ADS-B DIY Antenna

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xforce30164

Active Member
How do you think you messed up the HDMI, break a connector on the board? I haven't gotten the heat sink kit for the Pi 2 yet. I've been thinking of making one out of scrap aluminum.
Connector seems fine, might have been due to hotplugging, or some software bug.

I used an old gpu-vram coolblock for the cpu, will take picture in a bit ;)

Edit: here's a (quite blurry) picture.

Edit2: I'm getting quite nice coverage with the dual receivers now, tracking flights from Amsterdam Schiphol Airport, up to slightly further than Brussels =]
flightpath.png
 
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You reminded me of my old faithful!!!
Slide Rule: the best calculator before electronic calculators became popular.

View attachment 1298
"Slide Rule: the best calculator before electronic calculators became popular."
And is still the best.
I have a sun hemmi vectolog model circa 1970 from japan.
My Mitutoyo instruments come in handy for antenna construction too !
Some things you just cant throw away as they are so good,, made right first time and dont rely on batteries.
Nice one ab cd !
Still got your log tables I presume ?
 

jepolch

Active Member
Connector seems fine, might have been due to hotplugging, or some software bug.

I used an old gpu-vram coolblock for the cpu, will take picture in a bit ;)

Edit: here's a (quite blurry) picture.

Edit2: I'm getting quite nice coverage with the dual receivers now, tracking flights from Amsterdam Schiphol Airport, up to slightly further than Brussels =]
View attachment 1318
Very good work! As for the heat sink, I'll look on a old motherboard and see if there's anything I can scavenge.
 

jepolch

Active Member
1) Unless you have an overloading problem, the diplexer hurts not helps.
2) The balun is a big help.

-- Doug
Well, this is what I'm trying to find out. When I look at the graphics for the dipole, there are lots of spikes that seem to be diminished when I use the diplexer. It seems the dipole is more sensitive that the spider - or the spider is more discriminating? I really don't know.
 
For those constructing coco in Europe, Webro coaxial cables are very popular especially in BskyB TV installations. Cut lengths can be obtained very cheaply from ebay/amazon suppliers . Satcure have a online store supplying cable (in various colors if that takes your fancy) & matching connectors in the UK here
http://www.satcure.co.uk/accs/WF100_cable.htm

If you are in the USA or Canada (or anywhere else for that matter) , I can wholeheartedly recommend Davis RF, quality second to none for cables in my opinion, fantastic products & service I have received (even for my small orders delivered direct to my home QTH in the UK) over the years. This company take coaxials and amateur cables to another level, far exceeding my expectations every time.
http://www.davisrf.com/coax.php

Here are the data sheets for Webro with the mechanical and electrical properties,plus the all important velocity factors (aka velocity ratio).


wf65.JPG

wf100.JPG

hd100.JPG
 
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Sjacket99

Member
Just want to let you all know I'm still here. Been busy running new RG6 cable to my TV's. Making a platform in my attic to mount a UHF and VHF antenna. I'm cutting the cord for paying for TV cable. My wife and I don't watch that much TV. So if I can save $80.00 a month, I'm going to do it.
 

jepolch

Active Member
Just want to let you all know I'm still here. Been busy running new RG6 cable to my TV's. Making a platform in my attic to mount a UHF and VHF antenna. I'm cutting the cord for paying for TV cable. My wife and I don't watch that much TV. So if I can save $80.00 a month, I'm going to do it.
Good for you. I dumped Dish a couple of years ago. I have a Roku box and subscribe to Netflix streaming. When cable or satellite let me pick the channels I want to watch - not a "package" - then I might consider going back. I wouldn't mind paying about $30 a month for a dozen good channels of my choice.
 

ab cd

Senior Member
...snip...

I'll finish with a picture of the dipole with balun (also knows an a Pawsey stub) and the reference drawing.
Well, the Pawsey stub need not be a 1/4 wavelength piece of coax. A 1/4 wavelength piece of wire can do the same job.
After soldering/shorting core & coax at both ends of stub piece, electrically the 1/4 piece of coax is no more a coax, it turns into a 1/4 wavelength piece of wire with diameter of braid.
 
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ab cd

Senior Member
"Slide Rule: the best calculator before electronic calculators became popular."
And is still the best.
I have a sun hemmi vectolog model circa 1970 from japan.
My Mitutoyo instruments come in handy for antenna construction too !
Some things you just cant throw away as they are so good,, made right first time and dont rely on batteries.
Nice one ab cd !
Still got your log tables I presume ?
My slide rule was from Faber-Castell, Germany (Looked very similar to the one in the Photo I posted). Nice piece of equipment!
Lost the Slide Rule & the Log / anti Log tables long ago. :(
 
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DougJohnson

New Member
Well, the Pawsey stub need not be a 1/4 wavelength piece of coax. A 1/4 wavelength piece of wire can do the same job.
After soldering/shorting core & coax at both ends of stub piece, electrically the 1/4 piece of coax is no more a coax, it turns into a 1/4 wavelength piece of wire with diameter of braid.
I was speculating that this morning. Thanks for confirming.
-- Doug
 

jepolch

Active Member
Well, the Pawsey stub need not be a 1/4 wavelength piece of coax. A 1/4 wavelength piece of wire can do the same job.
After soldering/shorting core & coax at both ends of stub piece, electrically the 1/4 piece of coax is no more a coax, it turns into a 1/4 wavelength piece of wire with diameter of braid.
Yeah, it would have been easier to make with just a single strand of wire! o_O So why do you suppose the examples show a piece of coax used instead of a single wire? Also, in Giacomo's post #2131, the examples are different. In the top the center core of the stub isn't even used. Why did they use coax? And in the example attached below, the connection is different still from the two in post #2131. It seems they had some reason for using coax instead of a single strand of wire, no?

pawsey1to1stub1.GIF
 

giacomo1989

Member
VERY GOOD!
Take care the leads of capacitor do not touch the housing of splitter.
Alternatively, if you make the leads short, the chances of accidental touching will reduce.

View attachment 1325
Damn 2D photos :D :D :D There's lot of room between the capacitor and the box.

BTW I'll reduce the length of capacitor's wires. It will also help in preserving signal.

PS: Nice illustration man :)
 

Sjacket99

Member
Good for you. I dumped Dish a couple of years ago. I have a Roku box and subscribe to Netflix streaming. When cable or satellite let me pick the channels I want to watch - not a "package" - then I might consider going back. I wouldn't mind paying about $30 a month for a dozen good channels of my choice.

It would be nice to pick what channels you want.. I have Dish now, I like it a lot. Works good. But we don't watch that much to pay what they want. For each day you don't watch you're TV service, thats money down the drain.
 
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