No, I'd disagree. After installing hundreds of NMO permanent mount antennas over the last 30+ years, I have not found a real downside.
The downsides that are often brought up are usually excuses by people that don't understand the importance of properly installed antennas, are too lazy to do a proper install, or are not permitted to do those sorts of modifications to a vehicle.
But the drawbacks are not physical or technical, they are perceived drawbacks.
Using the correct tools, parts and techniques does not have any "potential problems". I've never had a properly installed NMO mount leak. I've never had one fail.
I think it my career, I've had to partially drop a headliner once. I've never had to completely remove a headliner on any vehicle.
Routing wires is part of doing a good install. No professional would leave exposed wires. It's called being a craftsman. Maybe it's the difference between a hobbyist/amateur and a professional.
Often people will claim "resale value" as a drawback.
I've installed permanent NMO mounts on all my vehicles since 1990. Never, not one time, have I had it detract from the sale price of the vehicle. This goes back to doing a professional job and paying attention to details. The last vehicle I sold was a 2011 F150 with about 100,000 miles on it. It had 2 NMO permanent mounts on the roof. The dealer didn't care. Because I'd maintained the vehicle correctly, it was in good shape inside and out, and I'd looked after it, I received higher than blue book value for it. The dealer didn't care that it had two antenna mounts on top.
There's nothing to accommodate if the install is done correctly.
If someone doesn't feel like installing a permanent antenna, then fine, they should just say that. But magnetic mount antennas are not as good as a permanent install.
If that works for you, then great. Magnetic mount antennas are a reasonable solution for some users.
On the other hand, you could install a permanent mount NMO on all three vehicles. Buy two rain caps and one antenna. Swap antennas around as much as you want. Get the best of both worlds.
No, I can appreciate what you are saying, but disagree.OK. I guess it's not possible for a pro who has made a career of radio applications and has drilled hundreds of holes for antenna installations to see the other side of the coin where some less-experienced folks reside.
All good points. And you also might agree that there are also a few disadvantages to the alternative permanent mount in the roof, including having to punch a permanent hole in the roof and potential problems relating thereto, having to remove and/or otherwise deal with the headliner to make the install, having to route the wires in sometimes hard-to-negotiate places, et al.
Yeah, I believe I have a response in that thread; it's on page 10 if it is the long thread I'm thinking it is. I didn't see it until it was just about petered out.If you want to read more, this topic has been pretty well beat to death over on this thread. Some good points of view from both sides:
These 2 photos show why NOT to use magmounts. This is my 2014 TDI Jetta, that I have used a magmount on for 2 years. The one photo shows the scratches on the edge of the door pillar where the coax goes in the door. The second photo is my roof. The coax has scratched the roof. The magnet has...forums.radioreference.com
I guess I just cannot understand why some folks continue to attack the preferences of others in their choice of antennas when there are truly two sides of the coin; pros and cons; positives and negatives.
A currently popular phrase for such a phenomenon is "haters will hate."
Read through that thread. It demonstrates it very well.
I've seen a lot of casual antenna-performance comparisons on the Internet through the years, and the general results were that, inch-for-antenna-inch, the magnet-mounted antennas were as effective as those permanently mounted in a hole. The key seems to be the antenna length and where it is placed on the car, the best generally being in the middle of the roof. This is one recent example I ran into:
"Magnetic mounts (good quality ones anyway) have little significance on an antenna's performance, just as the Larsen PDF illustrates: a tiny loss of 0.2 dB with a magnetic antenna vs a permanently mounted antenna. That paper also states the minimum amount of effective ground plane needed for several frequencies; but, of course, CB @ 27MHz will require much more ground plane than 150MHz will, making it all the more detrimental to the signal pattern to have it on the fender of the vehicle instead of the roof. I've seen it many times in the real world too, where I could clearly hear a buddy of mine who has a magnetic roof-mounted antenna, but signals from others who had various non-roof-mounted antennas (most being non-magnetic) were not even detectable."
Where can this Larsen PDF that you mention be found? I didn't see a link posted for it in any of the previous replies.
Do you want to know what CB can really do? It’s gonna run you $500 and the labor is yours.Mag Mount plus cigar lighter = “CB Radio is dead. I just drove XXX miles and there’s nobody out there. I’m sticking it back in the attic”.
This is the reality of the temporary install:
1). Not very good antenna.
