RC Radios, Transmitters, Receivers, Servos, gyros Discussion all about rc radios, transmitters, receivers, servos, etc.

AM FM

Reply

Old 07-13-2007, 10:19 AM
  #1  
sol451
Member
Thread Starter
 
Join Date: Mar 2003
Location: windsor, ON, CANADA
Posts: 36
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default AM FM

If two people were racing and one had 75 fm channel 68 the other
was using 75 Am channel 68 would there be a problem with
interferance .
Thanks Ken
sol451 is offline  
Reply With Quote
Old 07-13-2007, 10:40 AM
  #2  
piper_chuck
My Feedback: (12)
 
piper_chuck's Avatar
 
Join Date: Jun 2004
Location: Columbia, SC
Posts: 8,039
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: AM FM

Only for the first few seconds. After that, they'd both be watching everyone else race.
piper_chuck is offline  
Reply With Quote
Old 07-13-2007, 10:41 AM
  #3  
fizzwater2
My Feedback: (60)
 
Join Date: Aug 2004
Location: Paola, KS
Posts: 2,765
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: AM FM

Yep.
fizzwater2 is offline  
Reply With Quote
Old 07-13-2007, 11:11 AM
  #4  
pilotpete2
 
pilotpete2's Avatar
 
Join Date: Oct 2002
Location: Lyndonville, VT
Posts: 3,298
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: AM FM


ORIGINAL: piper_chuck

Only for the first few seconds. After that, they'd both be watching everyone else race.
ROFLMAO
Happened to me last year, a fellow flyer had a brain fart and turned his old Futaba Attack AM Tx on to check the battery, luckily I was 3 mistakes high[sm=spinnyeyes.gif].
Pete
pilotpete2 is offline  
Reply With Quote
Old 07-13-2007, 11:41 AM
  #5  
bruce88123
 
Join Date: Nov 2004
Location: Memphis, TN
Posts: 11,703
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: AM FM

And in case you're wondering, PCM would be just as bad.[:@]
bruce88123 is offline  
Reply With Quote
Old 07-13-2007, 11:47 AM
  #6  
pilotpete2
 
pilotpete2's Avatar
 
Join Date: Oct 2002
Location: Lyndonville, VT
Posts: 3,298
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: AM FM


ORIGINAL: bruce88123

And in case you're wondering, PCM would be just as bad.[:@]
Except that with PCM you'd have "crash safe" kick in to save you.
Pete
pilotpete2 is offline  
Reply With Quote
Old 07-13-2007, 12:27 PM
  #7  
bruce88123
 
Join Date: Nov 2004
Location: Memphis, TN
Posts: 11,703
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: AM FM


ORIGINAL: pilotpete2


ORIGINAL: bruce88123

And in case you're wondering, PCM would be just as bad.[:@]
Except that with PCM you'd have "crash safe" kick in to save you.
Pete
What??? No such thing would happen. Still be a garbage bag full of trash. "Failsafe" doesn't prevent crashes or prevent frequency interference. At best it moves controls to a preset condition which the controls will hold until impact or until the cause of the failure is removed. Most often the impact will come first in the category we're discussing.
bruce88123 is offline  
Reply With Quote
Old 07-13-2007, 12:37 PM
  #8  
RCKen
RCU Forum Manager/Admin
My Feedback: (9)
 
RCKen's Avatar
 
Join Date: Jul 2002
Location: Lawton, OK
Posts: 27,099
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: AM FM


ORIGINAL: pilotpete2


ORIGINAL: bruce88123

And in case you're wondering, PCM would be just as bad.[:@]
Except that with PCM you'd have "crash safe" kick in to save you.
Pete
Better take along lots of bags then if you are counting on failsafe to save your plane. Failsafe is not an "auto pilot" that magically saves the plane. What failsafe does it move the controls of the plane to a pre-set position (normally throttle idle back and a bit of up elevator) that holds the plane level until the cause of the failure is gone (if it does go away). This is designed to help avoid minor glitches that occur when flying. But it won't save the plane in the event of total loss of signal, complete interferrence, or somebody else turning their radio on.

Ken
RCKen is offline  
Reply With Quote
Old 07-13-2007, 12:51 PM
  #9  
piper_chuck
My Feedback: (12)
 
piper_chuck's Avatar
 
Join Date: Jun 2004
Location: Columbia, SC
Posts: 8,039
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: AM FM

Looks like a couple have you might have missed the little "75" clue that leads me to believe the OP is talking about racing either cars or boats. If it's cars, the consequences might not be too bad, but I've seen quite a bit of damage done to/by an out of control boat.

