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Travis Harris
25th January 2014, 09:05 PM
Hey guys..

To some of you who follow me on many of the other topics here relating to Quads.. I am going to play around with a high powered FPV truck. I bought a new Summit, and want to see how far I can push this.

First, I have a general question.. and please.. understand that I have a fair amount of FPV experience (quads) and have a very elaborate ground station, and know a fair bit about 1.3 (1280mhz) video.. BUT.. I wanted to talk about 900mhz, and see if that makes more sense for a ground based system at range?

Either way, I am looking for excellent penetration through woods, small hills, and perhaps some buildings.. and thinking about 1.5W of power.. possibly more (RMRC's selection).. and I either will roll with 1.3 or 900..

Currently I have a 11bd gain cross hair, with a diversity box and a cloverleaf / sky hammer for my quads running on 1.3. This is using a small 300mw 1.3 tx on the quads. However, 500-meters out, low behind trees.. the signal gets pretty weak. Obviously I can't run too much more power on the tx side, as it's on a quad… but.. for the truck, I can run more power on the tx side for sure. But, am un-sure if 1500mw will be enough on 1.3.. or should I go with 900?


I am looking for 1 maybe 2km range.. I may buy a yaggi for the ground station, and replace the crosshair. I already own the Dragon Link system.. and intend on using this also.

Thoughts?


EDIT - Updated with some pics…

http://www.mediafire.com/convkey/00c6/9tqwc9vru75hr2w6g.jpg

http://www.mediafire.com/convkey/2198/hnxqc1an06gd4xd6g.jpg

http://www.mediafire.com/convkey/a290/j45m9fg11f6i4306g.jpg

criccio
25th January 2014, 09:22 PM
I think I spent a few hours reading through this thread. As far as I know, one of the best thread's on FPV ground pounders. IIRC he dabbled with 900MHz.

If you're serious about this, read this thread.

http://www.rcgroups.com/forums/showthread.php?t=1333642

Travis Harris
25th January 2014, 09:47 PM
WOW! LOL.. 359 pages long! Do you happen to know a page I can jump in? Or did you happen to read the part about 900 vs. 1.3?

criccio
25th January 2014, 09:53 PM
Couple months back I read the whole thing LOL. About everything you'd encounter was covered in the thread at some point but no, I really don't remember where specific things were. I was just reading it for entertainment so I wasn't really retaining anything.

Travis Harris
25th January 2014, 10:40 PM
Yeah, I just read most of it.. looks like he switched to UHF, and settled with a 1500mw vtx. He seems to have issues using 1360 and 433 together.. humm.. One thing tho, he never really shows the total range with the new gear.

I guess I can slap on a DL rx, and the 2W VTX.. LOL and see how far I can get. There maybe a balance in VTX power, vs. the 433 UHF for RC control. I know as a general rule it's always best to roll with less power VTX, and a better antenna.. (that I have already).. but, with the nature of the ground being so close to the VTX, I think like he saw the more power was better. 1500mw maybe the sweet spot. I will find out.

Travis Harris
26th January 2014, 06:57 PM
I'll throw this out there now.. and see if anyone chimes in with a good idea.. but, one of the things I hope to overcome with this project is the shaky FPV view while driving over rough terrain. For now, I am not going to use any HD camera (go pro).. just the small CCD for navigation. I want to fabricate a system in which the camera is isolated as much as possible from the harsh bumps from the truck. I am thinking of wrapping the camera in Moongel, or some other way to suspend it without hard mounting it to the body / frame. THIS would make such a big difference in the actual FPV experience.. because, to be honest most of the footage I see on-line.. well.. it makes me sick to my stomach.. (because of the movement). Kinda like being on a roller coaster ride. I think it's a simple thing to fix, and I am really really surprised no one has taken the time to take this approach.

I will be using two CCD cameras on my truck with a camera switch on a remote. The first will be dampened as described above and will be the front primary camera to drive with. This will also be using a wide 150-deg. FOV lens. The second camera will be a tiny 520line 90-deg. FOV "back up camera", and will be fixed to the camera switch so when I go into reverse, I can flip a switch (if needed) and get a few from the back of the truck. This camera will not need to be dampened at all as it will be only used very little.

Thoughts?

