ADS-B DIY Antenna

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Todd

New Member
left photo: amplifier center, coax from DC blocking on L, coax to power inserter (black coax) on R
center photo: antenna (black coax) to DC block, white coax to amp LNB port
right photo: white coax on R from 14v power supply, white coax on L from amplif RCVR port, black coax on top to dongle

multimeter measures 15v + on center wire from DC power inserter

Any thoughts?

Todd
 

ab cd

Senior Member
left photo: amplifier center, coax from DC blocking on L, coax to power inserter (black coax) on R
center photo: antenna (black coax) to DC block, white coax to amp LNB port
right photo: white coax on R from 14v power supply, white coax on L from amplif RCVR port, black coax on top to dongle

multimeter measures 15v + on center wire from DC power inserter

Any thoughts?

Todd
Thank you for posting the photos. It is now clear what went wrong. You have used "diplexer" in place of "dc inserter/dc combiner". The diplexer has completely different function (separating/mixing two adjuscent frequency bands), while dc injector/dc combiner has another function (mixing/separating dc and a band of frquencies). These cannot be used in place of each other. You will have to replace the diplexers by the dc injectors/combiners.

DC Inserters
http://www.ebay.com/itm/371094073702
power inserter-1.jpg

http://www.ebay.com/itm/131249139257
power inserter-2.jpg

http://www.ebay.com/itm/131506454888
power inserter-3.jpg


Instead of purchasing two dc inserters/combiners, you better purchase one dc inserter/combiner and one dc blocker, which will be installed in place of dc inserter/combiner located between antenna & amplifier.

DC Blocker
http://ebay.com/itm/370609430351
dc blocker-1.jpg

http://ebay.com/itm/251432963230
dc blocker-2.jpg
 
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bramj

Member
@bramj:
Which antenna are you using?
The Spider, or any ¼ wave whip+groundplane of any type, has an apple or donut shaped radiation pattern (curve titled "Unity" in sketch below). This type of curvr gives high output dB for nearby planes, and very low output dB for far away planes.

A high gain antenna has a sqeezed apple or donut shape (curve titled "5dBd" in sketch below). This type of curve gives low output dB for nearby planes, and high output dB for far away planes, and hence is helpfull in crowded air traffic location like yours.

View attachment 1994
I'm using a 12 elements coax collinear...super donut :)

without amp it has a range of 200Nm see picture
The overlay shows the range of the collinear ,you can clearly see that the trails are much shorter now...with amp..:-(


Screen Shot 2015-05-13 at 09.44.06.png


without amp.

Screen Shot 2015-05-13 at 10.29.51.png
 
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ab cd

Senior Member
I'm using a 12 elements coax collinear...super donut :)

without amp it has a range of 200Nm see picture
The overlay shows the range of the collinear ,you can clearly see that the trails are much shorter now...with amp..:-(


View attachment 2006

without amp.

View attachment 2007
Wow, great antenna! Did you make it yourself or purchased it? If purchased, How many dB gain?

Your amplifier seems to work as an attenuator. This can happen if:
(1) Amp is wrongly connected i.e. the amplifier's port which is marked ANT/LNB/IN is connected to DVB-T, and the port marked RCVR/TV/OUT is connected to antenna. It should be the other way round.
(2) Amplifier is not getting DC Power, or getting a DC Voltage much below/above its rated value. Normally satellite amps are rated for 13V to 18V, but will work for 12V to 20V.
(3) The DC Polarity is reversed. Correct polarity is core=positive (+), braid=negative (-)
(4) The amplifier is defective.
(5) The power inserter is defective, or a piece of similar looking, but improper equipment (diplexer or splitter) is used as dc inserter.
 
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Todd

New Member
>>>Instead of purchasing two dc inserters/combiners, you better purchase one dc inserter/combiner and one dc blocker, which will be installed in place of dc inserter/combiner located between antenna & amplifier.


Hi

I found the last power inserter in Tucson.

I have an attenuator from Dish TV: see attached photo. Will this work as a dc blocker? I haven't found a dc blocker locally. Would anything else work?


Thanks
Todd
 

Attachments

Todd

New Member
Found this description of the DishTV attenuator online..hopefully this helps:
Dish Network 122698 10 dB UHF Signal Attenuator Pad Inline DC Block Female to Male F-Type 75 Ohm In-Line Fixed 22 Gauge Nickle Plated Coupler Connector 1 Pack, Part # 122698
 

ab cd

Senior Member
Found this description of the DishTV attenuator online..hopefully this helps:
Dish Network 122698 10 dB UHF Signal Attenuator Pad Inline DC Block Female to Male F-Type 75 Ohm In-Line Fixed 22 Gauge Nickle Plated Coupler Connector 1 Pack, Part # 122698
This will not work as dc inserter.

