FPV Tech Mictronics. On this page you will find some information about the equipment I will use for FPV flying. Video Transmitter and Receiver. The transmitter and receiver was taken from a video link set like this Such set includes a big transmitter, which was rated on the box for 3. W. A measurement discovered 5. W of output power using a tuned antenna for good VSWR. Another video link set exists with a small transmitter rated for 2. W. Measuring the power showed really 2. W output power. To compare the transmitter size I disassembled the receiver and put the tuner and PCB in my DIY antenne tracker, see below. Antennas. Receiver. Since the video downlink is working in the 1. Curiosity Development Board. Your next embedded design idea has a new home. Curiosity is a costeffective, fullyintegrated 8bit development platform targeted at. GHz range I ordered a patch antenna RE1. P SM from L com which covers the range and the size and weight is not to much for use with a DIY antenna tracker. The antenna is rated from 1. MHz with a SWR lt 1. Bi. To proof this parameters I performed some measurements with a network analyzer with the following results The plots show that the antenna is only usable in a maximum range from 1. MHz where the VSWR is lt 2. Best VSWR is 1. 0. MHz which is close to channel 3 1. MHZ of my video downlink which I will use then. So the antenna parameters, at least the VSWR, provided by the manufacturer seems to be dressed up a bit. Since I replaced the coax cable with a more flexible one, due to use of the antenna with my tracker, some pictures are discovering the inside of the RE1. P SM antenna. By this chance I took also measurements of the antenna patch construction. Yagi was reviewed by members from RC groups and rated for very good results. So I could not resist to order and try myself. The new Yagi came from China for around 1. This antenna performs best for the price. A range test was stopped at 1. But its sure 1. 5km can be reached as long as you have line of sight to the transmitter. Vol. 7, No. 3, 200405. Study on Bilinear Scheme and Application to Threedimensional Convective Equation Itaru Hataue and Yosuke Matsuda. Contents. Quick Guide MVG, the Broadest Choice of Antenna Test and Measurement Solutions Antenna Measurement and Radome Testing Systems 2. Multiprobe systems. Notice that the output of the chip is actually differential but the matching components convert it to a singleended output. Essentially this allows you to use one. Fig. 1. Homebrew Curve Tracer a very handy Tool All we need is an Oscilloscope with an x and an y input. This feature is available in almost every Oscilloscope. On this page you will find some information about the equipment I will use for FPV flying. Video Transmitter and Receiver. The transmitter and receiver was taken from. US/airport/airport-menu-open-wireless-diagnostics-window-scan-scan-now.png' alt='Rssi Measurement Tool' title='Rssi Measurement Tool' />This section will list several projects which will allow you to build your own RF design test equipment. Microwave construction techniques and basic electronic skills. Speed radar gun. Pocket Radar revolutionized the radar speed gun with the speed testing radar that is conveniently sized and accurate. No more missed important software updates UpdateStar 11 lets you stay up to date and secure with the software on your computer. PDW30_both_close_up_0.png' alt='Rssi Measurement Tool' title='Rssi Measurement Tool' />Although the Yagi is rated from 1. MHz it worked best for me at 1. MHz. Therefore I changed my transmitter frequency to a new channel. Side effect of the frequency change is also that I got rid of the LPF. At 1. 20. 0MHz GPS is no longer affected by the VTX. You can order this antenna at e. Bay http cgi. Bay. ISAPI. dll View. Item item2. Transmitter. On the transmitter side it makes only sense to use an omnidirectional antenna since the transmitter will move around during flight. A usable solution will be a lambda4 or lambda2 dipole, where the halfwave dipole has the advantage of a small or even no ground plane required. I read through all types of possible antennas and there advantages and disadvantages, also about the construction details and impedance matching. My first try will be a coaxial antenna made from a small brass tube and RG1. Such antenna is easy to construct and matching is also easy since you just need to cut the upper part of the dipole for best VSWR. For all tests the brass tube remains the same length of 6. Reduction factor 0. The first attempt for impedance matching was to measure the current drawn by the transmitter. With 7. 