carbon and interference

[Dionysos]

Hi guys,
I have seen a few threads, all telling me that carbon ain't no good for fpv. Why so? Is there anyone who can offer some numbers and quantitative explanation for this phenomenon... I have gathered some equipment (network analyzer) and I wanna do some tests.

If you have some info on this, please share...

Thanks and regards,
Dio

[aeryck]

Simply put, carbon fiber is electrically conductive and will interfere with rf signals. Put a cf tube around your receiver antenna and then do a ground range test.

[Reverand Blue Chip]

It doesn't even have to be that extreme. I used a CF mast on the tail of my last plane to hold a V antenna. Range was less than 600 feet before the picture got crazy. This is on a rig that I have taken 4+ miles out.

[Dionysos]

Hi,
understand, but has anyone done tests on this? Carbon is a conductor, but a really terrible one. There is carbon resistors, remember? I'm thinking of building a ball out of crp, say one lay er 220gramm fabric carbon, another one with 2, maybe a third one with three. Put some transmitters in there, I mean one only at a time but with different frequencies and a reference tx next to it for verification, i.e. with an oracle, maybe an attenuator.
Then I get qualitative results. How can they be quantified easily? Could somebody advise on how to tap out the rssi, or simulate a signal?

The other test I would like to run is placing different length carbon next to the antenna, orientated say parallel or 90 degrees to the antenna. Some small tube having the same lambda or lambda half/fourth etc as the transmitting frequency. What could happen? I believe nothing much. Any hints? There must be a critical frequency I believe, maybe 5'8, when you get some interference, but I believe that carbon attenuates the signal, but I think there won't be much reflections. Even in the carbon ball, there are holes, so it's not critical. My example is always the 787, the whole fuselage is made out of carbon... What do you do there? Place the antennas outside, of course, but interference problems? Haven't heared of any...

Thanks and regards,
Dio

[Dionysos]

Hi,
@aeryck. Can you put it complicated, please

[volto]

From what I understand, anything electrically conductive near the antenna will distort the radiation pattern, so the signal will still be strong in some places, but have nulls in other places. If your receiver isn't in the null then you won't notice. If you post a picture of the inside of the receiver you are going to use, someone can tell you which pin is RSSI.