This is an attenuator, and attenuates (i.e. reduces) signal by 10 dB, so your DVB-T usb receiver will get almost zero signal from antenna. It is therefore useless as dc inserter.

It will work as dc blocker, but since it eats up all signal due to its 10 dB attenuation, it is useless as dc blocker as well.
 
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Todd

New Member
That's what I figured..will have to order a dc blocker

Just curious..is there anything that I could build that would substitute for the dc blocker?

Thanks ab cd

Todd

This will not work as dc inserter.

This is an attenuator, and attenuates signal by 10 dB, so your DVB-T usb receiver will get no signal from antenna. It is therefore useless as dc inserter.

It will work as dc blocker, but since it eats up all signal due to its 10 dB attenuation, it is useless as dc blocker as well.
 

ab cd

Senior Member
That's what I figured..will have to order a dc blocker

Just curious..is there anything that I could build that would substitute for the dc blocker?

Thanks ab cd

Todd
The first photo below shows how to make a DIY power inserter. The dc inserter has two components: an inductor and a capcitor.

If you install only capacitor, it will become a dc blocker.

The second photo shows my setup using DIY dc inserter & dc blocker.

how to make diy dc inserter.jpg


DSC02844R.JPG
 

Todd

New Member
never mind :)

found another actual power inserter in my other junkbox and did the setup a la Dave...success!! Lots more planes than before for this late hour in Tucson

Todd
 

ab cd

Senior Member
never mind :)

found another actual power inserter in my other junkbox and did the setup a la Dave...success!! Lots more planes than before for this late hour in Tucson

Todd
GREAT, CONGRATULATIONS!
 
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ab cd

Senior Member
Thanks again
How were you able to remove the back of the splitter?
never mind :)
found another actual power inserter in my other junkbox and did the setup a la Dave...success!! Lots more planes than before for this late hour in Tucson
Todd
For the sake of those interested in making DC inserter:
The back cover of Splitter is NOT designed to be removable. It is fixed to the housing by some adhesive, and can only be forced open.
I put a flat screwdriver in the middle of back cover, and lightly hammered the screwdriver. The cover bent down in the middle, and its edges popped out of housing. I inserted a smaller screwdriver beneath the popped up edge and forced the cover open. This process deformed the back cover. Later I hammered the back cover to flatten it back, and glued it to housing.
 
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xforce30164

Active Member
Some nice stats with the amplifier:

Before: (~€60 ebay antenna)
Average positions: 111K
Average planes: 3368

Currently: (one of the earlier spiders with amp)
Average positions: 139K (roughly 25% increase)
Average planes: 3760 (roughly 12% increase)
amped-stats.png


Range/radar plot with ebay antenna (peak ~125NM)
range_2_5_15.png


Range/radar plot with spider+amp (peak ~150NM)
range_13_5_15.png
 

Todd

New Member
I'm thrilled by the improvement with the in-line amp..major improvement.

What software do you guys use to plot coverage and superimpose on the map?

Thanks
Todd
 

caius

Member
Virtual Radar Server can superimpose range over google maps. This shows the overall range, but you can also add the range for different heights.

VRS.PNG


ADSBscope can plot the maximum range on the chart, and SBSPlotter can give you an outline file that can be displayed in a variety of software.

OBJ's plotting scripts give quite a nice output that shows where your signal is being obstructed by terrain or buildings, and also gives an idea of the reliability of the signal you are receiving. It doesn't overlay over a map though. This is several hours data:

polar.png
 

bramj

Member
Wow, great antenna! Did you make it yourself or purchased it? If purchased, How many dB gain?
DIY project.:)

I found a bad contact in the wiring...there is a performance boost.:)
setup is, Antenna--> dc-blocker--> amp-->dc-injector-->rtl-sdr dongle..

polar pattern before

Screen Shot 2015-04-30 at 19.54.16.png


After , touching 400KM 200+ NM

polar amp.png


Position reported higher..
Screen Shot 2015-05-14 at 20.01.19.png


Wiring problems, and problem solved.

Screen Shot 2015-05-13 at 09.44.06.png
Screen Shot 2015-05-14 at 18.06.46.png
 

ab cd

Senior Member
@Todd:
If you feed data to planefinder, then your data will be plotted in graphs, number of planes in cartesian and range in polar. Due to crash of my RPi, I am currently not feeding data to any tracking site, but you can see my data curves of last month plotted by plane finder. CLICK HERE. (Scroll down page to see max range curve)
 
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