range issue and poor vid quality with 5.8 ImmersionRC 600mw transmitter

[nate0624]

Hey Gang,

Hardware involved: ImmersionRC 600mw vtx (sold by GetFPV.com), Fatshark Predator V2 goggles, two iBcrazy bluebeam ultra antennas, Sony 600TVL camera, Pololu 12v step up, LC Filter – all on my Blackout mini H Quad.

Problem: Static and lines on my Immersion RC 600mw vtx and Fatshark goggles. Poor range – no more than 10-15 feet w/ motors on or off. VTX is extremely hot to the touch.
This is a brand new build with less than 1 hr of flight time.

It has been two weeks now. I’ve narrowed it down to two likely outcomes – either faulty ImmersionRC VTX or Fatshark goggles. The only reason I may suspect the goggles is because there is no other way for me to test the video display.

Unfortunately, this is the only rig I have right now, so there is no other benchmark to measure faulty equipment against.

Solutions tried (not listed in order):
1) Desolder all connection points related to FPV or FPV power
2) Changed channels on goggles and VTX
3) Wiggled all connections/wires to camera
4) Swapped wire harness to camera AND VTX
5) Installed 2 different Pololu step-ups
6) Tested all Red&Blk points w/ multimeter – getting approx 5v and 11v where needed.
7) Installed and reinstalled LC Filter (sold by GetFPV) ( Not convinced this was ever needed).
8) Changed antennas from IBC to standard cloverleafs, even duckys (desperate).
9) Removed all SMA cables / eliminated all RP-SMA
10) re-wired yellow vid wire through PDB

I am completely at a loss here. I'v posted this on a few other sites - no solutions yet. Any suggestions?

 

[kloner]

I would move the vtx top side of the plate and get rid of the extension,,, this isn't that easy especialy with 5.8.....

if the vtx was ever powered up without an antenna, that might be fried..... only way to see a number as in good or bad is the immersion rf analyzer, but for sure 5.8 can not have extensions, the length of the antenna mast is a tuned thing.... and extending it untunes it, 5.8 is super high bandwidth, almost hd capable so it is weaker than the narrower bands needing things kept tuned or it falls apart.

it is really hard to screw up fatsharks, if it sees anything, it's working, problems almost always happen on the craft side. a good way to check this out is to take it all out of the craft, power it up in the hand and check it out.... don't expect it to go through walls, but it should be clear when you can see the vtx from the goggles..... i can get these to go miles in the sky

if the lc filter and 12v step up are on the immersion vtx, take that off, you want straight power going in, theres already a filter and the voltage is good from 2-6s unregulated.

 

[nate0624]

I would move the vtx top side of the plate and get rid of the extension,,, this isn't that easy especialy with 5.8.....

if the vtx was ever powered up without an antenna, that might be fried..... only way to see a number as in good or bad is the immersion rf analyzer, but for sure 5.8 can not have extensions, the length of the antenna mast is a tuned thing.... and extending it untunes it, 5.8 is super high bandwidth, almost hd capable so it is weaker than the narrower bands needing things kept tuned or it falls apart.

if the lc filter and 12v step up are on the immersion vtx, take that off, you want straight power going in, theres already a filter and the voltage is good from 2-6s unregulated.

Hi,

Thanks for replying. I have tried setting this puppy up every single way -the pictures are posted our of order, but it is currently off of the top frame and the extension cable has been removed.

I have set it up with and without the step-up and with and without the filter. I've read about the filter in the ImmersionRc 600mw VTX so only added it as a precautionary measure when it wouldn't worked - this was based on the suggetsion from a uer on RCGroups.

I would agree re: the Fatsharks. The image is very clear and crisp when I'm within 4-5 feet and then I move or try and walk away and it looks like garbage - wavvy lines and static.

iBcrazy antennas are brand new and I've swapped out and tried two other kinds of cloverleafs and the stock rubber duckies.

Re: the possible fry from running without antenna - I just learned that that is a possibility. To be honest, it is not likely, but I cannot say with 100% confidence for me to say it is not what happened.

I have reached out to GetFPV.com (which is a great company) to see if they'll swap it. hopefully they'll respond soon.

 

[kloner]

it is true with anything that transmits rf that you can't take the antenna off.... if happened it burns out the amp and your vtx turns into a 25mw that takes a ton of vigilence to make work at all....

Again, if you remove it from the rig, wire it up so can be handheld, will tell you if the craft is spewing rf making a noise floor too tall to get over..... everthing else you have it with makes rf....

 

[nate0624]

That shouldn't be too difficult. Assuming it was the RF emitted from the rig, how can that be cured? where does this usually come from? the Rx, ESCs?

