RunRyder RC
 2  Topic Subscribe
WATCH
 1 page 776 views POST REPLY
Scorpion Power Scorpion Power
HelicopterRadio - Spektrum DSM › I need help on the range of my radio
08-04-2013 12:24 AM  4 years agoPost 1
donny_boyette

rrNovice

Robertsdale, Al, Usa

My Posts: All  Forum  Topic

I have a 72mhz fm radio( jr 9303) I flying a scale 600 size md 500, but before the first flight i noticed problems with the range. I had the reciever wire coiled up on the inside and a small amount running to the outside. What would be the best way to run the wire?? Maybe down the tail on the inside of the fuselage( but i think that the mechanics tail is carbon fiber) If I did it this way, i would have to cut about a foot of the reciever wire off( its pretty long) Any ideas????

PM  EMAIL  GALLERY  Attn:RR  Quote
08-04-2013 01:35 AM  4 years agoPost 2
Zaneman007

rrElite Veteran

Texas - USA

My Posts: All  Forum  Topic

The length of the wire is a quarter wave length of the frequency. This is important. Do not cut the wire, unless you want the Rx reception to be crap. Run the wire the length of the heli and straight.

If you do not want to see the antenna, get a 2,4Ghz system.

Old Guys Rule!

PM  EMAIL  GALLERY  Attn:RR  Quote
08-04-2013 02:11 AM  4 years agoPost 3
aerocal

rrApprentice

Central California

My Posts: All  Forum  Topic

Oh yeah.I remember that problem.IIRC quarter wavelength of 72 is 32" or something like that.Dont cut or change the length of the antenna.Bad plan. You dont want to coil it or cross it back over itself.Big range issues very likely.So... what we did was to use a base loaded antenna.
There were several available.Or what I did as I was only kind of flying 450s then was to get a kabob skewer and coil the wire around it leaving like a wire diameter or two between each wrap.IIRC it came out to about 3-4 inches long maybe a little more.
I saw alot of whacko ways to try and route the entire length of the antenna around a heli to keep it from looping or crossing itself.Many times it was marginally successful and pretty impractical.I had all kinds of hella glitching problems at first.I think I used a Deans base loaded on one heli and the okie base loaded wrap around a kabob skewer on a few.Both ways worked fairly well for me and gave alot more range than any other method.A Berg Rx will go a long way to reducing interference glitching too.
Keep your bearings well lubed.

True going to 2.4 will pretty much eliminate this specific issue but if done right you should be able to get a 72 system to work reasonably well.Do a search for base loaded antennas.That should get you in the right direction.Think about a Berg Rx.They really do reject interference better than anything else Ive used.I think I have a box of that stuff laying around but it is all set up for positive shift(F brand) or Id be willing to send something to you.

PM  EMAIL  GALLERY  Attn:RR  Quote
08-04-2013 03:55 AM  4 years agoPost 4
dkshema

rrMaster

Cedar Rapids, IA

My Posts: All  Forum  Topic

The best solution is a Deans whip antenna if you can find one...

http://www.wsdeans.com/products/antenna/index.html

Installation requires some soldering skill.

-----

Otherwise, stretch your antenna out its full length, and DO NOT cut anything off. That 39 inches is important.

-----

This worked in the days I was flying 450's on 72 MHz, and didn't want to mess with the whip or have a dangling antenna.

Most heli kits still seem to include a length of small diameter plastic tubing that the 72 MHz antenna goes through, and which would mount to some molded in bumps on the skid struts.

I took that plastic tube, and neatly wound the antenna on it, using some large diameter nylon fishing line (think leader line for fly fishing) as a spacer between each wrap. Tie it all in place with heat shrink tubing. Mount away from the electronics and do some range checks before you fly.

-----
Dave

* Making the World Better -- One Helicopter at a time! *

Team Heliproz

PM  EMAIL  GALLERY  Attn:RR  Quote
08-05-2013 12:48 AM  4 years agoPost 5
donny_boyette

rrNovice

Robertsdale, Al, Usa

My Posts: All  Forum  Topic

Thanks Guys for your help, but I think the receiver is faulty, I've been flying 72 mhz for 7 years and never had a problem. I've run the wire down the tail, and even though the range is alot better, it's no where close to flying range. I ordered this reciever on ebay used as a replacement to my reciever that had its wire pulled out. It looks fine, but I don't think its working properly. ?????? Does horizon or anyone else do reciever repair.

PM  EMAIL  GALLERY  Attn:RR  Quote
08-05-2013 03:41 AM  4 years agoPost 6
aerocal

rrApprentice

Central California

My Posts: All  Forum  Topic

39" sounds more right IIRC for quarter wavelenght.Thanks Dave.Its been awhile.

donny
Did you measure the total length of the antenna? If it actually intact it should be that length/If you simply ran it down the tailboom it seems like you should have quite a bit left hidden somewhere or have a fairly long tail dangling out the back.
I would honestly take Daves(and my) advise and make a whip by wrapping it around a plastic or wood tube/dowel.it will work better than other arrangements.Theres really no better way to do it for best results.If you purchase a length of 24ga stranded wire you could replace the entire antenna yourself or get someone to do it for you.Its pretty simple.

If your really intent on sending it somewhere for service I would use RadioSouth.Top notch reasonable service.

http://www.radiosouthrc.com

PM  EMAIL  GALLERY  Attn:RR  Quote
WATCH
 1 page 776 views POST REPLY
Scorpion Power Scorpion Power
HelicopterRadio - Spektrum DSM › I need help on the range of my radio
 Print TOPIC  Make Suggestion 

 2  Topic Subscribe

Monday, October 23 - 11:00 am - Copyright © 2000-2017 RunRyder   EMAILEnable Cookies

Login Here
 New Subscriptions 
 Buddies Online