We had to restart a heat last weekend when a boat lost control. It started doing circles at full throttle. Fortunately, instead of having to play dodge boat, the CD told the rest of us to come in. The circles got closer and closer to shore, but fortunately, it ended up spinning out just before a loop that would have put it smack in the side of the aluminum retrieve boat. Cause of the problem? Driver forgot to check the battery charge, they were dead!
piper_chuck is offline  
Reply With Quote
Old 07-13-2007, 01:06 PM
  #10  
bruce88123
 
Join Date: Nov 2004
Location: Memphis, TN
Posts: 11,703
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: AM FM

Failsafe doesn't work with dead batteries either.[:@]
bruce88123 is offline  
Reply With Quote
Old 07-13-2007, 01:19 PM
  #11  
piper_chuck
My Feedback: (12)
 
piper_chuck's Avatar
 
Join Date: Jun 2004
Location: Columbia, SC
Posts: 8,039
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: AM FM


ORIGINAL: bruce88123

Failsafe doesn't work with dead batteries either.[:@]
Nope, it doesn't.
piper_chuck is offline  
Reply With Quote
Old 07-13-2007, 03:45 PM
  #12  
pilotpete2
 
pilotpete2's Avatar
 
Join Date: Oct 2002
Location: Lyndonville, VT
Posts: 3,298
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: AM FM

Ken,
That's why I fly good old PPM receivers, if I get a glitch, I'd rather know about it right away. Or maybe I'm just to "frugal" (read cheap) to go with PCMs
Pete
pilotpete2 is offline  
Reply With Quote
Old 07-13-2007, 05:55 PM
  #13  
Robotech
Senior Member
My Feedback: (9)
 
Join Date: Jan 2002
Location: Pine Bluff, AR,
Posts: 1,504
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: AM FM

Actually, no. I used to fly with a buddy all the time that was using 72Mhz AM Ch.54 and I was using 72Mhz. FM Ch.54. Never had even a glitch.
Robotech is offline  
Reply With Quote
Old 07-14-2007, 05:51 AM
  #14  
marcellus
Senior Member
 
Join Date: Apr 2005
Location: Frampton-on-Severn, UNITED KINGDOM
Posts: 190
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: AM FM


ORIGINAL: Robotech

Actually, no. I used to fly with a buddy all the time that was using 72Mhz AM Ch.54 and I was using 72Mhz. FM Ch.54. Never had even a glitch.

Sounds like they were both out of tune in opposite directions! Can't think of any technical reason why you both were not shot down...
marcellus is offline  
Reply With Quote
Old 07-14-2007, 10:41 AM
  #15  
dirtybird
My Feedback: (5)
 
Join Date: Jan 2002
Location: San Tan Valley, AZ
Posts: 5,768
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: AM FM


ORIGINAL: Robotech

Actually, no. I used to fly with a buddy all the time that was using 72Mhz AM Ch.54 and I was using 72Mhz. FM Ch.54. Never had even a glitch.
I suspect one of you had the wrong crystal in your transmitter. At any rate I hope no one else tries that.
dirtybird is offline  
Reply With Quote
Old 07-23-2007, 06:48 AM
  #16  
aeajr
My Feedback: (2)
 
aeajr's Avatar
 
Join Date: Jan 2003
Location: Long Island, NY
Posts: 8,567
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: AM FM

The car market is moving to 2.4 GHz very very fast to eliminate this issue completely. If you have a new purchase in mind, go 2.4 GHz.

But AM and FM channels, whether 72 MHz planes or 75 MHz cars will definately interfere with each other if they are on the same channel
aeajr is offline  
Reply With Quote
Old 07-23-2007, 07:03 AM
  #17  
bruce88123
 
Join Date: Nov 2004
Location: Memphis, TN
Posts: 11,703
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: AM FM

A friend of mine and I found out accidentally one afternoon that his channel 18 PCM and my channel 18 PPM could co-exist quite well. We inadvertently got in the air at the same time and WERE glitch free. I did land ASAP when we realized what had happened so as not to press our luck. Further ground checks after verified we were both on 18 and that neither had any problems. All equipment was Futaba. He and I were standing about 25 feet apart on the flight line.

This is NOT recommended though and we still don't understand why we had no problems.
bruce88123 is offline  
Reply With Quote
Old 07-23-2007, 07:32 AM
  #18  
aeajr
My Feedback: (2)
 
aeajr's Avatar
 
Join Date: Jan 2003
Location: Long Island, NY
Posts: 8,567
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: AM FM

I have heard such reports based on Berg receivers too. Some of these claim to recognize the unique signature of your transmitter's wave form, but I would not depend on either. Smart to land ASAP!

I have been promoting 2.4GHz with all the new flyers so that this problem can be a thing of the past. Get them into the current wave and let those of us on the old technology deal with it until we move forward as well.

aeajr is offline  
Reply With Quote

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