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Kermet

5.8GHz Rx module wanted for DIY goggles

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Hi , I want to build a set of DIY FPV goggles and use the fatshark band so I can still use my fatshark goggles for a second person to view

perfer the rx to be lite and 8 channels ok, 32 better if that was possible, BUT has to be the correct match on fatshark band

not those ones that say eg.5740Ghz then a bottom note that says they may not work on fatshark Tx.

and just wonder if for the extra bucks just use the fatshark 5.8Ghz module from Hobby King as they have free shipping and its small and light or is there some thing else I can use ?

Cheers Brett

Thomas repled......................

Hi Brett,

What 5.8GHz vTx will you use with it? Exact part number please.


- Thomas

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I'd recommend the FatShark NexWaveRF 5.8GHz vRx module because you are using FS and IRC vTx's.

To help wire it up you can follow the Airwave AWM662RX datasheet. The module will be missing the pin for the bypass cap because it does not need it.

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Great thanks,have ordered one

there are two test circuits I have come across both slightly different

Is the Video output cap make any difference if you are feeding a 5" monitor ?

can I ground the audio outputs if not used ?

the second circuit does not use the bypass cap is this needed ?

http://www.hobbyking.com/hobbyking/store/uploads/166660136X982663X10.pdf

http://www.hobbyking.com/hobbyking/store/uploads/793538455X103925X59.PDF

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Video output cap should be 470uF for best vertical sync performance.

Do not connect anything to the audio outputs if you do not need audio.

The bypass cap is not used on the Fatshark module. The module will be missing the pin for the bypass cap because it does not need it.

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ok thanks,

Can you explain in techno terms where the RX system is different in the fatshark say compared to boscam ?

is it video bandwidth or what

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ok thanks have read that

So it boils down to the video emphasis, video bandwidth, and audio sub-carriers specifications

I got my nexwave module today, just out of interest i pulled the cover off my 5800 Duo V4 and it has the same two modules in it

so im guessing as this Duo Rx covers 32 channels that the video emphasis, video bandwidth, and audio sub-carriers specifications are less affected in this RX or might i see lack of quiality over distance using a 32 ch TX with the Duo ?

post-5144-0-22504900-1433501727_thumb.jp

post-5144-0-30109100-1433501868_thumb.jp

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The new 32 channel NexWaveRF module's RF demodulation is configured for ImmersionRC and FatShark. They added more frequencies but the video emphasis and bandwidth characteristics remained mostly as-is. So it is not 100% fully compatible with the other Chinese brands. FWIW, FatShark offers a 24 channel 5.8GHz "Beta" module that is intended to be used with the Chinese brands. http://www.dpcav.com/xcart/FatShark-Dominator-5.8GHz-Receiver-Module-32-Channel-BETA-Band.html

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Thomas ive setup my goggles with fatshark module and 5 inch screen and 5volt ubec to power the module with 12 volts straight to screen.

Im getting blue screen before the static appears now but with my first testing of screen and rc305 RX it would hold static to un viewable picture then blue screen for very short time(split second) then back into picture again....the monitor is know to blue screen but only after extreme static

It is worse or even back to front using the fatshark module and fatshark tx

I have used the 470uF cap at the monitor end that shouldnt matter ?

Also using them with another mini quad 32 channel Tx i get thick band Horizontal lines across the screen when the motors are running ( at any range) and i dont with my FS Attitude goggles

any ideas

Brett

post-5144-0-34816800-1434080520_thumb.jp

Edited by Kermet

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I have used the 470uF cap at the monitor end that shouldnt matter ?

That is the correct cap value for the vRx module's video output. The cap's + leg should be on the side that directly connects to the vRx module's VIDEO pin. Confirm that is how you installed it.

There should also be a large value cap (470uF) directly connected to the vRx's 5V & gnd pins. Do not mount it remotely, install at the vRx.

Also using them with another mini quad 32 channel Tx i get thick band Horizontal lines across the screen when the motors are running ( at any range) and i dont with my FS Attitude goggles

Regarding the better success with the FS Attitude goggles & 32CH Chinese vTx, keep in mind that success is possible due to component tolerances in the vTx & vRx. But as mentioned, I do not recommend the 7CH/32CH brand mixing.

So use a FS or IRC vTx to test the FS vRx module. Since the banding problem occurs with motors running then that implies your vTx, or OSD, or camera has dirty power or insufficient voltage under load. Test with a separate battery powering the vTx system to see if the problem goes away. If a separate battery works then your shared battery needs to provide cleaner power. That's when a LC filter is usually installed.

And be sure the vRx and vTx channels are setup to match. It's possible to still have a video link with incorrect channel settings, but range will be short and you will see more video breakups.

Lastly, are you sure that antenna has a SMA on it? It's one of those Chinese "cloverleaf" clones and they often have RP-SMA's on them instead of SMA. For sure, if it works well on a RC305 then I'd expect it has a RP-SMA, which is the wrong RF connector for a FS vRx module's SMA.

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Yes i have the 470uF cap + facing vRx ( had to pull out to double check my work)

Only had 1000uF or 330uF so fitted the 1000 on vRx end and will test tomorrow thanks i missed that.

has my FS Attitude goggles got any more filtering in them apart from the module itself of which is the only part im using in this head set project ?

what could the RC305 have over the FS Nexwave module to hold static longer on the same monitor screen ?

I did not change the tx channels on any Tx's and always fly the same channel 5740, so the FS Diy module is connected all pins to earth as in the second PDF above

Regards to the SMA yes i have both pin and unpin version, I have had good range with the cheap antenna 2ks on my planes, i trust the ones i have.

thanks for pointing that out as it is a trap.

So ive added the 1000uF power cap to vRx and testing tomorrow if fine

regards

Brett

oh and thanks heaps Thomas

post-5144-0-42071600-1434099767_thumb.jp

Edited by Kermet

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has my FS Attitude goggles got any more filtering in them apart from the module itself of which is the only part im using in this head set project ?

Ignoring the completely different video monitor components, the only significant difference would be the power supply and overall construction.

what could the RC305 have over the FS Nexwave module to hold static longer on the same monitor screen ?

The RC305 has nothing in its design that would make it better to reduce blue screen. Both use the same RF chip set. In practice you should have more problems using the RC305 with FS/IRC because of the compatibility issue.

FWIW, the RC305's power supply uses a linear VReg. Your 5V UBEC VReg is probably a DC-DC switcher that may have excessive noise. And be sure to check that it is 5.0VDC under load. Furthermore, simple things like wire length and construction techniques can contribute to differences in performance.

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