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 Post subject: Re: Three Easy DIY Antennas for Beginners
PostPosted: Sat Apr 08, 2017 12:20 am 
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joelwiley - FlightAware user avatar

Joined: Mon Mar 12, 2012 7:46 pm
Posts: 844
AlpineMeadows wrote:
Thanks. I'll give your microwave suggestion a try. Will also try and compare 1 day to another with the PVC pipe as well as the microwave test at 2.45Ghz might not be applicable at 1.09Ghz. The PVC I was going to use is the thin white stuff used for landscape drainage/French drains - thin stuff.
I have had success with white 1/2 inch schedule 40 irrigation pipe. I had to paint it to camouflage it from the HOA. I sprayed the paints on paper towels and microwave tested. A few heated up and would have been a problem.

Good luck.


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 Post subject: Re: Three Easy DIY Antennas for Beginners
PostPosted: Thu Apr 13, 2017 9:11 am 
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zeek70706 - FlightAware user avatar

Joined: Wed Apr 23, 2008 6:00 am
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Location: Baton Rouge KBTR
AlpineMeadows wrote:
AlpineMeadows wrote:
Got my SMA to F adapters in the mail so I built a cantenna tonight. Right now the location is where I had my un-trimmed RTL-SDR antenna (on the window sill) except I used double sided tape and taped the can to the middle of the window. Hoping for better stats tomorrow.

Once I get enough free time I'll put it on the roof.


Compared to what I had before (RTL-SDR mag antenna untrimmed on window sill), my cantenna double sided taped to the inside of my window is a much better performer. Was topping out at about 70-75K hits/day, now hitting ~ 130K per day.

Time to put it outside! However I'd like to enclose it to protect it from water.

Question for the group - at what point does a plastic enclosure affect the performance? If I put it in a piece of 4" PVC drain pipe with end caps, will the PVC affect the antenna RF performance?


The coax is inserted through the lid then connected directly to the cantenna. Next to that hole, the lid is screwed to the stick. The cantenna then sits on the lid and the plastic jar is screwed on. I did not seal the lid to the jar, I added a few small drain and ventilation holes around the edge of the lid.

Image


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 Post subject: Re: Three Easy DIY Antennas for Beginners
PostPosted: Thu Apr 13, 2017 3:53 pm 
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TomNJerry - FlightAware user avatar

Joined: Sat Mar 19, 2016 7:58 pm
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Location: Canada
zeek70706 wrote:
Image


Excellent!! Neatly built.
How it performed?


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 Post subject: Re: Three Easy DIY Antennas for Beginners
PostPosted: Sun Apr 16, 2017 11:31 pm 
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AlpineMeadows - FlightAware user avatar

Joined: Tue Mar 21, 2017 12:07 am
Posts: 25
It's on the roof! Reception is much better, already surpassing the distance stats I've had before.

Ended up buying 2 qty 3" end caps and 1 qty 3" coupler for landscaping drain purposes (plastic is thinner, end caps are flat), stacked and taped together at the seams.

Used a short section of 1/2" PVC as a standoff on the inside which also served to pass the RG6 cable into the stack which was taped together. This all was mounted at the peak of the roof. The attic space in the garage has the Pi + stick + POE power supply inside an old metal dewalt cordless drill carrying case.

Keeping my fingers crossed I'll be the 'high point' winner for stations near me.


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 Post subject: Re: Three Easy DIY Antennas for Beginners
PostPosted: Sun Apr 23, 2017 12:31 pm 
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AlpineMeadows - FlightAware user avatar

Joined: Tue Mar 21, 2017 12:07 am
Posts: 25
Amusing discovery. I asked on Amazon if anyone went from the cantenna to the FA 26" antenna and what difference they saw and 2 of the 3 people answered that the cantenna is directional vs the FA antenna.

If one googles adsb and cantenna, the soda can antenna comes up. Google cantenna by itself and this directional antenna comes up.
https://en.wikipedia.org/wiki/Cantenna
and this one.
http://www.cantenna.com/

I remember the 'pringles can' antennas many years ago - popular back with most people didn't have their wifi secured.

I deleted my question on Amazon.


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 Post subject: Re: Three Easy DIY Antennas for Beginners
PostPosted: Sun Apr 23, 2017 6:42 pm 
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abcd567 - FlightAware user avatar

Joined: Sat Feb 15, 2014 3:08 am
Posts: 1980
Location: Toronto CYYZ
AlpineMeadows wrote:
Amusing discovery. I asked on Amazon if anyone went from the cantenna to the FA 26" antenna and what difference they saw and 2 of the 3 people answered that the cantenna is directional vs the FA antenna.

