frakkar

I recently purchased a second Aerohawk after not so successfully repairing the main motor FET, too hot an iron and too large. Not sure if this board can be saved...

The original TX is a Futaba Skysport4, the new one just says Smartech FM 4CH, probably GWS.

I attempted to fly the new bird with the Futaba, stated at 72.95 MHZ, while the crystal in the Smartech says 72.870.

...Just wanted to take off uncontrolled, no control at all. I transferred the batteries from the Futaba to the other TX and I have had great success in hovering thru 5 battery packs so far.

Is 72 MHZ not 72MHZ?

Any thoughts?

Mark

Thrasherg

Hi Mark,

are you mixing the Tx and Rx crystals? Due to the receivers having a single or dual stage IF, the crystals have different frequencies!! If I look at the receiver crystal for channel 58 (single stage IF), it lists it as 72.87MHz, so I think you have mixed transmitter and receiver crystals!! You should have a 72.95Mhz in the Tx and a 72.87MHz in the Rx.

I am not aware of the transmitters having different frequencies, I believe that if you are on channel x, then the crystal required is the same regardless of the make of transmitter!!

For the Tx (Transmitter), 72.95Mhz is channel 58 where as 72.87 is channel 54, normally this should not work with the same receiver unless you change the receiver crystal! What crystal do you have in the receiver and what model receiver is it (single or dual IF stages)?

My gut feeling is that you have just compared the Rx and Tx crystals and it is completely normal that they are different, just make sure you put the correct crystal in the Tx and Rx otherwise nothing will happen!

Gary

VinceHerman

Refer to this handy dandy frequency chart:
Fuaba Frequency Chart
The transmitter and receiver need to be on the same channel.

Thrasherg

The trouble with the chart is that it only gives the Tx crystal frequency, not the Rx frequency.
But Futaba probably have a Rx frequency chart on their WEB site somewhere.

Gary

iml2860

My Feedback: (1)

The RX Crytal has 73.125 printed on it but according to Helihobby.com, the RX is on Channel 44. Is that correct??? I dialed the Spectra Module in my Hitec Eclipse 7 to Ch. 44 and everything works fine!!!! Aren't we supposed to stay within the 72 Mhz range???

Henry

Coasty

As Vince said - the transmitter and receiver need to be on the same channel. In fact they MUST be on the same channel if you want to have any control

You have multiple channels within 72 Mhz band. You have to pick just one - then make sure your transmitter and receiver crystals are the same.

born2net

Hello,

Please note that the numbers will be diff but the freq is the same.
Please look here:

http://www.helihobby.com/html/ch.htm

Regards,

Sean - HeliHobby.com