ADS-B DIY Antenna

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jepolch

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Today's shopping #2 - RCA D903 amplifier Canadian $ 4.46 (including tax) = US $3.93 - No shipping/handling charges, in-store purchase.
No Noise figure given on the packing.

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Nice hardware. I can't believe how cheap that amp was. I'll keep looking for one around here, but the only place I can think of looking is Radio Shack and they didn't have them. What kind of copper wire will you use for the radials? I think mine is 14 gauge. Do you think a thinner wire than 14 gauge would be better? Good luck and have fun building your antenna! I'm looking forward to hearing your comparison with the cantenna.
 

jepolch

Active Member
I made a little graphic to show how my coverage grew over a two week period. I'm hoping today is just a slow day, because I'm not seeing a lot of planes. o_O
 

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ab cd

Senior Member
Nice hardware. I can't believe how cheap that amp was. I'll keep looking for one around here, but the only place I can think of looking is Radio Shack and they didn't have them. What kind of copper wire will you use for the radials? I think mine is 14 gauge. Do you think a thinner wire than 14 gauge would be better? Good luck and have fun building your antenna! I'm looking forward to hearing your comparison with the cantenna.
Look in Satellite Dish shops & Hobby Shops. The shop I purchased from is an electronics & hobby shop
Main Page: http://www.sayal.com/
RCA Amplifier: http://www.sayal.com/zinc/zinc_SEARCH.asp?txtSEARCH=216962
 
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ab cd

Senior Member
Nice hardware. I can't believe how cheap that amp was.
That is why I put the receipt besides the amp when I took the picture, else no one will believe me. :D
What kind of copper wire will you use for the radials? I think mine is 14 gauge. Do you think a thinner wire than 14 gauge would be better?
I dont think wire diameter matters, except for mechanical strength & beauty. Mine is indoor installation, and I dont have any other wire with me except core of RG6 which is 18 AWG (1 mm dia). I will use it, with it's white insulation to make it look beautiful & mechanically stronger.
 

jepolch

Active Member
That is why I put the receipt besides the amp when I took the picture, else no one will believe me. :D

I dont think wire diameter matters, except for mechanical strength & beauty. Mine is indoor installation, and I dont have any other wire with me except core of RG6 which is 18 AWG (1 mm dia). I will use it, with it's white insulation to make it look beautiful & mechanically stronger.
I think I will make one of these for Christmas for my son-in-law. He has a Raspberry Pi and I have been encouraging him to get into plane spotting. He wants to, but he has a very busy job and doesn't have as much free time as I do to build antennas. Maybe if I give him the antenna it will motivate him to install the software on his Pi and get started with the hobby. :)
 

kucengemok

Member
That is why I put the receipt besides the amp when I took the picture, else no one will believe me. :D

I dont think wire diameter matters, except for mechanical strength & beauty. Mine is indoor installation, and I dont have any other wire with me except core of RG6 which is 18 AWG (1 mm dia). I will use it, with it's white insulation to make it look beautiful & mechanically stronger.
so u put the antenna indoor? what about the reception in terms of coverage? mine also indoor but the reception is not strong in coverage...just 3 planes spotted.
 

ab cd

Senior Member
so u put the antenna indoor? what about the reception in terms of coverage? mine also indoor but the reception is not strong in coverage...just 3 planes spotted.
Yes, my entire installation is indoors. I live in an apartment at 60 feet above ground. My antenna, receiver, computer (and I, me, myself also :D) are all located inside my apartment. The antenna is seperated from receiver+desktop horizontally by 50 feet.

Since antenna is located near outer glass wall of apartment on 3 sides, coverage is semi-circular, 250nm in unobstructed dictions. In the directions of tall buildings aroud, the range drops sharply to about 50nm.

Number of planes plotted on the VRS vary from as low as 2 or 3 in late night, to 30 during peak hours. The total number of planes picked by antenna+receiver ranges from 5 low to 120 peak at any time, but only a fraction are plotted on map as a large number of planes dont give their position info (i.e. their latitude & longitude from their GPS). If you look to 'LAT' and 'LONG' columns in the table at right side of adsbScope, you will find a lot of planes with these two columns empty.
 
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jepolch

Active Member
My reception has totally gone down the tubes. Things went bad after I installed the ground plane antenna. Even my reception with the cantenna is very poor. Each antenna has its own coax cable leading into the house. When I added the ground plane on the roof I ran its cable parallel to the cantenna's cable. I tied them together with zip ties thinking it would look neater. Could this be causing my problem? Could the cables be interfering with each other? Only one antenna is connected to the receiver at a time, of course, and only one amp is receiving power at a time.

I just cut a few feet off the cable leading from the ground plane to the house and tested for shorts. It looks fine. When I connect the coax directly to the receiver I get OK reception, about 25% of what it was getting with the amp before things went bad. When I connect the amp to the ground plane antenna (near the receiver) the reception goes to nil.

It's a pretty nice day today, so in a while I'm going to go up to the roof and do these things.
1. Swap the new ground plane for the old one.
2. Attach the amp close to the ground plane.
3. Separate the coax cables on the roof.
4. Cross my fingers and hope things go back to normal!