RonSII
26th January 2014, 07:19 PM
Hey Travis, Have you thought about a gimbal...I've tried different mounting techniques and the main problem is simply the amount of angle deviation the frame encounters... no way around this except to stay on smooth terrain...

Travis Harris
26th January 2014, 07:25 PM
Hey Travis, Have you thought about a gimbal...I've tried different mounting techniques and the main problem is simply the amount of angle deviation the frame encounters... no way around this except to stay on smooth terrain...

Hey Ron! Thanks for stopping in and offering your thoughts!

The gimbal would give me a two axis correction in regards to where the camera is pointing.. this I am not worried about as much. I don't intend on driving over many hills (there are none here in Florida LOL).. no, the issue I am talking about is the "bumpy" ride. This is something that a gimbal won't correct for I am afraid. Rather, a dampening system of some type for the tiny little CCD cam.

Make sense?

RonSII
26th January 2014, 07:35 PM
I know what you mean about the bumps/shakes, my rover has no suspension and adding some memory foam and other things will stabilize some of the jitters but any time I am on anything more coarse than 5/8'ths crushed rock the picture is mighty shaky... My thoughts were to put a 2 or 3 axis gimbal on it just to experiment and have it to 'damped follow'... but right now it's a cashflow issue ;)

Travis Harris
26th January 2014, 07:41 PM
True.. I will figure it out.. I have some ideas that I can try and will post as I made progress. All I care about now, is getting a bit more smoothness to the FPV experience.

I will say, that I have four gimbals on some of my quads.. and have spent the past year tuning them, and getting them perfect. I don't think the gimbal will help at all with the vibrations form the truck, unless the entire thing is completely isolated from the truck's vibrations.. (what I am trying to figure out now)..

Wish me luck!

RonSII
26th January 2014, 08:21 PM
True.. I will figure it out.. I have some ideas that I can try and will post as I made progress. All I care about now, is getting a bit more smoothness to the FPV experience.

I will say, that I have four gimbals on some of my quads.. and have spent the past year tuning them, and getting them perfect. I don't think the gimbal will help at all with the vibrations form the truck, unless the entire thing is completely isolated from the truck's vibrations.. (what I am trying to figure out now)..

Wish me luck!

Hmmm. gives me an idea... strap quad to top of 4x4 and see what happens...

FPVRockApe
27th January 2014, 05:50 PM
I'll throw this out there now.. and see if anyone chimes in with a good idea.. but, one of the things I hope to overcome with this project is the shaky FPV view while driving over rough terrain. For now, I am not going to use any HD camera (go pro).. just the small CCD for navigation. I want to fabricate a system in which the camera is isolated as much as possible from the harsh bumps from the truck. I am thinking of wrapping the camera in Moongel, or some other way to suspend it without hard mounting it to the body / frame. THIS would make such a big difference in the actual FPV experience.. because, to be honest most of the footage I see on-line.. well.. it makes me sick to my stomach.. (because of the movement). Kinda like being on a roller coaster ride. I think it's a simple thing to fix, and I am really really surprised no one has taken the time to take this approach.

I will be using two CCD cameras on my truck with a camera switch on a remote. The first will be dampened as described above and will be the front primary camera to drive with. This will also be using a wide 150-deg. FOV lens. The second camera will be a tiny 520line 90-deg. FOV "back up camera", and will be fixed to the camera switch so when I go into reverse, I can flip a switch (if needed) and get a few from the back of the truck. This camera will not need to be dampened at all as it will be only used very little.

Thoughts?

Travis, you are running a summit, the suspension is so good that a vast amount of the vibration is taken out. If you dampen it too much you will find that the in-car video will jello. Better to just add a dense foam to the camera mount, I used a thin mouse mat. Personally I am quite happy with the results on most of the Tonka Summit videos. But if you are really that worried just add a two axis gyro to the pan and tilt, others have done this before with great results.
I also have a RV camera but it is switched on when I select reverse via a pololu relay switch, then back to front facing GoPro when forward is selected, no need for a manual switch.
You can see it working in this video :- http://youtu.be/caZEpt18Do0

FPVRockApe
27th January 2014, 05:54 PM
Hmmm. gives me an idea... strap quad to top of 4x4 and see what happens...

