ADS-B DIY Antenna

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ab cd

Senior Member
@jepolch:
I checked again the specs for RG59 and found it is manufactured in two versiond, one with FPE (VF=0.83) and other with PE (VF=0.66).

You have to check if your RG59 has FPE or PE insulation. Check with manufacturer's data.

In appearance, generally FPE is opaque & milky, while PE is translucent or transparent.

FPE Insulation
RG-6_coaxial_cable.png



PE insulation
330px-RG-59.jpg
 
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jepolch

Active Member
@jepolch:
I checked again the specs for RG59 and found it is manufactured in two versiond, one with FPE (VF=0.83) and other with PE (VF=0.66).

You have to check if your RG59 has FPE or PE insulation. Check with manufacturer's data.

In appearance, generally FPE is opaque & milky, while PE is translucent or transparent.

FPE Insulation
View attachment 607


PE insulation
View attachment 608
The one I have is the lower one in your pic. That's the one you gave me the specs for, VF=.066. It's working fine, but I'm still going to build another one out of RG6. Thought I might do it tomorrow, but I have computer problems on my main computer, so I may spend tomorrow rebuilding it.
 

jepolch

Active Member
OK, got a question for you ab cd. I bought a small inline amp for my antenna. I put it between the antenna and the receiver and - no reception. I'm assuming it needs power. I have a power supply for Dish Network, along with a splitter which was connected to the power supply when I had Dish. Now these are spare parts as I no long have Dish. Here's my question. Before I attach the power supply to the amp and my antenna, I wanted to ask if you think these components will work without blowing up my receiver. I'm thinking they will, but I wanted to check. See the pictures. One shows all the parts. The other is the specs for the amplifier. Thanks again!
 

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ab cd

Senior Member
OK, got a question for you ab cd. I bought a small inline amp for my antenna. I put it between the antenna and the receiver and - no reception. I'm assuming it needs power. I have a power supply for Dish Network, along with a splitter which was connected to the power supply when I had Dish. Now these are spare parts as I no long have Dish. Here's my question. Before I attach the power supply to the amp and my antenna, I wanted to ask if you think these components will work without blowing up my receiver. I'm thinking they will, but I wanted to check. See the pictures. One shows all the parts. The other is the specs for the amplifier. Thanks again!
No, it wont blowup your receiver uf you connect it as shown in the diagram below (RF OUT to Receiver, RF-PWR to Amplifier). Test with a multimeter there is no short in your antennam else the short-circuit current may damage your amp or power inserter or DC Adaptor. I have fried one of my power inserters when I connected a shorted antenna to Amplifier.

jepolch.PNG
 

jepolch

Active Member
No, it wont blowup your receiver uf you connect it as shown in the diagram below (RF OUT to Receiver, RF-PWR to Amplifier). Test with a multimeter there is no short in your antennam else the short-circuit current may damage your amp or power inserter or DC Adaptor. I have fried one of my power inserters when I connected a shorted antenna to Amplifier.

View attachment 611
Thank you so much for taking the time to show the correct way to hook everything up ab cd. I'm very grateful for all your help. I'll let you know how it works.

As for checking for the short circuit, I'm not sure how to do that. I love tinkering and do lots of computer work, but I have no experience with electrical circuitry. I do have a multimeter and I know how to check for continuity, but not for short circuits. I'll google that and give it a shot. I hope to get the next coco started today.
 

ab cd

Senior Member
what is good directional antenna to be made easy and quickly....
I have 2 receivers....one is for feeding "other site" with own antenna, and one is RTL dongle with DIY antenna.
now....i want rtl dongle to cover only one direction....
Reply is late, but better late, than never....try Yagi
You can start with the simplest first: the 3 element Yagi (pictures at left & center below). Later you can build Yagi with larger number of elements (picture at right below).
Yagi Calculator: http://www.k7mem.com/Electronic_Notebook/antennas/yagi_vhf_quick.html

Yagi-Uda Antenna

Yagi_Uda.PNG.png . Yagi-Uda on Tower.jpg . Yagi-Uda 2.jpg

The Yagi-Uda antenna consists of a number of parallel thin rod dipole elements in a line, usually half-wave dipoles, typically supported on a perpendicular crossbar or "boom" along their centers.

