JettPilot

My Feedback: (6)

All my planes are gas powered, and I get no vibration in the camera. I use RC 1/2 inch latex foam to isolate the cameras, that soft rubbery stuff... You can buy it at www.horizonhobby.com and many hobby shops. It usually takes me a couple trys with different amounts of foam to get the vibrations out of the camera, but I always do. I fly with a G-45 , G- 26 , Saito 82, and a .46 2 stroke. None of them are rubber mounted, and some of those vibrate more than your G-38... Keep working at it and you will find the right amount of foam to get rid of harmonic vibration in your camera.

As close as you are flying, that your TX antenna will work from any direction. You are so close that there is still enough signal off the top for the antenna to work well at any angle. That will change as you get further away....

JettPilot

S_Dave

Hello, Bill and Steve,

I've been letting my work load interfere with the AP and flying, but had to contribute something here. We've got a Hyperlink HG2409PCL patch antenna and I put a quick test together in the lab. I ran a signal generator into the patch antenna and measured the power level on the spectrum analyzer to note the power level. The antenna was rubber-banded to a 20" tall thin fiberglas cylinder about 6" diameter. I faced the patch toward the spectrum analyzer antenna (a rubber duck) with no obstructions between. Both were vertically polarized. When I turned the antenna around with the back facing the spectrum analyzer (receiver), the power level dropped 6 dB. Now, this is not an ideal measurement, since there are reflection sources all over the place, etc. And it shows a backlobe stronger than Hyperlink's printed patterns, but it's one data point for your files. Keep up the good work, guys, and thanks!

Dave

p.s. I've attached Hyperlink's antenna pattern from their website http://www.hyperlinktech.com/web/hg2409pc.php for your consideration.

wjglynn

JettPilot,

Thanks for your thoughts. I have an additional challenge in that I am using a PTZ mount and a one pound camera. With the camera so far behind the wing protruding above the fuselage my weight has soared up to about 20lb to get it all balanced. For your stationary mount application I can see where foam can do the trick. On mine I have a heavy camera out on the end of a fairly long lever (mount). I have to fasten it all solidly to the airframe. I am about to give up on this above the fuselage design and go to an electric with a fluid head tripod mount under the plane right on CG. My camera weight will still be substantial because my goal is hi-res imagery. With the new mount I should have about 140 degrees of rearward pan and 90 degrees of tilt which is better than my current config.

Dave,

Thanks for the data point. I had previously found and studied those antenna diagrams and your test observations help too. Seeing those small lobes off the back of the antenna made me think that I would not get a good signal from there. I expect that JettPilot is correct in his assertion that as close as I am it just doesn't matter. In earlier posts I had been fighting some interference problems. The source of that ended up being in the Nikon 5400. it just does not output a consistant signal when subjected to the rigors of flight. Perhaps it is in its 3.5mm stereo A/V connection. I may end up opening the camera up and soldering it solid.

steve_molmer

Sorry about the long delay since my last post on this forum.
I have been out doing some testing out over the gulf. With a new telemetry system. My hopes are to be able to allow a plane to find a moving target out over the water. The pilot will then be able to pickup the cargo in mid air and return it back to the launch site.
The final setup will be able to retrieve small drones as they are returning from a mission.
I will post some photos and video from the test in a few days.

Wmacky

Steve,

Can you recommend a paticular LNA for this appication? Also, Could I get those PDF's for your receiver? I've PM'd you my email address!

Wmacky

Thanks for the docs. I only have a few questions.

1.Are you using the new lawmate receiver that comes with the square case?

2. Did you have to mod the lawmate "can" to get the S meter to work? The Lawmate can is flipped compared to the comtech receiver, and the pads can't be easily reached for the mod required on some boards?


3. Removing the old pic. On the lawmate, I believe the pic in question is on a sub board on the back of the main board. Did you just remove the entire sub board, or did you cut the traces to the pic?


4. I've considered just using the comtech 2.4 receiver. How do you feel it compares to the Lawmate? Would there be an issue here involving De- emphisis? Would the Lawmate transmitters, and comtech receivers be incompatible as used stock due to this issue?

Thanks
William

Brett Horton

My Feedback: (17)

Hey guys I am selling my NIB Lift Meister.
New in box just taken out and inspected.
Will sell for $250 + shipping.
http://www.rcuniverse.com/market/item.cfm?itemID=303271

JettPilot

My Feedback: (6)

I know some columbian guys in Miami that would be interested in that system .

