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AM or FM

Old 11-08-2004, 08:46 PM
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toyboy63
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Default AM or FM

Is there a big difference between an AM and FM radio ? I have three AMs. Is there a difference in range ? There appears to be some good AM radios out there. Does the AM get glinched eaiser ? I am sure some of you have an input about this from exspearence .I know the PCM radios with the built in failsefe are the way to go , but we all do not have the big buck to spend . I put a fail safe in my boat, but when it gets out a ways (within reason ) the throtle starts to act up . It was fine before I did this, or at least I thought it was. Batterys are up.
Old 11-09-2004, 03:51 AM
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Default RE: AM or FM

AM radios are still a viable alternative for those looking for a low dollar radio. The FM is much less susceptible to "strikes" from other RF sources, and there for a better choice. The advantage of a PCM, besides the afore mentioned fail safe, is it's almost impossible to get an RF strike. The PCM is also a more accurate signal than the standard AM or FM. As for the throttle glitching, try this. While on the beach and with the motor off, turn on the radio and have someone start walking away with it while it's on. If and when the throttle starts acting up, have the person with the transmitter come part way back and turn off the transmitter. Remove the fail safe and repeat the procedure. You could have a bad fail safe, a bad servo, a bad receiver, or a weak transmitter. If you have a spare servo or receiver, you could try them as well till you isolate the bad component
Old 11-09-2004, 11:51 PM
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Ron Olson
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Default RE: AM or FM

The prices are really starting to drop on the FM radios so for around $20.00 than more than an AM system it's worth the price. When I ran indoor off-road track at a LHS, the fluorescent lights would interfere with AM radios. The range is really any more or less. The radio are limited to only so many milliwatts. The amount is limited by the FCC so some systems may have less than others to keep them under the maximum.
Yes, it sounds like failsafe problems.
Old 11-10-2004, 05:28 PM
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Captain Ramius
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Default RE: AM or FM

Depends on whose FS you are using those el cheapos sold on eebay are junk,and some are actually to sensitive.
FM is the only way to go,the cost is so close to AM its not worth considering the AM.

Check you connections,if they are loose that could be the cause of the glitching and look at anything else you may done while installing it.You didn't mention if this is a nitro,electric or gas boat.
Old 11-10-2004, 07:17 PM
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CFRACR
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Default RE: AM or FM

IMPO, AM IS OK FOR CARS/TRUCKS BECAUSE YOUR NOT NORMALLY AS FAR OUT AS BOATS. FOR BOATS I WOULD GO WITH THE 75MHz FREQ IF AVAILABLE IN THE RADIO THAT YOU WANT. MOST HAVE A CHOICE BETWEEN 27 & 75. I HAVE FOUND THROUGH EXPERIENCE THAT BEING ON THE HIGHER BAND IS MORE RELIABLE. A BIT CLEANER SIGNAL FROM WHAT I UNDERSTAND.

AS FOR FM , 27 & 75 ALSO AVAILABLE. I WOULD THINK THAT THE SAME APPLIES, BUT I HAVE A FM 27MHz AND HAVE HAD NO PROBLEMS SO FAR.


72MHz IS RESERVED FOR AIR. THEY HAVE AM/FM IN THAT FREQ AS WELL. I USE FM OR PCM TO FLY. AM IS OLD SCHOOL AND TO MUCH INTERFERENCE TODAY TO PUT SOMETHING IN THE AIR WITH CONFIDENCE.
Old 11-10-2004, 09:18 PM
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toyboy63
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Default RE: AM or FM

Failsafe is new from towers, and in a gas boat . Haven`t walked off the distance to see if the light blinks or not . Installed it with a volt watch so I can keep track of the batt. , when I don`t run it for a week or so. You guys all say to use a FS, so that is what I did. In my mind, I like the idea. I run it off the back of my powerboat, and around other boats. I think it is the FS. I have run it a lot farther away then that, with out it. Didn`t know if the FM would cure the problem of distance. I think it was around 30 to 40 bucks, can`t remember. When I flew planes, you could fly them as far as you could see them.
Old 11-11-2004, 12:29 AM
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Mr Cajun Gator
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Default RE: AM or FM

Alone with the restof the post,I would make sure that water is not causing the problem, any dampness in the radio box will cause the receiver, servos and the failsafe to have a water build up inside the plastic cases. Corrotion can also cause your problem. Also look close at your linkage, with the gas engines the linkage at times moves sothat it begins to rub. the linkage rubing on any metal will cause a glitch, and as your running the boat, with the viberation and a weaker signalfrom gaining distance alone with linkage rubbing adds up to a radio glitch.
Old 11-11-2004, 07:04 AM
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LtDoc
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Default RE: AM or FM

toyboy63,
Is there a big difference between an AM and FM radio ?
-Yes, in several areas. Probably the biggest difference, or the one most noticable, is in price. The second big difference is in the number of channels available, AM has fewer than FM, which means that there can be fewer operators running at the same time (FM has more channels).

Is there a difference in range ?
-Not really, but yes, depending on the frequency of use. There's no big difference in range between AM/FM if they're both used on the same band.

Does the AM get glinched eaiser ?
-Yes, unfortunately. By the nature of the signal being 'AM', it's subject to more 'types' of interference than 'FM' is. Most man-made noise/interference is AM in nature.

I put a fail safe in my boat, but when it gets out a ways (within reason ) the throtle starts to act up . It was fine before I did this, or at least I thought it was. Batterys are up.
-It's the 'nature of the beast'. A failsafe works by setting a minimum limit for the received signal. When the minimum signal level is reached, things quit. The receiver may still be able to get a usable signal at a lower limit than what the failsafe is set at, so the usable range can be affected. All transmitters/receivers/antennas are not created equal, but the failsafe people had to put a limit somewhere for the ~typical~ transmitter/reciever/antenna combination. A failsafe can/could/might be 'tweaked' for each individual model since they are not all the same. (Lordy! Don't ask me how, I have no idea and don't even wanna think about it! LOL)
A simple way to check the failsafe is by removing it. If there's a big difference in range then I'd have to say it was the 'fault' of the failsafe. A 'quick'n'dirty' fix for that is to get your receiver's antenna higher/taller. Not 'longer', but higher above the surface of the water. That may or may not be an option depending on your boat...
- 'Doc

PS - There's always more than one way to 'fix' a problem. The trick is finding the one that works best for you.

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