Re: [Paparazzi-devel] Lisa/M questions

[Chris Gough]

Hi Eric.

The first reason is spectrum:

 * For me, 2.4 GHz is the only practical spectrum for analog video tx.
   Because my FPV equipment jams WiFi so effectively, I'd be nervous
   about using it with 2.4 GHz RC.

 * My local regulator has licenced some VHF spectrum exclusively
   for RC usage. Physics of VHF are nice, even though there is no SSFH
   RC equipment down there. And as other people switch to 2.4 GHz, the
   VHF spectrum allocated to RC is becoming less crowded :)

 * It's not inconceivable that I would want to use some of that long range UHF
   equipment, although I don't need it at the moment and am unsure of the
   legality/licencing issues in my region.

My other reason is the fleet of VHF radio gear I already own. I've got
a box of spare receivers, including some fancy expensive ones, so
using one on a project effectively costs me nothing. A PPM encoder
costs about the same as a satellite, a possibly inferior but adequate
solution that I can use with my primary transmitter (or the identical
spare I keep charged in my flight box, with the other charger and
those stupid cables I paid to much for).

If I was starting again I might chose 2.4 GHz equipment exclusively
(if I could figure out the analog video issues, perhaps a higher
quality transmitter would do it). As it stands, I'll probably end up
with some 2.4 GHz equipment sooner or later, and then expect to have a
"mixed fleet" for some years after that.

Chris Gough


On Wed, Jun 8, 2011 at 2:57 PM, Eric Parsonage <address@hidden> wrote:
> Hi Chris
>
>
>> I emailed Jobey this question, Piotr replied that only the Spectrum RC
>> is currently implemented (not PPM). He hinted it would be possible
>> port the PPM stuff to Lisa/M. I suppose if you aren't using a pair of
>> spectrum satelites there would be two UARTs going spare, no idea if
>> some of that IO could be re-purposed for PPM input though.
>
> I wrote the spektrum parser so can give you a definite answer on this. YES 
> the UART pins can be used as general purpose i/o and could be used for ppm 
> input. I don’t think it would take that much effort to re-map to use one of 
> those pins.
>
> Why would you want to though ? The Spektrum satellites can be purchased 
> individually for less than $35 for a genuine Spektrum satellite receiver and 
> the clone receivers can be had for $15
>
> Quality PPM receivers are not any cheaper than this and hacking a receiver to 
> get ppm out adds risk whereas the Spektrums  satellites need no modification. 
> If you where not thinking of hacking a PPM receiver but instead using an 
> encoder board then you end up with the ugliest wiring ever.
>
> I am really interested in hearing why it is better for you to use PPM it 
> might hep with future development.
>
> Eric
>
>
>>
>> I didn't ask about open source hardware, but I did wonder :)
>>
>> Chris Gough
>>
>> On Tue, Jun 7, 2011 at 9:51 PM, Christoph Niemann
>> <address@hidden> wrote:
>>> Hi community,
>>>
>>> having a look at the wiki-site of the Lisa/M I was a little bit confused. Is
>>> the only possible RC Spektrum (and JR and Hobbyking)? Or is it also possible
>>> to use classic PPM and JETI 2.4Ghz?
>>> The other thing, that would matter in the process of deciding, whether to
>>> purchase it or not is, will it be OpenSource or not?
>>>
>>> Thanks for your answers
>>>
>>> Christoph
>>>
>>> _______________________________________________
>>> Paparazzi-devel mailing list
>>> address@hidden
>>> https://lists.nongnu.org/mailman/listinfo/paparazzi-devel
>>>
>>
>>
>>
>> --
>> .
>>
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