ADS-B DIY Antenna

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jepolch

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Oh, I did not realize the problems you will have to face in swaping. No, dont do the swap. Your safety and comfort is very important.

I will do the comparision myself from the comfort of totally indoor installation inside my apartment.

Can you please give me the dimensions & construction details of your ground plane antenna? I want to build one, then test, then swap by cantenna, and test again, keeping everything else same (i.e. placement, coax, receiver, laptop). To see the real difference, i will first test both without amplifier, and a very short coax 15 feet. Later with amplifier and 50 feet coax.
Last night I thought of the same thing. It would be easier for you to test than it would be for me. The antenna only took maybe an hour to build. I used 14 gauge copper wire. It's been a very popular topic on the FlightAware forum and several people are building them. Visit this web page and scroll down til you see the link to download the PDF file called Your First ADS-B antenna.
http://www.atouk.com/wordpress/?page_id=237
 

jepolch

Active Member
In case you have any trouble getting the PDF, I'm attaching just the picture of the antenna dimensions from the file. I tried to attach the PDF here, but I got the error message "the file is too big".

When I made my antenna I didn't make the "shoulder" in the radials. I just bent them down right from the corner of the chassis connector.
 

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ab cd

Senior Member
Last night I thought of the same thing. It would be easier for you to test than it would be for me. The antenna only took maybe an hour to build. I used 14 gauge copper wire. It's been a very popular topic on the FlightAware forum and several people are building them. Visit this web page and scroll down til you see the link to download the PDF file called Your First ADS-B antenna.
http://www.atouk.com/wordpress/?page_id=237
Thanks a lot. I downloaded the pdf file and have quickly browsed it. Plan to build it this weekend.
 

ab cd

Senior Member
In case you have any trouble getting the PDF, I'm attaching just the picture of the antenna dimensions from the file. I tried to attach the PDF here, but I got the error message "the file is too big".

When I made my antenna I didn't make the "shoulder" in the radials. I just bent them down right from the corner of the chassis connector.
(1) Did you use SO-239 connector or BNC connector? I have to check my local store which one they have.
(2) The book's design is 6 groundplane wires, you used 4. Is the reason easier construction?

(2) Did you fix groundplane wires to the connector platform by screws or by soldeing?
 

ab cd

Senior Member
I'm looking forward to your test. I think I mentioned that I'm using different amps on the ground plane and cantenna. Could that make a difference? On the cantenna I'm using an RCA D903, like yours. On the ground plane I'm using this one: http://www.ebay.com/itm/281500624570
The extra height of groundplane antenna over cantenna is definately a factor due to surrounding trees.

Amplifier is also a likely reason. The RCA amplifier has a sloped gain i.e. 13 dB at 950 Mhz, gradually incresing with frequency to 18 dB at 2050 Mhz. Since 1090 Mhz is close 950 Mhz end, the gain will be higher than, but close to 13 dB, sy 14 dB.

The other amplifier does not indicate sloped gain as it gives only one figure (20 dB) for the entire frequency band.

This means it will give 20 dB at 1090 Mhz also, which will result 20-14=6 dB more gain than RCA.

Note: For making their amplifier look more powerful, some manufacturers mention only higher end gain on amplifier label, although their amplifier is sloped, and the lower end gain is mentioned only in detailed specs sheet.
 
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jepolch

Active Member
(1) Did you use SO-239 connector or BNC connector? I have to check my local store which one they have.
(2) The book's design is 6 groundplane wires, you used 4. Is the reason easier construction?

(2) Did you fix groundplane wires to the connector platform by screws or by soldeing?
1. SO-239
2. Actually, the instructions show to use 8 radials. I saw that most ground plane antennas used 4, so I did that - and it seems to be working fine.
3. I used solder, and it was a pain. Also, the center insulating material was labeled as Teflon, but it started to melt while I was soldering. I injehcted hot glue into the center, then screwed the PL-259 connector to the bottom to hold things together while the hot glue melted. It came out OK. I would recommend using screws and that's what I'll do next time.
 

jepolch

Active Member
The extra height of groundplane antenna over cantenna is definately a factor due to surrounding trees.

Amplifier is also a likely reason. The RCA amplifier has a sloped gain i.e. 13 dB at 950 Mhz, gradually incresing with frequency to 18 dB at 2050 Mhz. Since 1090 Mhz is close 950 Mhz end, the gain will be higher than, but close to 13 dB, sy 14 dB.