There is a single driven element driven in the center, consisting of two rods, each connected to one side of the transmission line.

There are a variable number of parasitic elements (reflectors & directors). The reflectors are on one side & directors on the other side of driven element.

The parasitic elements (reflector & directors) are not electrically connected to the transmitter or receiver, and serve as resonators, re-radiating the radio waves to modify the radiation pattern.

Typical spacings between elements vary from about 1/10 to 1/4 of a wavelength, depending on the specific design.

The lengths of the directors are slightly shorter than that of the driven element, while the reflector(s) are slightly longer.
.
The radiation pattern is unidirectional along the axis perpendicular to the elements in the plane of the elements, with the main lobe off the end with the directors.

Parasitic elements (reflector & directors) have a point of zero RF voltage at their center, so they can be attached to a conductive metal support at that point without need of insulation, without disturbing their electrical operation. They are usually bolted or welded to the antenna's central support boom.

The driven element is fed at center so its two halves must be insulated where the boom supports them.

Only one reflector is generally used since the improvement of gain with additional reflectors is negligible.

However increasing number of directors improves gain & directivity. Yagis have been built with up to 30-40 directors.
 
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ab cd

Senior Member
..........As for checking for the short circuit, I'm not sure how to do that. I love tinkering and do lots of computer work, but I have no experience with electrical circuitry. I do have a multimeter and I know how to check for continuity, but not for short circuits. I'll google that and give it a shot.........
Short-circuit is tested same way as continuity. Only the results of two tests are OPPOSITE i.e. if there is no short-circuit, meter should show "no continuity".

1) Set the mutimeter for continuity test
2) Touch the two probes with each other. You should hear a buzzer/beep soud & indication light (if any on your meter) will light up.
3) Disconnect the antenna coax from the amplifier.
4) Touch one probe to shield and other to core wire of the disconnected coax.
(a) If meter gives NO buzzer/beep & NO light, there is NO short-circuit.
(b)If meter gives buzzer/beep & light, there IS short-circuit.
Please see sketch below showing where to connect the multimeter propbes.

jepolch-test.PNG
 

jepolch

Active Member
Short-circuit is tested same way as continuity. Only the results of two tests are OPPOSITE i.e. if there is no short-circuit, meter should show "no continuity".

1) Set the mutimeter for continuity test
2) Touch the two probes with each other. You should hear a buzzer/beep soud & indication light (if any on your meter) will light up.
3) Disconnect the antenna coax from the amplifier.
4) Touch one probe to shield and other to core wire of the disconnected coax.
(a) If meter gives NO buzzer/beep & NO light, there is NO short-circuit.
(b)If meter gives buzzer/beep & light, there IS short-circuit.
Please see sketch below showing where to connect the multimeter propbes.

View attachment 615
Thanks again! No short in the antenna. Did several continuity tests as "controls". Multimeter works fine.
 

jepolch

Active Member
Reply is late, but better late, than never....try Yagi
You can start with the simplest first: the 3 element Yagi (pictures at left & center below). Later you can build Yagi with larger number of elements (picture at right below).
Yagi Calculator: http://www.k7mem.com/Electronic_Notebook/antennas/yagi_vhf_quick.html

Yagi-Uda Antenna

View attachment 612 . View attachment 613 . View attachment 614

The Yagi-Uda antenna consists of a number of parallel thin rod dipole elements in a line, usually half-wave dipoles, typically supported on a perpendicular crossbar or "boom" along their centers.

There is a single driven element driven in the center, consisting of two rods, each connected to one side of the transmission line.

There are a variable number of parasitic elements (reflectors & directors). The reflectors are on one side & directors on the other side of driven element.

The parasitic elements (reflector & directors) are not electrically connected to the transmitter or receiver, and serve as resonators, re-radiating the radio waves to modify the radiation pattern.

