Deadeye

So, I ordered two of these RX's (for electrics) not realizing they had full range antennae lengths. They came with a small strip of plastic, referred to as a 'bobbin'; claiming you can wrap up to 18" of RX ant, being careful to wrap in one direction, and don't overlap, etc. So I tried it on my Polaris tonight, and couldn't get more than 40 feet away with one antennae section extended on my TX in range check (72 mhz) without massive servo glitch.

So what is the deal? I had always been taught to never wrap or coil an RX ant. Why would the radio mfg suggest this? And what the hell am I gonna do with 18" of extra ant. sticking out the back?

freeair

if your using this radio in a car or boat all is fine with the bobbin wrap but with air models you MUST use the total antenna wire length .

Deadeye

But these are 72 mhz RX.

A.T.

The "Bobbin" is included so as user can reduce antenna length on helicopters, Indoor flyers, Park Flyers, slope soarers and other models which are not intended to fly at full range.
Instruction card to which bobbin is afixed on receipt:
"Included as an accessory for your new receiver is an antenna bobbin. This device was designed to allow the user the option of winding upto 18 inches of receiver antenna on it, this will shorten the antenna length that sticks out of the model.
NOTE: It is not mandatory that the bobbin be used. To use the bobbin correctly:
1.Start winding the antenna wire onto the bobbin approximately 3-4 inches from the receiver.
2. Do not cross the wire on the bobbin. It should be wound smoothly in a spiral onto the bobbin."

Much more information, with performace specifcs, is available at
Alan's Hobby, Model & RC FAQ Web Links
under "Radio Systems, Accessories, Alterations and FAQ" sub sections "Rubber Duckie, Micro & Whip Antenna - replace long aerials with loaded base antenna" and "Receiver - FAQ, guides and aids to best reception.."

The use of the bobbin or base loaded RX antenna is not recommended in models which can easily use the antenna at full length. In applications with two receivers, make sure the antenna are not parallel to each other see also the sub section "Giant Scale, Large RC models, Twins & Multi Engines" on my web page and discussions regarding the use of dual RX.

Regards
Alan T.

Deadeye

Alan,
I read that too. The Polaris is a park flyer that rarely gets beyond 200 yards away. My question still hasn't been answered. I used the other RX in an Adrenaline, which didn't need the bobbin. No problems on that one.

A.T.

Sorry, I do not know what a Polaris is but the general rules are all the same. Use of a bobbin should not effect range within 200M. If short range or glitchs are experienced, cause is usually with RX being mounted to close to a motor, ESC, switch, battery connection or wires or wrong brand of crystal. Rarely is the problem within actual receiver.
Electronic Speed Control - Why BEC and LVC cause most EP RX problems
Guide to receivers - and solving apparent RX & "Interference" problems
Transmitter On First - Off Last
See also sub Sections
"Range check and Range problem solving
"Glitches & Jitter in Receiver, Servo & ESC - causes and cures "
"Radio Systems, Accessories, Alterations and FAQ." at:
Alan's Hobby, Model & RC FAQ Web Links
Regards
Alan T

Dsegal

Get yourself a short Azarr antenna from http://www.ecubedrc.com/shop/

freeair

to answer your question. if your flying the model in close range of say 200 feet, use the bobin to shorten the antenna length if you feel this is the only way to do so. otherwise use the full length antenna and feel safer. in Australia we use 36 meg compared to your 72 meg radios and when a bobbin wind is added to the antenna , range is reduced alot. maybe you should do a couple of range checks with the bobbin wrap and without and then you will see what i mean.