The other amplifier does not indicate sloped gain as it gives only one figure (20 dB) for the entire frequency band.

This means it will give 20 dB at 1090 Mhz also, which will result 20-14=6 dB more gain than RCA.

Note: For making their amplifier look more powerful, some manufacturers mention only higher end gain on amplifier label, although their amplifier is sloped, and the lower end gain is mentioned only in detailed specs sheet.
I like your thinking about the situation. I'm sure the added height helps, but it's only about six feet higher. The amp may be helping more than the height. There were no detailed specs provided with the amp.
 

ab cd

Senior Member
1. SO-239
2. Actually, the instructions show to use 8 radials. I saw that most ground plane antennas used 4, so I did that - and it seems to be working fine.
3. I used solder, and it was a pain. Also, the center insulating material was labeled as Teflon, but it started to melt while I was soldering. I injehcted hot glue into the center, then screwed the PL-259 connector to the bottom to hold things together while the hot glue melted. It came out OK. I would recommend using screws and that's what I'll do next time.
Thanks. Very useful information. Good that you mentioned PL-259 connector. When I visit my local store to purchase SO 239, I will purchase PL-259 also. I will also purchase BNC panel mount (4 screw type) and it's connector to see if that type is easier to solder.

The PL-259 takes RG6 or RG58 coax?
 

jepolch

Active Member
First of all, my new antenna has quit working after one day. Actually, I believe that the amp has burned out, because everything is in place and looks good. It seems to have quit working right around the end of the UTC day, 12/19. Check out the positions I reported compared to previous days. http://flightaware.com/adsb/stats/user/jepolch

I will check on the amp tomorrow - actually I don't know how I'll be able to do any testing from the ground, but I can at least test for a short circuit. I would rather not go up on the roof, if I don't need to. I mean, I will eventually have to go up to change the amp, if that's the problem, but that can wait for a while. I'm back to using the cantenna.

I have some PL-259 connectors that are supposed to be used with RG-58, but I managed to shove a section of RG-6 into one. On the other end of the short cable stub is an F type connector. So I go from the SO-239 to the amp using the short stub. Look back at post #568 and you'll see the cable I made. This PL-259 connector is similar to RG-6 connectors that you fit onto the bare end of a coax cable. You push the cable into the PL-259 until the center wire comes out the top and then solder the tip. I know I did that right, because it was working perfectly til tonight. That's why I'm suspecting the amp. Now that I have the cantenna hooked up and working, I know that both the power injector and power supply are good, because I have two coax feed lines coming down from the roof, but only one set of power supply and power injector that I switch the antenna cables to. I hope that makes sense.
 

ab cd

Senior Member
First of all, my new antenna has quit working after one day. Actually, I believe that the amp has burned out, because everything is in place and looks good. It seems to have quit working right around the end of the UTC day, 12/19. Check out the positions I reported compared to previous days. http://flightaware.com/adsb/stats/user/jepolch

I will check on the amp tomorrow - actually I don't know how I'll be able to do any testing from the ground, but I can at least test for a short circuit. I would rather not go up on the roof, if I don't need to. I mean, I will eventually have to go up to change the amp, if that's the problem, but that can wait for a while. I'm back to using the cantenna.

I have some PL-259 connectors that are supposed to be used with RG-58, but I managed to shove a section of RG-6 into one. On the other end of the short cable stub is an F type connector. So I go from the SO-239 to the amp using the short stub. Look back at post #568 and you'll see the cable I made. This PL-259 connector is similar to RG-6 connectors that you fit onto the bare end of a coax cable. You push the cable into the PL-259 until the center wire comes out the top and then solder the tip. I know I did that right, because it was working perfectly til tonight. That's why I'm suspecting the amp. Now that I have the cantenna hooked up and working, I know that both the power injector and power supply are good, because I have two coax feed lines coming down from the roof, but only one set of power supply and power injector that I switch the antenna cables to. I hope that makes sense.
Ohhhhhh....so sad!!!! Only if the amplifiers were not below antenna, but besides the power inserter near your computer, it would be so easy to replace burnt PerfectVision amplifier by RCA amplifier.

By the way, I found "PL259 UHF male plug to F Type female for RG6" on eBay. I will check if my local store has it, as it is very convenient.

