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Posts posted by Hartwig

  1. Hi,

    just in case you're still in trouble with those goggles, I've seen this on other goggles as well. As far as I found out, it's a connection problem inside the Kopin module itself. The actual LCD screen connection to the flat ribbon cable gets bad with time. Though all seems well when the module is cold, as it heats up, the connection gets loose and the electrical levels on the LCD start fluctuating. This results in a huge brightness shift, and contrast reduction, which ends up in a white screen.

    So far I have not found an easy way to fix it. You might be successful in opening the module and find out if you can locate the exact location of the loose connection by pressing and bending specific spots. Only do this at your own risk, and if the warranty period is over!

    Good luck,


  2. I managed to find my plane a couple of times with a simple 8dBi patch. Wave it and walk towards where the image looks best or the missle of the range where it's good. But,

    most times that's what happened.

    Indeed. I got led bargraph displays on my reciever and it's very useful as long as the video TX still transmits, and as long as there are no other TXs on similar frequencies near. In my area, they are :( The last 2 crashes I had got the front half of the plane crushed into pieces, and nothing survived. The lipo was squezzed and I found the videoTX 5meters apart from the plane.

    What you really want is a reliable beacon that stilltrasmits when everything else doesn't work anymore. It has to be "crash-proof", needs it's own battery, and has to be totally independent.

    The second thing you will love is a simple Lost Model Alarm beeper for the "close range approach".

    From my experience :o , I can only recommend this! ;)

  3. hm.. i´ve got a related problem..

    i am thinking about using a ubec for my ES, but so far i don´t understand how it is best incorporated in the current hardware...

    Afaik the UBEC is also connected to the main power source (lipo) ... right? The red cable of the BEC has to be severed (as mentioned above)... so far so good..

    How do i connect both the ESC and the UBEC to the Lipo? I guess i could rig something but i´d like to know if theres an elegant option... :P

    Thx in advance :P

    Well, you might like to solder a T-style-adapter made of a male and a female Deans plug, and a cable with a JST connector on the other end to which you will connect your BEC. The ESC is plugged into the Deans connector as usual. Alternatively you can just solder the cable with the JST connector directly to the battery connector of your ESC and forget about the 2 extra Deans plugs.

    On the output side make sure that there is NO electrical connection between the 5V out of the BEC and the 5V out of the ESC! Otherwise you will fry one of them or both.

    You can supply, for example, elevator and rudder Servos and the receiver from the ESC, and ailerons and pan/tilt from the BEC. Just make sure that the signal wires from the servo connectors is plugged into the proper sockets of the receiver. The servos will get their power and GND via the BEC (and the others via the ESC).

  4. I am interested in buying/building a low-cost wireless RF video system for a film production project I'm working on. I simply need to take the video out signal from a digital camcorder (both s-video and RCA video outputs are available) and transmit that video signal wirelessly to multiple LCD monitors and or TVs.

    If anyone would be kind enough to comment on the applicability of your systems to this purpose, I'd be very grateful. If there is a newbie post section I should read, please direct me there as well.

    Video image quality is the greatest concern, while range is not as important. The remote monitors and/or TVs will likely be within a couple hundred feet of the camera.

    You probably found out about this already, but anyway, here's the link:


    Choose one of the systems that suits your area. You might like to try a 500mW TX to make sure it still works in noisy environments. (Oh, yes... Be aware that you might need a license for this amount of power. 10mW is ok without a license in all places I've heard of.)

    Rangevideo offers TX and RX seperately so you can buy one TX and as many RXs as you need.

    Enjoy! :-)

  5. Gentlemen,

    It was with great interest I read through this thread, but why did it suddenly stop?

    Did anyone come to a conclusion? Was is possible to transmit the NMEA signal and was the received signal good enough to use?

    If a product came out of this, I would really like to buy a couple :D


    Hello Jan,

    I tried this and it works fine. The only thing is that you have to limit the NMEA output of your GPS receiver to the sentences which you definitely need, and at a reasonable rate. The circuit needs some "recovery pause", as Thomas mentioned before. I limited it to RMC and GGA, both at 1Hz which seems to be fine.

    Jeff (jparisse) offered the kit a while ago. Maybe he still does. You might like to send him a pm and ask.



  6. All those are illegal however. I haven't checked what they were assigned to, but it might also be an interference source...

    Yeah, good point! I haven't used them, yet. Do you have a link to a good information source on this that you can give me?

    I guess 2490MHz should be within legal limits. I was looking for good information pages on it but all I found was the information that 2.4-2.5GHz ISM is usable for video transmission. Is that correct?

    The highest WLAN center freq (chnl14) is at 2483.5MHz, so 2490 should have the least interference problems of all channels in the 2.4-2.5GHz range.