 

[kloner]

everything emits some, it's just a matter if it conflicts with the rest. a big killer is cameras,,,, on long range fpv rigs we use big rigs to seperate all this stuff to make it better, nothing cures rf like shielding the offender, after that the best next move is seperation

 

[nate0624]

everything emits some, it's just a matter if it conflicts with the rest. a big killer is cameras,,,, on long range fpv rigs we use big rigs to seperate all this stuff to make it better, nothing cures rf like shielding the offender, after that the best next move is seperation

The VTX is on it's way back to GetFPV and once I get a new one I will try to run it. If the problem persists, my next step will be a complete bench test off of the rig. I'll gladly update.

thanks for commenting.

 

[Av8Chuck]

everything emits some, it's just a matter if it conflicts with the rest. a big killer is cameras,,,, on long range fpv rigs we use big rigs to seperate all this stuff to make it better, nothing cures rf like shielding the offender, after that the best next move is seperation

What do you use for shielding?

 

[nate0624]

I am also very envious that you have a blackout. I have all the parts for a blackout build, just no frame.

Thanks. Obtaining the parts was just as challenging as the build. Aside from this issue, I love flying mine.

Here is my maiden flight: http://youtu.be/ecm2nXKqHPI

 

[nate0624]

well, this is an area I know little about; however, I did twist some of the wires leading from the ESCs to the FC and wrap them in mesh - nothing special.

I really used the "typically build" for a Blackout as my benchmark and nobody has mentioned shielding in particular.

I hav enot wrapped my VTX or RX with heatshrink. Does that do anything related to RFs?

 

[SilentGloves]

I would move the vtx top side of the plate and get rid of the extension,,, this isn't that easy especialy with 5.8.....

if the vtx was ever powered up without an antenna, that might be fried..... only way to see a number as in good or bad is the immersion rf analyzer, but for sure 5.8 can not have extensions, the length of the antenna mast is a tuned thing.... and extending it untunes it, 5.8 is super high bandwidth, almost hd capable so it is weaker than the narrower bands needing things kept tuned or it falls apart.

Just as an FYI, extending from a transmitter to an antenna does not necessarily "detune" an antenna. It's a bit more complicated than that. If the coax you're using to extend from the Tx to the antenna has an impedance that does not match that of the antenna system and the impedance the Tx was designed for, that's where you will get into problems. Impedance mismatch causes VSWR to increase, and this can fry a Tx (this is why you don't run without an antenna, because impedance shoots skyward, and RF is reflected back into the Tx finals). Additionally, coax is an unbalanced line, and an antenna is a balanced system, but I won't go down that road because it gets a little too complicated for this venue.

In more simple terms, you can extend from the Tx to the antenna all you like, as long as the coax and connectors you're using to do so matches the impedance presented by the antenna at a given frequency, and this system has to match the impedance that the Tx is expecting.

 

[kloner]

on a 5.8 system of any brand it WILL DEGRADE performance

 

[Jindalee10368]

Hey Gang,

Hardware involved: ImmersionRC 600mw vtx (sold by GetFPV.com), Fatshark Predator V2 goggles, two iBcrazy bluebeam ultra antennas, Sony 600TVL camera, Pololu 12v step up, LC Filter – all on my Blackout mini H Quad.

Problem: Static and lines on my Immersion RC 600mw vtx and Fatshark goggles. Poor range – no more than 10-15 feet w/ motors on or off. VTX is extremely hot to the touch.
This is a brand new build with less than 1 hr of flight time.

It has been two weeks now. I’ve narrowed it down to two likely outcomes – either faulty ImmersionRC VTX or Fatshark goggles. The only reason I may suspect the goggles is because there is no other way for me to test the video display.

Unfortunately, this is the only rig I have right now, so there is no other benchmark to measure faulty equipment against.

Solutions tried (not listed in order):
1) Desolder all connection points related to FPV or FPV power
2) Changed channels on goggles and VTX
3) Wiggled all connections/wires to camera
4) Swapped wire harness to camera AND VTX
5) Installed 2 different Pololu step-ups
6) Tested all Red&Blk points w/ multimeter – getting approx 5v and 11v where needed.
7) Installed and reinstalled LC Filter (sold by GetFPV) ( Not convinced this was ever needed).
8) Changed antennas from IBC to standard cloverleafs, even duckys (desperate).
9) Removed all SMA cables / eliminated all RP-SMA
10) re-wired yellow vid wire through PDB

I am completely at a loss here. I'v posted this on a few other sites - no solutions yet. Any suggestions?

Just came across this thread.
I assume you had the correct SMA connector on the antenna lead to mate with the connector on the TX?
(Need to be mindful of RP SMAs)

 

[cootertwo]

I agree, you gotta watch those antenna types. I received a TX one time, that was SMA, but had RP-SMA antennas. If I hadn't noticed, and powered up the TX with the RP-SMA dipole that came with it, it would have fried.