Air to ground video downlinking, status in October 2004

<body topmargin=0 leftmargin=0 marginheight=0 marginwidth=0> <table cellpadding=0 cellspacing=0 border=0><tr> <td valign="top" colspan=2 height=82 BGCOLOR="#006699" TEXT="#080000"> <div> <FONT SIZE="5" COLOR="#FFFFFF" FACE="Arial" ><B>JBVM Delemarre</B></FONT><B>     |     </B><A HREF="index.htm" TARGET="_top" TITLE="JBVM Delemarre"><U><B>home</B></U></A></div> <div> <A HREF="id107.htm" TARGET="_top" TITLE="Air to ground video experiments"><U>Air to ground video experiments</U></A>   |   <B>Air to ground video downlinking, status in October 2004</B>   |   <A HREF="id118.htm" TARGET="_top" TITLE="Build up of a transmitter"><U>Build up of a transmitter</U></A>   |   <A HREF="id120.htm" TARGET="_top" TITLE="Power supply for TX and RX module"><U>Power supply for TX and RX module</U></A>   |   <A HREF="id119.htm" TARGET="_top" TITLE="Sound amplifier"><U>Sound amplifier</U></A>   |   <A HREF="id115.htm" TARGET="_top" TITLE="Links on air to ground video downlinking"><U>Links on air to ground video downlinking</U></A>   |   <A HREF="id108.htm" TARGET="_top" TITLE="Photographs of video experiments"><U>Photographs of video experiments</U></A>   |   <A HREF="id113.htm" TARGET="_top" TITLE="Photographs of video experiments 2"><U>Photographs of video experiments 2</U></A>   |   <A HREF="id114.htm" TARGET="_top" TITLE="Photographs of the Calmato video plane"><U>Photographs of the Calmato video plane</U></A>   |   <A HREF="id121.htm" TARGET="_top" TITLE="A new video plane"><U>A new video plane</U></A></div> <div> </div> </td> </tr><tr> <td valign="top" width=210 BGCOLOR="#FFCC66" TEXT="#080000"> <div> <A HREF="id107.htm" TARGET="_top" TITLE="Air to ground video experiments"><U>To previous page</U></A></div> <div>  <A NAME="de_start_1"><IMG BORDER="0" SRC="1x1.gif" HEIGHT="1" ALIGN="bottom" WIDTH="1" HSPACE="0" VSPACE="0" ></A><A HREF="id113_start_groot.htm" TARGET="_top" TITLE="Photographs of video experiments 2"><U><IMG SRC="24db3860.jpg" border=0 width="179" height="134" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></U></A></div> <div> The first test setup on the flying field of the GMVC</div> <div>  <A NAME="ant_test"><IMG BORDER="0" SRC="1x1.gif" HEIGHT="1" ALIGN="bottom" WIDTH="1" HSPACE="0" VSPACE="0" ></A><A HREF="id113_ant_test_groot.htm" TARGET="_top" TITLE="Photographs of video experiments 2"><U><IMG SRC="254b3860.jpg" border=0 width="179" height="134" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></U></A></div> <div> Antenna testing on the Telemaster</div> <div>  <A NAME="tx_power"><IMG BORDER="0" SRC="1x1.gif" HEIGHT="1" ALIGN="bottom" WIDTH="1" HSPACE="0" VSPACE="0" ></A><A HREF="id113_tx_power.htm" TARGET="_top" TITLE="Photographs of video experiments 2"><U><IMG SRC="268b3730.jpg" border=0 width="179" height="115" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></U></A></div> <div>  <A NAME="tx_sound"><IMG BORDER="0" SRC="1x1.gif" HEIGHT="1" ALIGN="bottom" WIDTH="1" HSPACE="0" VSPACE="0" ></A><FONT SIZE="2" COLOR="#003399" FACE="Arial" >Transmitter....