How to tune up the frequency on video tx and rx

[kaos]

well, can't wait for that idea. Just made a quick test hooking up the cam/vTx to one of my plane and used a 5V ext BEC from the balancing lead of fly pack and run full throttle on the plane. The video is crystal clear, no noises at all. this is a quick test, cam/vtx is only a couple ft away. But I think the theory a BEC/DC-DC convert will filter out the noises from motors does work. for smallermicro planes use a light weight BEC, larger plane a little heavier BEC will work just fine. I did not test straight from fly pack without BEC, but from everybody is saying, it should create noises. Whether this noise only applies to quad or not, I don't know for sure either.
This FPV thing starts to come together now. Time to order LTC now.

[Kilrah]

Yes a BEC should work - but again there's no rule and depending on the particular BEC and other equipment on board it may or may not work well - the ultimate way to know for sure is just to try.

LTC solution is different, I had some left from a time where I was manufacturing micro sets that were based on components requiring 5V, and for weight savings I wanted to power them with a 1s lipo. It worked fine sharing model batteries, so I jsut reused what I had.

[kaos]

for the X4/Q-bot micro something like LTC may be the only solution because of the weight to be practical. for the V212 size, no need to worry about extra 1S lipo, that is what I am doing now. but a small BEC and use fly pack battery definitely streamline the operation a lot better. I was a handful just to trying to fly, think about the connections/wires, fly pack, 1S lipo, Tx, goggle, A/V out, DVR all hooked up is about a dozen connections/switches. Any where can be saved is a plus.
I am sure going through this, I will get it more streamlined some how. I already have the goggle can be powered by the T9X charging port, the pocket DVR has its own power can run A/V out from goggle to record. just need to figure out how to put them in my pocket or some where on me nicely. hmm, may be a fishing vest is on the menu.
I have seen people using a head gear with a flip goggle so you can put goggle down or up easier. that may be worth looking into as well.
Next couple days when I have a chance I will try the ant in the field again (if I don't crash it and break the set up ) will show you guys a vid to see about the vid image. it will be recorded straight out of the goggle A/V so what is in the vid will be what I see.

once I get the LTC will start to put them together for the new Q-bot micro which is now over pacific. I want to keep my current Q-bot as acrobatic one, beside it has been abused so much by me tumbling around already.
I will put a roach trap paper on the floor when making this DC/DC converter.

Also I like to know, to further reduce weight. If I solder a whip ant wire directly to ANT spot on vTx, I don't need any gnd right? just strip the 5.8 GHz coaxial to center wire and cut it to the correct length and solder directly to the ANT spot on vTX. Will that work? and if I am correct, I need to cut it a hair longer and start trimming the tip till I get a good image. Is this the right way to make it?

[kaos]

Had a chance to change the angle of the cam pointing a little downward and tried in the front yard. Wonderful. A lot more depth and height perception than before. Some more adjustment may be even better. Using a simple whip Tx ant and 4 leaf rx antenna.
http://www.youtube.com/watch?v=4lvhrEl6Guo

[kaos]

OK, test the DIY 3 leaf and HK 3 leaf vTx Ant. Looks like all 3 (and short whip Ant) together the DIY has a better image with less noises. All of them were using a HK 4 leaf Rx Ant on goggle. all 3 vids are recorded through A/V out from goggle to DVR. Also noticed my cam does not like bright light, with bright and dark area together the image is not as good as indoor deem lighting. It is a night vision ready (0.008 lux according to spec), but I think bright sun light is just too much for this cam.

here is the DIY Ant:
http://www.youtube.com/watch?v=hAe6i38k2rM

here is the HK 3 leaf Ant:
http://www.youtube.com/watch?v=leDioYH0noU


Also tested on the quad with one power source and two BEC, one to motor/main board (i am using a 3S pack with BEC to convert to 5V power to main board), one to vTx/cam, no noises with motor running. Looks like two BEC also work well for quad as well.

the chance for two LTC from one power source to work without noises is looking good.

[kaos]

some progress here. 1st, exchanged the V212 with v959 which I gave my dad. (I think the V212 self stabilization would be good for him. ) put the set up on V959 and using T9X/SKY9X Tx. what a difference in fly character. I already can fly down the street and back without problem barring the video interferences from the tree on both sides.
The signal is breaking at around 50-60 yards, but this is through a street with large trees/leaves on both sides. Once I can work out the transmission range (probably because of the antenna). V959 FPV is a done deal.

