aeajr

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SPEKTRUM RECEIVER INSTALLATION BEST PRACTICES

Friends,

I have been following the 2.4 GHz market closely. About a month ago I became a Spektrum module owner for use in my Futaba 9C. I have only taken one flight at this point, with an Easy Glider and an AR6100. Now I am planning installation of 2 AR7000s and an AR6200.

I thought it would be good to gather some tips, tricks and recommendations about how and were to install Spektrum/JR receivers and what to avoid. It is my hope that this thread will become a resource for all Spektrum/JR users. The information is scattered all over the place mixed in with DX6, DX7, JR and other threads.

Maybe we can gather all those experiences and best practices here. As I do testing I will report my results here. Hopefully people will find them useful.

THIS IS JUST ABOUT BEST PRACTICES FOR INSTALLATION OF SPEKTRUM/JR RECEIVERS.

Please do not post things about XPS or Futaba or questions about how to program flapperons. Those are also all over the place. This is about receiver installation and I would like to keep it a focused resource thread.

Here are some questions that come to mind.


BATTERIES

I presume that NiXX packs will fully block the 2.4 GHz signal. Is this true? If so, how do you avoid this in your planes that use NIXX packs, especially with the AR6100 which is sold as a parkflyer receiver. After receiver packs, the motor packs on parkflyers are probably the most common place for NiXX packs to be used.

What about Lipo packs? Will they block the signal? They are not metal but do contain metal foil, I think. Many are wide and flat creating quite a shadow, if they do, in fact, block the signal. If they don't, then we may prefer to use Lipos with these receivers. Clearly the AR6200, 7000 and 9000, with their remote receivers, would be less prone to problems with the battery. But how much of a concern is it? And how long must the signal be blocked before it becomes a problem?

Examples

In my SmoothE the lipo sits around the middle of the plane laying flat on the battery try. The receiver is normally installed on the other side of the same piece of wood, so it is effectively sitting on top of the battery. Will it block the signal to an AR 6000, 6100 or 6300 that is placed right above it? Since the battery is below, it could be placed between the pilot and the receiver at times. Will the Lipo block the signal?

In my Easy Glider the battery is above and behind the typical receiver placement. The only time it would likely be between the pilot and receiver would be for a moment while performing a loop, or inverted flight going away from the pilot. If that were to occur, how long can the blocking be tolerated?


MOTOR

The motor profile in most small electric planes, say less than 4 pounds, would not appear to be large enough to block out the signal to the receiver unless the receiver it is right behind the motor. Would that be a fair assumption? Can we be less concerned about the motor as a blanking issue?


ESC, SERVOS AND WIRES

Supposedly 2.4 GHz places the receiver well above the noise generated in wires, ESC, the motor and the servos. But are there cautions still to be observed in this regard? Do we still need to avoid these components in our crowded equipment compartments? Are chokes still useful? The marketing literature would seem to suggest we do not need to be concerned with these things. What is your experience?


CARBON

We know that an all carbon fuselage pretty much blocks the signal and that carbon mixed with other materials can reduce the signal. From what I have read, that is the only commonly used construction material that presents this problem. Are there others?


METALLIC COVERINGS AND FIXTURES

I have heard that metal coverings will have a similar effect. In glow planes, I understand the metal fuel tanks can be a problem. What about metallic coverings, like chrome monokote? I don't believe that is actually metal. Are they a concern? What about other coverings present a problem? What are your experiences?


SIGNAL RECOVERY

We know if the power drops too low, the receiver reboots and recovery takes about 3-5 seconds. But what of a blocked signal? If I lose signal on both channels for 1/4 second, will it instantly reconnect? What is your experience or what testing has been done?


THANKS

Your experience reports and testing reports would be appreciated. Photos are always helpful. If you have already posted them, then a link would be helpful. There is so much info and noise out there, that when you try to focus in on one element, installation best practices for Spektrum/JR receivers, it can be hard to find what you need.

Thanks for your help and for sharing your experience.

Khatsalano

Ed,

I've had only experience with 2.4ghz as I've never owned an FM system but that's because I'm newer to the hobby. I've found that you can have significant performance deviations based on where you place your receivers. They seem highly vulnerable to metallic and composite fuselage shadowing, as well as interference from current running in wires. I've had 6 signal losses where they are near misses, and 2 planes crashed due to signal lockout. Here are my best practices:

1) The farther the aircraft goes, the more receivers you need. I no longer use any AR6100's as I've lost a plane and had many incidents in the under 500ft range with this receiver... on a slow flying foamie. AR6200's seem to do ok on smaller planes but for larger planes, you want as many receivers, up to 3 or 4, as you can get to avoid those big batteries and engines from shadowing the tiny antennae. Check out the distance where I lost signal in this crash video: http://www.youtube.com/watch?v=lXY23SD-Wa8

2) Keep the Rx away from the battery or the motor. They don't cause interference, but huge blocks of metal will shadow the signal. To illustrate this, try transmitting to your Rx with your real car in the way ... instant signal drop if less than point blank range.

