ADS-B DIY Antenna

Status
Not open for further replies.

jepolch

Active Member
No, it comes ready assembled. It's a very basic circuit - there are only 7 components on the board in total. The amp IC, a couple of caps, an inductor and a few bits on the power traces. It uses the same amplifier IC as the one you have ordered, however that HABAmp also includes a SAW bandpass filter, so should have a significant advantage.
I'm hoping for some improvement with the HABAmp. I hope I'm not disappointed, i.e., ₤50 disappointed. ;)
 

ab cd

Senior Member
There was some discussion about this amp on FlightAware. At the time, it was on sale at Kmart for $5. By the time I heard about it they were sold out. I found one on eBay for $10 +shipping.......
......Nice thing about this is you get the amp and charger and don't have to buy a power injector.
http://www.ebay.com/itm/Alphaline-s...-in-Box-with-usb-cable-charger-/271855541293?.......

My cantenna is now operational, in test in my office.......Amp should arrive tomorrow. I'll post more later.

The amp I ordered from cosycave arrived today. Inserting it inline, so one amp at the antenna, one right before the receiver gave poor results......
.........I also ordered one of their modified R820T2 dongles - it has a reinforced MCX socket and apparently a better crystal, which should improve stability. It appears to be slightly better than the other R820T2 I was using - message rate is up and range slightly increased.

I'm hoping for some improvement with the HABAmp. I hope I'm not disappointed, i.e., ₤50 disappointed. ;)

HAPPY EXPERMENTING! Bonne expérimenter! Gelukkig experimenteren! Glückliche experimentieren!
 

jepolch

Active Member
Can anyone tell me why VRS is displaying these impossible plots? I thought maybe dump-mut was giving it bad information, but @obj says that dump will reject any out of range plot, so the issue is with VRS. I have the receivers set to "AVR or BEAST Raw Feed" and port 30005. Anyone know how to fix this?

Edit: I thought that it was only necessary to set the receiver range in dump-mut, but I see it's also necessary to set it in VRS as well. After I reset the receiver range in VRS it deleted my range plots and started to create new ones.
 

Attachments

  • vrs spikes.jpg
    vrs spikes.jpg
    204.4 KB · Views: 56
  • recv range.png
    recv range.png
    32.4 KB · Views: 42
Last edited:

ab cd

Senior Member
Today about 2½ hrs ago, I formatted the microSD card and made a fresh install of software. I installed only 3 softwares: Raspbian Wheezy, dump1090-mutability, and rrd tools collectd. No data feeder is installed. I will now run it for few days to see whether or not dump1090-crashes. If it does not crash, I will install data feeders, one at a time, then trial run for few days. Let us see what happens. Happy Experimenting!

06may-dump1090-rpi-acs-24h.png


06may-dump1090-rpi-cpu-24h.png


06may-table-rpi-core_temp-24h.png


 
Last edited:

caius

Member
This is due to VRS decoding the raw format and accepting spurious data as valid. There are some options you can tweak to make it more conservative.
Can anyone tell me why VRS is displaying these impossible plots? I thought maybe dump-mut was giving it bad information, but @obj says that dump will reject any out of range plot, so the issue is with VRS. I have the receivers set to "AVR or BEAST Raw Feed" and port 30005. Anyone know how to fix this?

Edit: I thought that it was only necessary to set the receiver range in dump-mut, but I see it's also necessary to set it in VRS as well. After I reset the receiver range in VRS it deleted my range plots and started to create new ones.

This happens because VRS is decoding the raw data itself and not using dump1090s in built filter. In the raw decoding options you can adjust the parameters to try and remove spurious data. If you use the decoded port 30003 output from dump1090 then you don't need to worry about it, but this increases the cpu usage of the process on the raspberry pi quite a bit; and VRS doesn't get the full data that is available from the raw feed.
 

ab cd

Senior Member
Even without any data feeder or VRS, the dump1090-mut load is 30% to 35%. I have noted in previous installs that it remains same even with data feeders installed.

Screenshot_2015-05-06-17-36-50.png

 

jepolch

Active Member
Today about 2½ hrs ago, I formatted the microSD card and made a fresh install of software. I installed only 3 softwares: Raspbian Wheezy, dump1090-mutability, and rrd tools collectd. No data feeder is installed. I will now run it for few days to see whether or not dump1090-crashes. If it does not crash, I will install data feeders, one at a time, then trial run for few days. Let us see what happens. Happy Experimenting!

