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Sep 14, 2014, 01:21 PM
Registered User
Dudley Dufort's Avatar
New Product

Have You Hugged Your Receiver Today

Unexpectedly, my plane would make a 50 foot “dive bomb” maneuver every once in a while. At a safe altitude, this behavior was little more than frightening. However, had it occurred closer to the ground it could have been disastrous. Suspecting an intermittent receiver, I bought a new AR9310. Following the replacement of the suspect receiver, Jim Thomas loaned me his “data logger” to test the new installation. The device proved so helpful, I thought I’d share what I learned. Thanks JT!

The Spektrum 9310 is a 9 channel, carbon-fuselage receiver with long “whiskers” that allow you to orient the antennas away from the carbon components in carbon-reinforced glass fuselage or extend the antennas outside of the fuselage in the case of an all-carbon fuse.

The tiny device plugs into the data/bind port of your receiver. Following a flight, the data logger allows you to read actual data loss to the various antennas. That in turn, permits you to fine tune the location and orientation of the receiver’s antennas.
The codes are;
A—Antenna fades on receiver A
B—Antenna fades on receiver B
L—Antenna fades on the left receiver
R—Antenna fades on the right receiver
F—Frame loss

A “fade” is a signal loss to one of the antennas. Fades are to be expected in small numbers. A “frame loss” is when all the antennas, momentarily, lose signal. Those should be very few. A “hold” represents a “fail safe” condition following 48 consecutive frame losses. You don’t want to see any holds!

The Spektrum Flight Logger costs about $30 and is available at R/C Country or from on-line retailers. The otherwise comprehensive instructions don't show which antenna goes with the various logger codes. The photo below shows the assignment of the four antennas on the 9310.
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Nov 03, 2014, 11:38 AM
E sailplane thermal hack
Yes Dudley , that data logger is worth it's weight in gold!!
Also very useful for checking an antenna installation, or in my case verifying a field with interference problems,, using the data logger (in my case using telemetry also gave same info)
I was able to verify that I was indeed having reception problems ONLY at one particular field where I fly here in Chico.
I've now become somewhat paranoid about my antenna installs.
I'm wondering Dudley ,, where you using a separate satellite antenna with your 9310??
The 9310 is same receiver I use in pulsar 3.6,,it has TWO separate internal receivers, one for each antenna, plus capability of adding up to 2 external satellite antennas. On my 3.6 pulsar
I have the two main antennas coming off the main receiver poking out the fuse 180deg from each other and angled back slightly, PLUS I have a THIRD satellite mounted foward with its antenna poking straight up towards the sky just in front of canopy opening. Is it overkill??
Most likely,,,, but,,, even at my problem field in Chico,,I've had 0 reception problems verified by
The data logger. With soooooo much carbon in our planes now,, I think it's important to pay REAL close attention to your radio/antenna install.
Last edited by Airman74; Nov 03, 2014 at 11:55 AM.
Nov 03, 2014, 11:59 AM
E sailplane thermal hack

The above is an excellent article by Sherman Knight from HH about 2.4ghz antenna installs
In Sailplanes. It's on pages 14-21
Nov 03, 2014, 04:50 PM
Don McCullough's Avatar
All telemetry-capable Spektrum transmitters and the STI iPhone telemetry receiver also show antenna data until the receiver is shut off. You can set real time alarms as well.
Nov 14, 2014, 03:52 PM
Registered User
RPinCA's Avatar
I have a data logger and went through a lot of mods to get solid reception in my planes. I've used the 9310 Dudley mentioned. I also use a carbon satellite (with a long wire) with other receivers. After nearly a year of dealing with "2.4 antenna issues" I learned something. These are Spektrum-specific issues. I thought it was characteristic of 2.4GHz, but that doesn't seem to be the case.

I've been working with Lenny Keer, who is on America's F5B team. I bought the Avionik B-12 he used at the Worlds. Completely graphite fuse and wing. He installed the motor, ESC and electronics for me, but ran into a problem.

Most Spektrum receivers have a 22ms frame rate. The 7610 and 9010 are 11ms. I feel the difference and prefer them. For carbon planes, I change their normal satellites to carbon satellites with the long wire. But it was not possible to install an 11ms receiver in the Avionik's thin fuse and get good reception. I would need to use the 22ms 9310. That made no sense for such a fast ship.

Lenny uses Airtronics equipment for his personal planes. Both the Futaba and Airtronics systems have 7ms frame rates - 3x the typical Spektrum. What's more, both brands have receivers with two long antennae. Carbon is not a problem, you just route them outside. In F5B all-carbon competition planes, the link is solid and there are never any 50' surprises.

After thinking through the choice of 22ms Spektrum or buying a new Airtronics setup, I bought the new TX. I am very happy I did. The Avionik is wicked fast; on 3S it climbs at 9000fpm (102 mph). I put an Airtronics receiver on the Graphite with the carbon wing, which flies high. I have zero dropouts with either plane. The link is solid and direct, no matter where the plane is or how fast it's going.

This is all news to me. I have a DX-18 and went through the issues discussed here. It's nice to be without them. The photos show the simple installation. The Avionik is the way Lenny flew it. The Graphite is waiting for a proper installation but shows that a lot of wire is available. Both planes have flown 7-8 times without a glitch.

This is not meant as Spektrum-bashing. Just sharing this surprising new information with you.
Nov 16, 2014, 09:35 PM
E sailplane thermal hack
Thanks RP!!!! Always appreciate the TRUELY unbiased input

ATX has ALWAYS supported sailplane users going a looooooooooong ways back!!

Ps edit : I guess I heard the sirens call like many others with HH's fancy tech ;-)

Ps ps edit : I DO like the voice feedback of my Spektrum ,, but as many have noted,
The ATX systems have far more programming flexibility and lack of reception issues. There's rumors of ATX coming out with a new updated radio.
I think I'd dump my DX9 if they did.
Last edited by Airman74; Nov 17, 2014 at 11:22 AM.
Nov 26, 2014, 03:29 PM
Registered User
RPinCA's Avatar
Always appreciate the TRUELY unbiased input
The forum would be rather boring if we all had to be (or pretend to be) unbiased. : ) I hope my biases are helpful to others - not offensive.

ATX has ALWAYS supported sailplane users going a looooooooooong ways back!!
I hear that. I have a Stylus I can't get myself to sell. To my surprise, they make a 2.4 module for it. Granted, it is the slower FHSS-1 protocol, but still - as they say on their site - they take care of their customers.

I guess I heard the sirens call like many others with HH's fancy tech ;-)
For sure, I'll sign up for that! The DX-18 and DX-6 are SO nice to program! The ATX is a bit klunky, but it can do a lot more if you learn it thoroughly.

lack of reception issues
Nothing is more important to me than the quality of the link. I was truly disturbed by that 50-foot dive-bomb experience, which I am finding is common with Spektrum. Why should we need to use a data recorder and have so many antennae? Other mfrs don't have this problem, using only two simple antennae. I have had *zero* dropouts in almost 50 flights. It's wonderful!

There's rumors of ATX coming out with a new updated radio. I think I'd dump my DX9 if they did.
It may be the one I bought, a black SD-10GS. I am completely happy with it, and like it more all the time. If you have bind'n'fly planes, you will still need a Spektrum. I can't get $400 for the DX-18 so maybe your DX-9 will hang around for a few years.

We need to say "Hi" at SVSS sometime. We've chatted more on-line than in-person! : )

Happy Thanksgiving to all!

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