HELP!!!! SPECTRUM RECEIVER TROUBLE

[tanky]

Hey dudes and dudessess

Hmm, where do i start...

Here goes in laymans terms....

In the past I have never bothered to range test my spectrum dx7 radio (uses a 7 chaneel AR7000 receiver) for helicopter flying, dont ask me why, perhaps Im lazy.

Anyway, having completed the build on my 76" Edge 540 and doing all the preflight checks etc I found that I could not get a signal from 30 paces away when the plane was poiting at certain angles while holding in the range check/bind button.

NOTE: According to the manual you must have at least 30 paces.

So, the minimum amount of paces I could walk away from the model while range testing was 20 before loosing the signal (the model was at 90 degrees to the radio, or in other words it was facing the side of the fuselage).

The maximum I was able to get was 50 paces with the canopy off and the model tilting towards the radio and there was a clear line of sight from the radio to reciever.

I tried swapping the reciever and satalite reciever and the result was the same. I also had the same result with the receivers out of the plane well away fro the wiring.

A freind of mine that has openly admitted to not bothering to range test tried with his helicopter, the result was the same 20-50 paces depending on orientation.

Another freind of mine is able to range test upto 55 paces at any orientation, his model is a small electric parkflyer, the receiver is not enclosed or in anyway hidden.

Do other spectrum users feel this is acceptable? I want to fly this plane badly and it has been to the site 3 times allready without leaving the ground due to 'not playing untill it's perfect' syndrome.

This is a fairly large plane with a 40cc 3.5hp so it needs to be good.

What do you very helpfull people think, is 20-50 paces -depending on angle to model- good enough for a range test?

Cheers
Tanky
Guernsey

[smokin]

your ant. is not pointing straight out and right at the model when this occurs is it? always use some degree of angle on your ant. just wondering?????? good luck.

[pepatrick]

I would be a little careful on that one. I have a Comp-Arf 3.0 Yak. It has 2 R921 Spektrum receivers and 2 satellites on each. I am able to get over 50 yards with the bind button pressed before I lose signal. This with me walking away from the plane and radio in front of me (no line of sight)...I have a smaller ar6000 receiver that is only good for about 20 paces on a foamy..but I am not as worried about it as it will not fly so far away..but I would purchase an extension for the AR7000 and put the satellite farther away from the main receiver.

[tanky]

Hi smokin....

Yes mate, the antenna is at an angle, not straight.

[tanky]

Pepatrick

Cheers mate, thats not a bad suggestion because i am still using the stock lead that joins the 2 receivers together. Coincidentally, i thought i had ordered one but have never seen it arrive!

Just a thought, can more then one satelite receiver be added to the AR7000?

[tanky]

I,ve moved the sat away from the main receiver by about 30" (as far in the tail as I could reach, it gets a bit tight towards the rear!).

Will test tommorrow and see if it's any better, have also moved the main receiver away from the batteries and regulator by about 6" (it was only 1" away before.

Thanks for the help so far guys.

[bodywerks]

You need to orient the two receiver on different plains - basically, orient the the main receiver so that the antennae are on the horizontal plain, and the satellite receiver so that the antennae are on the vertical plain - VERY IMPORTANT!!!!
Also, make sure both receivers are at least 2-3 inches away from anything metal or carbon and especially your fuel tank.
If you hold your transmitter level (not pointed up or down), then angle the tx antenna to 90 degrees. I did a range test with a data logger and got a difference of 25-40 fades just by doing this test on the ground (at 90 degrees, I had only 1-2 fades per antenna). In the air, the difference was in the 200's! So definitely angle the tx antenna 90 degrees.

[tanky]

Cheers Bodywoerks.... The way it is now mounted checks out as per the manual and your reccomendations.

I was intrigued by the results of your data, it really just goes to show how important it is to mount the receivers on the correct axis. I must look into getting a logger, the reciver in the plane is the later one with the logger imput, seems a handy telltale tool.

[bodywerks]

If your receiver has a data port, get a data logger YESTERDAY!!! It will tell you all you need to know to set up a system right.
If you get it, and do the extended range check as outlined in the data logger manual, you should get only a handful of fades per antenna (like 0 to 15 ish) and no frame losses and certainly no holds.
For a typical 10 minute flight, you should see no more than a couple hundred fades (max- an excellent setup will yield no more than about 75) per antenna, no more than a handful of frame losses(ideal is still zero, maybe 1 or 2), and again no holds.
I almost lost a 40%er due to overlooking my rx antenna vertical orientation and being too close to the tank. When I landed, I had as many as 655 fades on the antennae, and like 75 frame losses!!! After fixing it, and turning my tx antenna up 90 degrees, I went down to an average of 40 fades and only one frame loss...

[Zeeb]

Well if you have one of the newer AR7000's it will have data port capability but not the older ones. I sent the two I have in for the firmware update (which you should do if yours does not have Quick Connect) and despite what some others have said, that update did not allow my 7000's to use the data logger.

I've only flown one of the 7000's but the ground range check was well over the 30 paces (90 feet) mentioned in the manual, somewhere in the neighborhood of 150 feet. My gassers with R921's and two satellite rx's each will go three times the recommended distances before losing signal.

Bodywerks hit on the importance of separating the rx's and the antenna plane differences. In my experience they don't care to be real close to batteries and the signal will improve with some separation.

In my ground testing with one of the gassers, the tx antenna orientation doesn't seem to make a lot of difference. The worst readings I got was with the model pointed straight at me so I had the engine, ignition battery and wing tube between me an it, the tx antenna straight out and pointed at the model, it was still 240 feet before it gave up. It was a bit better with the tx antenna tilted up 90 degrees, but my take on that is I ususally fly with the tx pointed slightly at the ground, so even when pointing toward the model, it's got an angle to the model. Now if I were to point the antenna up, that would actually point the antenna at the model while it's flying. Some advocate turning the tx antenna sideways 90 degrees, but I just don't see the necessity considering the small difference it made in ground testing.

Then there is the part about how long that elbow connection in the tx antenna is going to maintain it's ability to lock in place when tilted? I haven't got a clue but I do know Horizon will not sell you a replacement antenna for you to install, it's got to go into the service center. Or at least there's a pretty good size thread over on RCU about that exact issue....

[tanky]

Guys - thanxs for all your help and info, very useful info and much appreciated.

The problem is fixed now. I bodged a 18" servo extension lead together so I could extend the distance between the satelite and main receiver. With the main receiver mounted away from regulator/batteries etc and the satelite receiver well down in the tail end of the fuselage it range checks as one would expect it to.

It has no problem picking up the signal from my radio at any orientation. I get well past 55 paces with the button pressed in and I began to loose count after 75 paces.

Thanks again

Tanky