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Aug 14, 2018, 11:04 AM
Thermals, Tom
RyanNX211's Avatar
With the Cheap Chinese knockoffs, protocol seems to be what determines if the ignition affects them.
A Futaba clone is resilient like a Futaba A Spektrum clone goes goofy like a Spektrum.
Is anyone cloning XPS?
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Aug 14, 2018, 11:16 AM
Thermals, Tom
RyanNX211's Avatar
Back in 2007, we jumped on the DX7. A buddy is a multiple champion and had to sit out that year because he got rid of his 72mhz and couldnít get DSM2 to work.
He was on FAsst the following year and hasnít had issues since. Same with those who use that $89 FHSS system from Futaba (although the single antenna occasionally shows some issues at distance and some angles)

XPS only shows a problem with the Mk3 in the throttle channel. No issues have been observed in units that use a servo operated kill switch.
http://www.modelflight.com/larrydavidson.html

Horizon sent us some of their higher end receivers and some suppressors. That latter did nothing for the receivers that acted up. In the interest of honesty and full disclosure, TWO OF THE SPEKTRUM Receivers WORKED. These receivers had more channels than we need but somehow they couldnít be made to act up. The receivers with <8channels are not helped by HT resistors or suppressors nor any of the techniques carried over from 72mhz.
Latest blog entry: Steak and Old Timers
Aug 14, 2018, 11:20 AM
Thermals, Tom
RyanNX211's Avatar
Jim:
You say that FrSky and Futaba use the same chips but , if you see in the video, we initially had the same issues with FrSky. Several modelers brought this to their attention and they came out with a receiver for ignition. What did they change?

Also, I havenít heard of problems with their 900MHz system.
Latest blog entry: Steak and Old Timers
Aug 14, 2018, 06:39 PM
Quote:
Originally Posted by RyanNX211
Is anyone cloning XPS?

Of course not. The XtremeLink protocol uses dual layers of encryption to prevent them from being controlled by an external source. This is why our system has ITAR restrictions.
Aug 14, 2018, 06:44 PM
Quote:
Originally Posted by RyanNX211
Jim:
You say that FrSky and Futaba use the same chips but , if you see in the video, we initially had the same issues with FrSky. Several modelers brought this to their attention and they came out with a receiver for ignition. What did they change?

No idea, it's not my product.

I don't see any video that you are referring to. I also do not understand what problem you are actually having using an XPS receiver. I am not sure how your setups are done. I see your diagram, but it doesn't make any sense to me because there is nothing connected to a receiver anywhere. Certainly having a spark-gap coil setup will generate a huge amount of RF. You can minimize the RF the same way you do in an automobile, and that is with a large capacitor. Back when we had points in cars, you could here the ignition noise through the radio. Adding a cap to the coil eliminates the noise.
Aug 15, 2018, 05:10 AM
Thermals, Tom
RyanNX211's Avatar
Okay. No other issues with XPS except that the FG conversion isn’t working in the Radian.

They’ve been great receivers.
Latest blog entry: Steak and Old Timers
Aug 15, 2018, 01:47 PM
Again, what problem are you actually having? I don't see anything other than "there is a problem".
Aug 15, 2018, 05:54 PM
Thermals, Tom
RyanNX211's Avatar
Quote:
Originally Posted by JimDrew
Again, what problem are you actually having? I don't see anything other than "there is a problem".
::snip::
Last edited by JimDrew; Aug 16, 2018 at 01:11 AM.
Aug 15, 2018, 05:55 PM
Thermals, Tom
RyanNX211's Avatar
::snip::
Last edited by JimDrew; Aug 16, 2018 at 01:11 AM.
Aug 15, 2018, 05:59 PM
Thermals, Tom
RyanNX211's Avatar
Now XPS only failed once and with one motor. AND, only the throttle channel wouldn’t work with the Mk3.
Remember, it is a servo eliminator. Once the engine was running, the transmitter could not turn it off.
Latest blog entry: Steak and Old Timers
Aug 15, 2018, 06:03 PM
Thermals, Tom
RyanNX211's Avatar
And a Lemon copy of Spektrum provided by JMP Electronics (France) for an unbiased evaluation.


::snip::
Last edited by JimDrew; Aug 16, 2018 at 01:22 AM.
Aug 15, 2018, 06:05 PM
Thermals, Tom
RyanNX211's Avatar
In this test environment, XPS would pass because switching the engine on and off is accomplished by a manual switch.
Latest blog entry: Steak and Old Timers
Aug 16, 2018, 01:10 AM
Ok, once again I have no clue what problem you are actually having! You keep posting videos of other companies products, which do not apply to our products.

Can you tell me what the ACTUAL problem is? Are you losing signal, are surfaces moving on their own, etc? I really have no clue about what you are trying to show with OUR products (I really don't care about any others).
Aug 16, 2018, 01:34 AM
Quote:
Originally Posted by RyanNX211
Ok, so I read through this thread.

I *think* you guys are having problems with servos moving on their own? Andy's explanation is 100% correct in that this is a SERVO issue, not an RF issue. Andy mentions that Spektrum receivers use high impedance servo outputs. So do all XPS receivers. The reason for doing this is that if you have a short circuit on the servo bus it won't kill the CPU, and thus crash the model. A lower impedance output would certainly help drive the servo to the proper position by having a signal level higher than the noise threshold, but you run the risk of killing the receiver completely should a servo short out (like signal to ground). I could make a receiver with low impedance outputs that would probably resolve this, but I am not thrilled with the idea of releasing something that could knowingly kill itself. The notion that one brand is better over the other because of this particular point is a bit silly. If you changed the output resistors on a Spektrum, XPS, Lemon, etc. to a low impedance value, they would all work just fine because they are all 2.4GHz devices and are immune to this type of noise from an RF stand point.

I am guessing that various receivers have different output resistors to set the impedance and those are typically parts with 5% tolerance in their spec, so I could see that maybe some of the exact same receivers might behave differently all depending on how much RFI/EMI is occurring.

Now... I will say this.. in my experience, when a Spektrum receiver's LED starts flashing it is because it rebooted. XPS receivers have done this for years, and Spektrum copied this behavior. I don't know any other reason why a Spektrum's receiver LED would flash. If you see our receiver LED flashing, it rebooted due to loss of power. That's the only way that can happen.


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