2nd: look what I get in the mail today:

now the questions are: on the LTC3200-5, which side is which? looking at the 'LTSH' marking, the 3 feet above that is from left to right SHDN, GND, Vout and bottom 3 feet from left to right is C-, VN C+?

and the 2.2 uF caps, I see the two metal ends are different colors, one side is silver, one side is kind of goldish. but these are supposedly nonplarized caps right?

Kilrah: I assume you are using this layout:

bridge C- C+ with a 2.2 uf cap, bridge the Vout and GND with a cap, bridge the Vin and GND with a cap?
I think you may have put a conducting strip/solder from Vin to the other side of the chip to join GND?
Did you use solder paste instead of solder?

[kaos]

I was reading the LTC3200-5 data sheet again. Looks like the " ^ " mark is marking pin 1 which is Vout? can some one confirm this?

I played with the 'micro Lego' a little, looks like it could work. just need to find a fine tip to put them together.
By the way, you forgot to mention one thing: Don't sneeze while playing with micro Lego.

[kaos]

Was playing Lego a little more, hmm looks like it can work:

Although still waiting my 20X loop, I said to myself: heck what can I lose, the worst is wasting a few Lego
so I tried this free hand and without a loop:

BUT, 4.14V in, 0.01V out
Read the data sheet (like I really know how to read an IC data sheet ) again to see if I 'guessed' the pins wrong, then I was looking at the SHDN, so tried this:

Wala, 5.08V coming out.
It is not going to be a winner in beauty contest but it is working. Will see if it will filter out the motor noise and sustain the Tx current draw after I make another one.

By the way, the blue 'roach trap' does help working with these micro Lego. Did not loose one Lego.

the whole thing weighs 0.06 gram vs a 470uF cap weighs 0.83 gram. two of them will save 1.5 gram in weight. wow.

[thomas9x]

Glad to see you are making progress. I've found that best way to succeed is to just roll up my sleeves, warm up the soldering iron, and learn from the adventure. Sounds like you are following that plan too and getting good results.

- Thomas

[kaos]

Not without your and others help. thx.
still need to work out the range issue. will test this wkend in the field with the resoldered antenna.

[kaos]

he he, left side 5.08V, right side 5.06V
will give them a true test over the wkend after finishing the Ant range test.

[kaos]

Too hot to fly. So why not run a test on the Kilrah design - LTC3200-5.

Did a quick soldering attaching the two LTC and the vTx (5813) together, made a few quick connector just to hook up the main power to this new VTx. It looks ugly, but when it goes into the Q-bot micro all components lay out may change.

with a hand made 5.8GHz whip Ant and all those tiny solder joints. Any where could go wrong. So crossed the finger and power the V959 with only one lipo to power everything.
Wala! Steady video with no noises/interferences at all from the motor, at full throttle or change from high to low or low to high throttle.
http://www.youtube.com/watch?v=_ftGer4IHgw

Kilrah: brilliant design!

Thomas: that is the 3rd module which I tore apart before. Looks like the Ant and Gnd test open or shut does not matter. all 3 modules works.

[thomas9x]

Thomas: that is the 3rd module which I tore apart before. Looks like the Ant and Gnd test open or shut does not matter. all 3 modules works.

That is fantastic news.

- Thomas

[kaos]

Tried to do some range tests. But end up only did one try. Using the repaired DIY 3 leaf Ant and separate power pack for vTx and cam as before. I lost the radio and video at around 150-160 yards (I measured from Google earth). V959 end up in the tall grass on the swamp land. Got my feet all wet to retrieve it and ended more testing.
The V959 is bond and flown with Flysky module, I though I would get more range than the stock tx (spec says 100-150 yards with stock). But no I lost the radio control around 150 yards could not turn it back when the video seems to go out too. Once the v959 dropped into swamp in the tall grass I lost the video completely.
Here is the video of the fly and see what you think. There seems to be a problem with my DIY Ant. video is really not that good. or may be it is over the swamp/wet land? Within 100 yard, it seems to be doing ok beside today I had some motor signal noise (louver look) which I did not have before.
http://www.youtube.com/watch?v=_iEbn9rUhQw

[thomas9x]

Regarding the video banding noise:
1. You mentioned the DiY Cloverleaf was on the vTx. But what antenna is on the vRx?
2. Is the DVR connected to the goggles? If the DVR is connected to a second (separate) vRx, how far was it from the R/C Tx?
3. With RF, all the little details matter. So it may help see some clear photos of the video equipment in your "ground station" and aircraft.

