Author Topic: Long coax cable between UHF tx and antenna? (Read 684 times)

MK1G4V · « **on:** August 07, 2014, 05:13:32 PM »

Howdy pilots! I'm new here And not very knowledgeable at all On FPV flying and so I have a question I'm hoping you good fellas here could help me with..

Should I choose to add a good few meters of high grade coax cable from my UHF tx and its antenna. Is that likely to cause me a great deal of signal loss?

'really hoping I could mount the antenna up high on a nice big pole and Connect it to my Tx so I could possibly fly from indoors.

Any help would be appreciated.

Cheers!
Gav

bigMouse · « **Reply #1 on:** August 07, 2014, 07:03:45 PM »

Radio Shack Tandy Cable RG-58 which is probably what is sold here:

http://www.hobbyking.com/hobbyking/store/__21270__RG58_Patch_Cable_SMA_Female_to_SMA_Male_5_Meter_.html

This will lose about 1.5db (or 1w in 0.7w out)

The loss is linear with length so

http://www.hobbyking.com/hobbyking/store/__21271__RG58_Patch_Cable_SMA_Female_to_SMA_Male_10_Meter_.html

This will lose about 3db (or 1w in 0.5w out)

There are other more exotic cables around but the best solution would be to have the Tx near the Antenna and make the long leads connect the controller (in the house) to the rf Tx (on or near the roof) These long leads would be prone to rf interference, would need to tried and see the results...

MrBen · « **Reply #2 on:** August 07, 2014, 08:41:02 PM »

you are better off leaving the antenna on the UHF tx module and extending the PPM wires in between the transmitter and the UHF module instead, although both work fine

MK1G4V · « **Reply #3 on:** August 07, 2014, 09:29:08 PM »

Oh right I see, I'm sure I did think about that. I guess I dismessed it for reasons like.. the module has ubs ports and a few more ports ect that I don't yet understand. Thought It would be handy to have this indoors or at least have easy access to it. And I'm not sure what the PPM wires look like or how many wires there is . Or if I could buy and extender cable of sorts. Ill be sure to check that out guys thanks for the help!

Gav

MrBen · « **Reply #4 on:** August 07, 2014, 09:33:59 PM »

I use ezuhf the usb port is only used for flashing the firmware, there is a lo/hi power switch on the module though which could be used in flight if you start getting loss of signal, however i ezuhf you can actually assign this to a spare channel switch on the tx so you really do not need to be sat next the the uhf module at all. ezuhf used a S-video type cable where it plugs into the uhf module and servo pins the other end so I just bought a 4m s-video lead cut one end off and crimped on my servo connectors (you could solder a servo cable on if you dont have a crimper) most uhf units have a servo type connector both ends so even easier.

MK1G4V · « **Reply #5 on:** August 07, 2014, 09:41:05 PM »

Oh this is great news! I will be using the same EzUhf module kindly suggested By Xxpitt , Do you use an extension of some sort yourself then bud?

Cheers!

EDIT . Oh sorry You clearly do..