Air to ground video experiments

<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> <B>Air to ground video experiments</B>   |   <A HREF="id110.htm" TARGET="_top" TITLE="Air to ground video downlinking, status "><U>Air to ground video downlinking, status in October 2004</U></A>   |   <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"> <bR> <bR> <div>  <A NAME="telemaster_met_videobox_on_top"><IMG BORDER="0" SRC="1x1.gif" HEIGHT="1" ALIGN="bottom" WIDTH="1" HSPACE="0" VSPACE="0" ></A><A HREF="id108_telemaster_video_on_top_groot.htm" TARGET="_top" TITLE="Photographs of video experiments"><U><IMG SRC="21fb3850.jpg" border=0 width="179" height="133" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></U></A></div> <div> Telemaster with video TX</div> <bR> <div>  <A NAME="inside_videobox"><IMG BORDER="0" SRC="1x1.gif" HEIGHT="1" ALIGN="bottom" WIDTH="1" HSPACE="0" VSPACE="0" ></A><A HREF="id108_inside_videobox_groot.htm" TARGET="_top" TITLE="Photographs of video experiments"><U><IMG SRC="220b3860.jpg" border=0 width="179" height="134" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></U></A></div> <div> Inside video TX box</div> <bR> <div>  <A NAME="antennas"><IMG BORDER="0" SRC="1x1.gif" HEIGHT="1" ALIGN="bottom" WIDTH="1" HSPACE="0" VSPACE="0" ></A><A HREF="id108_antennas_groot.htm" TARGET="_top" TITLE="Photographs of video experiments"><U><IMG SRC="22ab3860.jpg" border=0 width="179" height="134" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></U></A></div> <div> Antennas used </div> <bR> <div>  <A NAME="peter_veerman"><IMG BORDER="0" SRC="1x1.gif" HEIGHT="1" ALIGN="bottom" WIDTH="1" HSPACE="0" VSPACE="0" ></A><A HREF="id108_veerman_groot.htm" TARGET="_top" TITLE="Photographs of video experiments"><U><IMG SRC="22fb3860.jpg" border=0 width="179" height="134" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></U></A></div> <div> Peter Veerman brings the plane in after the first successful flight</div> <div>  <A NAME="ccd_camera"><IMG BORDER="0" SRC="1x1.gif" HEIGHT="1" ALIGN="bottom" WIDTH="1" HSPACE="0" VSPACE="0" ></A><A HREF="id108_camera_panasonic_in_box.htm" TARGET="_top" TITLE="Photographs of video experiments"><U><IMG SRC="241b3860.jpg" border=0 width="179" height="134" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></U></A></div> <div> The Panasonic CCD camera in its box</div> <div>  <A NAME="eerste_verkleining_zender"><IMG BORDER="0" SRC="1x1.gif" HEIGHT="1" ALIGN="bottom" WIDTH="1" HSPACE="0" VSPACE="0" ></A><A HREF="id108_eerste_verkleining_zender_groot.htm" TARGET="_top" TITLE="Photographs of video experiments"><U><IMG SRC="235b3860.jpg" border=0 width="179" height="134" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></U></A></div> <div> First reduction in size of the video transmitter with sound amplifier</div> <bR> <div>  <A NAME="laatste_versie_zender_1"><IMG BORDER="0" SRC="1x1.gif" HEIGHT="1" ALIGN="bottom" WIDTH="1" HSPACE="0" VSPACE="0" ></A><A HREF="id108_def_versie_zender_1.htm" TARGET="_top" TITLE="Photographs of video experiments"><U><IMG SRC="233b3860.jpg" border=0 width="179" height="134" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></U></A></div> <div> Final version and second reduction in size..</div> <div>  <A NAME="ontvanger"><IMG BORDER="0" SRC="1x1.gif" HEIGHT="1" ALIGN="bottom" WIDTH="1" HSPACE="0" VSPACE="0" ></A><A HREF="id108_ontvanger_groot.htm" TARGET="_top" TITLE="Photographs of video experiments"><U><IMG SRC="23cb3770.jpg" border=0 width="179" height="119" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></U></A></div> <div> Receiver with dipole antenna</div> <div> <A HREF="id110.htm" TARGET="_top" TITLE="Air to ground video downlinking, status "><U>To </U></A><A HREF="id110.htm" TARGET="_top" TITLE="Air to ground video downlinking, status "><U>next page</U></A></div> <bR> </td> <td valign="top" height=398 BGCOLOR="#FFFFFF" TEXT="#080000"> <div> <I>Air to ground video experiments</I></div> <div> While working on the air to ground photography setup, I cam across the <A HREF="http://www.towerhobbies.com/rcwebnew.html" TARGET="_top" TITLE="http://www.towerhobbies.com/rcwebnew.htm"><U>"new links"</U></A> part on the <A HREF="http://www.towerhobbies.com" TARGET="_top" TITLE="http://www.towerhobbies.com"><U>Tower Hobby </U></A>site and found the remarkable web site of Dennis Gratton, known as <A HREF="http://www3.sympatico.ca/denisgratton/angdiver.html" TARGET="_top" TITLE="http://www3.sympatico.ca/denisgratton/an"><U>VR-flyer</U></A> on the <A HREF="http://www.rc-cam.com/forum/" TARGET="_top" TITLE="http://www.rc-cam.com/forum/"><U>RC-cam forum</U></A> as I found out later.