JettPilot

My Feedback: (6)

Havent heard anything from you Steve in this thread for a while. That must mean you are doing lots of flying I look foward to more pictures and post about your project.

JettPilot

JettPilot

My Feedback: (6)

Hi Steve,

I got the MobiComm receiver and digital tuner to improve the range of my 2.4 GHZ video systems. I mounted everything in a nice, grounded, shielded case and put it on the back of an 18 dBI patch antenna.

The performance of this receiver is horrible The sensitivity is not anywhere near what my lawmate reciever is, and putting a 25 dbi gain LNA on it did not help much... I tested it both ways. Where I get a clear picture with my cheap lawmate receiver, I get a very weak signal and a bunch of snow with the MobiComm reciever. Even when the signal is strong, the picture from the MobiComm just plain sucks. The contrast is so high the picture is not nice to look at and takes the fun out of FPV. I have adjusted the video level with no success, the best it does still looks far worse in contrast and color than my cheap lawmate receiver.

This is not a tuning issue, or IF shift issue, I have gone down that road and everything is on frequency... What is your experience with Mobicomm receivers ? Your results seemed much better than mine ? Is this a bad receiver, or am I doing something wrong here ?

JetPilot

S_Dave

Hi, Jetpilot,

Sorry to read about the trouble you're having with the receiver. I'm very interested in this. Could you please provide a URL and model no. on the Mobicom so I can look it up?

One possible cause that I'm almost embarrassed to mention: could you be getting zinged by the @#$%^&*!! reverse-polarized SMA connector issue that gets people all the time? Some of these can seem to mate correctly but you could get a female-to-female pin situation where the signal loses interest in jumping across a short gap and your level goes down.

Please don't ask how an otherwise brainy guy like me (ask my mom) could let this happen to him....

I'm getting back to working on my plane setup. Some of those little video transmitter modules we bought have melted down or broken their wiring connectors. Have you located a robust video transmitter that you recommend?

Cheers,

Dave

JettPilot

My Feedback: (6)

Hi Dave,

Thanks for the suggestion, I checked all the SMA connections, and everything is correct... I am wondering if I have a defective receiver, especially given the poor picture quality at even close range, like right next to the receiver [:@]

I am not sure what the model number is, I got them from the web address Steve gave in this thread. I wonder who makes them ?

As far as the video transmitters, I have never had one fail on me. I put them out in the airflow, and they run very very cool. I have had the video transmitter wires break on me, they are very bad with vibration, so I cut the origional TX wires short, solder a RC heavy duty servo wire to the TX wires, and glue it all to the side of the video transmitter with goop glue. That way the only wire leaving the video transmitter is a RC servo wire which are very resistant to vibration and breakage. I have never had a failure after doing this.

JettPilot

steve_molmer

Jettpilot,
Sorry about the delay in getting back to you I have been out on assignment.
First off the receiver is most likely not getting a complete signal from the transmitter. You must first use a digital frequency counter to find out the exact frequency that you are transmitting. This is very important as the receiver must be set in the program mode to go to that range and step in frequency range it self. I this is not done you will see a washed out picture on the screen. Next once you have the unit on the exact frequency of the transmitter you will need to adjust the IF lock to show the best possible video with out waves or distortion. Now assuming you have built and installed the denfuses circuit on the receiver and fitted it with an adjustable rheostat you can fix the contrast of the signal and then adjust the signal level on the receiver for best picture. Last but not least you may wish to adjust the video level control on the transmitter, note that this is usually only necessary if you see a very dark image on your receiver side. I am sorry if you have had some problems with your setup. I have built a few of these over the past 2 years and I have had one that did infact have a defective receiver board. But that one would work off and on intermittently. Let me know what you find.
Also do all your setup with just a short stubby low gain antenna and no amps in the setup at all. This will prevent you from over compensating on your adjustments.

Regards

Steve

S_Dave

Steve,

Are you doing anything with Infrared cameras in your AP setups? I've been looking into those and it seems like the technology is getting smaller, better resolution, and less expensive.

Good to read that you're back in town.
Will you be at the CCRC club Swap Meet tomorrow (Saturday 21 Sept)? It's always good to see you and the other members are always impressed with what you're doing with aerial photography.
Best regards,

Dave

JettPilot

My Feedback: (6)

Hi Steve,

Good to see you back !!! I was beginning to wonder if we would never see you again here As far as the receiver goes, I have fixed the sensitivity problem, I had a reverse polarity SMA connecter, so for having no physical connection of the antenna, it is amazing I got a signal from 3 miles away [X(] Now that I have fixed the polarity, I have high expectations for the sensitivity of this receiver. I have a 25 dB LNA in line of the video receiver also.

