Dual Frequency Tx and Rx.
 

A local electronics wizard came up with a neato invention. It was a special receiver and Tx module with two crystals for two frequencies. I do not have a clue to how it worked, but some kind of failsafe or glitch counter was in the circuit and whenever it sensed trouble, the system switched over to the other frequency. I believe the Tx always transmitted on the 2 channels but the receiver only heard one at a time.

Recently, the guy has tossed that thing out of the window because now he is modifying brand receivers and Tx modules themselves to carry out that function. We will test this thing shortly in a little white trainer, but this guy is a real professional and his stuff really works well. Unfortunately, he is truly the mad scientist type when it comes to marketing and never really understands the commercial value of his inventions.

Has anyone else ever seen something like this in hobby R/C usage? This sounds like a really nice idea to protect those big money airplanes. Aside from hogging two pins, I can't think of anything negative about the system.

Mark

Dual Frequency Tx and Rx.
 

Sounds similar to a couple wireless training system I have seen on some German web-sites:
http://www.jamara.de/testberichte/wi...wireless-1.jpg
http://www.acteurope.de/html/t3s-system.html

I saw an english website with a similar product (wireless trainer) once, but I don't have a link to it. I can think of a few pilots who would be interested in adding that type of system to their already highly redundant systems.

Dual Frequency Tx and Rx.
 

While I may have the names wrong, I remember reading about a Spread Spectrum transmitter that would transmit on all 50 channels in a roaming fashion. With this said, you never really flew on one single channel so it made frequency boards obsolete.

Dual Frequency Tx and Rx.
 

All 50 channels at once!!! How can anyone else ever fly then???

Dual Frequency Tx and Rx.
 

Hi All,

What hasn't been mentioned is that this is in violation of FCC regs, therefore if you are flying with this gadget you are in violation of the AMA safety code, which invalidates your insurance coverage.

To make this legal he has to submit a prototype for FCC type acceptance.

Spred spectrum does not broadcast simultaneously on all channels, it uses a frequency hopping technique where it is broadcasting on only one frequency at a time, but rapidly hops from one frequency to another. This rapid hopping avoids interference with other users on the same cahnnel. This technology is being used in many military applications to avoid interception, it is also being used in cordless phones.

Look here for an explanation.

http://electronics.howstuffworks.com/question326.htm

Jerry

Dual Frequency Tx and Rx.
 

I didn't mention the FCC or AMA because they don't apply to Belgium fliers, where this device is being developed.

However, if the inventor would make a 72Mhz / 75Mhz version for North America it would need FCC certification as you said Jerry.

Dual Frequency Tx and Rx.
 

It was a different article that I read but it is the same basic concept. The article I read said they tried this using RC planes and it worked great. The problem is that anyone without a spread spectrum system will not be able to fly since the will get hit a lot!

Dual Frequency Tx and Rx.
 

What you are proposing has been done before. This French designer has posted the details for quite awhile (last update was 1996):

Supertef R/C System Overview
The PPM Rx
The Tx

This design uses frequency synthesis, so only one Tx Xtal is needed.

Dual Frequency Tx and Rx.
 

There was a company in France that came out with a TX using two RF deck and two antennas, you would install two receivers with different frequencies. They stopped making them for some reason.

I will be flight testing my Dual Receiver recuncency system shortly.
On the bench it has worked flawlessly. Now there is no need to loose half the airplane should you lose a receiver.