4mm length of the upper part the lowest current around 1. A 1. 2V was drawn. Later on a VSWR measurement showed best resonance at 1. MHz which is far of the desired frequency 1. MHz. While connected to the VNA I cuted the antenna until I got the best VSWR for my desired frequency at 1. MHz ending up with a length of 5. A 1. 2V drawn by the transmitter on power up. The length of 5. 6mm corresponds to a reduction factor of 0. I found in the books. Here are the resulting details of my coaxial antenna for the 1. GHz video transmitter One important thing to keep in mind for such type of antenna is the fact that the lower part, the brass tube, must be isolated to ground because the tube is a radiating part as well While the receiver antenna has been changed the one on the transmitter was changed as well. Now I use a DIY IBCrazy inverted V antenna, measured and tuned at 1. MHz. As shown on the picture the inverted V antenna is now integrated in the leading edge of the left wing. With both antennas, the e. Bay Yagi and the inverted V, I archived the range of 1. LOS while video was crystal clear. See this thread on RC groups about all details of the inverted V antenna http www. Also check IBCrazys blog on RC groups for more DIY tutorials regarding FPV http www. GHz Helix Antenna. GHz Helix Antenna. GHz Helix Antenna. Adobe Flash Player Setup on this page. Low Pass Filter. Using a a medium or high power video transmitter together with a 2. GHz remote control will cause heavy interferences due to second or third order harmonics. A drastic loss of performance and decreased range of the remote control will be the result. Also when a GPS receiver might be influenced by a 9. MHz or 1. 2. GHz video transmitter which could lead to decreased performance or even to the complete loss of the GPS fix. In all cases a low pass filter between the video transmitter and the antenna will help to reduce interferences to a minimum. DPCAV LPF 9. 00. The following pictures showing the low pass filter LPF 9. Since 2. 01. 0 they introduced a new version with reduced size. The plot shows the performance of the LPF 9. MHz 2. 5. GHz. Attenuation for the GPS L1 frequency at 1. MHz is 3. 7d. B while at 2. GHz the attenuation is even higher with 5. B. Pass through attenuation is lt 3d. B at 9. 00. MHz and 1. GHz. Mini Circuits VLF 1. Another low pass filter I have tested is the VLF 1. This filter is rated up to 1. W input power. Pass through attenuation is lt 2d. B at 9. 00. MHz and 1. GHz. Attenuation for GPS L1 is 3. B and 3. 9d. B for 2. GHz. Conclusion. All in all such filters are suiteable if you have interference or performance loss with your GPS or 2. GHz remote control. Antenna Tracker. This is my DIY antenna tracker. Based on a Hammond metal box it includes everything necessary for video and telemetrie downlink reception. The arm beside the patch antenna will hold a 5 elements Yagi for 8. MHz later on. The lower part of the box holds a 5. V2. A power supply, a 1. V1. A regulator and a part of the video receiver. The upper part of the box holds the pan servo, video tuner module, the tracker controller board and the RSSI indicator. The tracker controller is based on ATmega. FT2. 32. R. The board accepts control inputs from a PC by USB and uses the Pololu protocol for servo commands. One serial input of the ATmega. Wi. 2. 32 moduleto receive telemetrie data and of course the aircrafts position. A second serial input can receive optional NMEA data from an external GPS module not used for now. By a jumper block the serial signals can be routed from and to the PC andor the controller board to the Wi. MK Tool, Mission cockpit on the PC. Actually the controller board can drive 4 servos but only two are in use. With 4 jumpers the servos can be inverted independently from software. The connector front provides USB, video and audio, power input and a DIP switch to select the video channels. In the following picture you see the top of the box without pan tilt mechanic, only the  pan servo output shaft is visible. The whole mechanical part is fixed by a M2. The round base plate takes the wheight of the tilt mechanic and prevents it from shaking. For easy moving I put some grease on the bottom of the base plate. The pictures are showing also the cable routing for 9. The following pictures showing details of the tilt mechanic, cable routing and tilt bearings.