How to tune up the frequency on video tx and rx

[mbanzi]

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

This chip is a little harder to implement than the LTC3200, as it may need to be on a PCB for heat dissipation, requires a few more components and is TINY!

Looking around eBay, someone has done something similar: 3-Terminal 5V 1A Switching Voltage Regulator Power Supply. This entire board is the size of a LM7805, so I think it's worth a try to see if it happens to filters out the motor noise. There is also a 3.3V version available. Could be an easy solution if it works!

[kaos]

the one on ebay seems requiring 7-17V input which won't work for 1S lipo?

note: LTC3200 is TINY too.

[mbanzi]

I missed the 1S part , but there are even more options on eBay for small 5V boost power supply boards. Some have a USB connector which can be removed, while others have adjustable voltages. Think I'll order a couple to see if they work.

[kaos]

great. have a link?

[mbanzi]

All items are from China of course:

http://www.ebay.com/itm/400345678301

http://www.ebay.com/itm/130945415164

[mbanzi]

All items are from China of course:

http://www.ebay.com/itm/400345678301

http://www.ebay.com/itm/130945415164

[kaos]

that might just work. looks like the size of a usb connector wide and thick, twice in length. I may try one too.
Nowadays, what is not MIC. Boscam is MIC.

[kaos]

ordered two from http://www.ebay.com/itm/400345678301
it is cheaper than the second one. used my ebay bucks and end up with 2.44 for two.
By the way, when you order two, they still charge the same 1.00 shipping.

[kaos]

Q-bot micro FPV: 5:30 min fly time.
Still debating I should mount the lens at the tip of canopy and and make a hole at the canopy or just leave it as is.
10 mW module above main board attached to the under side of canopy and 2 LTC3200. All the FPV stuff is attached to the canopy with only 2 wires soldered to the CB power pads. One power source. one plug to fly.

the cam is not 'permanently' fixed yet, may need to adjust the angle some what after several fly tests.

edit:
made several test fly in the house. Wonderful, but Q-bot is a really fast and twitching bugger (great for acrobatics). with my current skill in flying fpv- green horn, still figuring out what is the best setting (DR/expo/weight) to slow down to fly FPV in the crammed house and narrow passage. Can squeeze through 32" door now, but 25" opening is hard.
the tiny whip vTx antenna works well in short range, raining out side can't test the open range yet. But I noticed the reception is not as good as the 3 leaf vTx Ant when there is obstacle in between, brick walls and chimney. the 3 leaf Ant has some noise with these obstacle in short range, but tiny whip Ant has significantly more while still flyable though.

3 leaf wins here.

[kaos]

Raining off and on. Did not get to test the range for 3 leaf on v959. but did a little fly with Q-bot micro with its 1st FPV outdoors.
http://www.youtube.com/watch?v=pC2kS2_G2Ys

While doing practice in the house, I noticed one thing. the little pig tail Ant get bent when I crash it upside down. and I did break the ant at the solder point. I figure I need to mount the Ant inside the canopy and probably horizontally. So I made a dipole Ant I can place it horizontally just beneath the canopy cover. It is like this:

Any thought on this kind of placement of a dipole Ant?

[kaos]

here is the fly vid with the dipole ant mounted horizontally inside the canopy. Looks like it has more noises than the simple whip ant. even dipole mounted horizontally is not as good as a whip mounted vertically. Need to figure out how to mount the ant vertically while inside the canopy. As before the recoding is through goggle's A/V out directly to DVR. The goggle has a 4 leaf ant. What I really see is a little better than the DVR recording.
http://www.youtube.com/watch?v=CiAUHlb9rqM

[kaos]

Received the step-up power supply from eBay: http://www.ebay.com/itm/400345678301

Removed the USB connector and soldered a couple wires directly to the main power pack wiring, both vTx and video cam is powered by the 1S main power pack via this little thing at 5V. Flew one full pack in my house with this power supply.
Absolutely no motor noises.

Now my V959 is also one connection operation.

after removing the usb connector on this thing it weighs only 3.2x g, less than my 1S 137 mah lipo. so weight is not a problem for V959. You can actually further reduce the weight a little by cutting the pcb board under where the USB connector was. Just leave the + and - on the remaining board. According to seller spec, this thing can handle 500-600 mA. It would be good for the 200mW vTx and cam combination too.