If one googles adsb and cantenna, the soda can antenna comes up. Google cantenna by itself and this directional antenna comes up.
https://en.wikipedia.org/wiki/Cantenna
and this one.
http://www.cantenna.com/

I remember the 'pringles can' antennas many years ago - popular back with most people didn't have their wifi secured.

I deleted my question on Amazon.


I think I should give an explanation.

The name "Cantenna" is used for 3 entirely different products as detailed below.


(1) The Name "Cantenna" was first used for Heathkit's classic oil-filled dummy load resistor produced from 1961 through to 1983
Image




(2) The name "Cantenna" is being used since 1980s by Amateur Radio (HAM) enthusiasts for a monopole inside a wave-guide made of Pringles can. The Pringles can beamed entire power in one direction, making it highly directional antenna. It worked like the reflector of a flash light, which creates a beam of light in one direction.

Subsequently this wave-guide directional Cantenna was adopted by WiFi enthusiasts using many different types of cans.

Image . Image




(3) In 2014, without being aware that this name is already in use by two other different products, I gave the name "Cantena" to the adsb-antenna I made from soda can (Click Here).


The story of soda can adsb cantenna goes as follows:
In 2014, I made and put on trial run the old-timer coaxial antenna (also known as sleeve dipole). The original design had a narrow copper pipe/tube slightly bigger in dia than the dia. of feed coax. It performed inferior to other dipole / monopole designs.

I concluded that main reason of its inferior performance is the very narrow air gap between feed coax and copper pipe/tube, and decided to try a large dia version using drink can with lot of air gap between it and feed coax. When I put this wide-bodied design on trial run, it performed very well. This was the birth of adsb-Cantenna.

Initially I introduced it with its generic name "1/2 λ sleeve dipole" (Click Here).

Two months later, without being aware that the name "Cantenna" already exists and is already in use by two different products, I coined for it a simpler and meaningful name "Cantenna" (Click Here).

I came to know about about name Cantenna's earlier use almost a year later.



Adsb Cantenna is a hybrid of:
"1/4 wavelength ground plane antenna"
AND
"coaxial antenna" (also known as sleeved dipole)

Image


Image



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 Post subject: Re: Three Easy DIY Antennas for Beginners
PostPosted: Mon May 08, 2017 12:39 am 
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toxx - FlightAware user avatar

Joined: Sun May 07, 2017 12:52 pm
Posts: 10
Hi there

I am a newbie in the ADS-B thing and here is my equipment:

- Raspberry PI 2 (old version, 2USBs ETH port) runing piaware
- 4$ RTL SDR dongle with MCX pigtail

I live in Dubai, 15km from JLT/Dubai Marina towards desert side and i live in a flat so i am restricted for line of sight at NW, WNW, W, NE. South is completely blocked, as i run the antenna inside sticked to a window which is facing WNW. Moreover, the line of sight is blocked at 15km by the big towers in Dubai Marina/JLT/Barsha Heights.


I started first with a closed dipole , 150mm elements with 69mm in the back, 8mm stub, fed at 20mm and i got good results, but due to the fact that i don't have for now a soldering iron, i needed to improvise the cable connection. Also the RG6 cable i have is kind of thin, so the antenna won't sit firmly.

Last night i built a CoCo with 5 elements, 110mm each , open whip about 3 cm fed directly into the coaxial cable.

These are my stats with this antenna starting from 5pm UTC 7th of May 2017: http://flightaware.com/adsb/stats/user/toxx#stats-42774
Last night i watched the dump1090 virtual map and i could see a plane at 174.8 Nm with RF signal -28.9 dB and the updates were constant, some where in Arabian Sea near Qatar.

I want to let it run for 2-3 days and then build a Cantenna and see the results. I also hardened the dipole, cut the elements from 15cm to 13.8 and adjust the gap for stub to be less than 8mm

Cheers !


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 Post subject: Re: Three Easy DIY Antennas for Beginners
PostPosted: Mon May 08, 2017 12:25 pm 
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zeek70706 - FlightAware user avatar

Joined: Wed Apr 23, 2008 6:00 am
Posts: 67
Location: Baton Rouge KBTR
TomNJerry wrote:
zeek70706 wrote:
Image


Excellent!! Neatly built.
How it performed?