2). Questionable radio (unless details offered).
3). No external speaker.
4). Poor positioning of radio to be able to hear.
5). Likely overuse of Squelch, and not enough RF Gain.
6). Lack of familiarity with both radio AND how others are using it.
And so forth.
“Noisy Receive” is a topic we never get to try and help remedy. As the preceding problems are a huge obstacle. (“I’ve spent $136 and THAT’S IT!”).
— Self-fulfilling prophecy of timidity + quick rejection.
RFI Guy, your taking my quote out of context about religion makes you look like an MSNBC reporter, or maybe CNN[URL
unfurl="true"]Antenna Placement Does Make a Difference!, November 1966 Popular Electronics[/URL]
"It's almost like religion." No it is actually science.
A lot of newbies appear here and either ask "what is the best antenna to install" or "why doesn't my xyz antenna tune properly" . In the former case the best antenna is likely to be recommended, an NMO mount antenna on the center of the vehicle roof. In the second case, the OP usually has recently purchased a "magic" antenna that purports to "require no ground plane, no mounting holes, no tuning and supposedly can be mounted virtually anywhere".
Usually that antenna in fact requires a ground plane, some sort of mounting facility, needs to be tuned, and won't work where the OP wants to mount it.
My advice is generally to send that "magic" thing back for exchange for a Larsen NMO and borrow a hole saw. Otherwise there is a lot of back and forth trying to figure out which of the many "magic parameters" is not working.
RFI Guy, your taking my quote out of context about religion makes you look like an MSNBC reporter, or maybe CNN
That reference to religion was about those who go out of their way to throw shade on the nonbelievers who choose to use a magnet to hold their antennas on instead of drilling a hole through the roof. This holier-than-thou activity has been done to the point of religious zealotism; usually by hams, but not necessarily.
My point in the threads containing that "religion" reference is that there are pros and cons to both approaches. I'm saying that those with the hole-istic "religion" refuse to see that, and they can't hold themselves back from criticizing the nonbelievers.
I'm not disparaging your hole-in-the-roof advocacy. I'm just saying that there are valid reasons for both approaches. I won't take the time or space to repeat all that here.
And about the "science" you refer to, seeming to claim I am denying science: I abundantly recognized in those threads that "science" has determined that there is a performance penalty to the magnet mount antenna, and that it's around 0.1dB of additional loss. I also acknowledged that this fact can give the just-drill-the-damn-hole guys the right to say the mag mounts aren't as efficient. But only zealots would say this difference is significant. The loss of such a miniscule amount of energy cannot be detected by the human ear in any practical way. That, too, is science.
Addressing some other points in your post: I make no claim to any "magic" involving magnetic mounts. Nor do I say a mag mount doesn't need a ground plane. Nor do I say a mag mount doesn't need to be tuned. Any such statements are wrong and misleading.
Wow. This just keeps on and on. Amazing.
Honestly? None of us really care what you do.and they can't hold themselves back from criticizing the nonbelievers.
I'll dip my big toe in this for a moment just to stir things up a little more because I like it. The stated 0.1dB additional loss using a mag mount can be true at UHF and possibly other frequencies depending on mag mount size, shape and some other factors. I've tested some of my mag mounts at VHF and UHF compared to a hard mounted NMO and don't see enough difference to not use them. At 27MHz the loss is much more depending on mag mount size and lower frequencies get much worse. This is due to the capacitive coupling between the mag mount and vehicle body.
I've also done some testing at HF, mostly 3.8MHz, 7MHz and CB using a mag mount and a copper sheet 8.5 X 11 inches with some thin refrigerator magnet material attached and 2" of wide braid attaching the sheet to the mag mount ground. This raises the capacitive coupling of the mag mount from maybe a few hundred pf to many thousands of pf and seems to equal a hard grounded mount on all frequencies I tested.
The antennas were first tested and tuned on the hard grounded mount then moved to the mag mount in the same basic location. Without the ground coupling copper sheet the antennas at 3.8 and 7MHz were out the window on tuning plus there was a lot of RF on the coax due to the mag mount coax becoming a ground radial and performance was down. Adding the big capacitive sheet brought the tuning back exactly where it was with the hard grounded mount and performance came back.
So a mag mount can work the same as a hard grounded mount if it has sufficient coupling to ground.
I could not help myself in "bumping" this picture. "Wireless Mag mounts". The new doctrine.