RE: [Paparazzi-devel] downlink only

[gisela.noci]

Hi there

First time I am using this forum to comment on peoples comments, so hope I
get it right.

Cannot really comment on the main content of your problem Martin, but the
last para bothers me. How did you 'shield' the 'receiver cable'? Which cable
did you shield? Not the antenna cable , I trust. Or do you have an antenna
(whip or trailing wire) external to the fuselage, and the use a piece of
coax cable from the RX to the antenna? Are you using 2.4Ghz radio equipment
( for the radio control system, Spektrum or such like)or is it the 35MHz or
similar stuff. If you are using Spektrum, what other equipment do you have
on the aircraft, datalink, Video transmitters, etc, and are they in the
2.4GHz band as well? This is fraught with problems if so, since the very
close proximity of these elements WILL cause desensing of the Radio control
RX. There is nothing you can do about that; They ALL share the same 2.4GHz
to 2.5GHz band. If the RX is in the 35MHz (or 70Mhz, etc) band, it would be
better were is not for the fact the typical RX input selectivity is not
really that good, and the receiver is also desensed. I have had bad
experiences with JR 9 channel RX and the 9-Xtreme (900Mhz spread spectrum)
datalinks. The very broad band signal from the datalink severely
desensitized the RX, and range was reduced to less than 150meters! However,
removing the RX crappy wire antenna, and and connecting a thin (2mm
diameter) coax cable internally (shield to RX ground) and then routing the
Coax to an exit point in the fuselage and then connecting the original
antenna wire to the exiting coax center wire helped a lot. I easily get
600meter range now.  

THE FIRST RULE IS : whatever you are testing, be SURE that you have a safe
and tested means of taking control of the aircraft. Sure, a component
failure can still foil you, but I cannot condone taking of, intentionally or
otherwise(!), with your backup system ( manual RCS system) non-functional.
FIRST fix that!

I design Spread Spectrum systems, RF datalinks, Video link, etc, as well as
antenna systems of all types, for the aviation industry, both military and
commercial, so if there is any way I can help or advise, I will try. I am
flying Paparazzi for about 7 months now, but have designed my own ground
control station, and have extensively changed the autopilot - I fly V tails,
with ONLY rudder/elevator, ie, no ailerons, as well as a 4 meter wingspan
homebuilt A/C, fitted with ultrasonic height detection. This A/C does
auto-takeoff and auto-land (beautifully!). But I cannot help with any of the
issues related to the A/C  / GCS communication and control, since I have
done my own....Found the Paparazzi GCS very emcopassing and complete, but
far to complex, and impossible to certify , even in part, for use in
restricted civil airspace.

HAVE FUN, be safe...

Joe

-----Original Message-----
From: address@hidden
[mailto:address@hidden
] On Behalf Of Martin P
Sent: Monday, July 27, 2009 10:46 PM
To: address@hidden
Subject: Re: [Paparazzi-devel] downlink only

Hi, 

I do not intend to do any settings via the transmitter. 

However, I do not seem to have 2-way-communication via the modems. Although
I saw something with the scope, I am not able to use neither the settings
tab in the ground station nor the settings dialog from the tools menu. The
latter shows an empty window. 


On the field I used a modified flight plan which does not stop at the
holding point. First of all, uplink seems not to work an secondly, most of
the time I am alone on the field. 

Usually, when ground testing, the throttle reacted to the stick in AUTO1. 
Yesterday I switched to AUTO1 and the plane throtteled up and took off
before I expected (I use a landing gear). Switched to MANUAL and climbed,
then back to AUTO1. No throttle. Probably this is because I put the
vmode="throttle" in the takeoff block to get executed anyway. 

I havent't seen any vmode statements other than specifying "throttle". What
are the valid values for vmode? 
Could I automaitcally set the vmode to pitch in AUTO1? 

Managed to land manually, in spite severe radio interference. Radio
interference in spite having changed the receiver cable to a shielded wire. 

So, I am still struggling and learning. Every help is greatly welcome. 

Greetings, Martin 

-------- Original-Nachricht --------
> Datum: Fri, 24 Jul 2009 19:00:32 +0200
> Von: Pascal Brisset <address@hidden>
> An: address@hidden
> Betreff: Re: [Paparazzi-devel] downlink only

> Hi,
> 
> Martin P wrote:
> > I was wrong, I do have 2-way communication. Looked at pins 2 and 3 with
> the scope. (Could have done that earlier) 
> >
> > Then I do not know why I was stuck in holding point block (before I
> commented it out). 
> >
> > With or without 2-way-communication, I am still interested in flying
> without GCS interaction. Which means that, for the time being, I can only
> follow a pre-determined track and then (attempt to) land. 
> >   
>  The code to do a setting from RC channel is still there:
> 
>
http://paparazzi.enac.fr/wiki/Telemetry#R.2FC_Transmitter_Data_Uplink_.28Obs
olete.29
> 
>  But.
>  It has not been tested for months (years ?).
>  We will remove it asap
> 
> --Pascal
> 
> 
> 
> > Greetz, Martin
> > -------- Original-Nachricht --------
> >   
> >> Datum: Mon, 20 Jul 2009 23:11:58 +0200
> >> Von: "Martin P" <address@hidden>
> >> An: address@hidden
> >> Betreff: [Paparazzi-devel] downlink only
> >>     
> >
> >   
> >> Hello, 
> >>
> >> it seems that I have a common problem: GCS doesn't send to the plane.
> >> Removing the datalink section didn't help.
> >>
> >> Anyway, I am not so much interested in the uplink. When I am alone I
> >> cannot watch the plane and the computer screen at the same time. I know
> that
> >> Pascal Brisset strongly advises against removing the holding point
> block from
> >> the flight plan, but I might do just that. 
> >>
> >> My starting procedure would be like this: 
> >> Switch on the transmitter and switch to MANUAL, throttle off. 
> >> Power the plane. 
> >> Wait for GPS and do GeoInit. 
> >> Instantly go to Takeoff (a beep or LED signal would be nice). 
> >> As I am still in MANUAL, the propeller doesn't spin. 
> >>
> >> I don't know how to go on from this point. When I switched to AUTO2
> >> (without propeller, for safety) I expected the motor to start, but it
> didn't.
> >> Does the autopilot wait for a "launch" command which it doesn't get?
> Does the
> >> autopilot wait until I have stared manually? 
> >>
> >> Can you take off from the lawn (with a landing gear) or do you need to
> >> throw the plane? 
> >>
> >> Greetings, Martin 
> >>
> >>
> >> _______________________________________________
> >> Paparazzi-devel mailing list
> >> address@hidden
> >> http://lists.nongnu.org/mailman/listinfo/paparazzi-devel
> >>     
> >
> >
> > _______________________________________________
> > Paparazzi-devel mailing list
> > address@hidden
> > http://lists.nongnu.org/mailman/listinfo/paparazzi-devel
> >   
> 
> 
> 
> _______________________________________________
> Paparazzi-devel mailing list
> address@hidden
> http://lists.nongnu.org/mailman/listinfo/paparazzi-devel


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