[mbanzi]

That's great news! Mine are still on the way, even though I ordered at the same time

[kaos]

I was surprised when I saw the package. Did not expect it so soon either. this may be the fastest shipping/arrival ebay item from China I ever had.

this actually solved the problem with some vTx is 5V and some is 3.3V. Just add a simple 3.3V reg(LM1117-3.3) at the output to get 3.3V .

here is a question:
if I add the LM1117-3.3 at the out put of this 5V stepup converter, do I need to add the 10 uF cap at the input and output of the LM1117-3.3 as shown in the data sheet.

[jhsa]

at least on the output.. or you might get an unstable output..

[kaos]

I think I found a Tx5823 200mW module working at 5V. Hope it works with Boscam system since it is a TX5823. and this one says current draw is 150mA which is a lot less than the 3.3V ones drawing 350mA or so at the Foxtechfpv site.
http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 1079370240

PS: went ahead ordered one, will report back if it works with Boscam system. If it does work that would make the system much better. get the 5V from Rx goes to the 2.00 5V step up converter then goes to the vTx and cam. No extra plug at all. Of course this is for regular model using a regular RX operating at 5V servos. The main power pack will be the power source regardless of 2S, 3S, 4S... all down graded to 5V to RX through the main ESC/BEC.

[thomas9x]

I think I found a Tx5823 200mW module working at 5V. Hope it works with Boscam system since it is a TX5823. and this one says current draw is 150mA which is a lot less than the 3.3V ones drawing 350mA or so at the Foxtechfpv site.

There's an interesting discussion about those eBay sellers' advertised RF power here:
http://www.rcgroups.com/forums/showthread.php?t=1913364

- Thomas

[kaos]

Thx Thomas, this is the kind of info I am looking for. I will take a look.
There are tons of web info out there, but finding the 'right one' is hard.

[kaos]

Looked at the RC group 200mW moduel about the RTC6671.
Is there any way to test/check the out put power at the antenna side/older joint without tear the ground cover apart?

[thomas9x]

You'll need a RF power meter capable of handling 5.8GHz RF. Budget ~ $1K for something worthy to own. Or buddy-up with a ham radio operator that has a decent RF lab in his shack.
FWIW, it only takes a couple minutes to unsolder the tin lid from the RF module.

[kaos]

$1K
sounds like it is worth tearing/ruining 70 15.00 module to find out.

[kaos]

I got my 200mW module from ebay.
As Thomas mentioned and after searching the web for a while, obviously there are two types of tx5823 one is 3.3V and one is 5V.
the one from Foxtech FPV is Tx5823 1010i6 using 3.3 V. the one I ordered from ebay in their pic show the same as FoxtechFPV, but they list it as a 5V module instead of 3.3V. But the one I received from them is actually marked TX5823-120228.
I could not find any thing on the web about TX5823-120228. Any one knows if this is the 'real' version of true 200mW with 5V ability?

[thomas9x]

We can determine what you have if you unsolder the top sardine can lid and post a clear close-up photo of the PCB.

Off the record, I'd be very surprised to find it's an authentic 200mW module if it is the 5V version. My gut feeling is that it would be a challenge for the module to deal with the additional heat burden from the internal voltage regulator. But without looking at the guts it's all guess work.

- Thomas

[kaos]

haha, i was expecting/afraid you might say that.
I still have a problem with my wick when desoldering stuff from hard metal plates. I will give it a try and see if I will burn the module.

edit:
OK, here is pic after I removed the metal cap, RTC6705 and 6671 but with different other numbers on those two chip from RCgroup's pic, no Vreg I can see

edit 2:
the only difference in circuit from rcgroup is one smd resistor on the left of the RTC6705 is two position higher. other wise they look the same.

also, I just received a message from the ebay seller: "What we sell is 5V"
I asked for the datasheet and ask specifically if I can power it with 5V. only got one line answer as above.

[thomas9x]

You have a 3.3V / 18dBm (~60mW) module.

- Thomas

[kaos]

wow! which means if I use 5V power will probably burn it?
if so, why the ebay seller would told me it runs on 5V, not very good.

another question, after removing the metal cap, I found the RTC6705 chip is thin. so it never touches the metal cap hence the metal cap won't help the heat dissipation. I it seems to me it would be better to leave the metal cap off to get more air circulation for cooling??

[Kilrah]

I have often seen both 5V and 3.3V version as advertised, but never an actual difference in the module.
My gut feeling is that the 3.3V ones are just being mistreated with 5V but happen to hold under the abuse...

