Home made helical antenna test

Loaderbull · Aug 8, 2014

Hi all,

Just thought i would share my home made 4 turn helical i made today;

It's very small and i did 1.7km before i came back, but i'll do a full range test when i get chance and the weather is a tad more calm than it was today. No video loss, i'm using the IRC600mw vTX which performs well as you know, it has a spironet antenna. I have to say i'm quite impressed that for a first go it works and works well.

Here are some pics;

Materials used

Materials used

Attaching tube to plate

Finished without heatshrink

Finished with heatshrink

I used a double sided blank PCB for the reflector, cut it down to approx 52mm diameter, removed one side of copper with a sharp knife, then rotary sanded the surface. Then i lathed down a 40mm piece of plastics tube to approx 16mm diameter by 51mm long. Then i drilled a bore hole through to save on any weight once attached to the TX. The coils are approx 13mm apart x 4. I drilled a small 1.5mm hole at the top of the tube to push the end of the last turn into and glue it in place. Makes the finish a little neater this way rather than just having a sharp stop point. That is it, apart from the small matching strip.

Anyone else have any pictures to share? It's always nice to see people's home made items, my next will be a 6 turn.

Cheers,

tferrari · Aug 8, 2014

Looks pretty slick. It's even better that the unit works and gives you pretty good range.

What's the basis for your design? Did you just model it off of other antennas in production?

Loaderbull · Aug 9, 2014

tferrari said:
Looks pretty slick. It's even better that the unit works and gives you pretty good range.

What's the basis for your design? Did you just model it off of other antennas in production?

Hi,

Just using standard formula posted online, using the frequency you require - i went for 5740Mhz which i what i fly but there are a set of numbers you divide by your frequency to get coil spacing, length etc etc.

Obviously by hand it would be very difficult to hit measurements of 12.83mm for example, however if you had a 3D printer you would have a major head start.

You're right, looking good is only half the story, the fact i got 1702m with no problem speaks volumes, i don't know how far it will go but i'd imagine from the picture quality it's got at least another 500-700m left in it. But i shall do a range test and see for sure.

Thanks for your comments.

tferrari · Aug 9, 2014

Would you mind posting a link or two to some of the reference information you used? It might be interesting for some of the other forum members to see.

Thanks a lot.

FASTFJR · Aug 9, 2014

Want to sell any? I'm using a AVL58 transmitter to a Boscam 7 inch

Loaderbull · Aug 9, 2014

tferrari said:
Would you mind posting a link or two to some of the reference information you used? It might be interesting for some of the other forum members to see.

Thanks a lot.

Yes of course, here is the link that first popped up after a search;
http://www.rcgroups.com/forums/showthread.php?t=1377791

To be fair this is a hobby at the moment, yes it turned out good, materials not that expensive, more time consuming than anything. I'm in the UK so it would cost too much to ship to USA where FPVLR already has a good customer base there.

I may make a few for people over here who i know would want to try them out however.

Many thanks,