It has already been done watch this video :- http://youtu.be/_nnxk0bQtak

RonSII
27th January 2014, 06:19 PM
It has already been done watch this video :- http://youtu.be/_nnxk0bQtak

I like it :) the ultimate all-terrain tonka!

but I was more commenting on doing it for the gimbal test.

FPVRockApe
27th January 2014, 06:23 PM
Ah! Now I see where you were going. Mind you, it would solve Travis's vibration problem. Hehe!!

Travis Harris
27th January 2014, 07:53 PM
LOL.. cool. Yes, it's a summit. (love this truck). I am waiting for all my parts to come in.. and I can start testing with it. I am not using any type of go pro, or HD camera.. so that part I don't care about. It's the FPV camera's horrid bumps from faster off road driving I am trying to resolve (so I don't get sick from all the bumps!).

I'll play with it, and report back what I figure out! Thanks so much!

Bluestreak
27th January 2014, 08:26 PM
Hey Travis,

900mhz will get better range/penetration but tends to have things like cell phones interfere so it depends on the area you are in - because of this I tend to favour 1.2 ghz for video. Dragonlink works quite well for control - need to get the antennas as high as possible and separation (both on vehicle and ground station). Yagi is a good choice at base.
For a good camera mount - a cheap ($11) gyro makes a massive difference:
http://www.youtube.com/watch?v=AGBQycHyrR4
Make sure you use proper bearings and mount it solidly! (I wouldn't use any anti-vibration gel). I have found a good quality tilt only system works the best. (
http://www.youtube.com/watch?v=zfcbFpFsbLU) because if you use a pan servo on it introduces sideways gear slop (not so much with a light board camera though).
I have also tried my 2 axis gimbal but haven't had any luck (the motors couldn't cope with the forces): (demonstrated from the 2 min point in this video:)
http://www.youtube.com/watch?v=N2gVwAV1ajU
although having the roll gimbal was very good for the feeling of sideways slopes and I was using a nex5 camera which is much heavier than a board cam!. I might try a gyro on tilt and a single axis roll gimbal with a board camera at some stage.

RonSII
27th January 2014, 09:38 PM
Nice!!! Bluestreak :)

FPVRockApe
28th January 2014, 04:53 AM
LOL.. cool. Yes, it's a summit. (love this truck). I am waiting for all my parts to come in.. and I can start testing with it. I am not using any type of go pro, or HD camera.. so that part I don't care about. It's the FPV camera's horrid bumps from faster off road driving I am trying to resolve (so I don't get sick from all the bumps!).

I'll play with it, and report back what I figure out! Thanks so much!

One thing that we did find with the weight of the Tonka steel body, was the amount of rocking movement that we suffered when accelerating, breaking and hard cornering. We solved this by fitting the P2 Rockers, which stiffen the suspension just enough that it virtually eliminates the movement without losing the summits great ability to soak up the bumps. If too stiff you could find it tipping over when cornering hard.
If, however, you are keeping the standard body, then you can dial the movement out by just adjusting the shock spring compression. One tip on shock spring adjustment, take each shocker off to adjust, do not adjust in the car as it unwinds the cap and allows oil to seep out, don't ask how I know, took ages to mop up all the oil, it gets everywhere.
This short test video shows the difference that it makes :- http://youtu.be/4YS5OdrymqM

FPVRockApe
28th January 2014, 05:29 AM
Travis, are you planning to run your summit, FPV, with the stock body?
If so you might find the early photos of my summit build, using the stock body, useful, especially the FPV platform.
You can find them in the rcgroups.com, Tonka summit site, in my "FPVsummituk" profile, under attachments, look at the bottom of the photos.
My post starts on page 119, #1776, which explains what I did to the summit body and chassis.

Travis Harris
31st January 2014, 02:26 PM
Soooo.. I got in some FPV stuff for the Summit (rover) project.. and I did a rudeamentary range test today.

First, I am running UHF (DragonLink).. and there is no issues with that at all. Perfect.

I bought a 2500mw (2.5W) 1.3 (1258 or 1280mHz) VTX.. and I already had a bunch of CP Clover antennas from my quads as a test… so I used those. I just taped the VTX on the roof, with a 3S pack, and used a 90-dergree SMA so the antenna pointed up… I used a tripod on the receiver side.. and also had a clover antenna for that.