Mounted on the stick in the picture 4 feet above the ground with 5 ft of RG6, it performed as well as the FA 49" antenna at the same height. I did mount the cantenna on my tower for a few weeks at 35 ft above the ground and it did well but 45 ft of RG6 made it not perform as well as the 9 db FA antenna on the tower. I want to do more cantenna experiments but have been busy lately. When I do, I will post them here.


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 Post subject: Re: Three Easy DIY Antennas for Beginners
PostPosted: Mon May 08, 2017 2:26 pm 
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toxx - FlightAware user avatar

Joined: Sun May 07, 2017 12:52 pm
Posts: 10
Hey mates

Tried today the Cantenna with the same setup as the design, 69mm can height, 69mm insulated whip and the results were awful.

Maximum 20 tracked aircraft, 16 known positions, maximum 90 msgs/sec

I reinforced the joints on my 5 elements CoCo and i added another one to have 6 elements, last whip is not insulated (2.5 cm) and open end, now the results are better than 5 element Coco with 60 aircraft on the map and 310 msgs / sec

I am not running amplifier, and the antenna is sticked to the window with Scotch adhesive, not even outside in pvc pipe. 3.5 meters of unknown 75 coax (china, very bad quality, the braid is combined with aluminium wires and a flat aluminium band), and no name RTL SDR dongle. I am planning to keep this antenna and i have on the way from Amazon the FA filter, and i hunt for a RCA LNA on eBay.

The parts with the down drops after 12:00 are with Cantenna, the part berfore is 5 element Coco, the part after the drop is with 6 element Coco

Image
Image
upload pictures to



And the SkyView

Image
gif hosting


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 Post subject: Re: Three Easy DIY Antennas for Beginners
PostPosted: Thu May 11, 2017 10:52 am 
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toxx - FlightAware user avatar

Joined: Sun May 07, 2017 12:52 pm
Posts: 10
I am back with some findings.

I tried to add a lambda/4 whip to the 6 element CoCO from its initial 2.5 cms whip and for some reason its performance dropped a lot. Now i am using a coax made spider with 8 legs which gets maximum 200 Nm

I noticed the poor performance of the CoCo when i moved its position relative to the feeding cable. First, the feeding cable had almost a 90 degree turn the left :
|
| coco
feeeder-------|

after the feeder cable got shortened by my tests, it got almost inline with the CoCo which i believe acted as radiant. So, without decoupling and knowing the actual VF of cable and/or specialized equipment, don't try this at home or it will drive you crazy.


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 Post subject: Re: Three Easy DIY Antennas for Beginners
PostPosted: Fri May 12, 2017 5:58 pm 
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yeu2 - FlightAware user avatar

Joined: Tue Mar 22, 2016 9:27 am
Posts: 10
I have a small test coco antenna of 4 elements made from RG6 cable. The segments are 11.5 cm long and the cable run is around 1m (3ft). The performance is 200nm+. It takes around 15 mins to build this antenna and the required parts are 1m of RG6, some duct tape and some thermal shrinking tube. The tutorial to follow is here https://www.balarad.net/ . The end segment has the shield and the core of the coax cable cut at the same length(open end). And it is not mandatory to point the top of the antenna up(see the picture, is top down and works fine, the polarization is also vertical in this position as it is with the top up). For environmental shielding use some plastic pipe but this is not mandatory, the shrinking tube acts as hydro isolation too.

In my opinion this is the simplest antenna vs performance vs time to build vs costs( materials cost around $3, at least here in Romania :) ).

Image


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 Post subject: Re: Three Easy DIY Antennas for Beginners
PostPosted: Sat May 13, 2017 2:30 am 
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toxx - FlightAware user avatar

Joined: Sun May 07, 2017 12:52 pm
Posts: 10
Yeah, i am in Dubai, the cost was more than $3 but not much higher. Anyway, the first test was successful, 5 element CoCo with no VF adaptation (didn't shrink the element length based on cable VF because i didn't know it) so i put them together and i let the end element with open end and the whip about 2.5 cms than i inserted the feeder cable the same way i connected the elements.

It worked fine, 200+ Nm given the fact that it was sticked to the window glass and at 15km of line sight i have a set of horizontal towers each at least 30-40 floors high. Then, i wanted to extend the whip to lambda/4 as seen on balarad's site and the anntenna dropped the performance real bad. I removed the whip, leaving the antenna as before, performance still bad.

Tried the Cantenna, very bad performance, and now i am running with a 8 legged spider which is 20cm outside the glass , performance is really good.