View attachment 1902

View attachment 1903

View attachment 1904
Good luck! I hope you get to the bottom of it. Is this on the Pi 2?

Edit: It sure is nice having graphs, isn't it?
 
Last edited:

juha

New Member
Would a sat diplexer work as a power inserter for amplifier? Like this: 18V power supply -> diplexers power pass port -> coax to amplifier -> antenna?
I can't find a power inserter with a reasonable price and postage anywhere, but those diplexers are so cheap and available everywhere.
 

jepolch

Active Member
This is due to VRS decoding the raw format and accepting spurious data as valid. There are some options you can tweak to make it more conservative.


This happens because VRS is decoding the raw data itself and not using dump1090s in built filter. In the raw decoding options you can adjust the parameters to try and remove spurious data. If you use the decoded port 30003 output from dump1090 then you don't need to worry about it, but this increases the cpu usage of the process on the raspberry pi quite a bit; and VRS doesn't get the full data that is available from the raw feed.
I was getting the spikes when I was using port 30003 data. I thought that was the problem, so I switched to port 30005. I have dump-mut configured to reject locations over 225 nm away, yet I was getting spikes.
 

jepolch

Active Member
Even without any data feeder or VRS, the dump1090-mut load is 30% to 35%. I have noted in previous installs that it remains same even with data feeders installed.

View attachment 1905
I'm guessing you have the dongle in place, or dump wouldn't run. If that's the case, then dump is still processing the data it's receiving, just not feeding it to the site. Try with the antenna removed.
 

jepolch

Active Member
Would a sat diplexer work as a power inserter for amplifier? Like this: 18V power supply -> diplexers power pass port -> coax to amplifier -> antenna?
I can't find a power inserter with a reasonable price and postage anywhere, but those diplexers are so cheap and available everywhere.
I've wondered the same thing myself. It's worth a try. You'll know right away if it works. If you have an amp in your RF chain and you hook up the diplexer as you described, if you don't see any output in the dump web page, then the amp isn't getting the power.
 

juha

New Member
I've wondered the same thing myself. It's worth a try. You'll know right away if it works. If you have an amp in your RF chain and you hook up the diplexer as you described, if you don't see any output in the dump web page, then the amp isn't getting the power.

Ok, I will try when I have a little spare time. I will let you know if it works (or not).
 

ab cd

Senior Member
Good luck! I hope you get to the bottom of it. Is this on the Pi 2?
No it is on Pi B+.
It may be location related. Pi B+ was near desktop, connected to antenna#1 via amp & 50ft coax, while Pi Modl 2 was below antenna#2, connected to it by 12 ft coax, no amp. In this configuration, Pi Modl 2 was crashing, and Pi B+ never crashed.

When I retired Pi Modl 2, I moved Pi B+ at the location & configuration of Pi Modl2, and since then Pi B+ also started crashing! Location????
It sure is nice having graphs, isn't it?
It is not only nice, but also a very important tool for experiments & evaluation/comparision of various antennas & configurations.
 

ab cd

Senior Member
Would a sat diplexer work as a power inserter for amplifier? Like this: 18V power supply -> diplexers power pass port -> coax to amplifier -> antenna?
I can't find a power inserter with a reasonable price and postage anywhere, but those diplexers are so cheap and available everywhere.
Where will you connect cable to DVB-T dongle? The only port of Diplexer left is the TV port.

I have not tried it, but trying to visualize. The power pass port of diplexer not only passes power, but also satellite RF signal (in our case 1090Mhz). This RF signal will be short circuited through the DC adapter as there is nothing (i.e. no inductor) to block it from entering DC adapter. Secondly, the TV port is designed to pass only TV VHF/UHF band, the upper end of which is below 900MHz. It will pass 1090 Mhz signal with after greatly attenuating it.

However this is all theoretical. Best is to actually try & see.

Centuries ago, a wise man asked a group of top philosophers of his time that what is the reason that when a fish is put in a pot full of water upto brim, the water does not spill?