</FONT><A HREF="id113_tx_sound.htm" TARGET="_top" TITLE="Photographs of video experiments 2"><U><IMG SRC="269b3740.jpg" border=0 width="179" height="116" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></U></A><FONT SIZE="2" COLOR="#003399" FACE="Arial" > ....as used today</FONT></div> <div>  <A NAME="ant_quad"><IMG BORDER="0" SRC="1x1.gif" HEIGHT="1" ALIGN="bottom" WIDTH="1" HSPACE="0" VSPACE="0" ></A><A HREF="id113_ant_quad.htm" TARGET="_top" TITLE="Photographs of video experiments 2"><U><IMG SRC="26ab3940.jpg" border=0 width="179" height="148" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></U></A></div> <div>  <A NAME="ant_gpp"><IMG BORDER="0" SRC="1x1.gif" HEIGHT="1" ALIGN="bottom" WIDTH="1" HSPACE="0" VSPACE="0" ></A><A HREF="id113_ant_gpp.htm" TARGET="_top" TITLE="Photographs of video experiments 2"><U><IMG SRC="26bb3770.jpg" border=0 width="179" height="119" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></U></A></div> <div>  <A NAME="ant_quadhybrid"><IMG BORDER="0" SRC="1x1.gif" HEIGHT="1" ALIGN="bottom" WIDTH="1" HSPACE="0" VSPACE="0" ></A><A HREF="id113_ant_quadhybr.htm" TARGET="_top" TITLE="Photographs of video experiments 2"><U><IMG SRC="26cb3840.jpg" border=0 width="179" height="132" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></U></A></div> <div>  <A NAME="ant_dipole"><IMG BORDER="0" SRC="1x1.gif" HEIGHT="1" ALIGN="bottom" WIDTH="1" HSPACE="0" VSPACE="0" ></A><A HREF="id113_ant_dipole.htm" TARGET="_top" TITLE="Photographs of video experiments 2"><U><IMG SRC="26db3720.jpg" border=0 width="179" height="114" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></U></A></div> <div> Various antennas</div> <bR> <bR> <bR> <bR> <bR> <bR> <bR> </td> <td valign="top" height=398 BGCOLOR="#FFFFFF" TEXT="#080000"> <div> <I>Air to ground video downlinking, status in October 2004</I></div> <bR> <div> Because the antenna on a 2.4 GHz system can make or brake the efficacy of a system, it soon became clear that the wire antenna provided by Fels was not the best possible. I made the collinear antenna as described on the RC-cam forum and this was the first improvement. Soon the <A HREF="http://www.yb2normal.com/antenna3.html" TARGET="_top" TITLE="http://www.yb2normal.com/antenna3.html"><U>ground plane antenna</U></A> as described by Bill Strong, a.k.a. Yb2Normal on the web, was copied and this was the greatest improvement till today. That means: of the antennas tested till today. </div> <div> On the site of <A HREF="http://www.cyber-flyer.com/" TARGET="_top" TITLE="http://www.cyber-flyer.com/"><U>Val Petrov </U></A>in the USA and on the <A HREF="http://groups.msn.com/rccam/antennaideas.msnw?albumlist=2" TARGET="_top" TITLE="http://groups.msn.com/rccam/antennaideas"><U>photo part</U></A> of the old forum of RC-cam an antenna is described using a <A HREF="http://www.raditek.com" TARGET="_top" TITLE="http://www.raditek.com"><U>quadrature hybrid</U></A> so you can make a crossed dipole antenna with the radiation pattern 90 degrees out of phase between the two dipoles. This theoretically gives the best spread of the radio energy from the transmitting antenna.   </div> <div> This kind of antenna is also used by <A HREF="http://www.noskylimit.50megs.com/index.htm" TARGET="_top" TITLE="http://www.noskylimit.50megs.com/index.h"><U>Giorgio and Simone</U></A>, two modelers of Italian origin now in Florida, USA, attempting a new world altitude record. They have flown up to 6 kilometers with a good video connection!</div> <bR> <div> At the receiving end the antenna has to be of good quality also. A patch antenna was described on the RC-cam forum by Thomas Black also known as Mr. RC-cam. As long as you do exactly what he describes on the site you can not go wrong, hence he called it the Goof Proof Patch or <A HREF="http://www.rc-cam.com/gp_patch.htm" TARGET="_top" TITLE="http://www.rc-cam.com/gp_patch.htm"><U>GPP antenna</U></A>. I also made this one. </div> <div> Together with the quadrature hybrid crossed dipole antenna this GPP antenna has yet to be tested in field trials. Ever since the finishing of both, either weather was to bad or I had to work...so no model flying was done for some considerable time.