Edit: Reception was great for one day after I put up the ground plane, then it went bad. Why it was great, then bad after only 24 hours is the mystery.
 
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ab cd

Senior Member
I have several times experienced this sudden drop in range/number of planes. The first time it happened, I checked voltages across tips of my tiny dipole antenna, found DC 18V available. Then changed the amp with the spare one I had, no improvement. Checked coax between power inserter & receiver for short and break, found ok. I waited for another day, nothing. Then I got convinced that it is the receiver, ordered another one from Noo Electric USA (US $26), shut down my system waiting for new USB receiver to arrive. Next day, just out of curiocity restarted the systen, and I was shocked! the adsbScope screen was full of planes.

This abnormal increase in range somedays, and abnormal drop in range some other days has happened with me several times. Most probably it is due to some weather & atmospheric conditions.

I am now used to it, but twice this jump has put me to shame. Once I made & tested a coco using length by formula 275mm x VF/(1+VF), and got exceptionally good results, and posted in forum as success. When others at different locations tried, it gave poor results. I repeated trial run after two days and found poor results. I had to declare it failed experiment, and withdraw claim of success. What an embrasement. Similar thing happened when I tested my first twin-lead compensated coco.
 

jepolch

Active Member
It's been a pretty frustrating day. I went to the roof, replaced the old ground plane with the new one, tested the wires for shorts, put the D903 amp next to the antenna (facing the right way!), separated the coax cables on the roof so they're not touching. Came down and plugged it into the receiver and - nothing. No reception. So then I connected the cantenna to the receiver with power supply and amp next to power supply (inside the house) and it's working.

I'm beginning to think it's just a slow weekend for flights. I have no idea what to think about the ground plane antennas. The first one was working amazingly for 24 hours, then just quit. No clue. Here are some shots of the new ground plane. I made a little hat out of the bottom of a plastic bottle to keep the rain and snow off the top - also put silicone on the top of the S0-239.

My next plan is to buy another piece of high quality RG6 and make a new cable run and use the new PL-259 to F male connector when it gets here.
 

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ab cd

Senior Member
It's been a pretty frustrating day. I went to the roof, replaced the old ground plane with the new one, tested the wires for shorts, put the D903 amp next to the antenna (facing the right way!), separated the coax cables on the roof so they're not touching. Came down and plugged it into the receiver and - nothing. No reception. So then I connected the cantenna to the receiver with power supply and amp next to power supply (inside the house) and it's working.

I'm beginning to think it's just a slow weekend for flights. I have no idea what to think about the ground plane antennas. The first one was working amazingly for 24 hours, then just quit. No clue. Here are some shots of the new ground plane. I made a little hat out of the bottom of a plastic bottle to keep the rain and snow off the top - also put silicone on the top of the S0-239.

My next plan is to buy another piece of high quality RG6 and make a new cable run and use the new PL-259 to F male connector when it gets here.
I sympathize with your problem. If this happens with me, I will get very angry & frustrated though I dont have to go up & down the ladder. I admire your patience & persistance.

You are right to name it Sputnic. With platic cap, its photo resembles the photo of world's & Russia's (USSR at that time) first satellite "Sputnic1" launched in 1957
 
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jepolch

Active Member
I think the problem may be the cheap RG6 cables I've been buying on Amazon. $10 for 50 feet is cheap, but if they don't work, it's not a bargain. I'll get some good cables after Christmas and make new feedlines from the cantenna and ground plane and try again.
 

ab cd

Senior Member
My First Spider

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One Hour Trial Run- No amplifier, 5 meters/15 feet cheap quality RG6 coax between Spider Antenna & USB Receiver.
Max range 225 nm (Range Rings are 50nm apart)

Spider Antenna 1 hr trial run -Dec21, 2014.png
 
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jepolch

Active Member

jepolch

Active Member
@ab cd: When you get a chance, would you please give us a link to some commercial grade RG6 cable, like the kind you are using? Thanks.
 

ab cd

Senior Member
Excellent work, as usual! Saddest part of your graphic - "Disconnected Cantenna". :(

How did the range compare to your cantenna's? Is it as good?
I will run spider for 4 hrs total, then unscrew it from its mount & screw Cantenna to the mount. This way everything will remain identical for spider & cantenna. Then I will run Cantenna for 4 hrs and compre the ranges of the two antennas. The only thing which still can cause difference is the different times of test, as flights vary considerably from morning to noon to evening to night, and weekends to week days as well. The only solution is to have two laptops & two usb recevers placed side by side and connected to two antennas side by side, and tested simultaneously. I dont have two laptops, and moving desktop to below antenna & then back to its original location in the other room is difficult.
 

ab cd

Senior Member
@ab cd: When you get a chance, would you please give us a link to some commercial grade RG6 cable, like the kind you are using? Thanks.
I purchased a 100 ft/30 meters roll of my RG6 coax from the dollar shop in my neighborhood, for canadian $12 (including tax) = us $10.50. By "commercial" I actually meant "cheap". :D. I have now edited that post and replaced "commercial" by "cheap".

Since i use it indoors, running on floor along wall under the carpet, it does not have to face harshness of outdoors, and doing well. I think Wallmart or Radio Shack sell good quality cable which can sustain outdoor installation. I will check if I find a link, i will post it
 
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