Below is the satellite image that shows where the range started to really get snowy quick. I had to turn back.. this was 400-meters. The truck was behind the building this this picture..

To be honest, I was pretty disappointed with the video performance. I was hoping that at over 2W of power.. (I know some is lost due to heat.. but still.. the most powerful VTX I could find.. I wanted to get at least 1km on the ground, even behind objects.. and it does not look like thats going to happen..) UNLESS, there is a different antenna method I need to try. I will say this.. I tried both channels.. first was 1280, and that was not as good as 1258. ..

I am more then sure, that LOS (down that long road for example) I would most likely get much more range.. I am sure 1KM.. but, LOS is not really all that practical for a ground based FPV vehicle.

Thoughts?

http://www.mediafire.com/convkey/8683/lh89qwrs80srdwv6g.jpg

FPVRockApe
31st January 2014, 03:01 PM
Try the stock antenna, I have so far had good range with them, although I do have the Vrx on a GS relay that is 11.5ft above ground level. My VTx is, as I have said before, only 1500mw, so I agree with you, I would also have expected a better range than you managed.
But one thing that people have found before is that for ground FPV what gives good range in one location seems to falter in another location, don't ask why, after several years we still haven't solved it. Recently, one guy was almost ready to give up as he was only getting 200ft from where he lived, backing onto a field. He later tried somewhere else and had perfect video right up to where he ran out of available running space at 1500ft.
So maybe try another location and the stock antenna, see how it goes.

Travis Harris
31st January 2014, 03:17 PM
Sounds good. Great advice. I fly here often with my quads.. but, of course they are up high in the air.. so i realize it's a better signal as it's way up high.

Yeah, I have some light stands (I am a photographer).. that are 20-foot. I can use some sandbags at the base, and send the VRX up higher, and see if that helps along with the stock antennas. I also email the guys at RMRC.. and asked for their advice. Perhaps a few little tweaks will make it much better next time! I will keep you posted!

FPVRockApe
31st January 2014, 03:24 PM
If you plan to stick it up 20ft in the air, you may want to use a relay to send the signal onto your goggles, or screen, via a 5.8ghz VTx. Plus the fact that you can position the relay where ever you want it and sit elsewhere without the need for a long lead.

Travis Harris
2nd February 2014, 09:47 PM
New update. Same location, same antennas.. this time, I brought a professional light stand with me, that rises 20-feet in the air. I mounted two 25lb sand bags at the base.. and used a 5.8 relay as you suggested.. (worked perfect BTW, good idea! LOL).

The results were MUCH improved. I got about twice the range this time around.. With the exception of me getting "lost" a few times LMAO.. I was able to get a solid 600 - 700 meters even behind buildings that before were an issue.

I further will say, that I did a range test.. where I got the truck way out.. and then stopped it.. put my radio down, and started to lower my antenna mass… after about 12" of dropping the height, the signal got very bad… as soon as I raised it back up.. all better again.

So, now I know the limitations of the clover, and the range I can expect.. and what I need to do to get it.

Basically, I am getting 600 - 700 meters solid, with a 20 foot stand using a simple clover antenna. CP.

Next…

I will use a diversity system with a 10db gain cross hair, and the clover mounted to the top of my 20-foot stand (extra sand bag this time).. LOL.. and will note the difference, and how the directional antenna may or may not effect things.

I will have to post some pics soon.. I did a fairly clean install of the FPV gear on my Summit.. and looks pretty good. I also installed a three way camera switch, and I added a micro reverse camera! LOL. So cool!

More to come..

FPVRockApe
3rd February 2014, 06:05 AM
Don't forget to test with the stock rubber duck antenna. I'll be interested in your results.

Travis Harris
3rd February 2014, 09:48 AM
Don't forget to test with the stock rubber duck antenna. I'll be interested in your results.

I would, except I don't have another one for the rx side. :-( I only have CP antennas.. This is because when I built my ground station last year it was for flying.. so I never even considered using the stock LP antennas that ship with the gear, and I think I there most of them out. I have the one that I got with the new 2500mw VTX though, I guess I just need to buy another one.. and maybe grab a patch antenna too.. LOL.