Typical spacings between elements vary from about 1/10 to 1/4 of a wavelength, depending on the specific design.

The lengths of the directors are slightly shorter than that of the driven element, while the reflector(s) are slightly longer.
.
The radiation pattern is unidirectional along the axis perpendicular to the elements in the plane of the elements, with the main lobe off the end with the directors.

Parasitic elements (reflector & directors) have a point of zero RF voltage at their center, so they can be attached to a conductive metal support at that point without need of insulation, without disturbing their electrical operation. They are usually bolted or welded to the antenna's central support boom.

The driven element is fed at center so its two halves must be insulated where the boom supports them.

Only one reflector is generally used since the improvement of gain with additional reflectors is negligible.

However increasing number of directors improves gain & directivity. Yagis have been built with up to 30-40 directors.
Aren't Yagis directional? We want omni-directional for ADS-B, right?
 

jepolch

Active Member
No, it wont blowup your receiver uf you connect it as shown in the diagram below (RF OUT to Receiver, RF-PWR to Amplifier). Test with a multimeter there is no short in your antennam else the short-circuit current may damage your amp or power inserter or DC Adaptor. I have fried one of my power inserters when I connected a shorted antenna to Amplifier.

View attachment 611
Did this and actually saw reduced input - maybe 15-20% less. I pulled this all apart and went back to antenna straight into the dongle and reception increased to the previous level.

Then this morning I got to thinking about it. All my cables were RG59, except the one from the power inserter to the receiver. That one was RG6. Could that have made the difference? I don't have time to try it now, but either tonight or tomorrow I'll hook the amp/power supply back up to the antenna and use a RG59 from the power inserter to the antenna and watch the results. I'll let you know what happens. Thanks again for all your help.
 
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ab cd

Senior Member
Aren't Yagis directional? We want omni-directional for ADS-B, right?
Yes, Yagis are directional, but my reply was to the post which said:

"what is good directional antenna to be made easy and quickly....
I have 2 receivers....one is for feeding "other site" with own antenna, and one is RTL dongle with DIY antenna.
now....i want rtl dongle to cover only one direction....."
 
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ab cd

Senior Member
Did this and actually saw reduced input - maybe 15-20% less. I pulled this all apart and went back to antenna straight into the dongle and reception increased to the previous level.

Then this morning I got to thinking about it. All my cables were RG59, except the one from the power inserter to the receiver. That one was RG6. Could that have made the difference? I don't have time to try it now, but either tonight or tomorrow I'll hook the amp/power supply back up to the antenna and use a RG59 from the power inserter to the antenna and watch the results. I'll let you know what happens. Thanks again for all your help.
1) Using RG6 or RG59 between Power Inserter & Receiver will not make any noticeable difference. This does not seem to be the cause.
2) Check if your amplifier gets DC Power. To do this:
(a) Disconnect antenna cable from amplifier.
(b) Cut a 15 to 20 mm long piece of coax's central wire and insert in the central hole of Amplifier's antenna terminal.
(c) Set your multimeter to 50 Volts DC. Connect positive (+) probe to central wire & negetive (-) probe to threaded body of Amplifier, and measure voltage between the threaded body of Amplifier and the inserted wire. It should show between 12V & 18V DC. If no, or very low voltage is shown, your Amplifier is not getting power.

Before taking voltage measurement, make sure DC Adaptor is plugged in the power socket, and connected to power inserter

See Voltage measurement connection diagram below:
jepolch-test2.PNG
 
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ab cd

Senior Member
Did this and actually saw reduced input - maybe 15-20% less. I pulled this all apart and went back to antenna straight into the dongle and reception increased to the previous level.

