Hi all, some weeks ago, our dear forum member and friend Marcin (MDA), sent to me a compilation of info tu build a collinear antenna based on the CoCo design ( https://www.balarad.net ) but with some changes. With Marcin's help I built the antenna (with minor changes), and as I talked with Marcin I will post soon a detailed tutorial. Marcin named the antenna as "COCO+" We needed to compare the COCO+ performance with the famous FA antenna in the same conditions, so as I have installed a FA 66cm antenna with a FA Pro Stick Plus and a RP3, I taked a new RP3 and FA Pro Stick Plus to connect the COCO+ antenna, and of course, place it all together in my house roof. (the white box is where th RP3's are located) COCO+ antenna pictures: And now some results COCO+ vs FA Antenna: 24% more ADS-B positions. 14% more MLAT positions. 6% more "other" positions. 9% more Total positions. 1,78% more ADS-B aircraft. 0,41% more MLAT aircraft. 10,71% less "other" aircraft. 1,58% more Total aircraft. Coverage: Green-COCO+ Light Blue-FA Antenna Dark Blue- Shared coverage And it is all by now. I will post the tutorial soon if you are interested. If I did it you can do it too! Cheers
Hi Marcos forgot to inform you that before I made my first CoCo+ I've thrown away at least 2 CoCo's (basic) . 2 of 4 CoCo's, and one CoCo+ are collecting precious flight data. This antenna is not very complicated but results depends on quality/accuracy of maker. Try it, results can be very good or very bad, everything depends on you. BR Marcin
Hi All, In August 2014 I made my tuned 1090 Mc discone with a PL259 chassis part and phosphorus bronze wires. In preparation I placed the parts with staples on a cardboard and soldered it to each other. then bent the legs in the right position placed it against the chimney near a ara communication antenna. The height is about 10 meters above sea level. Greetings from the Netherlands, Joop.
So what are the magic modifications for the COCO+? I built a balarad collinear a few weeks ago which does perform very well, but now I'm curious what improvements can be made. I'm a ham radio guy so if you give some general information I'd probably understand.
Magic things are: balun in bottom side and shorted elements on top (1/4 wave in coax + 1/4 wave in air). Believe me, it works .
Hmm interesting. So it's effectively a 1/2 wave at the top? I wonder what the balun does. Both the antenna and the feed are unbalanced already.
Mine is an 8 element with the 1/4 wave at the top, no shorting. Adding the balun looks interesting and the 1.5pF capacitor should be easy to try (though I'm not sure what that does - maybe low pass filter?) My range is actually pretty good around 200 - 250 nm. But I feel a pang of jealousy toward a couple fellows near me that are just crushing it. My antenna is about 20' AGL in my attic. I'm hoping to remedy that soon too by putting a mast on the roof.
As HAM radio guy you probably noticed that very often theory is far far away from practice. Wish you success with placing your antenna over the roof. Marcin
Look at my stations: http://mda0803.duckdns.org:12100/VirtualRadar/desktop.html Some of them are really good .
I am puzzled by the number of people buying expensive LMR-400 coax and running it 50 ft or more to their SDR and RPi. Even good quality LMR-400 loses >4db per 100ft. Why give up half of your signal to coax. Why not use USB extension cables (passive or active) to get the same distance and put the SDR dongle directly connected to the bottom of the antenna with zero coax and only an N to SMA adapter? Obviously if outdoors you need to put the SDR in a small enclosure. (SuperG3 has it setup well) I prefer to have the RPi within reasonable reach if I need to mess with it.
The FlightAware Prostick plus has built in amp and filter. A run of good quality 25' - 50' of cable not a big deal (I've compared them both and with a Pi right next to antenna over a week and range plots were near identical) - plus it simplifies the mess of weather proof boxes, environment related failures do to solar heating, water, etc. https://www.amazon.com/gp/product/B00QZEQ5EA/ I get 350 miles with a FA antenna on a roof peak connect to 25' of coax cable. I can walk into my garage and pull the sd card and it kept temperature controlled and out of the rain. I'm willing to risk a few miles of potential reception. Also a few feet long run of USB cable will drop enough voltage and current that the Pi will become unstable - they are very power supply sensitive. Just my experience. Keep the feeder maintenance as easy as possible. Mostly because we're not dealing with military grade quality - we're dealing with cheapest bid China. I have a guy scaling a roof every time there is an issue with his Pi, which there are plenty for some reason. It's on the roof in a Tupperware container in northern country - temperature fluctuations are all over the place. It has power issues. Run a 25' foot cable and who cares if you lose 2dB. That's what amps and filterers are for.
Thank you for the feedback. I am going to upgrade my first feeder (KEDC) in the next few days to an external FA antenna with a very short (<3ft) run into the attic (going to have to watch temps carefully). If it overheats in I will extend the cable on into the garage. I might still do the full external solution at a friend's house. He has an old rotating beacon as a radio tower at his house so I thought I would put all of it in a box like SuperG3 did to keep it simple.
I just ordered one of these to try permanent 'near the source'. https://www.amazon.com/gp/product/B005UPAN0W/ Tips on how to make these remote install reliably work are appreciated! Maybe I can put up two and we can compare live! FOR SCIENCE!
LMR-400 is quiet expensive, Tri-Lan 240 or H-155 is better option (10m price is comparable to 10m USB active cable). Loss in cable does not have big impact if length is below 20m (60 ft). Stick installed directly under antenna needs enclosure and is exposed to high or low temperatures (depending on area you live). In Poland temperatures are between -25 Cesius in winter and +35 in summer. So IMO coax is better.
