Those of you with more experience with Spektrum systems, can you please take a look at this receiver installation and let me know if it seems OK?

You have the main horizontal, and the satlite one should be vertical. Also what I would do is rotate the main reciver 90deg to the centre so the antena is at right angle to the throtal cable, shown by green line.

Cheers

It's a clean secure installation which is excellent but the antennas on the satellite receiver are parallel to the ones on the main receiver as you have it. They need to be perpendicular. Just rotate one of them 90 degrees and it will be perfect.

You guys both told me exactly what I thought, as this is exactly what the instruction recommend. However, in the same instructions, there an installation picture showing the exact same set-up as mine (antenna parallel to one another.)

To be safe, I'll turn one of the them around 90*. Would it matter which one? It would be easier to turn the satellite receiver.

No it would not matter but it is easer to rotate the satlite.

Cheers

Remove the Hextronic voltage monitor from the top of the fuselage and mount the satellite receiver there, with the antenna elements 90° to the main receiver. Push the satellite receiver as far forward, as far away from the main reciever, as possible.

Ken

Hey Ken,

Why would this be better than just rotating the satellite 90*?

I couldn't tell from the picture if there was enough room on the side of the fuselage to turn the satellite 90° and still keep both antenna elements straight out. If you can do that then you will be ok doing it this way.

Ken</p>

Yeah it's hard to see, but there is plenty of room. Thanks for the clarification.

Use a Futaba FAAST radio system and you won't have to worry about satelite receivers.

But you will have considerably longer antenna leads to route - six of one solution, a half-dozen of the other...

That's easy to say for Futaba fans.It neglects to remember that the man has about $200.00 already in Spektrum technology that you advocate he dump and spend another $200-$300.00 in Futaba gear, simply because you're a fan. Not too wise in these Economic times, now is it?

As noted above, this simply brings up new issues with antenna routing. 6 and Half a dozen is correct regardingthis suggestion.

Could someone please explain to me why the main receiver and satellite receiver antennas need to be perpendicular to each other. If I am not mistaking they are both omni-directional antennas and will receive the same no matter what their orientation is to each other. Is it just for aesthetics or is there a technical reason for installing the receiver and satellite this way.

Thanks

Brett

Brett,

I won't be able to answer your specific question, but I do know that the receiver instructions do mention mounting the two perpendicular to one another, however, the picture that shows the proper installation is identical to the picture that I had shown above (receiver bodies perpendicular to one another, but antenna parallel to each other), hence my question. I have since turned the satellite 90* just to be sure, but as a matter of interest, I would like someone with more knowledge than I in this field to answer your question.

All - I would appreciate it if we would refrain from turning this to a brand discussion. There are no shortages of threads for that, and if you feel the need to be vocal about your brand preference I ask that you do so in one of those. I would encourage us to keep this discussion specific to the question at hand.

The reason they are mounted perpendicular is to provide diversity in the way your radio sees the incoming radio signal. Because 2.4 Ghz radios have a very short wavelength they are more prone to being shielded or blocked than older radio technology. Items such as the engine, muffler, fuel tank, carbon fiber, or other similar things can temporarily block out the signal to the receivers. If both are oriented in the same direction then when they are shielded is possible that both will not receive signal. By turning them perpendicular to each other you have a better chance of one still receiving signal when the other one is shielded. This is the same reason that the antenna elements in a FHSS radios (Futaba, Airtronics, Hitec, etc....) are placed at 90° to each other as well. It's done to provide your radio with better chances of keeping signal while flying.

Ken

Well said.

Thank You Ken.

Also, think of the RX antenna as a "net" to catch the signal from the TX. Oriented parallel to each other and running fore 'n aft as you have it, you won't get much of that "net" to catch the signal. Rotate one of the receivers so that the antenna runs vertical and now you'll get at least one receiver with the full span of the antenna exposed to the TX signal if it's headed away or toward you.

Thank you again for the info. I have a pretty good understanding of radio wave propagation. I know that transmissions in the 30 MHz and above propagate via space or direct waves (attenuated by the earth's surface and pass directly through the ionosphere) and have a short (line of sight) transmit distance without repeater stations. Also, the higher the frequency, the more the signal begins to act like light and is more susceptible to man-made and terrestrial objects. Wavelength refers to the distance it takes for a signal to complete one 360 degree cycle (for 2.4 GHz it is roughly 4.92 inches). For me and my work experience it seemed to be unnecessary, due to the proximity of the two antennas, and the fact the it would seem that the would most likely be subjected to the same interference, to place the antennas at 90 degrees to each other. Your explanations are great although I am still a little skeptical on alignment of the antenna... but not so skeptical that I will test it out anytime soon . I will follow your expert advice if I am ever in PPKK's shoes.

Thanks Again,

Brett

I'd call having a "pretty good " understanding of radio waves the understatment of this forum. You sound like you have a better understanding of radio than most people. Ishould probably recieve my new Airtronics 2.4 radio today. It shipped last week. It is my first 2.4 radio so Iwill be looking forward to installing the antenna inside the fuse. And to reading the installation instructions. The perpindicular rule seems to be what everyone says is the prefered method. I cant wait to see it in my bird. Good luck with your install.