3) Keep the Rx wires away from other high-frequency wires such as a switching BEC. I've also found that my regular 12 ga. power wires from the ESC to the battery also play a substantial role at reducing range. Keep them away!

4) I will no longer use integrated BEC's from ESC's on any plane that runs more than 4 channels and has the associated servo load. Voltage drops can kill your link unfortunately.

5) Don't count on signal recovery. The signal recovers in fractions of a second, but the software does not ... the Rx often reboots itself when you lose signal and it takes 4-7 seconds at best up to 15 seconds ... from my real crashing experience. 4 seconds is a long, long time.

If I could afford to use nothing but AR9000's with 3 satellite receivers in every single plane, I would. I would install the main Rx in the cockpit, one routed by extension wires to each wing, and one in the tail section of the fuselage. The more receivers the better. : ) Remember, your setup could perform for you 99% of the time and that sounds pretty good. But your 100th flight will lose you a plane ... in afterthought, I wish I had spent the little more money on the AR9000 and more satellites.

- K

Khatsalano

Ed has already seen this but for reference to our other readers, this is my previous thread compiling range information on these receivers:

http://www.rcuniverse.com/forum/m_6555830/tm.htm

... especially pay attention to the official response from Horizon.

- K

BalsaBob

My Feedback: (24)

As far as the mounting of the small satellite reciever(s) ..... I use Velcro. The velcro also allows you to change the orientation of the satellite receiver incase you need to for better reception (incase you are checking reception with the Flight log).
I have found canopies to be a great place to mount a satellite receiver ... as they are usually free of the items you mentioned that may block a signal. I have a satellite receiver mounted behind the pilots head in one airplane ..... and it looks good ..... the receiver sort of likes like some sort of old WW2 radio transmitter. Bob

Airforce7

My Feedback: (31)

I have an AR9000 Rx in my jet. It's controlled from my converted JR9303. Take a look at the install pictures. I'm using two remote receivers for a total of four antennas. One is mounted on Velcro over two electric pumps; the main Rx is mounted on Velcro next to two solenoid valves and two Matchboxes. It's also near a UAT, 3 liter bottle of fuel and two 5-Cell battery packs. The other remote antenna is up stream (towards the nose) about 20 inches. I've flown this setup three times and had no more than 44 fades on any one antenna as reported by the flight logger. I don't believe I need to change the setup if the flight logger tells me that my signal is good. I've actually flown this setup in a 60 size prop plane and had worse data as reported by the flight logger. In fact I have had as much as three holds in one flight and never noticed any loss of control of the plane. I really believe that it had more to do with hard aerobatics and low flying to the ground that got me those bad signals. Anyway, the only real issue I had with this setup in the jet was when I tried to bind the system. The second furthest remote antenna had trouble binding. The only visual you get is with the LED and it was not in sync with the other LEDs. Eventually after several re-bind attempts it worked. After that I've had good success with the Spektrum system.

On a side note, it turns out that the latency going from the old 9-channel Rx (JR 649) to the new DSM9/AR9000 is slower according to the RunRyder.com website. I noticed a difference in the latency on the first flight of my jet, but wasn't sure if it was slower or faster. It just felt different, smoother to be more precise.

I also fly the AR6100e in an Alfa Models A4. I have really good range and never noticed a problem with my electric setup. I'm using the same Tx with the DSM9 module. The Rx is in close proximity to a 4S battery and ESC. Again, never had any issues. Anyway, I'm happy so far with the Spektrum system and I really like the fact that the Tx antenna isn't in front of my face anymore.

Khatsalano

AF7, what size clear tubing is that you put over your little antennae? Great idea.

- K

harphunt

My question is this. Do the receivers need to be perpendicular vertically (one horizontal, the other vertical) or can they both be perpendicular on the horizontal plane?

Thanks

Panzlflyer

My Feedback: (15)

A 2.4 signal passes thru my house to the other devices i use, while the signal strength is lowered it is still there!

