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Mr.RC-Cam

Maxim's Loss-of-Video-Sync Alarm IC

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I just got home from a military trip, and I had my Oracle waiting for me. Thanks RC-Cam, for giving me the oportunity to play with this piece of equipment!

I also ordered the enclosure, and the second receiver I needed. I thought it would be best if I used identical receivers, so I ordered this one from rangevideo to match my original RX..

http://www.rangevideo.com/rx.html

rx_3T.jpg

Unfortunately, what I got instead was the newer, black cased RX. Based on what TTS said in an earlier post, I guess the guts are the same, but I'm still not pleased that despite the thorough description and pictures of the other style, what i got was different.

Anyway, I wanted to thank Lupy for the excellent work in creating a hole template for the enclosure, that will save alot of work.

Hopefully the weather in the northeast will improve so I get some FPV flying in soon.

Edited by rob10000

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Unfortunately, what I got instead was the newer, black cased RX. Based on what TTS said in an earlier post, I guess the guts are the same, but I'm still not pleased that despite the thorough description and pictures of the other style, what i got was different.

Yep. Some of the websites have not been updated with pictures of the new style yet. But yes, I was told the electronics are the same. So far, that appears to be true.

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Any new Oracle field test reports to share?

For those that are waiting for the production release, please be patient. That won't happen until the beta bugs are all identified and the field reports are positive. So, hug the beta users as often as you can. :)

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I just finished getting the Oracle fitted into the case, and hope to get all the final connections done this weekend. I'll either have a chance to fly it this weekend, or next.

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Mr RC-Cam. I just sent you a PM in response to yours. The weather has finally cleared up. I will be doing some more testing tomorrow morning. Stay tuned...

Edited by twinturbostang

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Well, I flew today, this time from a different location. Good and bad news. Bad news first... I crashed my plane again. :angry: I seem to be having bad luck lately. At a range of 0.35 miles, I got full receiver lock out. No control over the plane at all. It proceeded to nose over into an inverted state and did an inverted "landing". I'm convinced this is a completely unrelated issue that I need to sort out. I've had receiver lock out before, and with a completely different setup. Different receiver, different plane, even was close range, etc. My best guess at this point is the frequency module for my Futaba is bad. Perhaps it's not transmitting centered on the channel. Or maybe some other problem.

The good news is the video was PERFECT. Looked great with virtually no glitching at all. There were a lot fewer receiver switches (Oracle beeps) than flying from my other site. It's safe to say at this point, that my previous flying site has horrible interference on the 2.4GHz spectrum (if not all frequencies). I also was able to do a direct comparison of the Oracle and my buddy's RSSI based diversity receiver. We both flew our video planes, and both recorded all of the flights (4 or 5 flights I think). I'm planning on putting a video together in a "split screen" fashion, showing the differences (if any) between the two setups. However, my guess is they are both going to look very similar. Of course there will be some differences. I had a combination of a whip antenna and my GP Patch. My buddy had a whip and a patch also, but I'm not sure of the manufacturer or dB rating.

Something interesting... At .35 mile range, I had flawless video all the ways to the ground, even with terain elevation changes from me to the plane. And actually, It ended up being very useful having clear video all the ways to the ground.... At the time, I was flying FPV, and my buddy was spotting (visual line of sight). Since he had visual on the plane, he knew exactly where to go to recover it. So he went and got the plane, but it turned out there were a couple of pieces that had come off that he did not notice. Missing was the 1" square cover to my 2.4GHz transmitter, and my Dimension Engineering regulator (1" x .5"). VERY small components to try and find in the middle of a farm field! We went back over to try and find the crash site. Searched for 15-20 minutes maybe and found nothing. So I decided to replay the video of the crash. Watching the video, I determined we were looking in the wrong place. So I moved our search, and about 5 minutes later, I found the missing pieces within 10 feet of where I had concluded the crash was based on the video! :)

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That definitely takes the joy out of the otherwise good news. Sounds like a hideous crash too. One of the things I would suspect is BEC overload. It is easy to run into, especially if you are running a 3S LiPO.

I'm looking forward to seeing the comparison videos.