    I was talking about the systems from rangevideo, channels 5-8. I'm currently using airwave systems at 2410MHz which works very nice, but I "share" the freq with lots of others.

    So, after all, a tracking antenna seems to me a good solution in terms of "filtering" what's in the air because it "listens" into the right direction. It only needs a reliable repositioning control. I would consider a GPS downlink via a seperate TX on 433MHz or whatever, and a GPS at the ground station to calculate azimuth and elevation.

  7. Terry, I'd love to see you continuing your project :-)

    I have the same problems with WiFi noise and others. Maybe selecting the frequency to a channel that doesn't interfere too much, could help. Especially RSSI is sensitive to everything on the same channel.

    This is a channel table of WiFi frequs: http://www.moonblinkwifi.com/2point4freq.cfm

    So running the video link on 2370, 2390, 2490, 2510 MHz should be worth a try.

    I didn't have a chance yet to test it, but as soon as I have some results I will post them.

  8. I'm currently using an old Hi8 camera with an external video input jack. This seems to me a very reliable solution as it doesn't blank the screen or drop frames if the signal gets bad.

    I tried several DV recorders and it was just a matter of "signal disaster" until they stopped accepting signal and recorded a black or a blue screen instead.

    Anyway I guess most of us are using DV recorders successfully.

    Regarding the recording I just like to be able to record snow for minutes as long as there's a chance to get one usable frame, in case the plane gets out of range and might disappear or get lost. Just for that reason.

  9. Well,i powered complete system with a 10,8v Li-ion battery pack.I think wich that problem can be caused from a low quality recorder,i used a PDR100 recorder wich encode at 8mb/sec,wich is a good recorder,but not good for these videos..Next time i will use a miniDV recorder,wich encode at 25mb/sec!

    What do you think?WIch that poor quality doesn't depend of RF problems??

    I got 2 questions:

    1) Is there a big temperature difference between your indoor test and outdoor test? Meaning that there might be some detuning for some reason. Sorry, I know it sounds strange, it's just an idea.

    2) Is there another RF source (WiFi or whatever) that might desensitize your video receiver?



    PS: Any chance using a groundplane antenna under(!) the eagle?

  10. That is for FCC registered *digital* communications devices. Other countries have similar rules, but it is best to review their regs to see what is allowed. These RF devices employ spread spectrum technologies.

    AFAIK in Germany you are limited to 10mW EIRP for analog data, and to 100mW EIRP for digital data, at 2.4GHz.

    That means including the TX antenna Gain.

    Thus feel free to use a high gain antenna on the RX side, and a highly directional antenna on the TX side while "wasting" some power with (unnecessary...sigh...) long antenna cables to avoid breaking the 10mW limit.

    I know that really sucks, but that's what's legal.

    This calculator might be helpful:


  11. Great! The last one was about exactly what I was looking for! Pretty high gain and circular polarisation. Danke, mein Freund!

    You're welcome! :D As I see you discovered a lot of nice alternatives already :rolleyes:

    I was very much impressed when I read about your EOS1 a couple of months ago. I'm curious on the performance of the antenna tracking system.

    How will you send the APRS data down to the ground station? Will you use the audio channel of the videoTX or an extra TX?

    Will you add tracking equipment to your plane as well, as an emergency backup if the link gets interrupted?

  12. When the plane is so close to the high gain antenna, I'll guess it will get a good signal strenght no matter where the antenna points

    Hi jonpet,

    That's right. Just don't forget about dropouts due to reflections, wherever they may come from.

    I strongly recommend to go for a diversity solution. Interference occurs easily and when I watch the leds on my diversity system, it sometimes switches so fast between the two antennas because the wavelength at 2.4GHz is just about 13cm and dropouts are easily produced.

    I recommend a combination of a high gain vertically polarized antenna (14-15dB Patch or a 17dB Yagi which matches exactly the frequency of your videoTX because of their narrow bandwidth), and an 8dBi Patch or even an omnidirectional rubber duck for the near field. I had excellent results with this combination, even in urban environments with LOTS of other RF sources around, as there were very strong wireless room to room video transmission systems in the nearby houses, WLAN, Bluetooth, GSM,... Make sure you're the only one on "YOUR" channel, and you'll be happy with this setup :rolleyes:

    I'm very interested in your antenna tracking solution and I would love to see how you proceed and to see the results. I was thinking of exactly the same setup with the TinyTrak and so on. Just one little difference, I considered a seperate TX for the APRS to make sure it ALWAYS gets to you, regardless the video link. That's because you need the GPS data to control Az/El of the antenna for the video link, so you must not loose the audio link.



