A new way of making stripline antenna's

FlightAware ADS-B Flight Tracking
1

After several failed attempts at making various decent antenna’s for 1090MHz, including wire, coax-collinear etc I think this is a possible way for anyone with a few basic tools to create ‘stripline’ type antenna’s without the need to resort to etching of double sided PCB material.

It involves sawing off a length of 1.6mm FR4 fibreglass sheet, filing/sanding to size, sticking on some self adhesive copper tape and cutting to the required shape(s) with a scalpel or similar sharp blade.

Sounds simple, and more or less, it is, providing you take the time and effort to do it properly and carefully (a slip with a scalpel has potentially nasty consequences!).

I made my first effort of one of F5ANN’s printed circuit antenna’s, here
f5ann.pagesperso-orange.fr/Anten … index.html
drawing and dimensions here
f5ann.pagesperso-orange.fr/Anten … %20MHz.pdf

Materials required:-

Fibreglass sheet, like this
ebay.co.uk/itm/291661682784

Copper tape (don’t laugh, it works great and you can solder it)
ebay.co.uk/itm/330973120766

Scalpel + blades
I use the Swann Morton stainless steel handle and number 10 (rounded tip) and number 11 (straight, angled tip) blades.

Cut fibreglass sheet to size required, sand it to size (good accuracy is essential), clean it up so all dust and greasy fingerprints are removed.
Cut a length of the copper tape and peel off backing and stick it to one side of the prepared fibreglass board ensuring it overlaps all round, trim the edges to edge of the board.
Repeat on 2nd side of the board.
Carefully mark out all the sizes on the copper surface (I used a very sharp pencil).
Even more carefully, cut the marked lines and peel/removed the bits of copper tape not required. I used a steel rule as my guide for the scalpel (with number 10 blade).
Solder on a connector or coax direct to the board/antenna.

I’m quite pleased with the outcome and performance is about the same as a quarter wave ground plane, which is my standard antenna that all others are measured against.
On this little stripline antenna, I’m seeing aircraft out to 180 nautical miles and the antenna is in my attic with no pre-amp (about the same as my 1/4 wave GP).

I have no way of measuring it’s resonant frequency, so can’t say if it can be improved at this moment. I do have the small patch of impedance matching tape as suggested my F5ANN, but again, can’t determine if it’s beneficial or not without a prolonged test with/without it in place.

For use outdoors, I’d suggest a coat of varnish before installing it in a radome or similar.

Next up, a collinear array of initially 4 elements and if that turns out OK maybe an 8 element - check out F5ANN’s site for more useful info.
f5ann.pagesperso-orange.fr/Anten … index.html
f5ann.pagesperso-orange.fr/Anten … ipline.pdf

A picture paints a thousand words…

Nigel.

http://i269.photobucket.com/albums/jj54/Devonian20d/1090-1_zpsp5elzf4q.jpg

http://i269.photobucket.com/albums/jj54/Devonian20d/1090-2_zps5haxlc8x.jpg

http://i269.photobucket.com/albums/jj54/Devonian20d/1090-3_zpspdf5752q.jpg

http://i269.photobucket.com/albums/jj54/Devonian20d/1090-4_zpsremjj1zc.jpg

http://i269.photobucket.com/albums/jj54/Devonian20d/1090-5_zpslcoteekm.jpg

http://i269.photobucket.com/albums/jj54/Devonian20d/1090-6_zps6zp0enuv.jpg

2

Nigel,
Nice work 8) :slight_smile:
Keep us informed.
Trig.

3

Nice work. Is it actively feeding?

Cheers!
LitterBug

4

Nigel,
Great idea to use adhesive copper tape.
The ingenuity at work. Par excellence.
abcd

5

@ Litterbug

Yes, it is feeding at the moment, this is without any pre-amp (and it’s attic mounted so not optimum).
flightaware.com/adsb/stats/user/Devonian

It’s also available live/online here
nthead.co.uk/dump1090/gmap.html

with stats here
nthead.co.uk/collectd/

I swapped in the antenna at around 7pm local time on the 22nd Jan and looking at my stats, there was no significant difference in performance over a 1/4 wave ground plane.
Very early days of course, but it’s quite encouraging as a start.

If I get some time over the weekend, I’ll try a 2 element collinear as I have just enough fibreglass sheet to make one.
I use this sheet in another hobby, and have ordered a new sheet and it should be here in a few days, then I’ll try a 4 element one.

Nigel.

6

OK, I cut up some bits of my remaining fibreglass sheet and got a 6 element stripline ‘collinear’ antenna (7 elements if you count the top 1/4 wave wire element).
It’s 2 times 3 elements, joined in the middle.

This one is actually easier to make as it’s nowhere near as fiddly as the one in my first post.

When I make my next one, I will allow maybe 25mm/1 inch of extra plain fibreglass sheet at the bottom where I solder on my coax ‘pigtail’ and drill a couple of holes either side of the coax and cable/zip tie the coax to the board as a strain relief. Reason is that the copper tape lift’s without some strain relief and I wouldn’t want to use a coax socket as it will not survive.
So, if anyone else is contemplating building by the copper tape method allow some extra fibreglass at the coax feed end to provide for a strain relief and connect the coax by a short pig tail with the connector of your choice at the end of the pig tail.

So, outdoors at 2 metres above ground I was receiving out to nearly 200 nautical miles in my best direction.
Encouraged by this, I swapped out my antenna in the first post above and connected this 6 ele version (in the attic).
Too early to tell how much better it is as it’s wet outside on the roof tiles, but early indications are that it is a little better than a 1/4 wave and the antenna in my first post.
Ironically, I’m not seeing the 200 miles I saw when downstairs in the open.

I’m beginning to think that no matter what I do with my attic test rig, I won’t get much over the 180 miles I see with any decent antenna as no matter what I try, that seems to be my upper limit indoors with a ‘barefoot’ antenna (no pre-amp in use).

I have now fixed a dedicated antenna pole on the gable end of my property (it was dry enough for a couple of hours this Saturday!), but want to make sure I put the best antenna I can out there as my old bones don’t like walking up slippy roof tiles nowadays !!

As in my post above, it’s now online as of about 3pm local time today.

Nigel.

Pic…

http://i269.photobucket.com/albums/jj54/Devonian20d/1090-6ele_zpshwy0bsaq.jpg