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Yeah, it was a great day up until that point. We got several FPV flights each, plus flew a couple other planes as well.

No, I was using an external BEC, rated for the servo amp draw. I don't believe that was the problem. For a long time, I seem to have been suffering from reduced RC range. Today, I was seeing some noticeable glitching in the camera servos at that range, and I guess it finally was enough to lock out the receiver. I sometimes even see glitching at close range. 0.3 miles is definitely far for a park flyer size plane. But my buddy could still see my TwinStar (56" wingspan) at that range. And for large(er) scale models and gliders, 0.3 miles can easily be reached with no problems. From what I've heard, the range on RC transmitters is supposed to be 1-2 miles. And I'm not coming anywhere near that.

FWIW, my buddy has flown 0.64 miles at this exact location without a single glitch. I have a Futaba 9C. He has a 9C Super. I'm running a Berg 7P. So is he. He even is running a 1 Watt video transmitter, just inches away from his RC receiver. I'm running a 500mW transmitter. I don't get it. His system seems to perform much better than mine. He flew at least as far as I did today, and I didn't see ANY glitching in his RC system at all.

BTW, the crash was actually not as bad as you might think. It could have gone straight into the ground. But luckily it rotated to full inverted and then "landed" in that orientation. Nose in would have been ugly from that altitude (several hundred feet I'm guessing). I've got some work to do on it. But it's not a total disaster, and it WILL fly again! I will be sure to include the crash footage in the video. :rolleyes:

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From what I've heard, the range on RC transmitters is supposed to be 1-2 miles. And I'm not coming anywhere near that.

That is a reasonable range for a clean RF environment. But when you install switching regulators, video gear, ESC's, motors, and so on, the localized RF noise can be substantial. It can be a challenge to get everything to play nice together. Two identical models, with what looks like identical equipment, can have vastly different personalities when it comes to RF noise. So, don't get distracted by your buddy's success.

During your flights today, did you see any bad habits from Oracle?

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Received my Oracle beta unit today....right as I was heading out the door to go to the field! I don't have the case yet anyway so it wouldn't have mattered if it had arrived earlier.

Very nice looking board!

Going out today I've got some good reference video to compare to when I get the Oracle up and running. Today was the first time I used my "goof proof" patch with the 900MHz system. Yes, it's one BIG patch antenna! :D

Video quality was extremely good except on the field runway to the right or left, the real bad areas for the patch antenna because of where it was pointed. Previous videos with the standard whip antenna had no problems in these areas, but had more problems in other areas. The Oracle should be able to do its trick and make the takeoff/landing transitions seamless. The rest of my flights today looked so good the Oracle might not have to work too hard to keep things looking good.

My case should arrive this week and hopefully I'll be able to get the Oracle up and running by next weekend.

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That is a reasonable range for a clean RF environment. But when you install switching regulators, video gear, ESC's, motors, and so on, the localized RF noise can be substantial. It can be a challenge to get everything to play nice together. Two identical models, with what looks like identical equipment, can have vastly different personalities when it comes to RF noise. So, don't get distracted by your buddy's success.

During your flights today, did you see any bad habits from Oracle?

I have a question regarding the RF noise and sorry if this is not the right place to ask. Would it help if we used ferrite beads in our wiring accompanied with an (additional) equal antenna length attached to the radio RX? Making our RX a twin antenna system? I was thinking of cracking my Futaba RX open and solder an additional wire to spread across the main wing of my Twinstar for better reception. Would this work?

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I have a question regarding the RF noise and sorry if this is not the right place to ask. Would it help if we used ferrite beads in our wiring accompanied with an (additional) equal antenna length attached to the radio RX?

We're getting a bit off topic. RF beads are one way to cure common mode noise. However, it not effective for many situations. Keep in mind that noise can be from conductive paths, or can come from radiated sources. Or a combination of both. Solving RFI/EMI issues can be as simple as just moving the R/C Rx further from offending noise, or can be so evil that an arsenal of fixes are required (Faraday shielding, filters on power, filters on RF inputs, changes to cabling, witchcraft, etc.). There is no single fix for all situations. Plus, it could just be an issue with the R/C system itself.