- Thomas

[kaos]

A FATshark 4 leaf with a SMA F-M converter is on the goggle and the DVR is connected via A/V out from goggle directly. The same as I tried the 1st time without knowing my DIY might be damaged already. But at that time there was no banding. I don't know why the banding was not there last time but it is there this time. The banding seems to be noises from the motors. but this time the power to vTx and cam is still powered separately by a small 1S lipo not to the main power pack.
This time, after I repaired the DIY 3 leaf Ant on the vTx, the range is obviously farther than last time. I lost the video around 50 yard last time. But what puzzles me is the banding. cause all conditions are the same except the ant was repaired after last fly in the field.
and by the way, I even mounted the vtx ant the same way (or the bad way) as last time - placing it horizontally facing front. Just to see the difference. I was going to try different mounting position but stopped because the wet feet.
I did not know it was a swamp after that 60 yard mark till I started retrieving the v959. I thought that was just tall grass til I felt my feet were wet. The darkest strip was actually all water, I had to walk around to the other side where it is just muddy to retrieve the v959. When flying I was looking through the goggle like: hmm that looks like water/wet land there. Afterwards I was looking from Google earth photo which was taken a while ago, obviously that area has been like that most of the time only obscured by the tall grass when looking at that direction on ground.
another question is I would expect with the T9X/flysky tx module, I expect I would have longer radio control range than the stock 100-150 yard. But I obviously did not have longer range. If I had longer radio range I could just back off to the video range.
Like I said long time ago, radio transmission is voodoo to me.
I will try in a dry area next time to see if there is some radio monster in the swamp sucking radiowaves.

[thomas9x]

It would be quit unusual (read: very unlikely) to find that flying over the wet ground is causing the RF banding problem. At this point I suspect one of two things (or perhaps a combination of both):

1. The 2.4GHz RC Tx antenna is mere inches from your 5.8GHz Boscom goggles. The RC Tx's signal can RF overload the vRx. Due to the RC Tx's frequency hopping technique, this issue can occur intermittently, just as you experienced. Especially as the model is flown at distance, since the vTx signal becomes substantially weaker and easier to step on by the RC Tx.

What to do? As a test, place the video ground station (goggles, DVR, and its wiring) ten feet away from your R/C Tx. If you have other personal electronics move them away from ground station too. Turn on the vTx first, then the R/C Link. Fly (visually, not FPV) around the same large field. Review the recorded video -- I suspect the banding will be severely reduced or will be eliminated. If this helps, then change the video frequency to one that is cleaner when you FPV.

2. If the RC link is not causing any issues then it is possible that the vTx is being affected by your model's vibration/shaking. The aerial's length/mass leverages against the RF module, so the module will be flexed as the antenna moves. Even microscopic flexing can cause the pcb's microstrip inductor values to vary and affect video. Besides more precise prop balancing, mechanical changes to how the antenna and module are mounted may eliminate this issue if it is occurring.

Lastly, placing your antenna in a horizontal position will invite signal fading. As explained before, you need to get the cloverleaf antenna in a vertical position. The ideal choice for a helicopter is under the model, pointing straight down, away from its signal masking materials. To maintain a strong signal the vRx antenna must be able to "see" the vTx antenna, regardless of the model's orientation.

RF advice without all the little details is really just a haphazard guess. So at some point you'll need to get out the camera and show clear photos of the model and ground station setup exactly as you use them in the field. Even better, bring the camera to the field and snap them there.

- Thomas

[kaos]

You are probably right on both counts.
the T9x antenna is at about my waist, the goggle's 4 leaf antenna is of course above my head. BUT the v959 Rx Ant is about 1 cm from the vTx 3 leaf ant. so the vTx probably interfering the radio transmission and end up with what I considered a short range for T9X.
the vTx 3 leaf ant is kind of heavy in relation to the module, and it was fixed with tape under the belly of v959.

here are the pics for the v959 as it was flying. I can tell now it had all the bad things you just mentioned.

The horizontal clear tape is for attaching a small 137 mah lipo to power the fpv system for now. ;)

the little white stick is the rx ant 1 cm away from the vTx 3 leaf ant

I am doing this as a test before I permanently mount the components.
The final plan is to mount the vTx at top (inside the canopy), and fixed to the canopy, the vid cam will be on the similar place to be 'removable' to be used on other models when needed. To make the 3 leaf Ant upright, I will desolder the sma mount and flip 90 degree, so when the module is laying flat and the Ant will be pointing straight up. I envision the canopy will be 'replaceable'. When I am flying fpv I use one dedicated canopy with vTx mounted inside and plug in just one power cord to a pre soldered connector to the main power cord and a 2nd connector for the video cam and the canopy will have a mounting gig for the cam to go on easily. so one power source for both the model and the fpv system. that is why I am so interested in Kilrah's LTC3200 design. Only two plugs and ready to fpv. While I am not flying fpv, I just replace with a stock canopy to have less weight to do flips. The idea is to be 'modular'. Actually the cam will go on to this v959 will be a little heavier vid cam (1.5g more than the one in the pic). the 2G cam in the pic will be permanently mounted in my Q-bot micro with the module that has a tiny whip Ant (the one in previous post with the LTC3200 on it, for Q-bot micro long range is not expected).