Then this morning I got to thinking about it. All my cables were RG59, except the one from the power inserter to the receiver. That one was RG6. Could that have made the difference? I don't have time to try it now, but either tonight or tomorrow I'll hook the amp/power supply back up to the antenna and use a RG59 from the power inserter to the antenna and watch the results. I'll let you know what happens. Thanks again for all your help.
If voltage check shows amplifier gets the DC power, then most probably it is the amplifier itself.
Your amplifier is rated for frequency 54 - 2150 MHz.
I have tried an amplifier with frequency range 48 - 2400 MHz and it did not work.
When I tried another with frequency range 950 - 2500 MHz it work well.
It seems that amplifiers with lower frequency around 50 MHz do NOT work well with ADS-B, though they are good for Dish & TV.
The amplifiers with lower frequency around 800 to 950 work ok for ADS-B.

Same is experience of forum member 'trigger' as he mentioned in his post # 112 dated Mar 19, 2014 :
"Hi jmcq & ab cd,
I've been making progress with my setup and I can confirm that the amplifier above suggested by ab cd works. I've tried 2 amplifiers which cover the frequency 47 - 2400 Mhz and they don't work in this scenario. They are however, fine for boosting a satellite signal. I bought one which covers 950 - 2300Mhz and that works fine. http://www.ebay.co.uk/itm/Satellite...?pt=UK_Sound_Vision_Other&hash=item51a4d4b5b1
Maybe someone can explain why?
"

Try another amplifier with lower frequency around 900 MHz

jepolch-Amplifier Specs.PNG


My Amplifier
Amplifier-RCA D903.gif
 

jepolch

Active Member
If voltage check shows amplifier gets the DC power, then most probably it is the amplifier itself.
Your amplifier is rated for frequency 54 - 2150 MHz.
I have tried an amplifier with frequency range 48 - 2400 MHz and it did not work.
When I tried another with frequency range 950 - 2500 MHz it work well.
It seems that amplifiers with lower frequency around 50 MHz do NOT work well with ADS-B, though they are good for Dish & TV.
The amplifiers with lower frequency around 800 to 950 work ok for ADS-B.

Same is experience of forum member 'trigger' as he mentioned in his post # 112 dated Mar 19, 2014 :
"Hi jmcq & ab cd,
I've been making progress with my setup and I can confirm that the amplifier above suggested by ab cd works. I've tried 2 amplifiers which cover the frequency 47 - 2400 Mhz and they don't work in this scenario. They are however, fine for boosting a satellite signal. I bought one which covers 950 - 2300Mhz and that works fine. http://www.ebay.co.uk/itm/Satellite...?pt=UK_Sound_Vision_Other&hash=item51a4d4b5b1
Maybe someone can explain why?
"

Try another amplifier with lower frequency around 900 MHz

View attachment 618

My Amplifier
View attachment 619
Aha. Thanks for letting me know. When I bought that amp I was mainly looking at the higher frequency to be sure it would include 1090 Mhz. I didn't think the bottom freq mattered much. I was going to get an amp like yours, but they don't cost $4 anymore! They are $10-25 now. I don't know why - maybe discontinued? I paid about $6 for mine on Amazon. The brand is Terk. I'll look around to see if I can find an RCA 903 for less than 10 bucks. If you know where, please let me know. Thanks again.
 

ab cd

Senior Member
Aha. Thanks for letting me know. When I bought that amp I was mainly looking at the higher frequency to be sure it would include 1090 Mhz. I didn't think the bottom freq mattered much. I was going to get an amp like yours, but they don't cost $4 anymore! They are $10-25 now. I don't know why - maybe discontinued? I paid about $6 for mine on Amazon. The brand is Terk. I'll look around to see if I can find an RCA 903 for less than 10 bucks. If you know where, please let me know. Thanks again.
I ran a search on eBay.com, then sorted the results by "price+shipping lowest". The result is heap of amps from China in the beginning of list (i.e. lowest first) around $3+free shipping from China, which means 1 to 1-1/2 months shipping time.

