Jump to content

secretspy711

Members+
  • Content Count

    22
  • Joined

  • Last visited

Community Reputation

2 Neutral

About secretspy711

  • Rank
    RC-Cam'er

Profile Information

  • Location
    Denver, CO, USA
  • Interests
    FPV, CNC, DIY, Photography, Mountain Biking
  1. Hack successful! I measured 832mV immediately before the hack, and 948 after. I think I had better return the scope for now -- someone else may want to use it. This has been an enlightening adventure
  2. I test-flew the Pyle @ max setup this evening. It was a much more punishing 5 miles than my earlier tests due to flying low over many rock formations that would've been in the fresnel zone. The sync instability is much reduced, and was about on par with my friend's Uno as before, with a few bounces here and there, but overall it's much better and I'm pretty happy with it now. The picture also seems clearer at range compared to the RMRC receiver. The few bounces I saw were almost like a "pre-warning" that starts before the fuzziness you get when you start to fly a behind something, out of LOS. Haven't had a chance to swap out the resistor yet, there's only so many hours in the day and frankly soldering small things like that intimidates me a little bit. I don't want to screw it up before the annual FPV meet next weekend.
  3. I have an assortment of metal film resistors but not any 100 ohms. I could get close by using a couple of them in parallel but I decided to just order a few of the correct ones for a "cleaner hack". These are what I got: http://www.mouser.com/Search/ProductDetail.aspx?R=ERJ-T06J101Vvirtualkey66720000virtualkey667-ERJ-T06J101V I wanted to clarify something you said earlier. You said the entire waveform from the Uno was poor/disappointing with reduced bandwidth. What exactly are you looking at when you say this? Is the RMRC receiver better or worse in this regard?
  4. Fantastic! Does it need to be an SMD resistor or can it be a metal/carbon film type? Any idea what to expect the peak to peak voltage to be with this mod? 25% higher?
  5. I rigged up the Pyle (quick and dirty with long cables I had lying around). Here's a shot with it adjusted to 1Vpp. I am still able to produce some bouncing using my ground test procedure: And here is a shot with it adjusted to its maximum. I am NOT able to produce bouncing at this setting Overall level is high compared to the standard, but image looks ok in the goggles, at least indoors. I need to clean up the wiring to the Pyle and perform a flight in this configuration, but that will have to wait, maybe tomorrow.
  6. Full-size shots of the Uno PCB: https://drive.google.com/folderview?id=0BxRugM4Cs1qIaUd0U1M4ZTBPRGs&usp=sharing I'll let you study that while I work on wiring up the Pyle amp and see if that helps the levels. If it works then maybe we don't have to mess with the Uno's guts, but I'm curious if you are able to spot anything obvious that might help.
  7. Ok I'm just back from flying, typing on my phone at the field while it's still fresh in my mind. 1st flight, using my own Uno, started getting a lot of bouncing at 3.5 miles. Came back and landed. 2nd flight, using friend's Uno. Saw one or two bounces on the way out at about 3.5 miles, but nothing to complain about. Pushed on to 5 miles without any more bounces on the outbound leg. Turned around, again saw one or two bounces on the way back, but in general was clear. Just to be sure, I made a 3rd flight with my own Uno again. Bounces started at about 4 miles, pushed on to 5 miles anyway with bouncing the whole way. Turned around at 5, bouncing remained until I was inside of about 3.5 miles. In general it seemed like the overall video quality was not quite as good compared to my friend's Uno. I will post pictures of the PCB when I get home. I would love to be able to coax a higher signal out of it.
  8. Yes, I did that the other day, here is that image (with the Vector bypassed). I haven't tried the Pyle amp yet. I was about to go fly 2 back-to-back flights to 4-5 miles, one with my Uno, one with my friend's, and see if there is any difference in stability in a real-world test. BTW, I'm not sure if you picked up on this from the other thread, but when the Uno's first boot up, the waveform is significantly taller, around 1.2-1.3 vpp (and thus so is the sync.) After it beeps 3 times to indicate the # of cells it's connected to, it drops. Depending on which of my 4 vtx's I'm using it's slightly different, but in general mine goes to ~840-860 mV while my friend's goes to 920-930 mV. So maybe there is a chance I can send my Uno back to immersion and have them tune it to put out slightly higher levels. If my back-to-back flights show improvement with my friend's Uno, I will probably pursue that. My Uno at startup: My Uno after the 3 beeps: Friend's Uno at startup: Friend's Uno after 3 beeps:
  9. The signal out of my Uno is measuring about 840mV. My friend's Uno is showing about 920mV. Both syncs are very low, and make up the same percentage of the total signal, but since the entire signal is taller from his Uno, therefore so is his sync.
  10. Using the Immersion vtx, not high enough. Setting the power box on its highest setting results in just slightly lower levels than what I get straight out of the Uno, so it's like the power box is only meant for bringing down signals that are too high, not too low. I do have a Pyle amplifier/splitter I could try, from an old ground station build. Just seems odd to have to go to all this trouble to get in-brand components to work together, when the reason I went with Immersion is because I thought it would just work. The Chinese vtx has a pot yes, and it's overall level is a bit high while the sync is low. The Immersion does not have any adjustment. Ideally I would like to come up with a solution that uses he Immersion transmitter due to owning 4 of them already (with a 5th sunk in a lake) and because the Chinese one gets quite hot if uncased (I've heard they burn up easily) and is quite heavy and bulky with the case on. I'd also like to think the Immersion is more reliable, but who knows. I'm getting frustrated with them now, after all this scope testing with the levels still being low.
