All you say is true. I'm just having trouble envisioning what it is
about the mag mount's effective capacitor that could cause it to
dissipate 90% of the power being fed to the antenna. That's one
outrageous ESR, even more so considering the size of the effective
capacitor.

I personally find a mag mount to be convenient, since I use my two meter
radio only a few times a year at most, and in two different cars. I'm
perfectly willing to take a little hit in performance for the
convenience, but not to the tune of 10 dB or more like MK reported. And
if there really is any significant performance sacrifice at all, it
means that there's something I don't understand and would like to. If
there's a 10+ dB difference, there's something I *really* don't
understand. The fact that I get a nearly 1:1 SWR with the mag mount
makes it even more puzzling -- if the capacitor had an ESR of over 300
ohms (which it would have to in order to drop the signal 10 dB), the SWR
would be terrible.

But "Korbin Dallas" said: "Yes a properly installed antenna will out
perform a MagMount, always has alway will." That's a very positive
statement, with no room for exceptions. But so far I haven't seen any
reason why it should be true except for MK's single experience that
doesn't make sense unless there was some other problem, like damaged
coax, with his mag mount. (I can see the possibility for poor
performance in an HF mag mount -- but like the OP, I'm talking only
about VHF/UHF ones.)

I've used a VHF mag mount for over 20 years and have had to replace the
coax only once. But then again, I use it very infrequently.

Roy Lewallen, W7EL

SBC News Server wrote:
The mag mount depends on capacitve coupling to ground while the "drill a
whole in the roof" mount is directly connected to the ground plane.

Also, when using a hole in the roof antenna there is no problem withcoaxing
being crimped in a door or window, etc. I have used the NMO (Motorola
style) in the roof mounts for 2 meters and 450 MHz since 1978 with various
vehicles. No problems. IMHO, it is the ONLY way to go.

John