firestik on roof grounding issue

[redneckcellphone]

my friend has a ford exploder (lol) and has the 5 foot firestik mound the roof. the swr is off the charts bad. i know that he would need a ground strap from the mount to a good ground but where is there a good ground? and what guage wire should he use?

 

[KG4INW]

How's it actually mounted? The roof is the best ground plane (different from electrical ground) for mounting any mobile antenna.

 

[redneckcellphone]

http://www.firestik.com/images/k-4add.jpg on the back of the car on the roof with a firestik 2. the one with the tuneable tip. the swrs are off the charts in the red

 

[KG4INW]

I assume that's a permanent mount so the next thing I'd check is the coax itself. Perhaps there might be a break somewhere. If that mount is on a luggage rack instead of through the actual roof, then that could be the problem.

 

[redneckcellphone]

no the mount in on the actual roof not the luggage rack. hmmm...will check coax but the coax is pretty new

 

[KG4INW]

What kind of SWR are you reading?

 

[redneckcellphone]

its showing in the red. i forget what number though

 

[reedeb]

Get something else besides a firestick. They never work right [mainly on Ford exploders, sorry I couldn't resist]

 

[bryan_herbert]

If the needle is slamming to the far right its a coax or connector issue.

If it casually rises to a 3:1+ ratio its a grounding or tuning issue.

 

[redneckcellphone]

hmmm...that makes more sense. now if it is the connector or coax what is the best way to check it without buying a new one?

 

[LtDoc]

The best way to check for a short is with an ohm meter/multimeter. Measure across the center pin and the connector body. If there's any resistance at all then there's a short in that feed line. That doesn't necessarily mean that the connector is shorted though, there can be a short somewhere else. The most likely place that "somewhere else" could be is at the antenna mount. So check both the connector at the radio end, and the antenna mount. The easiest way I know of doing that is by visually inspecting the mount to see if it's installed correctly. If it appears to be 'right', then an option would be to remove the connector at the radio end of that feed line and re-install a connector, making sure that it's done correctly. That's not exactly the easiest thing to do, so either find out how to do it or take it to someone who does know how to do it.
- 'Doc

 

[JayMojave]

Hello

Yeah what Doc says:

Here is a great web page from Firestick on antenna mounts and PL-259 connectors.
Coax Cable Processing with Firestik® Connectors

A lot of other great antenna and antenna installation info on the Firestick web site also.

Jay in the Mojave

 

[redneckcellphone]

after looking at http://www.stu-offroad.com/cb/ant-mount.jpg we discovered that the insulated shoulder washer was missing. after getting a new one and installing it the swr went from off the charts to about 2. thanks for your help guys

 

[JayMojave]

Hello Redneckcellpone: Thanks for the come back saying you got it fixed, good call. A lot of help is offered here and on other web sites, and many times we don't hear back from the original guy asking for help.

Good going and good luck with your radio.

Jay in the Mojave

 

[redneckcellphone]

i guess somehow it was grounding itself out? yeah i always come here but dont post much.

 

[w2xq]

Not in this case, but the shield on the end of the cable attached to the antenna can be broken under enough duress. As discussed above a VOM is your friend. You can also check continuity of both the inner conductor and the shield. I've seen inexpensive meters at Radio Shack, sometimes for less than $10. A digital display isn't necesssary, IMHO.