[kip51035]

Before you go flying off the handle, Many radios use a loading coil at various positions on the antenna. At the base, center and top. Back in my CB days short antennas with loading coils were just as effective as those giant six foot ones. I hate to see 18" of antenna streaming off the back of an aircraft. I would think that dragging on the ground could easily whip off several inches of antenna, (Not Good). Could I wrap a foot or so around a piece of 3/4" balsa in the aft section and still get the same range?

Kip

[Max]

Originally Posted by kip51035

Before you go flying off the handle, Many radios use a loading coil at various positions on the antenna. At the base, center and top. Back in my CB days short antennas with loading coils were just as effective as those giant six foot ones. I hate to see 18" of antenna streaming off the back of an aircraft. I would think that dragging on the ground could easily whip off several inches of antenna, (Not Good). Could I wrap a foot or so around a piece of 3/4" balsa in the aft section and still get the same range?

Kip

You wont get the EXACT same range but it will work.

MOst heli guys use a base loaded antenna for the same reason- its better than having 36" of antenna trailing out the back of the heli. There is some loss of range but its not that serious unless you are flying a plane or glider that flies really high or far out.

These are commercially available but you can just as easily wrap it around a piece of balsa as you suggested. Just make sure you range check to make sure all is well

[Max]

These are the antenna's I have used:
https://www.quicktechhobby.com/Car_A...s/ws_deans.htm

I have both of these on different heli's and have not had any problems:

[Spitball]

I have had considerable success with an idea that approximates "distributed loading" by winding the 39" antenna around a thicker drinking straw with one turn the first inch, two the next inch, then four the next and so on, doubling the turns until you close-wind it on the last bit; about 6" of winds on a typical 7" straw. Punch holes through the straw to secure each inch of winds. It seems to work pretty well but I would be careful about shortening the antenna too much on these little Park Flier receivers, they don't have much range to spare. Haven't done any carefully controlled tests but my bit of knowledge of antennae in general, likes the idea.
Motto - 'Range Check, range check, then once again!'
Hitec Feather receiver actually give a small card former to wind a bit of the antenna, as does one of the P/Flier ARFs I believe. Wind a single smooth layer without crossing the wires. Even up to half the length, I'd say. It depends on how far you're likely to stray from yourself too!
Sorry to be long-winded.

[Chrisfly]

Okay...

So, why does this thread make me love my 2.4 stuff even more?



Oh dear - I asked for it...

[moo]

this is why ARRL publishes a handbook with several chapters on antenna design.

[Spitball]

Yup, and even another whole book devoted to it!

[kip51035]

So which direction do you position the coil, vertical or horizontal? I have had several portable radios with antennas wrapped around a tube that looked like a oversize straw and some of them were very directional sensitive. Hey "Moo" what was that book you mentioned, what is "ARRL"?

Kip

I failed mind reading 101.

[Spitball]

Hi kip - it doesn't really matter and you don't have too many alternates so try it pointing back inside the fuselage as if it was just the regular length of wire. But always range check, preferably on a cardboard box at first to raise the plane off the ground without anyone holding it - in fact do it this way first, then wind it on the straw and do it again and note the difference - it will likely be noticeable but not drastic. I feel it would not be a good idea to try and mount it outside!
Some of the Futaba micro rxs have an antenna as short as 15", I've noticed.
Yes Chrisfly but to change over from 72Mhz to 2,4Ghz is quite an outlay and (grin) the more people go on 2,4, the less congestion on the frequency board for 72Mhz fliers!
I'm not sure at this time you don't exchange one set of problems for a newer, less understood set of problems either!
Just my opinion though.

[hifly2104]

Yes Chrisfly but to change over from 72Mhz to 2,4Ghz is quite an outlay and (grin) the more people go on 2,4, the less congestion on the frequency board for 72Mhz fliers!
I'm not sure at this time you don't exchange one set of problems for a newer, less understood set of problems either!
Just my opinion though.[/QUOTE]
Hey Spitball yah got my vote on that one.

I have planes and Helis and on my last Heli I ran the antenae inside a piece of plastic down one side of the fuse thru silicone fuel line at the front of the Heli to turn it back (half circle turn) so it can go back in clear plastic again down the other side of the fuse. Works like a charm