Going NMO?

[BloodandRoses]

Try wax paper it worked for me...

 

[SteveC0625]

I’ve recommended helicopter tape several times here on RR for this problem. I had a 3x3 piece of it on the roof of my wife’s Grand Cherokee for a small mag mount UHF spike. Worked great and I just left it in place when we traded it last month. There was a dirt mark on it when I took this pic. It came clean with a damp cloth.

 

[Project25_MASTR]

Understood. Better to keep the wife happy.

The rubber boot on the mag mount can help prevent some damage, but it won't prevent scratches. Some put a plastic bag under the magnet base for short term installs. Might be an option.
Best thing to do is to clean both the mag mount and the roof before installing it. Use a buffer between the base and the roof. Attach/remove carefully. Issue usually comes from bits of metal that stick to the magnet and get pulled across the paint when removing the antenna. Rubber boots will not prevent that.

Reminds me...I recently bought a Jetta as a commuter and my wife asked me, "So when are you taking all the radios out of the pickup?" I replied, "When my NMO holesaws can get near your Lincoln." I'm just waiting to get close to the Jetta for my to track down some remote TIBs to convert the spare XTLs in the house.

 

[mmckenna]

... my wife asked me, "So when are you taking all the radios out of the pickup?"

Sounds like she has a quick sense of humor...

 

[BloodandRoses]

I have a Wilson roof mount and the adapter for the nmo and I cant get either one to tune... Help Mr. mmckenna please!

 

[mmckenna]

I have a Wilson roof mount and the adapter for the nmo and I cant get either one to tune... Help Mr. mmckenna please!

We'd need to know exactly what you have. Pictures always help, keeps us from having to guess.

 

[BloodandRoses]

It is just a regular Wilson roof top mount . The Wilson wont tune either. This is a 2017 F150 all aluminum body. then nmo adapter just screws down on the roof mount and I put the pin in the center of the mount in case I want to use the Larsen for 27MGZ.

 

[mmckenna]

I'm not familiar with Wilson antennas, so I don't know what a "regular" mount is for them.

Anytime you are using adapters, you need to be sure it's actually giving you everything you need. The base loaded antennas like the NMO-27 will need to see not only the center conductor, but the outer shield and the body ground to. Checking to make sure those are there with a multimeter would be a good idea.

Checking your entire coax run is a good idea too.

I've run Larsen NMO antennas on a lot of the newer Ford aluminum body trucks, so it's not an issue there.

 

[W5lz]

In no particular order;
The length of the feed line on most mag-mount antennas is just a guess. It -should- be enough to get from here to there in an average installation.
Where's the best place to put a mag-mount? In the ugliest place you can think of, naturally! Antennas would rather be on top of metal rather than beside or under metal.
What kind/size of coax? In most instances it will make no difference until you get above UHF, then it can make a difference and that difference is in losses in the coax. Below UHF the typical losses in coax just isn't worth worrying about. How easy would it be to run a length of whatever coax you can think of? The big stuff is more difficult, can't hide it as well, sort of.
Is a 'professional' installation better than you doing it your self? Maybe, but unless it's a total 'screw-up', yours will be as good as that 'professional' installation but may not look as 'pretty'. [Lots of variation in that!]
How about mounting the radio? Best advice is to don't use bubble-gum to stick it some place. After than, your imagination is the only limit. Is it going to be the absolute most-bestest in the world? Probably not, but who cares? [Besides your significant-other. It's your neck!] The best way of going about it is to over-think the pig until you decide not to do it. Works for me...

I think that about covers every mistake I've ever made. Your millage may vary...

Nope, one more!
The way to not let a mag-mount 'mar' the surface of your 'ride' is to clean under the #%$$ thing! Regularly! Fairly often. If it stays there for very long there -will- be marks, period. Move it a little every now and then, the paint won't fade quite as much, sort of...

 

[Ensnared]

Understood. Better to keep the wife happy.

The rubber boot on the mag mount can help prevent some damage, but it won't prevent scratches. Some put a plastic bag under the magnet base for short term installs. Might be an option.
Best thing to do is to clean both the mag mount and the roof before installing it. Use a buffer between the base and the roof. Attach/remove carefully. Issue usually comes from bits of metal that stick to the magnet and get pulled across the paint when removing the antenna. Rubber boots will not prevent that.

There may be scratches, but not like that which occurred with my K40 magnetic mount. Truthfully, there are no visible scratches in comparison. The only scratches present on this relatively new car came from the body shop recommended by State Farm. I suppose the farm vegetation scratched the side. Unless you are paying extra, you won't ever get a decent paint job to match factory levels. This is the main reason I started cursing when I hit that deer. That side of the car has crap paint that looks identical. The quality is much different than the other side..

 

[FiveFilter]

I don't have a problem with scratches and other marks from the use of a magnet antenna because I don't leave it on the vehicle for very long, and I'm pretty careful when planting and removing the thing.

For instance, I don't slide the antenna on and off the car. Doing that will create scratches for sure. Instead, I do the following:

When installing the antenna, I first tilt it towards me, then I touch the top of the car with one edge of the base, and once that small area of contact is made, I lower the rest of the base until it is in full contact.