I did a test setup with the FA filter, 7 foot rg174 cable with SMA cables and a small magnetic base antenna with 68cm whip put on a tuna fish can outside the glass and the performance was astonishing : 300Nm range, over 350 messages/s and more than 60 aircraft tracked. Anyway i can't put it together because i am still waiting for FA antenna and the connectors + good quality cable to set it up. I definitely need a filter in this area, there are lots of GSM towers and other transmissions. I ordered already a RCA D903 amp and a diplexer so i will get back on this thread when i put it all together and see the performance. Hopefully by next week i will get the transport from Amazon and next weekend i will setup everything.

At least for me, i was out of luck with the CoCo, as i don't even have a multimeter around to test for shorts when building it. I would love to test this when i return back to Romania as i can install it on my house with 360 view compared to here, where south is blocked by the building (no access to roof)

yeu2 wrote:
I have a small test coco antenna of 4 elements made from RG6 cable. The segments are 11.5 cm long and the cable run is around 1m (3ft). The performance is 200nm+. It takes around 15 mins to build this antenna and the required parts are 1m of RG6, some duct tape and some thermal shrinking tube. The tutorial to follow is here https://www.balarad.net/ . The end segment has the shield and the core of the coax cable cut at the same length(open end). And it is not mandatory to point the top of the antenna up(see the picture, is top down and works fine, the polarization is also vertical in this position as it is with the top up). For environmental shielding use some plastic pipe but this is not mandatory, the shrinking tube acts as hydro isolation too.

Image


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 Post subject: Re: Three Easy DIY Antennas for Beginners
PostPosted: Sat May 13, 2017 10:49 am 
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yeu2 - FlightAware user avatar

Joined: Tue Mar 22, 2016 9:27 am
Posts: 10
Why not improvising something cheap to test that your coco is not shorted? I've used an LED and a 3v battery and each time I was adding a segment I was testing that the node is not shorted by powering the led throug the antenna. And no multimeter is needed.

Also use gqrx or sdr sharp for a FFT on the spectum around 1090MHz to see if there is any pollution or interference. I'm always checking if the antenna receive something through gqrx before testing it with dump1090 or modesdeco.


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 Post subject: Re: Three Easy DIY Antennas for Beginners
PostPosted: Sat May 13, 2017 1:19 pm 
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toxx - FlightAware user avatar

Joined: Sun May 07, 2017 12:52 pm
Posts: 10
yeu2 wrote:
Why not improvising something cheap to test that your coco is not shorted? I've used an LED and a 3v battery and each time I was adding a segment I was testing that the node is not shorted by powering the led throug the antenna. And no multimeter is needed.

Also use gqrx or sdr sharp for a FFT on the spectum around 1090MHz to see if there is any pollution or interference. I'm always checking if the antenna receive something through gqrx before testing it with dump1090 or modesdeco.



yeah thanks, good idea with the led and battery i will try another coco next weekend. What size do you recommend, as i cannot install it outside for the moment and my glass can handle maximum a 5 element one


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 Post subject: Re: Three Easy DIY Antennas for Beginners
PostPosted: Sun May 14, 2017 5:01 am 
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yeu2 - FlightAware user avatar

Joined: Tue Mar 22, 2016 9:27 am
Posts: 10
Try with 4 elements. Usually coco antennas are made in increments of 2.


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 Post subject: Re: Three Easy DIY Antennas for Beginners
PostPosted: Sun May 14, 2017 5:16 am 
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toxx - FlightAware user avatar

Joined: Sun May 07, 2017 12:52 pm
Posts: 10
yeu2 wrote:
Try with 4 elements. Usually coco antennas are made in increments of 2.


Weird, i found the following scheme:

Image


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 Post subject: Re: Three Easy DIY Antennas for Beginners
PostPosted: Sun May 14, 2017 3:55 pm 
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yeu2 - FlightAware user avatar

Joined: Tue Mar 22, 2016 9:27 am
Posts: 10
I did not add that balun and all seems to work fine :) So try the first one from that scheme without that balun. Should work just fine.