Best practice is a clear shot, in reality the data logger reveals that not one of the antenas on either of my 35% planes loses the signal and fades are usually less than 40 and rarely above 100, No holds. Usually No frames lost.
At some point they must be transmitting thru the 100cc twin, 32oz fuel tank and all the other assorted paraphanelia.
I doubt that my Delta goes into hold or it would be over and the Ar7000 stuffed in it must lose sight of me at some point.

Signal recovery on the 7000 and 9000 seems near instant to me, try it, turn off your tranny, mine link up instantly no reboot that I can see.

Airforce7

My Feedback: (31)

Khatsalano, the tubing is SMC clear polyurethane at 4mm OD X 2.5mm ID. Send me a PM with your address and I'll send you some tubing in the mail. [8D]

Airforce7

My Feedback: (31)

harphunt, you can set it up this way. I put the AR9000 and the remote antennas on the same plane, and I tested the orientation of the remote antenna with the antennas vertical and horizontal. There was no significant difference between the two positions. I would however make sure the remote antennas are at least 2 inches away from the main receiver and its antennas.

Airforce7

My Feedback: (31)

Panzlflyer, did you actually turn off your transmitter and then on again while you were flying? Based on my ground test with the AR9000, which I have to do to confirm whether or not the mandatory failsafe for the turbine works, it took at least five seconds to reconnect. Not something I plan to test in the air BTW!

Zeeb

My Feedback: (41)

Yeah the minimum distance for the satellite rx's is two inches per the manual. I personally like the longer antenna extensions which give me more options for placement of the satellite rx's. I mount all of my satellite rx's with Velcro as someone else has already mentioned.

The results of the data logger on the two GS IMAC birds I have them in, show a very low fade count with no frame losses or holds. I think the shortest extension I have on either one of those is 12". I try to set one satellite rx in a 90 degree offest plane from the main rx, and the second satellite at a 45 degree offset from the main rx. From the results of the data logger, I think that's a good place to start. From experimenting with the data logger's information, I've found that having an rx in close proximity to the battery packs will affect the reception of whichever antenna/rx is there. Having an rx mounted right between two regulators for the Li-Ion batteries on these two birds does not seem to affect the signal reception, nor does a close proximity to either the wing tube (aluminum) or the fuel tank.

Now obviously if you're running anything smaller than the AR9000/R921, you won't be able to use the data logger on them, but what I've done with my AR7000 and AR6200 is to mount the satellite rx's with the antennas at 90 degrees to the main rx and it's been fine on the models those are used on.

There's a new rx coming out and I don't remember the exact name of the thing, but the model number is an AR9100. If you do a search on Horizon's site for that all you get is the soft switch it uses. Anyway, the important differences are two sets of 16g. power input wires, no rx's in the main body (they rely on satellite rx's only, minimum three) to prevent any possible power (EMF) issues, and finally they claim it's got a less than .5 second recovery time from power brown out. I'll be going to that rx and the A123 batteries for my next project.

There's also another thread where a poster has asked Danny (the Horizon rep) about comments from the Spektrum system designer about new stuff having a "rapid recovery". I've not seen an answer to the question yet, but if they've made changes to allow a faster reconnect after a low voltage rx shut down, that'll be great!

http://www.rcuniverse.com/forum/m_6773703/tm.htm

Now I don't know how that might affect your "failsafe" test for the jets when the tx is turned off. Once the tx is turned off and then back on, it will have to select two channels and then broadcast on them with the appropriate GUID numbers for the rx to re-link with the tx. It's not really a good test as a signal loss in actual flight would not cause the tx to change frequencies, and the rx would still be looking on the same channels, so in theory that should be a faster re-connect than would be seen by an off/on cycling of the tx power.

My battery systems are such that I don't anticipate a power issue, but it wouldn't hurt my feelings if they have come up with a way to get a faster reconnect/link on the systems....

Panzlflyer

My Feedback: (15)

Once in air when they first came out but normally on a ground test to check failsafe, I do it as a matter of course after rebinding, never takes 5 seconds, I increase rpm with a holder and move control sufaces so I can see them, tranny off makes motor to idle, surfaces neutral,flip on and never takes more than a second to regain control, if it did I would have been unhappy with the system.
I have done it with 5 of my models and quite a number of other peoples when setting up for them.
Are you using a module system or native.
Seems when my tranny beeps its connected.
I have heard people saying it took a long time but havent seen it with the Dx7 or 9303 2.4 not saying it doesnt happen as my Delta for some reason is the only one that can take a time to relink.

One issue I have had is the remote cable, must have had bad connectors because it would show 500+ fades if you wiggled it, replaced the cable and it went down to no more than 44