Saorview aerial from coat hanger (zero cost)

Sam Russell

Here is my design for an aerial made from a coat hanger plus normal TV connector stuff, some screws, and a bit of scrap wood.

The coat hanger should be silver type (galvanized) so you can solder to it and make electrical connection easily.

So, unbend the coat hanger so you have a straight piece of wire. (At least as straight as you can). You will need 19 cm of straight wire. I was able to make two aerials from one coat hanger.

Bend the wire into the shape in the instructions below. Now this works for Three Rock mux1 and mux2.

Now take the piece of scrap timber and attach the wire so the timber supports the connection part. See photo below.

Now I used a piece of Canadian Cherry, but any wood will do, but should be dry. Notice the screws are tightened to provide a solid support, with washers to provide a good connection. I soldered the wire to the coat hanger which should not be necessary, but it is a better solution. I had problems with the one I have been using for a decade and soldering resolved the issue.

The coax wire from an old TV connector cable is held in place by two further screws to prevent it breaking away. Now, it would be better to use satellite cable and F-type connectors, but this was done using bits in my 'old connectors' box.

This is the result for RTE1 and RTE2.

Now both muxes are received at 100% quality, and plenty of signal.

No special effort was made to maximise the signal. The aerial was just put out of sight. It is horizontal polarisation so the aerial is just laid falt, and pointed just about anywhere, but a bit of checking might be worth it. It can be affected by people waking around, but a decent signal should not be affected. If this happens, try and find a better location. An old TV might have a poor receiver with rubbish performance.

I am using three of these because one in in my bedroom with no cable connecting to the log periodic outside aerial and has been in use for about a decade.

The other two are being used temporally (but may remain) as I was losing RTE 1 (Mux2) with Signal quality down below 50% and down to zero on occasions. RTE2 did not suffer as much. I suspect the corrosion of the connectors at the aerial site is the culprit, but not certain yet.

If you wish to make this for another mast, adjust the length in proportion to the frequency - higher frequency means a shorter length of the 19 cm. the 3 cm should remain as is. Not sure how important that is, but it might help.

Request Can I ask anyone who makes this up, to post results. I would like to receive feed back as to how it performs.

I am in a high signal area near RTE, but the aerial results shown are on the far side away from Three Rock. I was surprised at how well it performed - it was better than the log-periodic I have installed pointing at Three Rock with higher signal strength and the same 100% quality.

Sam Russell

The aerial is basically a folded dipole, but it should have a balun, but it works without it.

More gain would be achieved by having reflectors and directors, as the Yagi design uses, but then it would not be basic and cheap.

Try it.

winston_1

https://www.boards.ie/discussion/comment/121156795#Comment_121156795

Indeed. And a folded dipole has an impedance of 300Ω not 75Ω so a 4 to 1 matching balun required. A straight dipole may be better, 2 straight rods 9.5 cm long.

Sam Russell

https://www.boards.ie/discussion/comment/121156929#Comment_121156929

What you say is correct, but the design works, well my one does. Aerials are a black art - and a balun would be tricky to build for no cost at 540 MHz.

Build one and try it.

Sam Russell

Did Garret FitzGerald say 'I know it works in practice, but does it work in theory?'

It does not cost anything to build one and see if it works for you. If you do, post the result here. The theory belongs in the classroom.

Sam Russell

Has no-one tried to make one of these?

Sam Russell

Bump

Sam Russell

bump

icdg

Sam, I think three consecutive bumps is quite enough, you’re talking to yourself at this stage. Thread closed.