  13. Mark, you're absolutely right! I recently lost a fully equipped plane because I did FPV at low temperatures and suddenly the motor stopped and 2 minutes after that the video screen just got black :blink: Usually when I fly at low temperatures I heat up the lipo's a little in those cases the Pizza Delivery Services use and it works great. But that time I didn't :unsure: , and also didn't have an osd to monitor the power status, so I had to pay an expensive lesson... :(

    But those Pizza cases are great for that! :-) Last winter I had 40 minutes flight time at temperatures below 0°C with a 2200mAh on my Easystar.

  14. Hi Denis, the lens is the key. The wider their angle the less separation, the less 3D effect. A standard or even more telescopic lens should give best results.

    I found a cool page some time ago, maybe some things on this page are interesting for you:


    Please keep us updated, I'm curiuosly looking forward to your next posts :rolleyes:

  15. Hi aerodolphin, this is a great project and really exciting :-)

    I don't know in which place you live, and so there might be certain rules/laws different from here. If you want ot make this UAV device available to other people, sell it to firms, institutions or whatever, make sure that it's equiped with sufficient emergency case functionalities. It is a good idea, for example to have sensors onboard to determine a rapid (uncontrolled) loss of altitude (="falling") and an algorithm that automatically kicks in and stabilizes the object and induce a controlled landing in the closest, unpopulated(!) area.

    Just to make sure that laws of airspace are taken care of.

    I don't want to sound nagging, but since our stuff is getting extremely powerful and breaks lots of limits that RC controlled "toys" usually have, it's no more a simple "toy" but becasue of its capabilities the criteria is getting merely towards those of "real" planes, we're entering the airspace of sports planes, helicopters, and actually everything occupying airspace.

    For example, a sports plane is allowed to fly as low as 150m above non-populated area, and about 600m above populated areas under certain circumstances. So with our rc controlled or even UAV objects we easily enter these areas, and everything is fine as long as nothing happens. Just as soon as we get involved, no matter how, direct or indirect, we are held responsible for the things that happen. For example it's enough that the object crashes close to a busy street, some person driving a car panics and swerves and hits another car or a street sign.

    No matter how good our skills are, glitches and interference may always cross our way and we can't predict them, so it's not always in our hands.

    This is something that can happen easily, and normally we don't think much about those things, but they might happen indeed.

    Therefore, in order to keep risks at a minimum, I think it's good advice to learn about the laws applicable to "the real planes", which are made to keep the airspace safe.

    I hope that was not too much nagging. I just think we need to remember those things from time to time, to not forget them ;-)

  16. Hi Daniel, nice music! Good choice! :-)

    Regarding the Camera, I suppose you used the KX-131. I did some comparison tests with another cam, the Mintron MTV-54C2AP (22x26mm / 5V), which is very similar to the KX-131. Here's a short summary of the advantages and disadvantages of them:

    MTV-54C2AP: + Automatic White Balance, warm picture with very natural colors

    + Wide Dynamic Range (You see much more detail in dark

    areas when flying into direct sunlight compared to the KX-131)

    -+ No case, therefore only 11gr weight

    - in low light conditions more noise compared to KX-131

    KX-131: - "Cold" picture, the white balance tends to to give the picture a

    blue/green tint

    - Poor BackLightCompensation, when flying into direct sunlight,

    most remaining areas of the picture are just dark.

    +- Solid Case.Excellent shield, but heavy (31gr)

    + in low light conditions clearer picture compared to MTV-54C2AP

    So when Backlight Compensation or Good White Balance and Color Temperature is an issue, the MTV-54C2AP is most definitely worth a try.

  17. E-Meeting Aspach, Germany

    As Thomas already announced this weekend there's the famous E-Meeting at Aspach, Germany. I was lucky to go there and see all the awesome place and feel the atmosphere of great things going on.

    Thomas was there to present the IFOSD with live video from his flights over the breath taking quarry, giving you kind of "flying over the grand canyon" feeling :-)

    So when he started his flights there was a huge crowd in front of the screens inside the big tent to watch live while he was flying over them, and see the information provided by the IFOSD in realtime and were amazingly impressed by its great features.

    We recorded some nice footage which will be posted later on.

    To give a first impression I will post a few pics:


  18. Wavess, Linear Regs regulate faster than switching regs. Due to the fact that spikes and peaks have a high slew rate and high frequency components, the linear reg will always perform better in terms of "filtering". However, it doesn't eliminate all noise, so in my tests I added a coil in series to the input of the linear reg and a 470uF Low ESR capacitor in parallel, and make sure it's definitely a Low ESR type. I never payed much attention to this until I tried them and saw what a big difference they make!

    Performs very well. You can increase the coil's and the cap's values to whatever your plane can carry :-)

    It's a compromise between performance and size/weight.

    Mr.RC-Cam, I would be very interested to see how you did the filtering on your switching reg, I'm always experimenting with this.

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