</div> <div> After extensively viewing his site I was hooked and wanted to make my own air to ground video equipment. This proved to be easier said than done! For starters you need a HAM license to operate any equipment that transmits video signals at a usable power level. I already had a lower class license so I immediately applied for the upgrade exams and started studying using the books provided by the Dutch <A HREF="http://www.veron.nl/hobby/nl/" TARGET="_top" TITLE="http://www.veron.nl/hobby/nl/"><U>VERON</U></A> club. This is the organization of radio amateurs in the Netherlands. After passing the exam (one fault out of fifty questions...) I went on with the development of my transmitter and the receiver. </div> <div> I had gathered a lot of information through the internet and e-mails from Dennis Gratton from Canada and soon the first experiments took place. I our garden I was able to pick up a usable video signal from a transmitter about 70 meters away. This system used a CMOS camera, operating on 12 volts, and a 50 milliwatt Fels 2.4 GHz transmitter and receiver operating on 5 volts. Because it was my intention to fly with the video camera and transmitter mounted on a Telemaster model airplane I did not want to use a 12 volt NiCad battery. Weight restrictions came into play. So I used a switching voltage multiplier that could produce a steady 12 volts at 1 ampere out of five volts. </div> <div> Soon it proved that, on the workbench, the switcher circuit produced not only 12 volts but also a lot of interference for the RC-receiver. The interference caused by the switching frequency of several hundreds kilohertz was very difficult to eliminate. On the RC-cam forum a lot of discussion was spend on this phenomenon. Also the camera picture showed an interference that was caused by this circuit. Changing to another fully integrated circuit did not resolve this problem so I decided to take it for granted at this point and go to the flying field of the <A HREF="http://www.gmvc.nl" TARGET="_top" TITLE="http://www.gmvc.nl"><U>GMVC</U></A>, the model aero club I belong to. There I did experiments with the camera-transmitter setup in one box and my plane and Multiplex MC-4000 radio control system. Using PCM coding and placing the box containing the camera and the transmitter as far away from the receiver aerial as possible, the interference to the radio control system was gone and a good ground range check was obtained. The receiver was connected to the television set borrowed from the clubhouse and the first flights with the video transmitter onboard were made. </div> <div> Because this was just to see if anything could be done with this setup, no video recording was done at that time. </div> <bR> <div> Pictures were taken of the equipment as used and are shown on the bar at the left side. Clicking on them will enlarge them in a separate window.</div> <bR> <div> The first video pictures on the TV screen caused quite some excitement. It was possible to transmit live video from a standard model airplane shortly after beginning with the exploration of a new field in electronics for me. I was very satisfied this far but I also wanted to record the video pictures on tape so I could review the video when flying the plane by myself. The initial flying was done by a proficient flyer at the GMVC, Peter Veerman, now a model jet jockey in his own right.  This was first done by using a standard home VCR, provided by Diane Waka another club member of the GMVC, but soon the need for a more compact system was felt and so the old Panasonic handy cam was replaced by a new Sony TVR-60 model. This has the advantage that this recorder has a digital output of analogue input signals and is capable of recording from an external analogue picture source.