Bonding the hood?

[12BNNT]

The antenna I have is a tuned dual band 140-148/440-448MHz antenna, i shouldn't need to tune it or "trim" it, its not a CB firestick

If i test the SWR before bonding the hood, i still have 2 variables, the ground plane, or the cable. If i bond the hood, i can remove one of those variables and then if its still bad, its most likely the cable. I can also remove the bond and see if that affects the SWR overall.

Sorry. I’ve got the same type antenna on my drivers side (see above photo). I hadn’t thought to check hood ground as the antenna wasn’t connected to it. I just checked continuity between the ground threads of the antenna and the chassis/engine. I just got my license a few weeks ago so I haven’t gotten into any local repeaters yet (or programmed my mobile unit). I did find local NOA weather broadcast last week while scanning and it was real fuzzy so I played with the antenna a bit raising it a hair and turning it so the bend where the coil starts was pointing front to back and it changed to crystal clear. Mine was supposed to be pretuned also but figure I changed it a bit when installing.

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[scotticus]

Well turns out it’s the coax! Also the aluminum hood is going to end up not being a great ground plane anyway.

 

[wannajeep]

The antenna I have is a tuned dual band 140-148/440-448MHz antenna, i shouldn't need to tune it or "trim" it, its not a CB firestick

If i test the SWR before bonding the hood, i still have 2 variables, the ground plane, or the cable. If i bond the hood, i can remove one of those variables and then if its still bad, its most likely the cable. I can also remove the bond and see if that affects the SWR overall.

Doesn't matter if it's a Firestick or a ham antenna, they're subject to the same rules. Actually, at (higher) ham frequencies one could argue it's even more critical. Even with a tuned antenna, its resonant frequency can be affected by nearby metal structure such as windshield frames. The antenna was likely factory tuned against an ideal ground plane, which you aren't likely to find in a mobile installation.

If your antenna is tunable (say with a set screw against the whip) throw an SWR meter on it and tune for the best, then remove the SWR meter and be done. If your antenna is non adjustable, as long as you're 2:1 or lower you're probably fine.

Likelihood of a bad store-bought cable is minimal compared to ground plane issues. If the cable is a DIY job that may be another matter,

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