Is my grounding OK?

[rangelia]

Hey yall, first post so please bear with my lack of knowledge. I mounted my antenna (Wilson 2k trucker) on top of the headache rack on my truck. I welded the mount to the rack. The rack is welded to the flatbed and the flatbed is welded to the frame of the truck. Is there any other type of grounding that I need to do as far as the antenna goes? Im running a cobra 29 ltd in the loop if that matters. on a side note, I was on 19 to see if everything in order and I was told I was herd about 9 miles away,,, not sure if that's true or not. Thanks for your time. spooky

 

[Tallman]

Try strapping cab to frame and cab to headache rack. Use brass braid if you can find it.

 

[rangelia]

thanks for the fast reply Tallman. Will do.

 

[hayseed]

Also, run a ground strap to the tail pipe(s)

 

[rangelia]

alright fellas,,, after I do this grounding what "improvements" should I be looking for? I understand what "grounds" do but why a exhaust? Is it just another line of defense against garbage bleeding in? thanks again.

 

[fourstringburn]

You're good, Every component is connected to each other and the final piece is connected connected to the frame.

If you have the antenna centered on the rack, even better!

 

[fourstringburn]

You're in a Big Truck I believe, not a car. You have way more metal than modern cars do.

On cars, the exaust pipe can sometimes act as sort of an antenna on certain frequencies. A ground strap on the exaust pipe provides more ground bonding of the vehicle against RFI.

Big trucks already have large metal clamps securing the exaust system so the bonding is already there.

 

[Road Squawker]

go here and look around.

https://www.k0bg.com/

 

[rangelia]

Thanks fourstringburn. Yea not in a "big truck" but a ram 3500 dually LWB with a 8'x11' steel flatbed. and yup, I put the antenna dead in the center on top of the rack so the base is at roof top level.
Thanks for the link Road Squawker, I'll check it out now.

 

[rangelia]

So I got to reading that link that Road squawker gave and I got 1 question.. Through out the link it said in multiple places that the ground plane in DIRECTALY under the antenna (I think I got that right). Im from the South the word "directly" is vague. "Directly" in front of you could mean at the tip of your nose, or 100 miles away, as long as its "directly" in front of you. Heres my question Is my antennas ground plane the 2"x 2" plate its bolted to, or is my ground plane pretty much the cab of my truck and the 8' X 11' steel flatbed that's 3.5' DIRECTALY under it? Also, in that link it talked about using the shield from RG8 to make your straps. I got to digging around and didn't have RG8 but I had RG6. Will RG6 work?? I took 3 -10" pieces and braded them together then beat them flat tryin to make them resemble a strap... Before I make any more,,, will these work? Thank yall for your time.
Spooky

 

[Handy Andy]

Not the best, I'd hate to bring you that news but it's RG-6 - uses aluminum in the braid and shield - it's like aluminum foil for BBQ's and Freezer wraps. Keeps food safe. But it's not the best for RF grounding.

Be careful with this, this may be aluminum versus copper...will react with galvanic-style corrosion - it'll oxidize and reduce quickly...(it can damage paint)

Applications

A common type of 75 ohm coaxial cable is cable television (CATV) distribution coax, used to route cable television signals to and within homes. CATV distribution coax typically has a copper-clad steel (CCS) center conductor and a combination aluminum foil/aluminum braid shield, typically with low coverage (about 60%). 75 ohm cables are also used in professional video applications, carrying either base band analog video signals or serial digital interface (SDI) signals; in these applications, the center conductor is ordinarily solid copper, the shielding is much heavier (typically aluminum foil, and 95% copper braid), and tolerances are more tightly controlled, to improve impedance stability.​

Aluminum versus copper, Aluminum may not be very effective...Dissimilar metals type of stuff...

Stick with copper (Cu)



Remember RG-6 is possible Copper Clad Steel - Already has a strike against it - Cladding means it's plated - and like chrome - will show wear and oxidize.

When it comes to grounding - Mobiles, like your truck, need to be made a single unit of ground for the image the antenna uses - called counterpoise. So not just below- but around the base of the antenna - and below the line of sight at the antenna so it can have free view of the horizon.

It's why most people install the antenna for best reception and performance - on the TOP of the vehicle - you're doing the right thing . . . KEEP GOING!

:+> Andy <+:

 

[fourstringburn]

Thanks fourstringburn. Yea not in a "big truck" but a ram 3500 dually LWB with a 8'x11' steel flatbed. and yup, I put the antenna dead in the center on top of the rack so the base is at roof top level.
Thanks for the link Road Squawker, I'll check it out now.

That's a big truck, just not a big rig!

You did your antenna right!

If want additional ground straps, keep them short like you did and go copper.

Auto parts stores sell short flat braided tinned copper straps with terminal rings for around $5.00.

 

[rangelia]

Cool, thanks yall. Ill just try to find some copper RG8 and do it again, only took a few minuets anyway. I hate paying for stuff if I can make it but if I see some somewhere out I might pick it up anyway.. OK Im going to admit 2 things here. 1- I plug my radio into the cig lighter. 2- I got crappy cheap coax. I have some 6awg (I think) cord that I use for welders etc..,,,, will something like that be OK to run for +/- to the radio? Also, if I choose to run a linear later on would the 6awg be ok for that? If so, I'll just go ahead and pull an extra set. As for the coax I'll just get more.

 

[M0GVZ]

www.k0bg.com and read the sections on grounding and bonding. In fact follow everything on that site and you'll have a fantastic installation. The guy whose site it is is the guy who writes the mobile antenna and installation section of the ARRL Antenna Book.

Mounting on any kind of rack will give you a poor RF ground no matter how many straps you use and where the rack is or where your antenna is on the rack. It is metal directly under the antenna at where the braid of the coax ends which counts and yours is a thin bit of bar or tube, not the nice flat metal sheet of the body below it even if you connect with ground straps. Body mount ideally in the middle of the roof is best.

9 miles isn't a great deal. Assuming nothing in the way I can do 30 miles mobile to mobile with 4W. Also it isn't just about transmit but noise on receive as well. I've got S0 even with the engine running once I get out into the countryside.

 

[rangelia]

How do you measure RF ground? 30 miles on a out of the box radio? I was under the impression that 7-10 miles was average. Sounds like I got a lot of room for improvement. One thing I cannot do is drill a hole in the roof of my truck so that's out of the question,,,, but surly a antenna moved 16" forward isn't gonna earn ya 20+ miles is it? If so, I can always go to a mag mount or something... Thanks for the link M0GVZ, gonna look over it again now.