The RTC is not the one who heats up much. And it works fine with the shield on, never heard of one that was burned.

[kaos]

Is there a confirmed site selling true 200 mW module then? ie Foxtechfpv, is that one a true 200mW module? or they are all 60 mW, some has a Vreg can truely run 5V while others are really 3.3 V or false claim for 5V like mine?

[thomas9x]

wow! which means if I use 5V power will probably burn it?

It means that the supplier is cheating by having you run the 3.3V module at 5V so that it puts out more RF power. In this case, the 60mW chip will probably be super-sized to about 150mW. Design practices like this are one of the reasons for the lower reliability of imported electronic products.

I it seems to me it would be better to leave the metal cap off to get more air circulation for cooling??

I highly recommend that you re-install the metal lid. It helps to make the PC board rigid (important) and in some cases the RF performance may by affected with it off. But I suppose a few small holes (1/16") can be drilled if you are worried about the heat. Regardless, the module will indeed run very hot so use a small fan when testing it on the bench.

My gut feeling is that the 3.3V ones are just being mistreated with 5V but happen to hold under the abuse...

The overclocking tricks are fine when they work. But it irks me when a proper fix could have been achieved for a few extra pennies. Sometimes I think that "quality" translates to "cheapest price" in China.

Is there a confirmed site selling true 200 mW module then? ie Foxtechfpv, is that one a true 200mW module? or they are all 60 mW, some has a Vreg can truely run 5V while others are really 3.3 V or false claim for 5V like mine?

Good question. I would expect the FoxTech module to be a good candidate to check out if your existing "200mW" module gives you any problems.

- Thomas

[kaos]

yes, I will drill may be 10 1 mm holes on the metal cover and put it back on. everyone is reporting it is running hot, with a cover like that just does not make any sense to me. I thought about lower the edges to touch the chip and put some thermal paste between then add a heat sink on top of the cover, but I think it is too much trouble and the two chips are not even/level when they are put on the PCB. so scratch that.
I think I will run this as 3.3V (and send a nasty note to the ebay seller ). if my calculation is correct that would give me close to 8 times range as the 10 mW module (did I figure this number right?), assuming all the other factors are the same. If the 10 mW can go 100-150m then 8 times would be around 800m to 1Km, that would be quite enough for most of my planes. these planes only have 7-10 min fly time any way. But I think it is fun to fly all of them FPV once in a while within 1KM. I always want to see how it looks/feels as a pilot if you are doing fast continuous rolls five times in a snap in a fast plane.

I am going to use this as an easy plug and play vTx with a 2-3g cam so it can be placed on almost all of my planes (800-1000mm size). running through Rx power (range from 5V-6V, my planes have BEC outputs from 5.0, 5.5 and 6V) with one plug and go.
probably better to get a 3.3V BEC to work as a filter at the same time, then I can run anywhere from 2S to 4/5S main power pack. But that does not solve the issue of noise filtering and the cam is running on 5V minimum while the module is running 3.3V.
But since I already have this ebay 5V step up convert (in previous post), I am thinking adding a LM1117-3.3 between the Rx power (5-10V at most, they have different BEC voltages) then go through the ebay step up converter (which by spec only operates from 0.9V-5.0V, can I push that to 6V for a step up converter? So far the highest Rx power on my planes are 6V) as a filter then use another Lm1117 between the step up and this module to run the module at 3.3V. another lead straight from the step up converter to the 5V cam. The step up converter supposedly can handle 600mA current.
Too complicated? any issue you may see if I do it this way? (I just happen to have 2 Lm1117-3.3 laying around )

IF I am not clear on my scheme, let me know.


The foxtechfpv 200mW module definitely is on the list to try. But I do have a set of 200mWTx+RC305 bought from HK, supposedly is Boscam (http://www.hobbyking.com/hobbyking/stor ... x_Set.html).
could that be a genuine 200mW Tx? That is the one I will use for longer range FPV with fly time > 30 min with OSD. Like the AXN floater. Remember that one kilrah?! I did not forget it, just too many fun stuff can be/need to be done.

PS: I do overclock my 2.4 GHz PC running at 3.2 GHz. but I used Arctic silver 5 thermal past and a big heat sink with 120mm heat sink fan for cooling. yep, overclocking is a c**p shoot. if you get a chip is capable you are doing great, if not, either it won't do it or crash and burn. I think my days of overclocking is over. It was fun though.