Surprising info – The Spektrum 2.4 ghz system apparently can be used with any old Futaba U series radio. $160 from Hozizon Hobbies for the module and rcvr.
All around good guy and well known reliable expert Steve Anddre on Windpower Discussion Group says that he uses the Spektrum 2.4 ghz system with his 8U radio.
His words:
I like my set. Only two precautions: make sure the receiver antenna sticks out at least one inch from the end of any plastic antenna tube; don't run out of batteries. The system goes into fail safe as soon as the battery voltage drops below 4 volts. No warning from the servos that I use! They seem to work normally and then, Boom! I now use 2700mAH to power the receiver and the winch.
I use the Spektrum on my......8 channel Futaba 8U. It works great, I don't need more than 3 channels so the Spektrum receiver works fine.
I was told that the Spektrum would turn off in a radio that had more than 3 channels. Has not happened yet. I wonder if this was a story to set the airplane guys "off the scent". There is not a receiver greater than 3 channels anyways, but I have heard that some of the crew at Spektrum are working on an air compatible system.
The Spektrum module fits into the 8U and 8U super like it was an original module. The old TP75FM and the newer TJ modules that fit in the 3PK are the ones that work in the 8U, and since the Spektrum was designed for the 3PK....
The only thing I need to do is turn on the transmitter first and then plug in the Spektrum module. There are 5 pins and sockets between the module and transmitter. Evidently one of them is redundant on the Spektrum module compared to the Futaba module, Instead of disabling the pin and and affecting the transmitter's use with my 27MHz and 75MHz modules, I just plug in the Spektrum after turning on the transmitter.
The body of the transmitter does have the circuitry that controls the pulse widths, but the carrier frequency of the signal is always is generated by the module regardless of the frequency band or modulation type of the RF circuit. The pulse width is not affected by the carrier frequency (channel) on a "healthy" transmitter. If a non-DSM RF module, crystals or synthesized, is not tuned properly, the pulse could be carried on another frequency and picked up by another receiver. On Spektrum modules, the frequency is "verified" and selected automatically preventing any Spektrum from taking control of a frequency that is already in use.
http://www.horizonhobby.com/Shop/ByCate ... ID=SPM1004
I hope Steve does not mind me reprinting his words and misspelling his last name.
Scott