EDIT - I know, your making me think this is the key.. imagine, I switch it out.. and the range is much better! That would be very interesting!

Travis Harris
3rd February 2014, 03:34 PM
- 2500mw 1.3 VTX

- Dragon Link UHF

- Three camera FPV system with three way switch. (150-degree super wide front camera, 90-degree micro rear backup camera, and a 90-degree micro side mounted camera that shows the front wheels, "prospective camera" for crawling over large things like a log, etc..

- Lost plane "alarm", both to locate the vehicle if video drops out.. and can be used as a deterrent if someone tries to steal the truck (although it weighs close to 35-pounds.. so this would not be very easy to get far with it).

- 8000mAh 4S power system offers 1+hours of continuous runtime.

- 25MPH top speed as configured.

- With the exception of the FPV gear, it is completely water proof.

- Range is estimated to be 2+km LOS.. and so far I have done about 700-meters non LOS. I am playing with different antennas.. and I want to improve the non-LOS range a bit more.

** Next upgrades will be a panning main drive servo, and an possibly an OSD.

Some pics:

http://www.mediafire.com/convkey/00c6/9tqwc9vru75hr2w6g.jpg

http://www.mediafire.com/convkey/2198/hnxqc1an06gd4xd6g.jpg

Note this last picture.. on the rear, where the left body pin would go.. notice the micro reverse camera! There is also another one mounted in the rear wheel well, aimed at the front tires. Works perfect!

http://www.mediafire.com/convkey/a290/j45m9fg11f6i4306g.jpg

FPVRockApe
3rd February 2014, 03:37 PM
Looking good, now we need the videos.

Jackella
3rd February 2014, 04:52 PM
agree some ground dvr....

Bluestreak
4th February 2014, 10:13 PM
Nice Work Travis ;)

If you can get the antennas on the vehicle higher that will help a lot! I made some coax extensions and mounted my dipole antennas on some car roof antennas (~1.6 metres from the ground).
Also remember - the circular polarized antennas won't improve the range but prevent multipathing.
If you manage 2kms let us know as I have never seen it done with a gound fpv system :)

Travis Harris
4th February 2014, 11:31 PM
Nice Work Travis ;)

If you can get the antennas on the vehicle higher that will help a lot! I made some coax extensions and mounted my dipole antennas on some car roof antennas (~1.6 metres from the ground).
Also remember - the circular polarized antennas won't improve the range but prevent multipathing.
If you manage 2kms let us know as I have never seen it done with a gound fpv system :)

Good info. So, your saying if I can get the antenna on the truck (video) higher / longer it will help. How can I do that and still keep it ridged yet flexible?

My UHF rc control seems to be fine so far. Just video is in need of improvement.

Bluestreak
5th February 2014, 12:18 AM
Good info. So, your saying if I can get the antenna on the truck (video) higher / longer it will help. How can I do that and still keep it ridged yet flexible?

My UHF rc control seems to be fine so far. Just video is in need of improvement.

It's a bit tricky with the cloverleaf because it is so bulky. If you can get some sort of flexible rod (fishing rod/fiberglass car antenna) and tape the antenna to the top of that would probably be the best.

paulaus
5th February 2014, 03:09 AM
40776

I dont want to rain on your parade, I built a tonka version a while back, it runs ezuhf with a 1.2 500mw lawmate with CP antenna..

1km straight out no poles etc..

FPVRockApe
5th February 2014, 05:31 AM
I achieved just over 1km LOS, with 2.4ghz Rx (18" antenna) and 5.8ghz VTx (4" SpiroNet antenna). The video was 100%, but the control was lost as I dropped into a dip in the ground.
Now that I run EZUHF, the control is so good that it hasn't let me down once in my trips, even behind earth banks, rocks and trees, this is using the stock twin 150mm diversity whip antenna. I have also built a twin diversity 500mm dipole antenna which I thought that I would require for long distance runs, but so far the weather is working against me to test it.
As far as video is concerned, I am now using a 1500mw 1.2/1.3ghz VTx, using the stock 175mm rubber duck antenna, this is also giving exceptional results, but once again I am waiting for a change in the weather to test properly.
But I have found that non-LOS, the higher the antenna the better.
I must admit looking at your photos, your antenna does need to be above your truck, as more than half of it will be masked by the truck itself, plus it is so vulnerable that low to the ground.