I was thinking of cracking my Futaba RX open and solder an additional wire to spread across the main wing of my Twinstar for better reception. Would this work?

This can earn you a couple dB of antenna gain, which is good. However, if your local environment is full of EMI/RFI, it won't help much (and could make it worse).

These things should be discussed in another thread so that this one remains on topic.

Edited by Mr.RC-Cam

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Thanks again MR.RC-CAM!!!!

Sorry again for jumping into this on this thread :( I read TTS mentioned something regarding glitching and couldn't resist the temptation to ask :rolleyes:

So next time I will bug you on the correct topic thread :D:D:D

BTW... I never thought about witchcraft as option to cure glitching :D

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RC-Cam, I know it's a long shot, but I'd like to be on a Beta list, presumably the Beta 3 list (i.e. standby for Beta 2s) of your Feb 24th post.

I'm keen on seeing how the Oracle deals with a site with a mobile phone tower in one corner! I can minimise 'sputtering' noise off the image by keeping the patch antenna's back to the tower, but I'd like to try two patches at 60-90 degrees to each other, to minimise the 'blanked off' quadrant that has the tower.

(It's a great site - on the edge of a pretty built-up suburb, a local farmer has given me permission to fly from the middle of one of his fields)

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During your flights today, did you see any bad habits from Oracle?

No I don't think so. Upon reviewing the video, it looks like there may have been a couple of small glitches. But they were very slight, and it looked MUCH better than at my previous flying field. There was one point close to the ground on final where the image garbled. But that could have just been an antenna orientation issue. I was landing behind the direction of my patch, which left only the whip antenna to pick up the signal.

I still have to capture all of the video that I took, and the video my buddy took and compare it all. I'm going on business travel part of this week, so it might not be until next week before I have something uploaded.

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Hi Mr RC-Cam,

I received my beta 2 test unit yesterday. Thanks. I'll spend some time on it this coming weekend and let you know how I go!

Cheers

B.

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Ok, here we go. Direct comparison between the Oracle diversity, and an RSSI based diversity receiver...

Diversity Comparison

Some notes... Both receiver systems were equipped with similar antennas, and oriented in the same directions. Everything was set to the same channel, so both receiver systems were picking up the one video transmission from the plane's video transmitter. Each receiver system had its own dedicated power supply, and also a dedicated video recorder (two miniDV camcorders were used). I captured all the video to my PC, and then compiled it in "split screen" mode. The two video feeds had to be synchronized together since the recordings were not started at the same time. It surprised me at how quickly I was able to get them sync'd together. When you first watch the video, it almost looks fake. Like I used one video and just put a black line down the middle. :) But you will see some slight glitching on one side, and then the other, proving that it is in fact two video feeds.

Overall, I'm very impressed. The Oracle seems to do just about as good a job as the RSSI based diversity receiver. For most of the video, there are just some very slight glitches. And the RSSI system glitches some too. So they're pretty much on par, at least in this test configuration. At the very end just before landing, there is a pretty significant glitch in the Oracle. But that could just be due to antenna placement. The RSSI glitches also, although not as bad. But the RSSI system was almost in front of the Oracle with respect to where the plane was. So that could have been causing some excess interference and/or multipathing for the Oracle, whereas the RSSI had a clear shot to the plane.

BTW, sorry for the bumpy ride. It was a bit windy at the time. And I think I was getting some RC glitching in there too. The crash I mentioned was on a subsequent flight. The landing (via goggles) on this flight was pretty smooth though! :)

Still to do... I would like to do the same comparison, but at a known noisy environment. Would be interesting to see how they behave with respect to each other in that situation. I also have not done any testing with the Oracle sensitivity set higher. I could try that and see if it helps a little with the slight glitching that is visible. Perhaps it will make the glitching shorter. And there's also the comparison test of one antenna versus Oracles switching between two antennas. That would really show the benefit of using a diversity receiver over a single antenna.

Brian

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wow, that's pretty cool. Right up to the end, I think the Oracle had the edge. There were a number of instances where the RSST version had breakup that wasn't present with the oracle. There certianly didn't apear to be a huge advantage of one over the other.

What rx's did you use? Was your RSST system a BW version or something else?