The blurryness and poor contrast of the picture is still a problem. I have checked frequency, its right on. IF is also adjusted for best picture. I have tried taking out the LNA, and tuning with a weak signal, same result. There is a large pot on the receiver board that has a huge effect on the way the picture looks, I have adjusted this to the best possible, but its still not good...

I dont know which circuit you are talking about building ???? I built the digital controller, but nothing else, that is probably my problem. I am using it only as an RX... What other circuit do I need to build ??

JettPilot

steve_molmer

Jettpilot,

Can you post a snap shot of the top of your receiver board so I can see the layout of the components. This way I can sit down Sunday night and try to find a solution to the picture quality issue for you.

PS. The rumors of my demise are greatly unsubstantiated.

Best regards

Steve

steve_molmer

Dave,

Good seeing you at the CCRC club Swap Meet. Sorry if I seemed a bit out of it. I had only about 2 hours sleep prier to my drive out to the club that day. Aerial photography and surveillance have had grate leaps in technology over the past year or so. IR type cameras both inferred and thermal are being used extensively on may platforms but one word of warning. I have been bit before by using an IR camera in conjunction with an horizon seeking type auto pilot. The interaction between the two can make for a real white-knuckle ride to say the least. If you use the BTA A7 type auto pilot you can avoid this problem.

Best regards,

Steve

wjglynn

All,

The new E-GBS made its maiden flight last Friday. We are using an E-Flite 160 motor and two five cell 18volt 6000mah batteries in series to spin the 18-10e prop. A Castle Creation 110 ESC controls it all. The rig weighed in at 19lbs. The ptz mount is now underneath and points backwards. It has 140 degrees of pan and 90 degrees of tilt. The fluid head mount sports a Sony MiniDV for the video cam. I have attached a short video to briefly show its performance. It is all very smooth. The small transmitter antenna disk shown on the bottom of the fuselage during takeoff works great close in.

Alas, further development has been delayed as on the second flight we had a situation where we ran out of altitude and airspeed before the final approach. A new fuselage is on the way and the ESC and motor have not been tested yet. All the rest of the electronics appear to have survived. The cam even returned to recording after initial impact. I am confident we are several weeks from being back ready to fly again. And of course this time no pictures were acquired during construction to share. I will on this next iteration. I have video from both flights made but am only posting a short clip here. I am very encouraged by our initial results. Can't wait to do the air to air tests with this rig.

http://rcuvideos.com/item/JNPLHRFSGFM0SLTC

Bill

S_Dave

Hey, Bill,
Wow! That plane takes off with AUTHORITY! It went up like you had rocket assist! Thanks for sharing your success with that great video clip. That's one of the clearest videos I've seen.

The field stays centered in the video--is someone operating the PTZ while you fly?

We had a meeting of the Atlanta Chapter of AUVSI (Ass'n of Unmanned Vehicle Systems Int'l) today. A student team from Southern Polytechnic did a talk on their robotic competition helicopter. They mentioned a computer-steered antenna. This kept their ground station antenna pointed at the aircraft during flight. They said it cured all their video dropouts. I'm going to inquire more about this useful device.

Sorry about the little mishap on landing. I'm confident you will be back in the air soon.

Steve,
Yes, it was good to see you at the CCRC swap meet, too. Sorry I didn't get to visit--I had some stuff to sell and didn't want any "live ones" to walk past without me explaining how much THEY needed new items.

I got a couple of big trainer-type planes, so this will jump start my AP efforts considerably. I look forward to sharing my own videos with you and Bill soon.

Best regards and happy Friday (almost) to all,

Dave

rc34074

My Feedback: (5)

Steve Molmer - which version of the bta-07 autopilot do you use? mpi shows an as-07 version for $300 and an as-07g with plane retriever for $700. how did you modify yours to go to numerous gps locations?

