I recently upgraded my nav plotter to a 24 inch LED TV [12v] from a 22 inch LCD monitor, mainly for the power-saving and a brighter picture. There does not seem to be any reasonably priced 12v large-screen monitors. Seeing I had a TV I might as well be able to watch it so I started looking at antennas. On my fishing vessel, I had a power stabilized TV antenna that cost a fortune but after a brief search, I stumbled onto fractal antennas. Fractal antennas are a recent invention and are what our mobile phones use.



There are plenty of articles online with plans and Youtube videos. I chose this design for its simplicity and ease of construction and made a rough one out of aluminium rod, copper wire, plywood and masking tape and tried it at home. They are supposed to be hung vertically inside a window for best performance but I was staggered how good it was! I'm about 30 miles from the towers. I rotated it, tried it horizontal and it worked great.




The measurements are in inches. I just banged nails into a bit of wood and bent the wire around. The second one I made using SS rod from an old Morse cable and mounted it on a piece of Laminex. This one is for the boat. They can be made from any wire or even aluminium foil just cut out with scissors. Cost is probably under $10 for the balun and cable and fittings if you don't have them laying about already. I rebuilt my first one, made it a bit more attractive for use at home.
Yesterday I was sailing offshore about 8 miles and still 30 miles or so from the transmitters and tested the antenna. I had it on a piece of cord and moved around the saloon, rotating it and even holding it horizontal but it was faultless everywhere. I just hung it temporarily at an angle out of the way in the end.
I will build another one without a balun for my FM radio and see how that goes. They seem to be very tolerant of frequencies.

Thanks Ramona, I'd heard of these but never got around to looking at it, sounds like they work a treat!
I found it difficult too to find any decent options for 12v displays, I ended up getting onto a mob out of Taiwan that have a pretty impressive range. They do variants for raw and enclosed panels, sunlight readable, IP68 etc etc, so the range is a bit daunting at first glance.

I import these, so if anyone does want a display panel let me know what options you want and I'll send you a price, it is not that difficult to get one-offs sent over on the back of a stock order, depending upon where they are at in production. This is not meant to be a sales push, there is no money in one off displays.
They make the panels from scratch, so adding or changing specific ports like a TV tuner or a RS232 port is a no-brainer, I think from memory a TV tuner adds $10 US dollars to the display.
www.litemax.com/

SB

Cabron said..
Do you think you need a reflector on the back board? Or good signal without? Seen some with aluminum foil isolated, but behind antenna?

I don't think so. I have my fourth one under construction at the moment. They work perfectly with the back or front towards the towers and all angles in fact. I was surprised they work so well inside a fibreglass yacht. I built that one in the photo above in SS because I thought it might have to go on the uppers somewhere.

Harb said..
Good wire to use is the 3.2mm TIG & gas filler wires

Could you expand a little (one/two sentences) about why these welding alloys would be better?
I would have thought pure copper or aluminium wire/rod would have best conductance, but I'm no expert on antennas.