You will find many from USA, if you go down the sorted list. If you live in USA, this will be better option due to much faster shipping (about a week?). The list is huge. Don't get distracted by large number of chinese ones at the top of the list, scroll down the list to see more from USA, though price will increase proressively as you go down the list.
Here is the link to the sorted list:
http://www.ebay.com/sch/i.html?_from=R40&_sacat=0&_nkw=satellite in line amplifier&_sop=15

I got mine for $4 because I purchased it from a local store, involving no shipping & no on-line sales.
It is not necessary you purchase one like mine, other makes also work good. In case you prefer one like mine, here are links:

One like mine (D903) US $9.99 + FREE Standard Shipping from USA:
http://www.ebay.com/itm/RCA-DBS-Sat...Signal_Amplifiers_Filters&hash=item5d5205f7bd

Another one like mine (it is not D903, but similar with number VH903N) US $6.48+ $2.50 Standard Shipping from USA :
http://www.ebay.com/itm/RCA-In-Line...=US_Video_Cables_Adapters&hash=item3f1a294933

Another Supplier of D903 (Philadelphia, Pennsylvania) US $3.95+$5 for orders less than $25+Shipping???:
http://www.matelectronics.com/rca-in-line-satellite-amplifier-video-housing/
 
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ab cd

Senior Member
Hi ab cd. Do you think this will work for powering an inline amplifier? http://www.satcure.co.uk/tech/dc_inserter.htm
I have seen this last year. It is very tempting as it is free of cost & without any special parts.

Theoretically, it should work as power inserter, but it seems to have following disadvantages:
(1) High risk of short circuit the power supply or the RF signal if not carefully done.
(2) The passage (capacitance) provided by the replaced shield to the RF signal may not be enough and result in reduction/attenuation of RF Signal (The site takes care of this situation by asking to add extra length of aluminum foil if this happens).
(3) There is no inductor to prevent RF passing to the power supply. This means a large quantity of RF Signal will be wasted in power supply, and only a fraction will go to the receiver.
(4) The circuit is broken by breaking the shield, not by breaking the central wire. Alternate path to shield sometime exist (through ground), which may cause some DC current to flow through these paths to the receiver, which is undesirable.

I have not tried it yet. The best way is to try it, to find out how it works with ADS-B (it is proposed for magic-eye controller)
 
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jepolch

Active Member
I ran a search on eBay.com, then sorted the results by "price+shipping lowest". The result is heap of amps from China in the beginning of list (i.e. lowest first) around $3+free shipping from China, which means 1 to 1-1/2 months shipping time.

You will find many from USA, if you go down the sorted list. If you live in USA, this will be better option due to much faster shipping (about a week?). The list is huge. Don't get distracted by large number of chinese ones at the top of the list, scroll down the list to see more from USA, though price will increase proressively as you go down the list.
Here is the link to the sorted list:
http://www.ebay.com/sch/i.html?_from=R40&_sacat=0&_nkw=satellite in line amplifier&_sop=15

I got mine for $4 because I purchased it from a local store, involving no shipping & no on-line sales.
It is not necessary you purchase one like mine, other makes also work good. In case you prefer one like mine, here are links:

One like mine (D903) US $9.99 + FREE Standard Shipping from USA:
http://www.ebay.com/itm/RCA-DBS-Sat...Signal_Amplifiers_Filters&hash=item5d5205f7bd

Another one like mine (it is not D903, but similar with number VH903N) US $6.48+ $2.50 Standard Shipping from USA :
http://www.ebay.com/itm/RCA-In-Line...=US_Video_Cables_Adapters&hash=item3f1a294933
Thanks! I just bought a D903 on eBay for $8.99 with free shipping. Looking forward to getting it!
 

ab cd

Senior Member
Hi ab cd. Do you think this will work for powering an inline amplifier? http://www.satcure.co.uk/tech/dc_inserter.htm
Please see my post on this very subject, and response of other members which follows my post:
Post #401 dated 2013-12-05 on page 41 of FR24 forum
(text & links are available without log-in, but you need to log-in to see images/attachments):
http://forum.flightradar24.com/threads/3831-best-antenna?p=42240&viewfull=1#post42240

See subsequent discussions: Post #403, 404, 405, 406, 407, 408, 409 & 410 on same page (41)
 
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