PL259 UHF male plug to F female RG6.jpeg
 

ab cd

Senior Member
@jepolch:
Why not install amplifier on the wall just before the point where coax goes up the roof. This way you will be able to access amplifier from ground using a step ladder, without need to go up the roof. You can also take advantage of this relocation by selecting a shaded location for your amplifier, protecting it from frying in sun during summer months.
 

jepolch

Active Member
Ohhhhhh....so sad!!!! Only if the amplifiers were not below antenna, but besides the power inserter near your computer, it would be so easy to replace burnt PerfectVision amplifier by RCA amplifier.

By the way, I found "PL259 UHF male plug to F Type female for RG6" on eBay. I will check if my local store has it, as it is very convenient.

View attachment 715
I actually ordered more PL-259 connectors for future use. They are PL-259 to type F male so the amp can be plugged directly in. http://www.ebay.com/itm/251029236846
 

jepolch

Active Member
@jepolch:
Why not install amplifier on the wall just before the point where coax goes up the roof. This way you will be able to access amplifier from ground using a step ladder, without need to go up the roof. You can also take advantage of this relocation by selecting a shaded location for your amplifier, protecting it from frying in sun during summer months.
That sounds convenient, but shouldn't he amp be as close to the antenna as possible? If I inserted the amp in the feed line at a point below the roof, the distance to the antenna would be about the same distance to the receiver - say half the length of the feedline. Would that make much difference in the operation of the amp?
 

jepolch

Active Member
I can't find any good specs for the PVAMP1 that's connected to the ground plane antenna, but one site had this to say:
Perfect Vision PVAMP1 Satellite Signal In-line Amplifier Booster 20 dB 950-2150 MHz LNB Dish TV Video DSS Channel Strength, 13 - 18 VDC
For some reason I guess the one I got couldn't handle 18 volts. There was no rain or bad weather today, so that's not to blame. And the temperature was less than 50 F.
 

ab cd

Senior Member
That sounds convenient, but shouldn't he amp be as close to the antenna as possible? If I inserted the amp in the feed line at a point below the roof, the distance to the antenna would be about the same distance to the receiver - say half the length of the feedline. Would that make much difference in the operation of the amp?
The only drawback in moving amplifier is that Noise picked by the piece of coax between antenna & amplifier is also amplified.

Since you dont have any electrical noise generating machinary nearby, such as communication/cell phone tower, have power cables or lines running very close and parallel to cosx for considerable length, electrical machinary like in a plant, there is practically nill noise to be picked by coax and amplified by the amplifier. This is advantage if living away from down town or industrial area & not in a high rise building complex: no air pollution & no signal pollution :D
 

jepolch

Active Member
The only drawback in moving amplifier is that Noise picked by the piece of coax between antenna & amplifier is also amplified.

Since you dont have any electrical noise generating machinary nearby, such as communication/cell phone tower, have power cables or lines running very close and parallel to cosx for considerable length, electrical machinary like in a plant, there is practically nill noise to be picked by coax and amplified by the amplifier. This is advantage if living away from down town or industrial area & not in a high rise building complex: no air pollution & no signal pollution :D
OK great to know. I'll keep that in mind.

The forecast is for rain tomorrow, so I will probably not get up on the roof to swap the D903 to the ground plane antenna, but if it turns out to be nice I might make another dreaded trip up to the roof. :eek:
 

ab cd

Senior Member
I can't find any good specs for the PVAMP1 that's connected to the ground plane antenna, but one site had this to say:


For some reason I guess the one I got couldn't handle 18 volts. There was no rain or bad weather today, so that's not to blame. And the temperature was less than 50 F.
Well all satellite amplifiers are rated for dual voltage: 13V & 18V. Reason is that the dish LNB can receive two bands, one horizontally polarized, other vertical polarized. The switching between two bands is achieved by dish receiver switching DC voltage to LNB from 13v to 18v and vice versa. Since this DC is also used to power the LNB as well as in line amplifier, all dish LNBs & all in line amplifiers are designed to operate perfectly well with both these dc voltages. The specs you quoted also says "13-18 VDC".
 

jepolch

Active Member
Well all satellite amplifiers are rated for dual voltage: 13V & 18V. Reason is that the dish LNB can receive two bands, one horizontally polarized, other vertical polarized. The switching between two bands is achieved by dish receiver switching DC voltage to LNB from 13v to 18v and vice versa. Since this DC is also used to power the LNB as well as in line amplifier, all dish LNBs & all in line amplifiers are designed to operate perfectly well with both these dc voltages. The specs you quoted also says "13-18 VDC".
I tested the power supply and it's putting out right at 18 volts, so I guess the amp just failed. The D903 was handling the voltage fine. Thanks again for the good info.
 
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