Bluestreak both Calidave and Roadgraders have driven past the 2km LOS, but they are the only people who have managed it so far, as far as I know.

Although we all want to get our range to its maximum, when on the ground you do get nervous when your truck is trundling along totally out of sight and 1/2mile away, all the what-ifs go through your mind. It's not like a plane, where, apart from a power failure, it will come back, on the ground there are so many unknowns that could stop you. So you will find that you will very rarely go further than 1km. It is driving around out of sight that is the real buzz as far as ground FPV is concerned.
I found that the more driving that I did, the more I found just how much fun it is to inter-react with the public, especially children. So you start to add things to the trucks to make them more friendly, a driver, with a camera for a head, and can wave to people, the ability to flash their lights, etc. etc. some of the Tonka guys have taken it a step further on and themed their builds, Scoobydoo, Flintstones and the Muppets, being among them.

Come on Travis, stick a Tonka body onto your chassis, and join us on the Tonka Summit forum. Hehe!!

Bluestreak
5th February 2014, 06:19 AM
Bluestreak both Calidave and Roadgraders have driven past the 2km LOS, but they are the only people who have managed it so far, as far as I know.



I can only speak definitively for my self but I don't think any of us have reached the 2km mark yet. I have reached 1.81km very non-line of sight, the reason I lost signal was because I was going way behind a hill. I'm pretty sure 2km shouldn't be too hard to do full line of sight but these things are easy to say :). Calidave did amazingly well to get 1.6km with a 5.8ghz setup but even he admits that if there was obstacles in the way he wouldn't have made it that far. Roadgraders made it 1.7kms with a 1 watt 1.2ghz setup.
By the way - I don't know if you guys have watched Bomb Patrol Afganistan but their $100k+ fpv robots only go to about 1.5kms ;)

When I get some time I should put my yagi up high on my Land Rover and go to an open area to see if I can get past that 2km mark - no doubt someone will beat me to it though because my crawler has a broken diff and my 1/5 scale trailblazer is sitting at the bottom of my dam somewhere together with my best video transmitter/dragonlink receiver my big antenna poles and a whole lot of other goodies! :( So because of this my latest creation is an FPV sub to go underwater searching :)

FPVRockApe
5th February 2014, 09:28 AM
Your right, I thought that I had read somewhere that Roadgraders had gone past the 1.6 mile mark, but it can't find it, so maybe it was just wishfull thinking.

Beachflyer
5th February 2014, 10:21 AM
Road grader documented record = 1.1 mile or 1.8 Km

Travis Harris
5th February 2014, 01:16 PM
I dont want to rain on your parade, I built a tonka version a while back, it runs ezuhf with a 1.2 500mw lawmate with CP antenna..

1km straight out no poles etc..

Nah, your not raining! LOL.. I appreciate the info! Thanks!

I feel tho, that it's so relative to each owns location, and surroundings.. that can make a big difference. What I should do, as someone already pointed out is try to drive in another location, and compare results. Being that I think the place where I am currently driving is a challenge for the video, I am going to stay there first.. and see how good I can get it.. thinking that anywhere else will be even better.

I have no doubt, that in a different place.. wide open, I would get some insane range as it is.. But, I first am interested to see how far I can push it in a more dense place.. and I think the higher antenna idea is good, and I will play with a few other types.

Travis Harris
6th February 2014, 11:37 PM
So, today I tried the stock antenna and then I used a patch antenna on the VRX side. I placed the patch very high in the air (20+ feet).. and I had great results. I did have to somewhat "aim" the patch in the general direction where I was driving.. but, thats not a big deal.

In terms of range, nothing new.. same.. but, perhaps a little better performance overall I felt.

I am wondering.. I saw (read) somewhere that a patch works best near the ground (on the ground).. so, I may try that next time and compare.

Next…

Will be to get the truck vtx antenna up higher (I am thinking 1 meter).. and see what that does.

FPVRockApe
7th February 2014, 05:40 AM
Lifting the VTx should give improvement over rough terrain, where you tend to drop below ground level in places, but flat LOS, probably won't make too much difference.
Have you tried a different location, yet?