HAM & CB antenna ground

[kai38]

I'm installing both a HAM & CB this weekend. I have antenna mount tabs on the side of a bed rack

Since the rack sits on the plastic bed rail and is mounted with the OEM tracks in the bed I don't think mounting the antennas will be grounded.
What do I need to do to install them?
Thanks for any help

 

[ericvs]

Hey, not sure about the HAM, but firestick has a TON of information on their website regarding grounding antennae (wire gauge, etc...). You will definitely need to ground your CB antennae.
http://www.firestik.com/Tech_Docs.htm

good luck, looks like it will be a pretty cool install.

 

[4x4junkie]

I think you'll be fine mounting the antennas there. That rack appears to have enough metal in it to provide a decent RF ground for good SWR.

For a DC ground, run a #12 or so wire from the rack to your truck's frame. This will prevent static buildup on it (and your antennas) if it's insulated otherwise.

If the rack has any joined sections, you'll want to make sure they are all tight as well (preferably welded). Any looseness in joints can cause static or crackling noises on your signal as well (both RX & TX).

 

[kai38]

I got to thinking and went out with the 12v test light and clipped it to 12v + and touched the mount and it lit up so the bed rack is grounded, I didn't think it would be, Thanks for the help.

 

[DaveInDenver]

Having a DC return is no indication you have a good RF return. Although, conversely, lack of a DC path does usually indicate that you do not have a good RF ground.

RF grounds should be wide and generally multiple conductors such as braided shielding or flat metal straps. If you have a ham license you might remember mention of the skin effect. RF travels on the skin, e.g. the outside, of a conductor while in DC it's generally a function of the cross section. So a thick chunk of metal is no better an RF conductor than a length of copper foil and a 12AWG solid conductor is a measurably worse RF conductor compared to 65 strands of 30AWG wire even though both have the same equivalent current carrying capacity.

If the rack is welded together, the best way is to put a 1/2" or wider strap between the bed and rack. Ideally you'd clamp the strap so that the whole thing is in contact with both, like a hose clamp on the rack and some sort of flat clamp on the bed rail, for example. You could also scrape paint of both the rack and bed rail under one of the mounting bolts or something.