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Old Apr 13, 2009, 05:11 PM
more coffee is offline
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Cheif Bottlewasher
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Another Noob Question ..AM/FM ?????


A: i dont know
B: somebody else may be thinking as well

I have a Hitec Ranger III 75Mhz channel 73 (75.650)FM transmitter /reciever

I have a chance to get a Futaba Attack 2DR 75Mhz Channel 73 (75.650)AM transmitter/reciever

Well they work together or do i have to change the crystals? The channels above are whats stamped on the crystal ..or is it a type "O"

I dont think I do given the difference between AM and FM in frequency modulation ...but thought I'd ask ..
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Old Apr 13, 2009, 05:49 PM
Ghost 2501 is offline
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no wings any more, just dust!
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M'C

AM or FM...?

well in short, AM is cheaper, generally two channels and slightly more suceptible to interferrence from motor sparking and things like power lines, (ever had the radio tuned in on AM and gone under a power line that spans the road?)

FM gives you the ability to get more channels on your reciever and is generally quieter than the AM stuff regarding interferrence.

AM crystals and FM crystals are not intermixable either, however you will still get interferrence from someone else who is on the same frequency regardless of what you are on, AM or FM as 75.650 is 75.650 regardless of how its sent up the antenna.

I have ran My neptun on AM and later on FM, and to be honest, apart from interference risk, which in many cases is OVER RATED, running on just 2 channels, there isn't much of a difference operationally, you will still get a good 300 feet from each type of radio, just be careful where you run the antenna.
Old Apr 13, 2009, 06:46 PM
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More Coffee,

Even though they are on the same frequency they will not work together if that is what you are wondering. They don't speak the same language, so if you put one in one boat and the other in a different boat you would still need to take both transmitters to the pond with you. You would be better off seeing if you can get another FM set and change crystals the in the new receiver to match your existing transmitter that way you only have to take one transmitter with you. You can run a Hitec receiver with a Futaba transmitter or vise versa as long as they are both on the FM band.

Andre
Old Apr 14, 2009, 06:55 PM
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Cheif Bottlewasher
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Alright heres how it goes ..I bought the Futaba radio ..all there including servo's...
I brought it home and filled the transmitter with batteries....I then switched it on ...after that i switched Bender on ..she has a Hitec HFS-O3MM RX FM reciever and runs the same chanel though FM ..

To my disappointment I have full function control ..though a little glichy ..nothing serious ,,of Bender using my Futaba Attack 2DR TX..

Need new Xtals for Bender ..

Futaba says in the book that i cant cange its Xtal unless i sent it to the factory for calibration .. What the ????.. Anyway

I think that maybe the Attack wasnt AM as was advertised or listed in the box ..think its FM...

I dunno ..In the future I'll stick with Hitec just because i can RE & RE the crystal on the fly ..
Unless i get one of the Ghz jobbies when they get cheap..
Old Apr 15, 2009, 03:08 AM
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no wings any more, just dust!
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the 2DR is AM

as for x-tal changes, that can be done by the home user, (just that it i think, is illegal under us law)
Old Apr 15, 2009, 03:45 AM
Umi_Ryuzuki is offline
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The AM Reciever will need to be tuned. the type of signal it uses is different
than FM. It may be just as economical to buy a new FM reciver to replace any
AM equipment you are using, if you want to use the same transmitter with each boat.

Old Apr 15, 2009, 02:46 PM
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Thanks for the info ..

I think i will just dedicate the AM Transmitter to a boat , leave it till it craps out or i can get a FM unit later .. and get a couple sets of Fm crystals for my Hitec gear ...

The system was new and just laying around , i got it for not much more than a couple pint's ...and tire wear to get it ..


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