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happyelectron

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About happyelectron

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  1. The problem with the unpointed antenna approach is that it is hard to get the kind of gain one could get with a well pointed dish antenna (or even patch). I've heard about using a GPS to point the tracking antenna, however, I like the idea of also using the signal strength information like these guys have. Also, I agree that a dish or helical is a real hassle to transport. So maybe a tracking patch setup with 5 patches would have some benefit. Anyway, it is neat to see a tracking system work so well.
  2. Sorry for the bad link, and Mr. RC-Cam, thanks for correcting it! I was wondering how they were getting the "circular" in the system. It makes sense to put a circular patch on the plane so that the linear tracking Yagi's always have something to pick up. However, the only thing I don't like about a circular transmit patch on the plane is that it is pretty directional. Otherwise, this is definitely one of the better set-ups that I've seen. Terry, that's a cool idea to do it with 4 patches. Were you going to physically align the four tracking patch's so that they were off ax
  3. I am copying this from a thread on the rcgroups website. Very Cool!!! http://www.ltu.se/polopoly_fs/1.266...newformat-1.pdf with a video of it working here: The only thing I can’t figure out is they say the video receiver is circularly polarized, but they are using linear PC Yagi’s . So as usual I’m a little confused … - Happy Electron
  4. I just ordered one, and will let you know how well it captures video. The helicopter photography website that I found it on said that it worked very well and they used it for pretty high-end applications. It seems that buying a little memory stick video camera, even on ebay, could set people back ~$200. I just thought it was a super inexpensive way to capture video. I agree that it would not be useful for realtime flying because of time delays. - Happy Electron
  5. http://www.adstech.com/products/PTV-370-EF...?pid=PTV-370-EF Here is a $25 PCMCIA video display and capture card. I saw it listed on a vendor of rc helicopter ariel photography equipment for $110. I have no idea how well it works, but at the price it definitely seems worth looking into. I like the idea of a bigger display out in the field, as well as not having the extra step of transfer the video from my camera to my pc to store and share on the internet. Happy New Year!
  6. Here is an email that I got from Dave today about the mysterious switching polarization. I kind of understand it ... Gobble! BTW, Terry, I am trying out various combinations of 900 mhz antennas to see which ones work best. I'm going to start another thread with this information once I get results. I am still leaning towards using Helixes though ... --------------------------------------------------------- I've been thinking about what you were told and what your friend related to you about circular polarization changing. In essence it does not. The article may have been re
  7. OK, so here is an update from the Antenna Turkey. (BTW, Mr. RC-CAM I flapped my arms around on Thanksgiving day trying your polarization experinment until my wife threatened to put me in the oven and serve me for diner.) Also, before I get into this arcane, tedious, and probabally marginally useful technical communicade, I must say that it only goes to show that even the experts don't agree as to what is going on with Antennas. So, if they can't agree, we are all probabally doomed to long and painful conversations about the relative merits of different antenna configurations. An
  8. Mr. RC-cam, all I can say to the above on this great Thanksgiving day is "gobble, gobble, gobble ..." As the big Thanksgiving Antenna Turkey, I am certainly confused how a certain handed xmitted polarized signal becomes the opposite handed polarized signal simply by having the Satellite move across the sky. However, the day I start believing my own personal theoretical speculation over the 19th edition of the ARRL Antenna Handbook is the day I know I've changed one too many diapers ... and should start wearing the old ones on my head ... and taking a number of deep breaths, etc... Al
  9. You are absolutely right, nobody makes or uses helicals without a ground plane. The ground plane is needed for impedance matching as well as to boost the signal gain from the antenna. I brought up the no-groundplane thought exercise to try to understand, why in Mr. RC-cam's Satellite example, reciever antenna's handedness would need to be switchable to get a strong satellite signal. In particular, I was trying to understand how a satellite with a particular handed helical xmit antenna, can deliver opposite handed radiation to a recieve antenna. Since there is no way for a xmit helical's
  10. I forward him an email invitation to join ... I agree that it is not very useful to use a circularly polarized antenna on the transmitter. They tend to be large and cumbersome, and only are circularly polarized if you look at them on-axis, or head on. The main reason to use a circularly polarized recieve antenna is to make sure that the recieve antenna can pick up both vertical and horizaontally polarized transmitted radiation. The price we pay for this is a 3dB loss in receive antenna sensitivity if it is fed by a linearly polarized source like a whip. A circularly polarized
  11. He said they use a standard 1/2 wave dipole whip antenna. I can't remember the power, but I think he said it was less than 5 watts. These systems are used on real helicopters for TV news and police video surveilance. He said on the transmit side they have an arm that they lower down below the skids of the helicopter so their isn't interference with the helicopter. He also said they sometimes use a conical helical antenna on the xmit side. With respect to the null on the whip, he said that when the helicopter is directly overhead, usually the distance is not that far and they don't
  12. Hi folks! It has been a while since I've posted - it turns out 3 kids are a bit of a handful. It amazes me how much you all have figured out since I was active several years ago!! In the meantime, between diaper changes, I've been pondering the general problem of getting realiable video. It amazes me that this is such a hard problem. In researching the topic on the Internet I ran across a company that had some intersting solutions/white papers that has really taught me a lot. I am not affiliation with them, but I thought their approach could help inform and guide some of the
  13. Wow! Pretty darn inspiring! The video looks awesome. No drop outs or anything. Are you still using your diversity set-up? If so, I am curious which transmitters/antennas you have mounted on the helicopter. On the website you show the 500 mW 900 Mhz and 2 2.4 ghz transmitters. Is that still what you are using. Also, which transmitter/antenna combination shows the strongest performance? Thanks again for making keeping us up to date with such fun and uplifting stuff. - Happy Electron
  14. The IP5 loks even smaller than the block cameras at a much better price! Good luck and look forward to the results! - happyelectron
  15. Cyber-flyer, Check out the FCBEX780S and the FCBIX10A block cameras from Sony Professional at bssc.sel.sony.com. The FCBEX780S has an image stabilizer built in. It is the smallest block camera from Sony that I found that had the image stabilizer built in it. The link is http://bssc.sel.sony.com/Professional/weba...&sp=10&id=63993 I just bought FCBIX10A for $450 - http://bssc.sel.sony.com/Professional/weba...&sp=10&id=64384 I really like it for the following reasons: It is only about double the size of the Panasonic 171, but for that you get a 10x zoom, automati
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