Futaba AM Receiver
#1
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Futaba AM Receiver
I bid on and won a Futaba 7 channel 'AM" channel 18 receiver on e-bay. Not knowing it was AM when I bid on it, thought it was a FM receiver. Knowing that AM is waaaaaay outdated, what is it good for ? Will my 7 channel Futaba 7CAP work with a AM receiver ?
I'm only out $9.99 plus shipping, so no big loss if cannot use it.....
I'm only out $9.99 plus shipping, so no big loss if cannot use it.....
#5
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RE: Futaba AM Receiver
ORIGINAL: mustangman177
Does anyone even sell a AM transmitter anymore ?
Does anyone even sell a AM transmitter anymore ?
72 mhz, 3 channel, single stick http://www3.omnimodels.com/cgi-bin/w...I=FUTJ51**&P=0
#12
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RE: Futaba AM Receiver
You have 2 choices, either buy an AM radio transmitter to work with the receiver or put the receiver back on e-Bay.
There are advantages and disadvantages to both AM and FM. AM signals will travel farther but are subject to radio frequency interference (RFI). FM tends to be line of sight (good for aircraft, not so good on the ground) but is less prone to RFI. It can be "masked" by buildings and terrain. I'm sure you've experienced "dead spots" on your FM car radio on occasion. I use 27 MHz AM for my ground systems radios. It's a lot better since the CB craze is over. I have 75 MHz FM for ground stuff but haven't yet used it. I have both 72 MHz FM and 2.4 GHz (haven't flown it yet) for my aircraft. As more and more people switch from 72 MHz to 2.4 GHz there will be less a chance of interference, just like on the 27 MHz band.
Oldflyer
There are advantages and disadvantages to both AM and FM. AM signals will travel farther but are subject to radio frequency interference (RFI). FM tends to be line of sight (good for aircraft, not so good on the ground) but is less prone to RFI. It can be "masked" by buildings and terrain. I'm sure you've experienced "dead spots" on your FM car radio on occasion. I use 27 MHz AM for my ground systems radios. It's a lot better since the CB craze is over. I have 75 MHz FM for ground stuff but haven't yet used it. I have both 72 MHz FM and 2.4 GHz (haven't flown it yet) for my aircraft. As more and more people switch from 72 MHz to 2.4 GHz there will be less a chance of interference, just like on the 27 MHz band.
Oldflyer
#13
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RE: Futaba AM Receiver
the primary difference between AM and FM in the car radio is frequency. Being a higher frequency, the FM broadcast band is more line of sight. That, and path losses are higher as you go up in frequency, so there is a LOT more signal loss at the FM broadcast band than there is at the AM broadcast band (roughly a 100X frequency difference between them, 40 dB difference in path loss)
AM really doesn't "travel" any further than FM on the same frequency at the same power level. The big advantage of FM in the models is better noise immunity - with the ASK (amplitude shift keying) used in AM radios, there is a "hole" in the transmitted signal between each control pulse, and the receiver is wide open to noise during that hole. FM is "on" continuously, helps add some noise immunity to the receiver. FM is also somewhat less susceptible to multipath problems - the "flutter" you hear in an AM car radio as you move is multipath interference.
AM really doesn't "travel" any further than FM on the same frequency at the same power level. The big advantage of FM in the models is better noise immunity - with the ASK (amplitude shift keying) used in AM radios, there is a "hole" in the transmitted signal between each control pulse, and the receiver is wide open to noise during that hole. FM is "on" continuously, helps add some noise immunity to the receiver. FM is also somewhat less susceptible to multipath problems - the "flutter" you hear in an AM car radio as you move is multipath interference.
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RE: Futaba AM Receiver
The only seven channel Futaba AM receiver that is narrow band is R117H and it can still be used with a narrow band AM transmitter at most AMA club fields. Any other product code on your seven channel receiver would be wide band and not acceptable at AMA fields. Also, AM receivers will work with AM transmitters of mixed brands.
#21
Senior Member
RE: Futaba AM Receiver
As long as the AM transmitter has been verified to be "narrow band" it will have as good a range as any equivalent FM transmitter with the same output power. Now, both AM and FM transmitters on the 72/75 MHz bands have the same maximum power input to the final as authorized by the FCC in the USA, which, if I remember correctly it less than 1 watt into the final amplifier in the transmitter. The AM will be less tolerant of man made noise than the FM but will have equal range. Of course range is more a function of the receiver than of the transmitter so I am assuming that you are using a receiver with a good design.
#22
Senior Member
RE: Futaba AM Receiver
ORIGINAL: BarracudaHockey A few people on an island way out the Pacific still use them, or so thats the urban ledgend.
(including Raratonga last time I was there)
If not broken, why spend extra $ for unnecessary "upgrade"
Alan T.