Building an ADS-B Antenna

[RobG]

I hope this is an appropriate place to post this...

The antenna that came with my dongle is probably less than ideal (it's mounted about 12' in the air and the max range I've seen is 106 nm) so I'm attempting to build my own. I was building the 8-leg "spider" design:

Screen Shot 2020-08-22 at 6.32.21 PM.jpg

Note: That is NOT my antenna; that's what it's "supposed" to look like. Mine has turned out mostly okay except I can't get one of the 45-deg legs to stay soldered to the base. I was using a small butane soldering torch to get the base hot enough to tin it but one corner was behing held by a work stand, so it didn't get tinned. I've tried tinning it with my soldering iron, even with the knob all the way on full, and it just won't stick. If I use the torch again, it will heat the whole thing up so much that the other legs will fall off and I'll get to start over.

Do you think a 7-legged spider will work?

Rob

[abcd567]

Even 4-legged Spider will work, but with slight reduction in performance.
The advantage of 4-legged Spider is that the SO239 or N connector on which it is built has 4 screw holes in 4 corners, and legs can be fixed to it with nut & bolts. No need for soldering.

Please see these two posts:

3 EASY ANTENNAS FOR BEGINNERS (Scroll down to 2nd post of this thread: EASY ANTENNA # 1 : SPIDER)

QUICK SPIDER - No Soldering, No Connector



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[fishymamba]

I had the same problem when soldering my 4 leg spider. I only have a cheap soldering iron and the only way I was able to get it to work was to use a bunch of flux and a fat spade tip. Slightly sanding before soldering also seemed to help.

Getting great performance with it! Peak range over 500nm! Going to try the 8 leg and see how it compares.

[abcd567]

I have built & used this 8-legged Quick Spider which does not require any connector, and therefore does not require any soldering. All its parts are made of RG6 coax cable. You will need about 1 meter of coax to build it.


QuickSpider-701x800.jpg

[fishymamba]

My problem is that I live in an apartment and I have to route the antenna through a window to keep it outside. I also have to keep the window closed because in the summer its 110+ Fahrenheit most days. I was able to file a small gap to get my current RG58 cable through, but I'm scared of loosing my security deposit if I make the hole any bigger for RG6. Its a large ~8 foot metal/glass window and I'll definitely lose a good chunk of money.

[abcd567]

My problem is that I live in an apartment and I have to route the antenna through a window to keep it outside. I also have to keep the window closed because in the summer its 110+ Fahrenheit most days. I was able to file a small gap to get my current RG58 cable through, but I'm scared of loosing my security deposit if I make the hole any bigger for RG6. Its a large ~8 foot metal/glass window and I'll definitely lose a good chunk of money.

If you have problems placing it outside (like me), place it inside near a window as I have done.


Quick Spider 768x1024px.jpg

[fishymamba]

If you have problems placing it outside (like me), place it inside near a window as I have done.

The windows in my building are extremely reflective to the ADS-B frequencies.
Screenshot from graphs1090, the only thing changed was placing the antenna outside the window.

[abcd567]

The windows in my building are extremely reflective to the ADS-B frequencies.
Screenshot from graphs1090, the only thing changed was placing the antenna outside the window.

Oh boy! You have to have your antenna outside.

My window glasses are nearly transparent to 1090 Mhz as these dont have any glazed coating, just slightly tinted to reduce glare of sun.