) which has been tested.

    Regards,
    Gregg
    Last edited by fungus; 2013-10-11 at 00:42.

  5. #5
    Flight attendant
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    ADSB ANTENNA.jpg

    Hi here is my latest attempt at a simple and lightweight low profile waterproof antenna.
    I used an independent raised ground from a UHF cb antenna, the bit you place on your bullbar to raise the whip a bit higher.
    The whip is an old cb whip that I removed the pvc jacket and unwound the copper wire , then rewound to my dimensions

    Mike

  6. #6
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    Update to my last post
    The whip as it is , is not waterproof. So when it rains the whip performs poorly and range is reduced. I encased it in heatshrink, but because of the loading affect this has, I had to cut down the top section to 80mm to bring it back to perfect. This is as good as any antenna I have made
    Mike

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    Tried the collinear with no success. Still prefer my quarter-wave groundplane antenna.


    Ricardo
    Brazil
    http://sbfiadsb.no-ip.org

  8. #8
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    Hi Richard, I have made many antennas mostly collinear type, some work and some dont. But one thing is for sure, unless you are extremely lucky, you will not build an antenna that doesn't require some trimming . At these freqs, 1mm will make a big difference. It also will depend what you encase your antenna inside, even different size pvc pipe will effect it differently. As an example - I built a collinear from here http://www.tech-software.net/1090_ant_02.JPG
    This is encased in 50mm pvc and the top element is trimmed from 205mm to 190mm to offset the loading effect. I encased this in 25mm pvc and had to trim it down to 183mm
    I use this one on my RasPi / Dump1090

    Mike

  9. #9
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    Quote Originally Posted by YWYY View Post
    Hi Richard, I have made many antennas mostly collinear type, some work and some dont. But one thing is for sure, unless you are extremely lucky, you will not build an antenna that doesn't require some trimming . At these freqs, 1mm will make a big difference. It also will depend what you encase your antenna inside, even different size pvc pipe will effect it differently. As an example - I built a collinear from here http://www.tech-software.net/1090_ant_02.JPG
    This is encased in 50mm pvc and the top element is trimmed from 205mm to 190mm to offset the loading effect. I encased this in 25mm pvc and had to trim it down to 183mm
    I use this one on my RasPi / Dump1090

    Mike
    Did you tune/cut it on a trial-and-error basis or did you use any specific equipment or software, like ADSB# ? The only test and setup equipment I have are for the FM broadcast band.

    Ricardo

  10. #10
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    Hi, I dont have any test equipment. I just use a trial and error system. When I build an antenna I make the top section 5mm longer. Then I place the antenna somewhere that I can easily access it from a stepladder so I can trim the top. I start by testing it for a day, then start trimming by 2mm a time, test for a day then trim. I continue this untill the sweet spot is found. Testing must be done with the pvc in place of course. I use Planeplotter to plot the trails, then change the colour for each time I trim the antenna. That way I can see which length gives the best range. Its very time consuming but the only way to get it correct
    Mike

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