So I went up for the 2nd time today. Much better this time around but anytime you go out and don't crash its always a good day. I found a large field that was about 400 square meters that gave me the confidence to do some testing. It was my first time out with the FPV. I'm using the quadrocopter monitor kit that has the 7" monitor, monitor shield and mounting for the receiver and the battery on the back of the monitor like in thsi video I didn't have the hardware to mount it to the MX20 yet so I just stuck it on a tripod. I'm using a yellow jacket receiver and the 500mv Mondo stinger. I kept having problems with the antennas on the yellow jacket they kept coming loose and to the point where the center wiring came off the solder joint. I think I'm going to upgrade receivers. I was having transmission issues but I think its because the antennas are messed up. I also moved my Go Pro2 below to the bottom hub using the mounting housing so I could angle it the way I wanted it. My footage was upside down though so I had to flip it in Final cut. Anyway I calibrated the compass to the location with the props off and then got everything together and made a quick up and down to make sure everything was good. It was 60 degrees here in Pittsburgh today and the snow was all melted but it sure made for a muddy field. Winds were about 5-10 mph and it varied quite a bit. For my second flight I started with PH on and then started the copter and went up. I then put altitude hold on and moved the copter around with PH and AH on. They both were very stable. I even tested CH and it came right back to where I was. I feel much better and relieved now that I know these work!!! I made 4 more flights and got some good practice in and some more confidence. Next time I go up I'll try the 2 axis gimble and the go pro 3. I balanced the gimble so its ready to go. I also bought some 12 LED light clusters http://www.hobbyking.com/hobbyking/store/__17192__12_LED_Cluster_RED.html I'm going to put Orange on boom 5, red on boom 1, and white on booms 3 and 7 to help with orientation. The youtube video for the 2nd flight I made today is here The landing is a little sloppy as I was still a bit nervous but I did improve I also posted the GPX file I don't see anything bad that sticks out and I don't see any errors but it would be good to get an extra set of eyes. I do have a few questions if I can get some input. 1. How do you sync up the video to GPX tools? I know how to import the video but where should I start the video? I mean where in final cut should I have the first frame? Upon startup? As soon as it launches? I would imagine that it would as soon as it launches? 2. Any recommendation for antennas? I imagine that I need 3? 2 for the RX and 1 for the TX? 3. Where does everyone mount their stingers? Any pics? 4. Is it possible to balance the C8 in the same manner as we do the gimble off the ceiling with fishing linen? I have strong fishing line that can take 75 pounds I just don't know about the mounting spot for the C8? I guess I could try it with the battery off and rig a fishing sinker under the center of the battery tray. Has anyone tried this? Just curious. My cinestar wanted to go a tad left on take off and in flight I image it's because of where I mounted the Go Pro, TX and lipo for the TX. 5. Can you change the orientation of the go pro picture in the go pro menu settings?
I think you're discovering a basic philosophy of copter flying, Dave. I have the monitors on a tripod too. I put Velcro on the back of the Small HD monitor and attached the Passport receiver there. You're doing all the right things, Dave. Baby steps and testing everything as you go. One thing to be mindful of is that the compass contributes to the stability of the Position Hold, so don't assume that a stable flight today means a stable flight in a different location tomorrow. Also the solar weather affects GPS performance, so check the solar weather before you fly. Specifically, lower center chart at http://www.n3kl.org/sun/noaa.html . Given that you're using FPV, consider the Smart On Screen Diisplay. One really useful thing it adds is the ability to see a visual orientation of the copter's heading using the compass (the so-called "radar view"). So you can glance at the screen before take-off, get a visual image of the magnetic heading that you can then compare with the magnetic heading as you fly -- it's easier to use the copter icon's angle than do the math in your head for given that the copter's currently at 250 degrees but you took off at 110 degrees. Use MK_GPXTOOL. Usually you can sync up with events like motor start or takeoff, and motor stop/landing. I use Blue-Beams. (The link is for 1.2Ghz Bluebeams -- if you're using 5.8 Ghz then use these.) You are correct. One for the TX and two for the RX. The Tx and Rx antenna are different so be sure to get the correct ones. See below: That's the correct way. I loop the mounting line (I just use string, but monofilament fishing line works well too) under the Velcro that holds the Lipos on. Balance with the Lipos! That's why we have trim controls! <evil grin> Hmm. Don't know I'm afraid. Andy.
Thanks as always Andy. I'm ahead of where I would be on my own had I didn't have this board for reference. I have learned that from you and even though it's a little more work I think you are absolutely right about recalibrating for each location. Too bad that MK electronics don't let you save location that you can just refer back to if you go back to the same location. Thanks for that tid bit of info. I didn't know anything about this. OK, I will give a try. I take it you have good success with them? I noticed that on that site there are different sizes? The ones you show are the small ones but I see that they also have rather larger ones. Do you know if I need SMA to RP-SMA cables or SAM to SMA cables? Is that your bird? I see the antenna pointing up and I was wondering if should be pointing down? I was thinking about powering them with the lipos but I don't know how I would get the fishing line straight up and centered if the battery was on the tray.
Dave, Regarding your antennas.... I had same problem. Made this upgrade and I fly out 500+ meters without a flicker. PERFECT. Here's the forum post.... You'll have to get the correct antennas from two different companies. Some of them are even hand made. Basically its combination of fan and cloverleaf shaped antennas. BTW - I run 5.8 ghz. http://forum.freeflysystems.com/index.php?threads/downlink-antennas.35/page-2#post-6580 Phil
Thanks Phil - I ordered the ventienas for the receiver and the blue beam for the transmitter as a starting point. Great info in the thread you posted.
A Andy, I concur.....per the folks at Readymade et al, they state TX antenna should point down while the group based antennas point up. The technical logic is that the antennas send/received signal in a "mushroom" fashion. So, essentially, the ground sends signal from a horizonal angle all the way to straight up. Therefore, the TX antenna should face down as it will send its signal horizontal all the way to a downward position, essentially pointing towards the ground receiver. Phil
The think that worried me is that given there is right hand circular polarization, when you invert the TX signal, from the ground's point of view doesn't that change it to left-hand? Hold a conventional analog hands wrist watch so it's facing down to the ground and you'll see that from up above it, it changes from clockwise to counterclockwise. I don't know enough about RF polarization/antenna design.... Andy