Ed Mullen

wjglynn

Dave,

My partner in crime, Robert Longyear, is the pilot. He flies the plane, I fly the camera. While many on this forum are using the streaming video to fly out of site we are concentrating on building a camera platform to shoot high quality video and stills while controlling the camera from the ground. We are pleased with the performance of the system but have not yet flown enough to get a solid grip on expected flight times as we previously preferred fossil fuel over electrons. Two static tests were performed on the motor/batteries before the maiden. In the first test we ran the motor at 50% throttle and the batteries lasted 31 minutes. In the second test we alternately ran the motor at 100% for 1min. and then at 50% for 2 min. This resulted in a 12min run on the batteries. We are hoping for an expected loiter time to be somewhere in between. The two test flights were about 8min. long and at the end of the second we lost power in the downwind turn resulting in the plane snapping over to disaster. Even with 1500sq. in. of wing, at 19lb. the wing is loaded enough to require close attention at slow speeds. Any loss of power when slow and low is a really bad thing. I hope to strip the components from the plane this evening to test the motor and ESC to prepare for the arrival of the new fuselage.

S_Dave

Bill,

Sounds like you and Robert have a very well organized research & development effort.
With my limited experience, there has not yet been an occasion for me where the plane ran out of battery before landing. I need to visualize this happening and plan for it--now that I'm aware of the reality of the problem. Since you didn't report the plane being totally destroyed, I'm guessing that your onboard receiver and flight controls are on separate power from the flight batteries, and you still maintained control, albeit without benefit of the motor.

You seem to have a very steady hand--there's no jumping around on your video where somebody had difficulty maintaining the target in the viewfinder. Practice? or limited coffee consumption before flight?
Looks like good flying weather coming up in the future days.
Hope you enjoy a fine weekend and get in some more good flights (or quality time working on planes).

Dave

wjglynn

Dave,

Our suspicion is that we had a calibration problem with the throttle/ESC as we do not think we were low on batteries. When the controls got sluggish Bob slammed the throttle forward and nothing happened. We had some mysterious ESC cut outs before the flight so there may have been some gremlins we did not find. Strange that it happened after about 7min. of great flying. When the wings run out of lift it just does not matter how much you slam the control surfaces around as the earth approaches.

I have practiced quite a bit with the camera controls when we were using the gas engine. Two big factors now are Bob's ability to make flat turns and my 9303's ability to slow the servo speeds down. we also added exponential to dampen the pan and tilt rates. The big ESC does not have a BEC so the plane reciever has its own battery. Thanks for the kudos. We are trying to systematically approach this challenge.

Bill

steve_molmer

Bill,
nice work.
sorry about the crash.
Don't feel bad I just completely destroyed one my big birds last week do to the receiver shutting off. A bad solder joint was the problem we found after all was said and done. This issue just add wood to the fire so to speak for my disdain for futobas lack of QC on the equipment the last few years.
I lost control just after take off, the plane plowed in at just over 60 mph. took a few hours to find all the pieces. What really hurts is that one of the last of my original US 41's is a total loss. A real shame, that engine had survived over 300 flight and 2 airframes not to mention several botched landings.

Bill I think if you switch over to that antennex antenna we went over several post back you will find that your range issue will be greatly improved.

Ed,
The BTA units you are looking at are the ones that are sold to the hobbies and not the mill spec unit that I use. However you can modify the unit that utilizes the gps receiver to act as a full GPS and wave point tracking unit but it take a good bit of mods that are far out of the limits that can be covered on this site.(NSA Limited)
Now that being said for the money the AS-07G is the best of the best of what you are going to be able to find for the price. It is rock solid and works ever time like clock work. Also you can connect into the GPS receiver for your OSD and video system.

All best regards

Steve

wjglynn

Steve,

On the gasser I was using an 8db patch antenna with 2" nylon standoffs from the bottom of the fuselage. On this new electric I tried out an Astron Low Profile "Disc" Antenna LP24. It is a 3db omnidirectional. I ran across it while looking for antennas on the internet. It was too cute not to try. In my previous post I stated that it worked well close in. That was because we only flew close in on the first two flights. Have not tried anything at distance. The only conclusion that I would like to draw so far from the gas to electric switch is that I am seeing a marked improvement in streaming image quality. Most of my interference problems have vanished. Whether it is an artifact of burst RF an other electronic gremlins or from the heavy vibration of the G38 I do not know? In any case the move to the "E" world of power and the redesigned camera mount have made a huge improvement in our results. Since I am capturing DV onboard I am not too particular about the quality of the stream as long as I can see well enough to frame the target. My limited testing on those first two flights with the optical zoom does not look promising. Unless I go down a path of Wescam type gyroscopic stabilization (yea right!) for the mount I do not think high magnification is going to be very practical.

Sorry to hear about that reciever problem. Just when you think you have all of the variables covered, Murphy shows up!

Bill