  11. Thank you Thomas. You have been a huge help and I've learned more than I could have hoped for. It does seem as though the RMRC transmitter with the Uno receiver produces the best sync level (though still short of the 280mV ideal) out of any combination I've tried. Alternatively, I wonder if I could replace the pot in the powerbox with a different one, to make it "go to 11" ? (spinal tap reference). The goal would be to make the entire signal, including the sync, taller, and may get me above the threshold needed to maintain stable video. The Vpp out of my Uno, when measured correctly as you pointed out, seems to be about 840mV. My friend's Uno is about 920mV, which means the sync portion on his is also slightly taller. Just an unfortunate luck of the draw I guess, but as you said, not the entire cause of my problems, most of which seems to be the transmitter.
  12. For some reason it won't let me upload pictures to this thread. Even though the 2 images I want to post are about 170kb each, it says "you are only allowed to upload 501.76kb." In that case I have posted 2 shots of the TV field from both the Uno and RMRC receivers (both without using the powerbox) using the RMRC transmitter. I apologize for all the linking away from your forum. When you say the sync level is still low, you are referring to the difference between: the middle of the lowest flat part (where your horizontal blue line is drawn) to the middle of the color burst, correct?
  13. I bypassed the Vector once more, using the original setup with the Uno and Immersion 25mW repeater. With attenuators and putting my hand on the antenna I was still able to produce some bouncing. For sanity's sake I wired my goggles to the Uno, did the same thing, and the picture was much more stable. Then I tried using a boscam 200mW transmitter as the repeater, and the bouncing was back. Routing it through the powerbox again did not help. I found an old 2.4 700mW RMRC transmitter I had laying around and put it on the plane. Receiving on the Uno (mixing brands), the waveform was much stronger looking (actually quite high at about 1.5 vpp, and the difference between the sync "bucket" and the color burst was much more well-defined.). Saw the same thing when receiving on the RMRC receiver. Routing these through the powerbox and adjusting the pot to approximately the middle of it's range, the vpp went from 1.5 to ~1v. But now the difference between the sync bucket and the color burst was lower, but maybe good enough? pictures here The only problem with this one is that it gets quite hot without the bulky blue anodized case, though some are having success with it. One of my flying buddies uses one of these and drilled 4 holes in the interior (silver) case for airflow. Not sure if that's a good idea or not... I tried removing the lid of the interior case on a 1.2GHz transmitter recently, and it cause the video to be very distorted. I think some heatsink fins would be better.
  14. No. I've used it in the past on other aircraft but am not currently using it here. I can... but I'm not quite sure I completely understand what you would like me to do. If I put a 5.8 vtx on the plane, I can measure the waveform between the camera and the vtx. Measuring at the groundstation as before would require an Uno5800 which I don't own. I can attempt to measure it directly on the goggles through the AV-in/out jack, terminated with a 75 ohm resistor, or I could probably rig up a way to connect the goggle module with jumpers instead of directly plugging it in, in order to access vid and gnd between the module and the goggles (the goggles would be the termination load). Something of note, several weeks ago I measured the goggle's module sockets with a multimeter and found the goggle video input to be 43.6 ohms. A far cry from the 75 I expected. But I'm not smart enough to know if that's a valid measurement or not, or if anything can be done about it if that is the problem.
  15. When I was attempting to get the field to show, inside the "Trigger" menu, I found a submenu called "Shortcuts", and inside that was an item called "...a TV or video signal." In the dialog box that popped up, it had several picks for different video standards. One of them was "NTSC 525/60." I picked it but the waveform would constantly scroll to the left. Another option was "User defined" so I picked it, at which point the waveform stayed put and this is what I used to generate the images, which I see now is probably not correct. I selected "all lines" in a drop down menu, and I zoomed out to see if the vert sync pulses were at 16.6mS as you said they should be, and they were, and then I took a screengrab. Notice the shot of mine shown above has a scale of 2 mS/div. I see that yours remains at 10 uS/div, so apparently I need to stay zoomed in to 10uS/division to get the shots you are looking for? I think I was almost there, I just need to put it back on NTSC 525/60, figure out how to get the waveform to stop scrolling, and zoom back in to 10uS/div. I used a servo Y harness to go directly from the camera to the vtx and bypass the vector, while providing power to both using a 3S battery. I was focused on making oscilloscope measurements and I didn't actually try to replicate the bouncing in this condition by simulating flying at range (installing attenuators, placing my groundstation across the room, and putting my hand on the receiver antenna). Of course the real test would be flying at 4 miles or so, but there are only so many hours in the day.
×