ADS-B DIY Antenna

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xforce30164

Active Member
Hi xforce,
In short..It looks like an SMD, In the few meetings we have had in the last 15 yrs or so,I cannot say we (Myself and SMDs) "get along".:mad: I am not equiped with boinic sight..Over and out !
That's true, I never used them before, and not sure If I will be using this one anytime soon :p first enough other things to try and experiment with!

ETA:
When I'm back in Eindhoven, first thing I'll do is replace the ebay-antenna with the spider antenna. when I switched them on 1-4 (from spider to ebay antenna) I went from 331k messages to around 100k messages currently with the ebay antenna.
antenna_swap.png
 
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jepolch

Active Member
1/4 wave 8 leg ground plane F connector Spider Experiment.

4 horizontal + 4 @ 45/60 deg. Centre element from some stripped down Webro WF100 coax core + dielectric.
A very apt backdrop in the photo too ! ;)

A bit too extravagant on materials here but what the heck, I pulled out all the stops here and threw caution to the wind.
I used one of my brand new F connectors.:)

From all the stuff on this thread, I bet some savvy people could flip a nice profit on fleabay or suchlike.
I'm actually running that exact (well, as close as I can to exact) configuration on one of my spiders. 4X90* and 4X45*. I didn't see any change at all compared to 8X45*. That's my second spider that's always 15-20% than my better spider. I moved the radials to that configuration to see if it would help or hurt. No change.

Edit: Yours was cheaper and easier to make than mine. :)
 

jepolch

Active Member
I didn't take a picture after I modified the spider with 4 horizontal radials, but it's the one on the right in this picture. Also, another 8-legged spider that I didn't make, but who appeared in my yard. ;)
 

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ab cd

Senior Member
I didn't take a picture after I modified the spider with 4 horizontal radials, but it's the one on the right in this picture. Also, another 8-legged spider that I didn't make, but who appeared in my yard. ;)
The "microscopic" inspection of garden spider revealed it is 6-legged, not 8-Legged: 3 legs on right-side & 3 legs on left-side.
A beautiful creature - reminds the greatness of The Creator!
 

jepolch

Active Member
The "microscopic" inspection of garden spider revealed it is 6-legged, not 8-Legged: 3 legs on right-side & 3 legs on left-side.
A beautiful creature - reminds the greatness of The Creator!
We get some big spiders here. Never saw one that color before. She was made up for Halloween. :)
 

jepolch

Active Member
I don't know if you guys read the FlightAware forum, but a while back a guy was talking about using a satellite diplexer as a high pass filter. I bought two of them and have been using one one one of my spiders while watching the other antenna to see how they compare. I have the filter on my better performing spider. You may remember that I said the "worse" antenna was about 15% worse than the better one. Since I installed the filter on the better one, the "worse" one is now 20% worse. Coincidence? I don't know. All I know is that the better one seems to have improved over the worse one and it certainly hasn't hurt the better one. Hey, if you're looking for a cheap high pass filter, try a couple of these. Your results might be even better than mine. I live out in the country and don't have an overwhelming amount of GSM noise - although there is some. I got TWO of these for $5 on Amazon. http://smile.amazon.com/gp/product/B00684D77A
 

giacomo1989

Member
I don't know if you guys read the FlightAware forum, but a while back a guy was talking about using a satellite diplexer as a high pass filter. I bought two of them and have been using one one one of my spiders while watching the other antenna to see how they compare. I have the filter on my better performing spider. You may remember that I said the "worse" antenna was about 15% worse than the better one. Since I installed the filter on the better one, the "worse" one is now 20% worse. Coincidence? I don't know. All I know is that the better one seems to have improved over the worse one and it certainly hasn't hurt the better one. Hey, if you're looking for a cheap high pass filter, try a couple of these. Your results might be even better than mine. I live out in the country and don't have an overwhelming amount of GSM noise - although there is some. I got TWO of these for $5 on Amazon. http://smile.amazon.com/gp/product/B00684D77A

With mine I still get gsm signals which are over 950 Mhz but I've to say that my noise
floor in the adsb band is very low in amplitude .

I've mounted it 2 meters far from the dongle and I still have some FM power cause the cable acts as an antenna!

I've also closed terrestial input with a cap and a 100 ohm resistance which is better (hope) than living it opened!
IMG-20150404-WA0005.jpg
 
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jepolch

Active Member
With mine I still get gsm signals which are over 950 Mhz but I've to say that my noise
floor in the adsb band is very low in amplitude .

I've mounted it 2 meters far from the dongle and I still have some FM power cause the cable acts as an antenna!

I've also closed terrestial input with a cap and a 100 ohm resistance which is etter (hope) than living it opened!
View attachment 1566
When you said "I've mounted it" do you mean a filter or diplexer?
 

xforce30164

Active Member
It certainly looks good. How does it compare to a conventional spider?
It seems to catch more planes, and get slightly higher msg rate, but need to do some more testing.

I also tried the 5/8L active + 4 5/8L radials, didn't work, (too much noise i guess), 5/8L active with 4* 1/4L radials didn't work either, back to 1/4L + 4*1/4L, working nice again. (Also @jepolch, your trick of twisting the wire really helps stiffen it up a touch and straighen it out, before I was rotating it and sliding side of the grip of my wire-cutter along it to straigthen it, having mis-interpreted it, but now I just grabbed one end of the copper wire with pliers, twisted the other end with a power-drill/cordless screwdriver combo and it works like a charm!)

ETA: I've moved the ebay-bought antenna up slightly, number of planes and messages increased noticably, now I'll need to wait and see in the next few days if it is a significant change overal (and not just that it was busier than normal with airplanes when I moved the antenna).

ATM i'm getting the following:
Ebay Antenna: 43Planes 260MSg/sec
1/4L twisted Spider: 31 planes 75Msg/sec
Triangle Spider: 39 planes 220/sec

the ebay antenna is higher than the other two though.

ETA: getting busy, trianglespider picked up 50 planes @ 280msgs/sec just now,
ebay antenna is also around 50 planes on roughly 300 msgs
 
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jepolch

Active Member
It seems to catch more planes, and get slightly higher msg rate, but need to do some more testing.

I also tried the 5/8L active + 4 5/8L radials, didn't work, (too much noise i guess), 5/8L active with 4* 1/4L radials didn't work either, back to 1/4L + 4*1/4L, working nice again. (Also @jepolch, your trick of twisting the wire really helps stiffen it up a touch and straighen it out, before I was rotating it and sliding side of the grip of my wire-cutter along it to straigthen it, having mis-interpreted it, but now I just grabbed one end of the copper wire with pliers, twisted the other end with a power-drill/cordless screwdriver combo and it works like a charm!)

ETA: I've moved the ebay-bought antenna up slightly, number of planes and messages increased noticably, now I'll need to wait and see in the next few days if it is a significant change overal (and not just that it was busier than normal with airplanes when I moved the antenna).

ATM i'm getting the following:
Ebay Antenna: 43Planes 260MSg/sec
1/4L twisted Spider: 31 planes 75Msg/sec
Triangle Spider: 39 planes 220/sec

the ebay antenna is higher than the other two though.

ETA: getting busy, trianglespider picked up 50 planes @ 280msgs/sec just now,
ebay antenna is also around 50 planes on roughly 300 msgs
Wow, great. I may try one of those triangle spiders. :)
 
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