Conversely, when removing the antenna, I first pull on the top of the base until it is tilted towards me in order to break the magnetic bond with the roof, then I pull up on the base to release the small area of contact that is remaining.

I believe most blemishes that can be caused by magnetic bases are due to their being left in place for too long without moving and/or cleaning underneath. Moisture will build up under the magnet and can eventually cause stains due to potential corrosion damage to the paint. Also, if the magnetic base is left in place for months in the sun, a "shadow" of a different shade might eventually develop on the paint beneath the base which was not exposed to the sun.

I haven't experienced such problems because my antennas are only on my vehicles when I'm actually using them, and I only use them when I'm on a highway trip or an off-road excursion. After the trip is over, I remove the antenna until the next time.

For me, the magnet antenna is desirable because I don't have to cut the hole, remove the headliner, find a way to snake the coax down the pillar and through the dash and etc. I don't want to go through all that, because I only need the radio for specific uses, and the rest of the time I don't, so the antenna is removed until the next call to duty. And it fits better in my garage that way.

 

[krokus]

Unless you are paying extra, you won't ever get a decent paint job to match factory levels.

Any decent body/collision shop can match the paint, and spray it well. It sounds like you need a different shop.

Sent using Tapatalk

 

[DJ11DLN]

Conversely I have used this stuff where temporary mag mounts were needed and it did a great job of protecting the paint. It can be easily removed with a heat gun or even a blow dryer when it's time to do so. And you can't tell anything was ever there once it's been peeled off.

https://www.amazon.com/Clear-Paint-...ocphy=9016690&hvtargid=pla-569046109371&psc=1

 

[riverradio68]

I have always preferred NMO over mag mounts due to the clean look and the optimal SWR. But found out quickly it's not for every antenna. If I run a 3 ft. FireStik it works ok but if I go to a 5 ft. they want to rip out of the body hole. Learned this when a diamond quad band ripped out on my and man was that a pain to fix. If you go NMO lip mount the heavier ones to ok but not recommended on the vehicle body at all.

 

[FiveFilter]

I believe the thin metal being used on vehicles today can aggravate the problem involving antennas being ripped out of their holes.

I've seen suggestions that one should attach a thicker metal plate beneath the hole in the vehicle's skin as a base to bolster the car's metal skin and to keep the skin from flexing-and-tearing due to the wind load or when the antenna hits an overhead obstruction.

As noted, the taller the antenna, the bigger the problem, which makes it especially applicable to 11 meter antennas.

Mag-mount antennas avoid this "thin-skin" problem because they usually have a pretty large base for the magnet. I've never had a mag mount fall off, even after hitting tree limbs and such. I use mag mounts with antennas from three feet to five feet in length.

 

[a417]

It rains a lot in my neck of the woods, and you could get arrested for putting a hole in the roof

i'll bite...how?

 

[mmckenna]

I believe the thin metal being used on vehicles today can aggravate the problem involving antennas being ripped out of their holes.

Thin metal, yes, but knowing where to install the antenna can address some of this. Mounting near existing cross braces will prevent flex. Cramming a hole saw in random places on the roof will not.

Not all vehicles have thin metal. Some low buck vehicles do, but it's not often you see cheap imports used in public safety service.

I've seen suggestions that one should attach a thicker metal plate beneath the hole in the vehicle's skin as a base to bolster the car's metal skin and to keep the skin from flexing-and-tearing due to the wind load or when the antenna hits an overhead obstruction.

That will help, but so will mounting near existing brace points. There's some skill that goes into installing this stuff, and it can't be gathered by reading posts on hobby pages. There's some brains that have to be engaged when doing installs. Not everything is in the book.

As noted, the taller the antenna, the bigger the problem, which makes it especially applicable to 11 meter antennas.

Why people are installing FireStick type antennas on NMO mounts is beyond me. Larsen NMO-27 is a perfectly acceptable antenna when installed and tuned correctly. The thin whip flexes just fine and will take tree branch and parking garages with ease.
Goes back to to the "brains need to be engaged when doing installs" I mentioned above. NMO mounts are not designed for stiff fiberglass antennas.

Mag-mount antennas avoid this "thin-skin" problem because they usually have a pretty large base for the magnet. I've never had a mag mount fall off, even after hitting tree limbs and such. I use mag mounts with antennas from three feet to five feet in length.

Mag mounts will flex metal too.
It is an easy solution that will work, though. But as more and more vehicles go aluminum to lower weight, it's not going to be an option.

You won't see mag mounts used in professional installations, either. Goes back to the professional install thing. There's a reason why pro's use NMO's and not mag mounts.

 

[mmckenna]

i'll bite...how?

The Antenna Police.

Properly installed NMO's will not leak. Issue is often with the installer. A bad installer/tech can destroy anything, just give them time.

 

[n3obl]

Why people are installing FireStick type antennas on NMO mounts is beyond me. Larsen NMO-27 is a perfectly acceptable antenna when installed and tuned correctly.

Cause good buddy that's what dem truckers use! Also need two whips so I can look cool!

 

[mmckenna]

Cause good buddy that's what dem truckers use! Also need two whips so I can look cool!

It's the magic SWR Pixy Dust that makes them "talk miles". Everyone knows that FireStick knows how to bend the rules of physics to make their antennas better….