5.8 antena

[Jazzz]

Does it mater if you use 50 ohm coax or 75 ohm when building your own antena for fpv on 5.8

[ched]

I think 50 Ohms but having difficulty finding definitive answer.
Just found this quote ';Simply put, 75 Ohm is for pictures and 50 Ohm is for information.';

Fundamentally its all about transfer of signal. If you match the impedance (measured in Ohms) of the transmitter to that of the cable and then the antenna you will get the bast signal path.

So I will keep looking.

Update. It would seem 75Ohms is best as it has less effect on high freq.

Mind you I believe using the wrong cable would give a 5% loss.

[Jazzz]

Thanks I';m going to try the 75ohm I';ve got some lying around

[bazzerh]

I use RG402 cable for all my antenna builds which is 50 ohms. they work just fine. think the coveted gavs antennae are also made with this stuff. its great as its semi rigid although its design is for installation in permanent locations so the rigidity can go weak over time or if its bent too hard.

think the most common cables used are RG58, RG316 and RG402. any of those will do you proud.

[Jazzz]

I use RG402 cable for all my antenna builds which is 50 ohms. they work just fine. think the coveted gavs antennae are also made with this stuff. its great as its semi rigid although its design is for installation in permanent locations so the rigidity can go weak over time or if its bent too hard.

think the most common cables used are RG58, RG316 and RG402. any of those will do you proud.

Great thanks just thought I';d give it a try to see if I can do better than the emax ones I got .

[bazzerh]

Great thanks just thought I';d give it a try to see if I can do better than the emax ones I got .

shouldn';t be too hard!

one nugget of info worth having is that the length of the antenna lobes is more crucial than how good you can make your bends and curves. dont try to tune an antenna for a particular frequency either, just go for the measurements for 5800mhz and leave it at that. best way to get precise lengths is set some callipers to the nearest .01 mm and cut slightly longer then dremel them down to be exact. also when you';ve finished one and want to protect it then clear epoxy is better than hot glue. hot glue can change the wavelength. kinder eggs closed around the whole thing make them much more suited to the rigours of miniquad life as well. i have to put mine on before i build the antenna as i use premade pigtails but if making the whole thing then its easy to slip one on just before attaching bottom connector

[forest]

50ohm  is right  one ,  ibcrazy said this i think over on rcgroups