I have a Grant XL that I have installed in a 2013 Chevy Tahoe. Power is direct wired to the battery and I have done all of the normal tests to ensure the radio/antenna/coax/ground wire/mount are all where they need to be with respect to resistance and Ohm testing. I am still seeing super high SWR readings (3+) so my next step will be testing the radio to ensure nothing is wrong with it. Is there anyone in Louisville, KY or nearby that can ensure/test the radio is operating as it should? I'd be happy to pay for the test and would be more than willing to bring the radio to you. It is a radio that was given to me and I can only assume it was working when it was taken out of the previous vehicle.
CB repair/testing
- Thread starter lunteben
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Are you using a dedicated meter to measure VSWR or the internal radio meter? If the VSWR measured with external meter is high its not the radio, its the antenna system and could be the antenna, mount, coax or antenna location and lack of ground plane.
DeeEx
Member
Have you tested the coax with your multimeter? Could it be shorting out somewhere? Pinched in a body panel, perhaps.
Its possible the internal SWR meter in the radio is off a bit. They all are but they should also show you the point were the antenna SWR is the lowest and be able do discern between ch 1 and 40 so you can tell if the whip is too long or short. If its super high everywhere then its most likely something else. What kind of antenna and where is it mounted?
TomLine
Member
Borrow somebody's magnet mount antenna and cable and see what you get ? Have you tried SWR on the high and low frequencies it can do? Maybe the previous guy had the antenna tuned to some freebird band or something?
Chronic...I would not be surprised!
High SWR on high and low frequencies.
I have my antenna mounted to an ungrounded roof rack and ran a ground wire to the body of the vehicle. Multimeter shows that the antenna is grounded when checked between the coax and negative battery post. Could this be an issue? It is a fire stick ground plane antenna.
High SWR on high and low frequencies.
I have my antenna mounted to an ungrounded roof rack and ran a ground wire to the body of the vehicle. Multimeter shows that the antenna is grounded when checked between the coax and negative battery post. Could this be an issue? It is a fire stick ground plane antenna.
Roof racks are typically a bad thing to use as a ground plane, especially for CB and HF. You can do a simple test by attaching 9ft of wire to the ground side of the antenna mount and stretch it out to the side of the truck. Maybe use a length of string and tie that to a fence or something to keep the wire going horizontal and off the ground. Try that and see if the SWR drops to something useful. If so then the roof rack is going to be a big challenge in getting the antenna to match. If the SWR is the same or bad then something else is wrong.
Great test to suggest. I know roof racks are not ideal but i was hoping the short ground lead to the ground plane would negate this. Been to busy at work lately to look at this but it has slowed up so i'll be looking at this again soon. Thanks for the info everyone has given/suggested.
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