Why we tell people to NOT use magmounts

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FiveFilter

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There's a lot of scare-mongering going on here.

I've been using mag mount antennas for a couple of decades now without the car-destroying scratches being depicted by some. I use mag mounts because I have several vehicles and use a radio only for certain occasions, so don't want a permanent setup which includes a hole in the roof.

If one is reasonably careful in placing and removing the magnet, eg not mindlessly dragging the magnet over the paint, there will be no damage; At least, there has been no value-destroying damage on the vehicles I've been using mag mounts on since about 1995.

And if the antenna coax is found to cause some abrasion from wind movement, I use a small piece or two of duct tape to keep it down where it is moving. It takes a second or two to place, and the tape is easily removed. No big deal.

And about the heralded performance differential: my radios with mag mounts seem to communicate as well as any other mobile units out there, watt for watt. I haven't tested the specifics myself, but I've read about tests done by others that show the performance difference with a mag mount to be about 0.1dB additional loss when compared to a permanent mount. Big deal. Sure, I guess you can say the hole will yield a better performance, but you also can say that only sensitive equipment will detect the difference; human ears generally not included. So why the exaggeration in this thread?

For some reason, some folks just seem to have a mission in life to throw shade on those of us who choose to not drive around with an extra hole. It seems to be almost like a religion, with the infidels put to shame. Come on. Each approach has its benefits. Enough with the exaggerations.
 

jonwienke

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So why the exaggeration in this thread?
You're misinformed. The performance difference is definitely more than 0.1dB, especially for VHF and below, where the capacitive coupling of a mag mount between the antenna and ground plane is generally not really adequate for the frequency range. That pushes up your minimum SWR, and reduces overall performance, sometimes by several dB. I'm also curious how you know mag mounts work just as well as permanent installs, if you've never done a permanent install.

And paint damage doesn't just come from careless installation/removal, it can also happen from the antenna oscillating and vibrating while installed, and moisture getting into the space between the antenna base and the vehicle. That may not be a big deal if the antenna is only mounted for a few hours per year, but if you leave it in place long term, a mag mount will definitely mark the paint.
 

dlwtrunked

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No, it is exaggeration--FiveFilter is right. I will say it again, I have a Toyota Corolla with over 299,999 miles (I estimate 350,000 miles based on oil changes as the odometer on the model-year stops at 299,999). It has had a Larsen mag-mount on the roof the entire time that is only removed at the car wash. No damage at all. There are many places on the front hood where thrown road grit damaged the paint but the roof is fine except where sun and tree sap damaged paint on the driver's side (the cable goes in the car on the other side). As I said before, take care of your car and it will be fine. That means clean it regularly (including under the car wash). The SWR is fine and comparisons while commuting with others with permanently mounted antennas indicates mine works just as well.
 

03msc

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You're misinformed.

And they will continue to repeat the same misinformation, based on no other experience, simply to convince themselves that they have quality installs. As you stated, the list of reasons that mag mounts are inferior is much longer than just the damage they cause. Well said. Some, it seems, would argue with a fence post about it, though.
 

dlwtrunked

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And they will continue to repeat the same misinformation, based on no other experience, simply to convince themselves that they have quality installs. As you stated, the list of reasons that mag mounts are inferior is much longer than just the damage they cause. Well said. Some, it seems, would argue with a fence post about it, though.

No one is arguing that a permanent installation is best, but we are arguing that a properly maintained mag-mount is not as bad as being portrayed.
 
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