</div> <div> This makes editing on a PC very easy because all you need is a firewire connection and the appropriate software, but that comes with Windows XP as standard (Windows media player).</div> <div> With the quality of the recording system at best, it was very obvious that something had to done on the video picture from the CMOS camera. This picture showed a lot of "ringing" or shadow pictures along the edge of contrast transitions. Also the handling of shadow to highlight transitions wasn't good as the camera blacked out for several seconds.</div> <bR> <div> Through a discussion on the <A HREF="http://www.rc-cam.com/forum/" TARGET="_top" TITLE="http://www.rc-cam.com/forum/"><U>RC-cam forum</U></A> it became obvious that the Panasonic board cameras could solve two problems at once. They operate on five volts and are of CCD quality. The power converting circuit could be eliminated and the video picture was the best possible in these circumstances. It took a while but I found <A HREF="http://www.1a-wengercon.de/" TARGET="_top" TITLE="http://www.1a-wengercon.de/"><U>a dealer </U></A>in Germany that could sell me such a camera at a reasonable price and the Panasonic KX-121 was bought. Unfortunately these cameras are no longer made by Panasonic....</div> <bR> <div> Once the camera was in house, a small box was made from thin plywood with a glassed front so the lens was kept free from oil from the engine from the plane. Also the transmitter was worked on and a sound amplifier was made, using the information available on <A HREF="http://www.mh.ttu.ee/risto/rc/logo20/wvideo/" TARGET="_top" TITLE="http://www.mh.ttu.ee/risto/rc/logo20/wvi"><U>Risto's site</U></A>. At first this was build using standard size parts but soon this was replaced by a SMD version. Together with the power regulator on one side, the sound amplifier was used to sandwich the transmitter module into a very compact unit weighing only 34 grams.</div> <bR> <div> The receiver was rather simple to make because this is an also in a modular form from Fels. I made it into a case also containing the power supply and the channel switch. As no space or weight limits were applicable I just took a case that was already available.</div> <bR> <div> Thus far it was all rather easy to do, more a matter of perseverance than intelligence, I would say.</div> <bR> <div> Experimenting with what I had at that moment, it showed quite readily that the antenna technique is something of its own. The quality of the antenna on the transmitter and the receiver can make or brake a system. I overcame most of the video problems with "white outs" i.e. loss of signal, by acquiring a Fels module with a higher output of 500 milliwatts.</div> <div> This was build up with the power regulator and sound amplifier just as the previous module. Then the experiments with the antennas started together with the replacement of the Telemaster. The plane was used for fun flying during the odd day that I was free from work and began to show signs of deterioration. Due the fact that several Kyosho Calmato trainers were flying at the club I was pretty convinced that this plane was an ideal follow up to the Telemaster. I bought one of these truly ARF models and build it up. This took me exactly one day and thereafter I was flying it much to my content. </div> <div> Initially I used it for another project that I was running in between. This had to do with datalogging during flight where the receiver output to the servos was logged together with the battery voltage and current used by the onboard RC-electronics. In this period the video experiment came to a temporary halt. This had also to due with the fact that I was making a new antenna for the transmitter for which I needed a special kind of coax cable that was difficult to locate. </div> <bR> <div> Where do I stand today? Have look at <A HREF="id110.htm" TARGET="_top" TITLE="Air to ground video downlinking, status "><U>the next page</U></A>.</div> <bR> <bR> <bR> <bR> <bR> <bR> <bR> <bR> <bR> <bR> <bR> <bR> <bR> <div>   </div> </td> </tr></table></body>