The ultimate test would be to use only two rx's, and split the video feeds so that each diversity unit had the same input. Then both will see the same interferance at the same time.

Not sure how hard that would be to do with a BW unit, since it's all in one box.

Ken

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wow, that's pretty cool.  Right up to the end, I think the Oracle had the edge.  There were a number of instances where the RSST version had breakup that wasn't present with the oracle.    There certianly didn't apear to be a huge advantage of one over the other.   

To be fair, there also were a couple of instances where the Oracle glitched, but the RSSI receiver did not. But I agree, they are very similar in performance.

What rx's did you use?  Was your RSST system a BW version or something else?

On my system, I used two Lawmate receivers, the ones you can buy from Range Video, Future Hobbies, BWAV, etc. And yes, the other system was the BWAV diversity. In a conversation w/ Mr. RC-Cam, I agreed not to provide that information in the video (so as not to step on any toes), but I agreed to share the info if someone specifically asked.

The ultimate test would be to use only two rx's, and split the video feeds so that each diversity unit had the same input.  Then both will see the same interferance at the same time.

Not sure how hard that would be to do with a BW unit, since it's all in one box.

Yes, that would be a direct apples to apples comparison then. I have heard about possible issues though, if you split the antenna between two inputs. Perhaps some sort of electronic gadget could solve any issues with splitting the signal. But that's beyond my knowledge/skills.

The BW unit has two SMA inputs on the back, so in theory it could be done quite easily, assuming whatever amplifier gadget you needed was not complicated.

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The side-by-side video is brilliant work. Thank you for putting it together.

I've watch the video several times and I cannot readily tell when the Oracle switched sources. Does a switch occur every time we see a bit of video distortion, or did it transparently switch at less obvious places?

Do you recall how active the switching chirp occurred on the two systems? BTW, if you record more sample videos, is there any chance you can plug a mic into the DVR so that we can hear the chirps? They will help indicate what the user sees at the moment a switch occurs.

Regardless, both units worked impressively well. My goal was to just have Oracle work nearly as good as a traditional RSSI based diversity setup. At this point, what I see in the video exceeds my expectations. For sure, the fixed Oracle firmware is working great!

Hopefully we will see more positive feedback from the other users. Maybe your video will create enough buzz to get all the beta users in the air real soon. :) BTW, that is a very nice flying site. I wish I had one, close to me, that was just like it.

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I have heard about possible issues though, if you split the antenna between two inputs.

I think he meant splitting video, not the RF signal. I.e tap into the BWAV box and pick the video signals to feed them to Oracle, so both switchers get the exact same video signals. That would eliminate antenna placement and RX performance "biasing".

Nice video indeed, it's funny to see that both nearly never glitch at the same time.

Edited by Kilrah

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Great video TTS, I don't think we need to compare the systems any further. Your test shows well enough that the systems are very close in performance, enough to make no real difference. It's good to see you confirm what I posted way back in this thread when I said

I have had a play with my diversity set up around the house and it works well but with 4 RX's and all the reflections indoors the unit never stops switching. I tried the unit without the video detection, just using the RSSI signals and it was rubbish indoors. I then tried it just with the video detection and no RSSI and it worked well again.

Looks like Oracle dose what it says on the box :D

I have only had one flight using Oracle on his own and he worked fine as expected. All other flights with Oracle have been with a 14dbi patch in ch1 and my 4way diversity in ch2, again no problems to report. Sorry there is no video but I only have a VHS recorder and it dose not transfer very well on to my PC.

I look forward to hearing more reports, who will be first to use 900Mhz with Oracle ?

A split screen video of a 2.4 and a 900 system would be interesting too.

Terry

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I should have mine back up and running this weekend. I plan on running the rx sound output into the "left" for one RX and the "right" for the other. That way, with recorded video, the sound should switch back and forth to indicate which RX is active.

I too found it interesting that the two diversity systems rarely broke up at the same time. It makes me think again that having a 4way would be better, but a lot more $$.

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I plan on running the rx sound output into the "left" for one RX and the "right" for the other.

If you have time, can you also record a flight with the sound connected normally? That way we can hear if you have mismatched audio levels, and if so, how it behaves during flight.

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