</div> <bR> <div> In the meantime, <A HREF="id114.htm" TARGET="_top" TITLE="Photographs of the Calmato video plane"><U>the new airplane was fitted out</U></A>  <A NAME="terugkeerpuint_van_vltg_pag"><IMG BORDER="0" SRC="1x1.gif" HEIGHT="1" ALIGN="bottom" WIDTH="1" HSPACE="0" VSPACE="0" ></A>to carry the video transmitter, a separate 5 cell NiMH battery and the camera. The battery and the transmitter are placed inside the fuselage while the camera is fixed underneath the left wing together with the antenna. </div> <div> I have flown the Kyosho Calmato with a dummy weight to check the load carrying capability and this proved to more than adequate. A slight uptrim while landing is the only difference compared to normal flying without the video system onboard.</div> <bR> <div> A mismatch in impedance between the video camera and the Fels TX module caused a ripple on the top of the video picture and on high contrast transitions. This can be seen on the video clip on the <A HREF="id65_airborne_video_download.htm" TARGET="_top" TITLE="Downloadable files"><U>"</U></A><A HREF="id65_airborne_video_download.htm" TARGET="_top" TITLE="Downloadable files"><U>downlink page</U></A><A HREF="id65_airborne_video_download.htm" TARGET="_top" TITLE="Downloadable files"><U>"</U></A>.  <A NAME="terug_van_downlink_page"><IMG BORDER="0" SRC="1x1.gif" HEIGHT="1" ALIGN="bottom" WIDTH="1" HSPACE="0" VSPACE="0" ></A>After extensive experimentation a small resistor in line with the video feed to the transmitter gave the solution. The second demo video is of better quality. This one was also made using a second camera placed in a housing with a sunshade on the side of a Multiplex electric aircraft, the Moviestar. Flare had proven be bothersome. The original shade was a bit to long as you can see that at the right side of the video picture where a small portion is cut of. </div> <div> Another small builders project was the video switcher as proposed by Mr. Rc-cam on his site. As the PCB for this project is no longer available no link is provided.</div> <bR> <div> To give an impression of the current status I made pictures of the airborne system and the receiving system with the various antennas. </div> <div> <A HREF="id65_videoclip2.htm" TARGET="_top" TITLE="Downloadable files"><U>Video clips can be downloaded</U></A><A HREF="id65_videoclip2.htm" TARGET="_top" TITLE="Downloadable files"><U> </U></A>so you can get an impression of what is going on. I hope you like it. The quality of the video clips has suffered tremendously from the compression to get it on the internet. The pictures I have from the original avi files are much better but they are several Gb in size!</div> <bR> <div> As soon as I have some more experience with the equipment as it is today, October 2004, I will update these pages of my site. This will mainly depend on the weather and my being free from work or not.....unfortunately.</div> <bR> <div> How do I make the modular TX to work? <A HREF="id118.htm" TARGET="_top" TITLE="Build up of a transmitter"><U>Look at this page</U></A>!</div> <bR> <div> For more information on this subject I placed most of <A HREF="id115.htm" TARGET="_top" TITLE="Links on air to ground video downlinking"><U>my favorite links here</U></A> <A NAME="terug_van_links_pag"><IMG BORDER="0" SRC="1x1.gif" HEIGHT="1" ALIGN="bottom" WIDTH="1" HSPACE="0" VSPACE="0" ></A> so you can also visit the sites that provided me with most of the information I needed.</div> <bR> <bR> <bR> </td> </tr></table></body>