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 Post subject: Re: Three Easy DIY Antennas for Beginners
PostPosted: Sun May 21, 2017 10:04 am 
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jatenelef - FlightAware user avatar

Joined: Sat Mar 25, 2017 11:19 am
Posts: 1
As a radio amateur, :) antennae are a hobby of mine but i am new to the raspberry pi and ads-b so from the novis aspect, getting my pi and the sky aware receiver and filter was a job of a couple of days work, i built the stack co linear with the stubs above and it has been at some 25 ft (8m) above ground and living in a radio hole (surrounded by hills) i was getting a range of around 30 miles. today i built the 16 section colinier and it sat outside the front door below the level of the eaves and WOW range now at this height over 120 miles. and from around 20 aircraft in the 0600 run into egll and egkk i shot up to 80 odd and now track as far as the coast of france altitudes from 1000 feet to 40 plus thousand a vast inprovement . I am no expert and all i did was to cut RG58 to length, trim and solder, then mount the total antenna into some 36mm white plastic pipe to give it support and weather proofing. on the cable end of (30m) 90 ft i have an f connector converted to an sma direct to the sky aware filter. i run version 3,5 and am delighted with the results. tomorrow, the old antenna comes down and the new 16 section coax colinier goes up (to around 25 ft) 8 plus m and we will see what we get then. Lots of comments state that this is a difficult antenna to build and get right. i dissagree. have a go cut one section and trim as shown above and then cut the rest using the first as pattern, i suggest making them all at the first cut 3cms longer than spec to allow for trimming and mistakes. its well worth the 4 hours i spent building it and what a difference. in conclusion, i have now made 5 different antannae, basic tin lid quarter wave, half wave dipole, stack colinier (4 element and 10 element) and finally 16 element colinier the best so far. if i may, i would recommend having a go, nothing to lose and the results may well surprise. and finally, thanks to the support team who ably assisted me in getting the pi up and running. :D
de g8nlf


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 Post subject: Re: Three Easy DIY Antennas for Beginners
PostPosted: Mon May 22, 2017 1:53 am 
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toxx - FlightAware user avatar

Joined: Sun May 07, 2017 12:52 pm
Posts: 10
Glad to hear that, but for me it didn't work, either the cable is very bad quality or i do something wrong. I built again one 6 element CoCo and tested it with a 12v car bulb at the end, and same poor result compared to the 8 legged spider. I also bought FA antenna, which is also poor performance, given the fact that its radiation pattern is more to the horizon (which is blocked for me at around 15-20 kms) and not much in a vertical manner

Last night my SMA to F connectors were delivered, and i was able to mount the 1090mhz band pass filter , which greatly improved reception.

I will get back with other results as i go along with the tests, current setup is :
- 6 meters of unknown china cable RG6U
- 8 legged spider antenna made with coax cable
- antenna is on the balcony , 1 foot outside on a L mount
- FA 1090 mhz band pass filter

Intended tests:
- LMR240 cable with same spider antenna , filter, amplifier, diplexer
- LMR240 cable with CoCo 6 elements open end, filter, amplifier, diplexer
- LMR240 cable with FA antenna, filter, amplifier, diplexer

I want to use amplifier because clearly i tried many types of antennas in this is the cap , what you see below in the graphs


This is what happened after i installed the filter, now the setup has longer cable than before (maybe 5-6 meters compared to 2.5)

Image
Image


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 Post subject: Re: Three Easy DIY Antennas for Beginners
PostPosted: Mon May 22, 2017 5:19 am 
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obj - FlightAware user avatar

Joined: Tue Sep 30, 2014 7:14 pm
Posts: 3463
Co-Co radiation patterns tend to be towards the horizon too. It is an inherent thing with antennas​ that to boost gain you trade off one direction for another. It is possible to design antennas with max gain not towards the horizon but most off the shelf designs will point the max gain lobe at 90 degrees


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 Post subject: Re: Three Easy DIY Antennas for Beginners
PostPosted: Mon May 22, 2017 1:45 pm 
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abcd567 - FlightAware user avatar

Joined: Sat Feb 15, 2014 3:08 am
Posts: 1980
Location: Toronto CYYZ
toxx wrote:
Weird, i found the following scheme:

Image


This drawing was prepared and posted by me 3 years ago in Flightradar24 and Planefinder forums. At that time I have not started participating in Flightaware Forums. It was intended to show varieties of designs available on the web, each design posted by a different persons.

29 May, 2014: https://forum.flightradar24.com/threads ... #post52586

31 May, 2014: https://forum.planefinder.net/threads/a ... 4#post-795

.


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 Post subject: Re: Three Easy DIY Antennas for Beginners
PostPosted: Mon May 22, 2017 11:26 pm 
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toxx - FlightAware user avatar

Joined: Sun May 07, 2017 12:52 pm
Posts: 10
I was almost 100% sure that it was your drawing ab cd , no copyright violation intended, i found it on some slovakian guy's blog where he wrote extensive details about how to build a CoCo with balun sleeve.


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