No-solder collinear antenna

[DaveNF2G]

In case you skipped the article in QST...

January's QST has an article starting on page 38 about virtual (aircraft) radar using a DVB-TV dongle as a SDR. Even if you're not interested in that particular activity, the article contains excellent instructions for building a coaxial collinear antenna without any soldering being required. The antenna described is designed for 1090 MHz, but it can be scaled for other bands as well.

 

[Project25_MASTR]

Sounds interesting. I just got a rtl dongle running as an I-gate on my server…something else regarding antennas to look into now.

 

[KC8ESL]

Collinear antenna....

Is there any specific formula to figuring out the diameter of the loops between elements of the antenna?

Furthermore, would it take into consideration the gauge of the wire being used?

I've also read that centering the elements to the coil doesn't work and rather feeding them from the side is what helps. True?

________0_____________0_____________0________

Not...

------0----------------0----------------0---------


Sorry for the extremely crude drawings.

 

[DaveNF2G]

The design in question does not include any "loops" or coils, so I don't know how to approach your question.

 

[Project25_MASTR]

I've seen the coax colinear without could but it requires soldering.

Sent from my ME173X using Tapatalk

 

[KC8ESL]

So this is the version of collinear that uses coaxial cable. My apologies, I don't get QST.

Every collinear antenna I've ever seen in practice have had coils(loops) to separate the elements. Those are the formula I have a question over.

 

[nd5y]

For 1/2 wave elements the coils or stubs are usually an electrical 1/2 wave.
For 5/8 wave elements the coils or stubs are usually an electrical 1/4 wave.

 

[KC8ESL]

So what your saying is that it isn't a function of coil diameter plus wire length but rather just the length of the wire in any given coil that fits your design needs?

 

[LtDoc]

Actually, it amounts to just the opposite of that. Size and shape do make a difference in the amount of inductance produced. That 'size/shape' isn't particularly specific, there are several that will fill the bill.
- 'Doc

 

[N0IU]

My apologies, I don't get QST.

Try the Morley Library at 184 Phelps Street. 440-352-3383. Although I am a member of the ARRL, my local library also gets QST.

I can't add anything about the collinear antenna, but I did order a dongle so I could build a virtual radar system. Can't wait!

And not to hijack this thread, but...

Wondering what else I can do with this DVB-T device?

 

[KC8ESL]

Never thought of checking the library so thanks for that tip! Personally in the professional world I use the dongle to check the audio quality of wireless microphones and use it as a 2.4MHz wide SpecAn. Can definitely be a useful tool and not a toy so long as you don't need perfectly calibrated results.

 

[Project25_MASTR]

Try the Morley Library at 184 Phelps Street. 440-352-3383. Although I am a member of the ARRL, my local library also gets QST.



I can't add anything about the collinear antenna, but I did order a dongle so I could build a virtual radar system. Can't wait!



And not to hijack this thread, but...



Wondering what else I can do with this DVB-T device?

I also don't get qst nor am I actually an arrl member.

I have one running as a aprs i-gate. You could also use one as a crude spectrum analyzer.


Sent from my iPhone using Tapatalk

 

[KZ9G]

Check out Home-brew Compact 6dBi Collinear Antenna. Theirs is for 2.4ghz but the plans can be easily modified with simple math to build an antenna for any frequency you are looking to cover.

 

[K5MPH]

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Check out Home-brew Compact 6dBi Collinear Antenna. Theirs is for 2.4ghz but the plans can be easily modified with simple math to build an antenna for any frequency you are looking to cover.

I have made this antenna a couple of years ago for 2.4 ghz and it works great has a lot of gain......

 

[eorange]

I built two 8-element collinear antennas for ADS-B reception, using RG-6 cable, with the no-solder approach. The performance is unbelieveable, actually kinda shocking. I can now track 90+ airplanes, plot 20+ of those who transmit their lat/lon, and at times have tracked airplanes close to 175NM east into Pennsylvania.

 

[N0IU]

<<<UPDATE>>>

For all those people who aren't members of the ARRL, the article in question in the January 2014 edition of QST is their feature article and is available as a "sneak peak" which I am (hopefully) assuming is viewable by those who are not members. Anyway, here is the link: http://www.arrl.org/files/file/QST/This Month in QST/January 2014/VirtualRadarJan2013QST.pdf

As far as the antenna, I was in such a rush to get my Virtual Radar system going, I just used the "dongle-tenna" that came with my stick and put it on the window sill. My record (so far) is tracking an aircraft from 210 miles away so now I am wondering if I should even bother making the collinear antenna?

 

[eorange]

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How many planes can you track? I jumped from about 30 with my dongle antenna up to 70-90 with the collinear. That proved it for me.

 

[N0IU]

How many planes can you track?

That's a hard question to answer because I have nothing to compare it to. I have enough RG6 in the house to build the antenna so I suppose I may do that one day when its really cold and there's lots of snow on the ground. Oh wait, that would be today!

But given the fact that I can receive data from aircraft over 200 miles away pretty much tells me that if an aircraft is out there within a 200 mile radius of my house (primarily to the north in my case since my antenna is in a window facing north) and they are transmitting ADS-B data, I can't see where the collinear would pick up any more aircraft than this antenna.

 

[eorange]

What I meant was...what ADS-B decoding software do you use (i.e. RTL1090, ADSB#)? RTL1090 shows how many airplanes it tracks. ASDB# doesn't, but you can still see the airplane count in ASDBScope & VirtualRadar.

You may be seeing planes 200 miles away, but there could be many more, much closeer, that you're just not hearing. That was my case with the dongle antenna. Once I build my collinear, the airplane count skyrocketed.

I built 2 for less than $15 total, and each took me about 30-45 minutes, so you really have nothing to lose, if you're so inclined.

 

[N0IU]

I am using ADSB#, but I guess I could also try RTL1090 and see if there is any difference. I am still pretty new at this and always willing to look at alternative methods.

All I need now is an MCX adapter. Got any extra laying around that you aren't using??? I plan on ordering a Hamitup upconverter and I was planning on order the adapters at the same time.