ADS-B DIY Antenna

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ab cd

Senior Member
MY NEW DESIGN:
HYBRID OF FRANKLIN & SPIDER


SPIDER
Spider.PNG


FRANKLIN-SPIDER

Franklin Spider.PNG
 
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xforce30164

Active Member
From those graphs it seems like the Franklin spider can see directly overhead where the regular spider can't. Am I reading that correctly?
Seems like that, In addition to that it should have 2dB more horizontal gain.

Mine seems to be performing on par with the ebay-antenna (which was outperforming my spider at the current height difference.)

ETA:

the frankenspider is outperforming the ebay antenna atm,

Ebay Ant: 28 planes, ~160msg/s
FrankenSpider: 33 planes, 220msgs/s
 
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jepolch

Active Member
first quick trial of th

Seems like that, In addition to that it should have 2dB more horizontal gain.

Mine seems to be performing on par with the ebay-antenna (which was outperforming my spider at the current height difference.)
I have a lot of catching up to do. I haven't built a new antenna in quite a while. I guess I got tired of going up to the roof. :( Also, when I do a test of an antenna indoors it really doesn't tell me how it will perform on the roof.
 
Thanks to ab cd for this one, some considerable work has gone into that idea for the benefit of all of us. Nice one ! ;)

Nice handy work again xforce, I bet your completed airfix, tamiya and revel kits were the envy of your buddies !:p

I eagerly await the results of bench testing the spider frank.:)
 
I have a lot of catching up to do. I haven't built a new antenna in quite a while. I guess I got tired of going up to the roof. :( Also, when I do a test of an antenna indoors it really doesn't tell me how it will perform on the roof.
Jepolch, you can simulate being on the apex of your roof by holding antenna in your right hand and raising your left leg 6 inches from the ground.
Any more than 6 or any less causes high inductance/capacitance.:)
 

xforce30164

Active Member
Thanks to ab cd for this one, some considerable work has gone into that idea for the benefit of all of us. Nice one ! ;)

Nice handy work again xforce, I bet your completed airfix, tamiya and revel kits were the envy of your buddies !:p

I eagerly await the results of bench testing the spider frank.:)
I once build a model A380, spend a week working on the landing gear, painting glueing making it fit perfectly. on sunday I was finally done, my dad came around to take a look, carefully took the plane from the table, was very impressed, but when he placed it back on the table didn't pay enough attention, it fell on the ground, landing gears all completely broke off, that was the last time I ever did one of those things again :p

also, spider-franklin currently @ 290msg and 44 planes

ETA:

I've been working some more on statistics/table overview, can't fully compare yet as for some reason my RPi at my parents house has died, and I can't get it to work over the phone. (giving instructions, but rpi should have internet and power but still doesnt work :/ )

its currently basic html table, but I'm working on a fancy graph implemented version of it!

http://dump1090.ayadex.com/table.php?receivers=1;1&time=last1min;last5min&type=html

(or for example)

http://dump1090.ayadex.com/table.php?receivers=1;1&time=all&type=html
 
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ab cd

Senior Member
Spider franklin has stub protruded on one side. Causes little bit of mechanical & electrical imbalance. Thought of using a zigzag stub. More compact & balanced. Right now only a concept, has to run simulation to see how it goes. Will do when at home. Prepared a conceptual sketch on phone, and posting from phone.

sketch1428438646297.png

Later Addition:
Important: Total length of wire in phasing stub = ½ wavelength = 138 mm.
(1) Straight stub = 66mm+6mm+66mm=138mm
(2) Zigzag stub = 32mm+5mm+64mm+5mm+32mm=138mm

Stub gap (center-to-center distance between horizontal wires of stub) is NOT critical. Can be 6mm +/- few mm.
 
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xforce30164

Active Member
Spider franklin has stub protruded on one side. Causes little bit of mechanical & electrical imbalance. Thought of using a zigzag stub. More compact & balanced. Right now only a concept, has to run simulation to see how it goes. Will do when at home. Prepared a conceptual sketch on phone, and posting from phone.

View attachment 1573

I'll try and make the radial, and see how it works on my trianglespider!

ETA:
I'm also thinking of trying slightly different triangle radials, currently I have them folded in triangle shape, but the end is insulated from the rest, I.E. it should work as a 3/4L radial. Im planning on making a second set of triangle radials where the end IS connected to the start to make a kind of butterfly-like connected 1/4L dipole with a slightly larger BW.

Once more, new antenna build, swapping it right now :D
IMG_20150407_232448_1428441898368.jpg


ETA2: first results with the triangle radials are a bit crappy, so switching to 1/4L 45* radials right now.
 
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xforce30164

Active Member
Take 100 lines, "I must keep my calculations @ 90 degrees to the vertical " for your maths presentation and be glad about it my boy or i will make it 200 !:)

Sir, Yes Sir! Excuse my writing, but may I take my antenna angles into account, for if that is the case I will only write one line ;p

Also, a slightly better explanation about the soldered/connected triangle is that it should act like many 1/4L radials all ever so slightly bend further down.
 

jepolch

Active Member
Jepolch, you can simulate being on the apex of your roof by holding antenna in your right hand and raising your left leg 6 inches from the ground.
Any more than 6 or any less causes high inductance/capacitance.:)
Excellent! I knew there had to be a way! :p
 

jepolch

Active Member
I once build a model A380, spend a week working on the landing gear, painting glueing making it fit perfectly. on sunday I was finally done, my dad came around to take a look, carefully took the plane from the table, was very impressed, but when he placed it back on the table didn't pay enough attention, it fell on the ground, landing gears all completely broke off, that was the last time I ever did one of those things again :p

also, spider-franklin currently @ 290msg and 44 planes

ETA:

I've been working some more on statistics/table overview, can't fully compare yet as for some reason my RPi at my parents house has died, and I can't get it to work over the phone. (giving instructions, but rpi should have internet and power but still doesnt work :/ )

its currently basic html table, but I'm working on a fancy graph implemented version of it!

http://dump1090.ayadex.com/table.php?receivers=1;1&time=last1min;last5min&type=html

(or for example)

http://dump1090.ayadex.com/table.php?receivers=1;1&time=all&type=html
Speaking of models, I've built some out of paper. https://plus.google.com/photos/107730019413900891611/albums/5303520088039189057
 

jepolch

Active Member
I'll try and make the radial, and see how it works on my trianglespider!

ETA:
I'm also thinking of trying slightly different triangle radials, currently I have them folded in triangle shape, but the end is insulated from the rest, I.E. it should work as a 3/4L radial. Im planning on making a second set of triangle radials where the end IS connected to the start to make a kind of butterfly-like connected 1/4L dipole with a slightly larger BW.

Once more, new antenna build, swapping it right now :D
View attachment 1574

ETA2: first results with the triangle radials are a bit crappy, so switching to 1/4L 45* radials right now.
Perfect! How did you do the bends in the radiator?
 

xforce30164

Active Member
Perfect! How did you do the bends in the radiator?
the 90* ones? I use the other end of the pivot point on my wire cutters, the gap in between the handles is ever so slightly smaller than the copper wire radius, so I can use it as a kind of miniature vice/vise (the big heavy things you can clamp stuff in). and just bend it by hand in one fluid go, afterwards I applysome pressure on both sides of the bend (if there is enough space) to make them even more straight/square. Ill post some pics/sketches tomorrow, for now its time to sleep ;)
 
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