Keep ideas and corrections/suggestions coming. this is a really good learning experience.

What is your set up's range with this 10/20 mW module? I assume you use a 3 leaf ant too?

out of the 3 modules I have, one is dedicated to Q-bot micro with tiny whip ant. the other one will have a 3 leaf ant for larger model (for size of 800mm size). if a whip ant can reach 300-500m reliably, I may use a whip ant for the v959 size model.
For full range FPV model I will use my 200mW vTx with helical rx ant, probably with tracker. I am thinking getting a set of ant from IB Crazy (one 3 leaf tx ant and a 7 turn helical rx ant put on a tracker device for long range. With full fledge fpv and OSD, I don't think I have the ability to check the ant sensitivity like IB crazy does his. of course this is after the Frysky have their 'long range - 5 Km' rx on sale to realize. 5Km is 'long' enough for me.

[thomas9x]

What is your set up's range with this 10/20 mW module? I assume you use a 3 leaf ant too?

The 10mW FPV is setup on a DJI 450 frame that I fly in a very small park environment (100² meter area). I have a Skew Planar Wheel (what you call a 4 leaf) on the vTx and a 5dBi circular polarized patch on the vRx. Signal is very reliable and even with nearby structures the multipath interference issues are minimal. A very fun FPV setup that gets flown several times a week.

-Thomas

[kaos]

I will make all the changes as you suggested and try again this wkend. I think the proximity of the vTx ant and the model rx ant is probably the main problem and the horizontal placement of the 3 leaf.
3 leaf /4 leaf is easier to type.

edit: I thought the 4 leaf is used for vRx while the 3 leaf is for vTx. you say you use a 5dbi polarized patch ant on vRx and 4 leaf on vTx. Sounds like we can use either 3/4 leaf ant on vTx or vrx?

[kaos]

Now the v959 is ready for a true test of vTx range and functionality. On the ground test video is doing fine.

[mbanzi]

I've been following this thread with interest, as I use a similar setup on my V929 quad. I ended up using a TX5823 200mW 5.8G transmitter as it was pretty cheap. I made a tiny custom PCB with a 3.3VREG & 2 caps to supply the camera & VTX, powered by a separate 1S 100mAh battery pack. The sleeve dipole antenna is soldered directly to the VTX and works pretty well. Total weight including battery is just under 12g, doesn't appear to affect the V929 too much. I haven't tested this setup beyond 50-80m, but it works perfect in that range. I'm curious to try the boost converter so I can drop the additional battery.

[kaos]

nice and neat as usual.
that 200mW module is on my next project. As you know the module operates on 3.3 V and ~340 ma. my next question would be : Can I use a LM1117-3.3 Vreg (cause I found a couple in my box ) and act the same way as the LTC3200-5 that will filter out the noises from the motor if using the same power pack from the model? I would use the LTC3200-5 again but it could not handle 340 ma needed for the 200mW module. Probably need a separate LTC3200-5 to power the vid cam though. My vid cam operates form 3.6V-5V.
I am looking at the cam you have, it looks the same as mine. Does it operate on 3.3 V? mine, according to spec, operate from 3.6V- 5V. I am not sure 3.3 V will work on mine? Have you tried to use the same power source of the model to your set up? if so, with that 3.3 Vreg, do you experience motor noises?

I believe V929,949,959 the basic frame and motors are the same. My V959 landing skid + the stock on board video cam is 15 gram. so adding 12 g to v929 is till 3 g lighter than the V959 with cam. And V959 with cam flies very well including flips.

I believe Kilrah uses his 20mW (not 200mW) module fly 300 meters out with a tiny whip ant without problem. But he is keeping it a secret.

[mbanzi]

my next question would be : Can I use a LM1117-3.3 Vreg (cause I found a couple in my box ) and act the same way as the LTC3200-5 that will filter out the noises from the motor if using the same power pack from the model? I would use the LTC3200-5 again but it could not handle 340 ma needed for the 200mW module. Probably need a separate LTC3200-5 to power the vid cam though. My vid cam operates form 3.6V-5V.
I am looking at the cam you have, it looks the same as mine. Does it operate on 3.3 V? mine, according to spec, operate from 3.6V- 5V. I am not sure 3.3 V will work on mine? Have you tried to use the same power source of the model to your set up? if so, with that 3.3 Vreg, do you experience motor noises?

