Re: [Paparazzi-devel] Aerocomm AC4868-250M Issues

[gatib]

Dear Christoph,

I am using AC4868-250M for two years at full power but I never experienced
the problem you describe. 2m distance between the two antennas seems
enough by me. How do you power the onboard module? I am using a linear
voltage regulator to provide 3.3V from the 5V bus of the paparazzi. (The
3.3V bus isn't enough powerful for such a long range modem)


Balazs

> Thank very much for your rapid reply Cristophe!
>
> I tried the Iridium file before. I now also tried the xbee file.I
> moved the ground modem two rooms away into the kitchen into the oven
> (switched off :-) ), trying to use it as faraday cage. The currently
> the modems are configured to 70mW like in the attached files. But the
> Problem currently is, it starts to send some packages and then quits
> operation. Do the screenshots look fine? Perhaps the modems draw to
> much current and I don't recognize it? I don't know :-(
>
> Christoph
>
> 2012/2/19, Christophe De Wagter <address@hidden>:
>> At full power you MUST put the modems far apart... like at least the
>> room
>> nextdoors. At Full power the 868MHz signal is so extremely powerful that
>> the RF-fronted of the receiver is completely saturated. Sometimes
>> removing
>> antenna's can help.
>>
>> The package size of aerocomm is also quite large, meaning that the small
>> paparazzi packages that are not sent simultaneously (gap between bytes)
>> are
>> sent with very low efficiency, sometimes as low as 20%. There is a
>> telemetry that groups packages in bigger packets.
>>
>> https://github.com/paparazzi/paparazzi/blob/master/conf/telemetry/iridium.xml
>>
>> To comply with regulations you should send at most 200 bytes per second
>> as
>> found from xbee868 tests.
>>
>> https://github.com/paparazzi/paparazzi/blob/master/conf/telemetry/xbee868.xml
>> should
>> do this trick.
>>
>> -Christophe
>>
>>
>>
>> On Sun, Feb 19, 2012 at 3:13 PM, Christoph Niemann
>> <address@hidden
>>> wrote:
>>
>>> Hi everybody,
>>>
>>> I'm currently trying to configure some AC4868-250M radiomodems. I saw
>>> there where some regulatory Issues
>>> (http://paparazzi.enac.fr/wiki/868MHz_Issues) and the implemetation of
>>> the aercomms cause them to drop data. What I want to do is to operate
>>> them at full power and 9600Baud. If I set them to 3 or 25mW it works.
>>> At 70 or even 250mW the range tests in the Windows Tool fail and the
>>> Paparazzi Telemetry doesn't work either. Some packages do their way,
>>> but it is not really possible to operate the AC this way.
>>> I know there are some users on this list, who use those Modems.
>>> Perhaps somebody could make a screenshot or supply his configuration
>>> files.
>>> If they worked it would be really cool since those Modems don't seem
>>> to interfere neither with my JETI 2.4Ghz radio nor my Foxtech 5.8Ghz
>>> video tx, so every help appreaciated :-)
>>>
>>> Cheers
>>>
>>> Christoph
>>>
>>> _______________________________________________
>>> Paparazzi-devel mailing list
>>> address@hidden
>>> https://lists.nongnu.org/mailman/listinfo/paparazzi-devel
>>>
>>>
>>
>
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