Re: [Paparazzi-devel] =?ISO-8859-1?Q? Re: Does the modem i?= nterfere with 2G4 rad =?ISO-8859-1?Q?ios??=

[martin]

Hi,

guess things are getting a little more complex with 2.4GHz. It will
never be like having the safe feeling of having your frequencies clip on
your antenna.

We did a test with seventeen "various brands" 2.4GHz aircrafts and a
XBee Series 1 controlled Paparazzi operated at the same time. There was
no issue for anyone, no packet loss - but this does not prove anything.

Martin

Am 13.07.2009 um  Uhr haben Sie geschrieben:
> Hello,
>
> yesterday I did some ground testing on the RC flying field. I am the
only one
> who uses an autopilot. I had warned the other pilots that I use 2G4,
just in
> case. One guy who was flying a Funjet suddenly shouted that his plane
doesn't
> react any more, so I quickly disconnected the power supply of my
aircraft and
> the USB cable of the ground statiion modem. Then he didn't have any
more
> problems and was able to continue his flight.
>
> I am using 1mw Xbee ZB modems. He flew with Futaba FASST.
>
> He is not 100% positive that actually there was an interference, it
all went
> very quickly. He took off while my modems were powered on. My ground
station was
> behind the safety fence (metal), the plane was parked on the actual
flying
> field. To me it looks as if an interference occurred when his plane
came in
> unobstructed line of sight to my ground station. It has been in
unobstructed
> line of sight to my to my plane all the time.
>
> My ground station modem is configured as coordinator, the other one is
> configured as end device. In the plane I use a Nintendo antenna for
the modem.
>
> What did you experience?
> Greetz, Martin
>
>
--------------------------------------------------------------------------------
> From:  chris
> Subject:  [Paparazzi-devel] Does the modem interfere with 2G4 radios?
(Martin
> P) answer from Chris Efstathiou
> Date:  Sat, 07 Mar 2009 19:54:22 +0200
> User-agent:  Thunderbird 2.0.0.19 (X11/20090105)
>
> Hi.
> I have recently equipped my Multiplex profi 4000 with the ACT S3D dual
FHSS
> system http://www.acteurope.de/html/start_english.html
> I only have one flight with it but a lot of ground testing and i am
almost
> certain that there is no problem operating a FHSS system like the s3d
or the
> Futaba FASST in close proximity with the Xbee 60 mw 2.4 ghz modem.
> The separation of the s3d dual receiver and the Xbee modem is about 60
cm (~2
> feet) on my Multiplex EasyGlider and the range is not reduced at all
during
> flight and during range checks.
> After all operating both a Xbee 2.4 ghz modem and a FHSS system is
like having
> two pilots flying two airplanes at the same time, one equipped with
say a
> Spectrum or JR system and the other with a Futaba FAAST system, a
rather usual
> situation.
> Chris
>
--------------------------------------------------------------------------------
>
> From:  Martin P
> Subject:  [Paparazzi-devel] Does the modem interfere with 2G4 radios?
> Date:  Sat, 07 Mar 2009 12:16:28 +0100
>
>
> Hi, everybody!
>
> I would like to know if anyone has experience with Paparazzi and 2G4
> transmission. I do not intend to fly Paparazzi with a 2,4GHz safety
link, but
> as 2G4 becomes more and more popular, I would fly near other people
who use 2G4.
> I don't want to cause a crash.
>
> Theoretically, it should not be a problem as the 2G4 radio should hop
to
> different channels and the interference should be very short. Unless
the modem
> uses too much bandwidth.
>
> On the other hand, I would like to know if the modem works while a 2G4
radio is
> near.
>
> Greetings, Martin
>
>
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