The LM1117 won't work in place of the LCT3200, as it is a linear regulator requiring at least 6.2V input to output 5V, whereas the LCT3200 boosts an input voltage of 2.7-4.5V to a 5V output, which is why it works on 1S. I'll take a look around if there's a similar chip with a higher output current.

My cam operates on the same voltage range (actually works down to 3.3V), but I run it straight from the battery. There are 5V & 3.3V versions of the video transmitter apparently, mine got hot directly from the battery, so I run it from 3.3V now, using a AP7215-33YG-13 (which outputs 600mA and has very low dropout). I tried running the setup from the V929's battery, but I experienced significant noise, therefore the separate battery.

[kaos]

It would be great if we can find a LTC like that has an output of 3.3 volt and enough current support.
You also mentioned there are two version of the 200mW module, 3.3 and 5V. Are these modules you are mentioning work with Boscam system or Fatshark system? I have the boscam and RC305 rx, the fatshark/immersion version won't work for me? The only 200mw module that works on Boscam system I found (or tipped by Thomas) is at Foxtechfpv and it only operates at 3.3 V.
The 200mW module, I actually only intend to use with models has 2S and up lipo. I just wonder if the LM1117 has the ability to filter out the motor noise. If so, I can use LM1117 to supply the power for the 200mW module and the power to the LTC3200 for the video cam.

[dbaldwin]

This is a great thread that convinced me to sign up and participate! I originally ordered this vtx:

http://www.ebay.com/itm/5-8G-20mw-Wirel ... OC:US:3160

and it's apparently a different frequency set than my Boscam RC 305 receiver unfortunately. I got everything wired up but could not get any sort of signal after going through all the channels. @thomas9x do you have any more transmitters left? I'd like to order two if you have them in stock. Thank you.

[mbanzi]

You also mentioned there are two version of the 200mW module, 3.3 and 5V. Are these modules you are mentioning work with Boscam system or Fatshark system? I have the boscam and RC305 rx, the fatshark/immersion version won't work for me? The only 200mw module that works on Boscam system I found (or tipped by Thomas) is at Foxtechfpv and it only operates at 3.3 V.

I got my 200mW transmitter from fpvmodel.com, it uses the 5705-5945 MHz frequency set A matching my RC305 (and your goggles). I believe the 5V version of the transmitter just has a built in VREG. Both the 2.8-4.4V & 3.7-5.0V versions are available from rangevideo.com, although I can't tell which frequency set they supply (possibly A judging by the sticker on the pictured transmitter). I notice fpvhobby.com sells a 3.3-5.0V version, including an antenna, with freq set A (they also have clover leaf versions!)

The 200mW module, I actually only intend to use with models has 2S and up lipo. I just wonder if the LM1117 has the ability to filter out the motor noise. If so, I can use LM1117 to supply the power for the 200mW module and the power to the LTC3200 for the video cam.

If you're going to be using a 2S supply, I think a simple LC filter feeding into the LM1117 could work. You wouldn't use the LCT3200 in this case, as you don't need to boost the output voltage.

[kaos]

thx mbanzi. that fpvmodel.com module specifies it is from 'boscam'. and it works from 3.5-5.5 V. That may have solved a lot of my problem for models with 2S or higher lipo.
Here is the idea, use a 5Vreg I have (LM7805CT) which is capable of 0.5 A current support. Add a LC filter as you mentioned. the 5V vreg with LC filter supply the vTx power, also it supply the video cam with a LTC3200. then I can use any lipo power pack upto 4-5S without adding a separate lipo. this can stream line the set up much better as compared to an extra power pack.

Now the question is do you have a recommendation of a LC filter? also, if one LC filter would be enough for both video cam and vTx? If so, then the LTC3200 won't be needed for the video cam any more.
main power pack -->5V reg --> LC filter -->video cam and vTx

The LTC can be reserved/used only for 'micros'.

[kaos]

Did a quick test with the new oreientation and position of the ant. Using the DIY 3 leaf Ant and went through the same route I did in previous vid. the video noises definitely is a lot less, almost none when I circle around the tree.
http://www.youtube.com/watch?v=eywNSS8onGY

[kaos]

Looks like I may have found a LTC3200 like chip to handle 500mA of current for the 200mW module. See if the electronic guru can confirm this:
It is adjustable to 4.5V or 5.0V output, this may be able to supply both module and cam's need out of one 1S lipo or 5V source like from the regular Rx.
http://cds.linear.com/docs/en/datasheet/32031fa.pdf

note: this post has been edited from original post