The group of philosophers deliberated for an hour and came back with an answer that the fish drinks the water and its body absorbs the water. The wise man said your answer is wrong. The philosophers asked what is the right answer? The wise man said bring me a fish & a pot full of water. The wise man then put the fish in the pot and water spilled! He said to philosophers my question was wrong, but you never bothered to test by experiment, you just applied your logic & theories and concluded!
Happy Experimenting :D
 
Last edited:

ab cd

Senior Member
Would a sat diplexer work as a power inserter for amplifier? Like this: 18V power supply -> diplexers power pass port -> coax to amplifier -> antenna?
I can't find a power inserter with a reasonable price and postage anywhere, but those diplexers are so cheap and available everywhere.
If you know some shops in your area which sells electronic components, check the prices of a 200pF ceramic Capacitor and a 4.7 micro Henry axial inductor. These components cost very little (fraction of a Euro), but actual price depends on the shop. If the prices are reasonable, you can try to make a home-brew power inserter using a TV Splitter housing, a Capacitor & an Inductor. See photo below.

Power_Inserter_steps-3.JPG
 

juha

New Member
If you know some shops in your area which sells electronic components, check the prices of a 200pF ceramic Capacitor and a 4.7 micro Henry axial inductor. These components cost very little (fraction of a Euro), but actual price depends on the shop. If the prices are reasonable, you can try to make a home-brew power inserter using a TV Splitter housing, a Capacitor & an Inductor. See photo below.

Thanks for the tip.
You were right that with a diplexer it didn't work.
But I found a 2 way splitter with power pass on both ports, 5-2500MHz, and it seems to work. Without amp my antenna was picking 0 planes, but when I put amp, instantly picked a plane and dump1090-muta show's RSSI around -3, so it clearly works somehow. (That's the only plane in possible range here)

It's pretty silent planewise around here so I can't really say how much it will improve my range yet. We'll see..

Photo of the splitter and amp attached.
 

Attachments

  • 2000022441.jpeg
    2000022441.jpeg
    40 KB · Views: 48
  • 67056.jpg
    67056.jpg
    23.5 KB · Views: 48

ab cd

Senior Member
Thanks for the tip.
You were right that with a diplexer it didn't work.
But I found a 2 way splitter with power pass on both ports, 5-2500MHz, and it seems to work. Without amp my antenna was picking 0 planes, but when I put amp, instantly picked a plane and dump1090-muta show's RSSI around -3, so it clearly works somehow. (That's the only plane in possible range here)

It's pretty silent planewise around here so I can't really say how much it will improve my range yet. We'll see..

Photo of the splitter and amp attached.
A power pass splitter will short circuit a large portion of 1090 MHz signal through DC Power supply as the splitter does not have an inductor to prevent short circuit of 1090 MHz. As a result the DVB-T USB dongle will get only a fraction of the amplified 1090 MHz signal.

The photo of home-brew injector I have posted above (post # 3195) uses a 2 way power pass splitter like yours, with Inductor & Capacitor added to it. Due to addition of Inductor to the splitter, the 1090 MHz signal is prevented from shorting through DC Power Supply, and all of amplified 1090 MHz signal will reach the DVB-T USB Receiver.

You will see many more and farther away planes if you add an inductor and a capacitor to your splitter .
 
Last edited:

airbus340

New Member
I am now trying a plate antenna and comparing it with my stacked dipole. It gives me about the same range, but a lot less messages. I have glued a Belling Lee through a hole in the plate so the top of the connector is on the top side of the plate. Should I measure 68mm from where the plate is or from the top of the connector? The Belling Lee is about 10mm high I think.
 

ab cd

Senior Member
Should I measure 68mm from where the plate is or from the top of the connector? The Belling Lee is about 10mm high I think.
69mm from top of the connector
Whip measurements-R-632x684 px.png
I am now trying a plate antenna and comparing it with my stacked dipole. It gives me about the same range, but a lot less messages. I have glued a Belling Lee through a hole in the plate so the top of the connector is on the top side of the plate.
Is the plate electrically connected to the metallic sleeve of Belling Lee, or the glue has insulated them? Check with a multi-tester/continuity tester.
 
Last edited:

airbus340

New Member
Thank you, then I have measured correctly. Yes, they are electrically connected as the Belling Lee is flat from where the cable connects, so the flat part is what the plate is resting on.
 
Status
Not open for further replies.
Top