Go Back  RCU Forums > RC Airplanes > Questions and Answers
Reload this Page >

Is Aerial lenght relative to frequency for 72Mh Radios

Notices
Questions and Answers If you have general RC questions or answers discuss it here.

Is Aerial lenght relative to frequency for 72Mh Radios

Old 09-20-2010, 05:24 PM
  #1  
LJR
Thread Starter
My Feedback: (8)
 
Join Date: Mar 2003
Location: Roselle, NJ
Posts: 47
Likes: 0
Received 0 Likes on 0 Posts
Default Is Aerial lenght relative to frequency for 72Mh Radios

I fly 72 mh channel 52. I recently bought a used Hitec receiver. I noticed the strain relief was not the original and upon further inspection , I see the aerial wire has been repaired /resoldered. Being curious I measured the aerial wire at 38.5 inches from the edge of the plastic housing to its end. I also have other Futaba and Hitec receivers and they all measure 38 inches exactly.
I know aerial lenght has an effect on frequency. Is there some tolerance for the 72 Mh frequency.

The reciever range checks fine but I do get a flutter on my throttle with the motor running. I changed to another receiver and the fluttter is gone( receiver #2). I have resoldered the aerial wire in the receiver #1 but have not cut the wire to the 38" lenght which seems to be the standard .

Could the extra 1/2 " have caused the flutter and should I cut it to exactly 38".
Old 09-20-2010, 06:01 PM
  #2  
RCKen
RCU Forum Manager/Admin
My Feedback: (9)
 
RCKen's Avatar
 
Join Date: Jul 2002
Location: Lawton, OK
Posts: 27,243
Likes: 0
Received 13 Likes on 11 Posts
Default RE: Is Aerial lenght relative to frequency for 72Mh Radios



The antenna on a 72 Mhz receiver should be approximately 39".  I would doubt that an inch is going to make a huge difference. If the antenna looks repaired it's possible that the antenna was pulled on severly causing damage to the circuit board in the receiver, or the receiver was in a crash causing damage. If you can't track down the cause of your problem don't use the receiver until it has been professionally serviced. I would send it in and have it checked.

Ken

Old 09-21-2010, 08:58 AM
  #3  
Rodney
Senior Member
 
Join Date: Dec 2001
Location: FL
Posts: 7,769
Likes: 0
Received 1 Like on 1 Post
Default RE: Is Aerial lenght relative to frequency for 72Mh Radios

Any length from 39 to 41 inches will work fine. I do not think you will be able to measure any difference in performance even if you shade that by an inch or two. Check out RCCam's web site for some interesting experiments on antenna lengths for receivers.
Old 09-21-2010, 01:35 PM
  #4  
Lifer
My Feedback: (1)
 
Lifer's Avatar
 
Join Date: Aug 2008
Location: Kansas City, MO
Posts: 4,331
Likes: 0
Received 8 Likes on 8 Posts
Default RE: Is Aerial lenght relative to frequency for 72Mh Radios

To be specific, the antenna needs to be one meter long. Variations of an inch or so won't affect your tuning. Always do a collapsed-antenna range check. Your range with an extended antenna will be approximately 30 times as much. Look for 100 feet of range with the collapsed antenna.

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.