Why we tell people to NOT use magmounts

[03msc]

Italicized tongue-in-cheek got past ya, huh?

1). The Breedlove mount mentioned first.

2). Unlikely electro-mag antenna mount release came last .

BUT THAT IS the product name.

Having read your other posts I appreciate the diligence. (Thx to all).

(Watch out for grammar; that hook set on first nibble, both you boys)


Best

Your post sounded like the typical mag mount defender. It was your first post here, too, or so it said, so nothing to go on.

We’re veterans of the forums here. You sounded serious.

 

[Sector46]

Well, the mess left from the magnet tells you where you need to drill the hole for the NMO mount.

5.5 inch magnet is SO STRONG ( NMO ) IM LEAVING IT ON and unscrewing the ant when I want to get on 2 meters . I have a Browning old stock 800 Mz antenna mounted inside by the rear window of my Tundra about a foot long which does great for the P25 local constabulary. Working on AMPED ext Speaker mounted in front driven by small 10 watt AMP. Wind noise Be Gone if windows are down Tested 5 inch Bearcat Speaker and it IS LOUD ( Whistler 1040 handy ._ ) Yes the 800 ant is grounded to the truck body. I removed the back seat .

 

[danesgs]

Luckily I cared more about the engine than the looks of my Toyota Tercel and later a Corolla which I was more kind to exterior-wise. Since I was the only one who really spent any time in both cars, and cared not that much about resale, I just went with it. That being said I had a 5/8 wave antenna for 2 meters on the Tercel once that damn near decapitated the car going into the underground parking garage of a Metro station once. It was lip mounted. As I have aged I would have done things differently now, but still had a good time when I was younger and stupid..

 

[k7ng]

I wasn't going to join in, but I felt the urge to jump in anyway:
It isn't just the potential for paint damage that makes mag mounts a second or third choice. Getting one strong enough to hold whatever antenna securely isn't necessarily a problem either.

The 'ground' of a mag mount is essentially a capacitor between the mount and the vehicle body. The poly plastic or whatever that's supposed to protect your paint is an insulator - so there's no electrical connection to the ground plane of the vehicle. The area of the mag mount base doesn't amount to a hell of a lot of capacitance so as you go lower in frequency, the mag mount becomes less and less efficient the lower you go. I have used a fairly large area mag mount on 23cm mobile antennas and am not sure I ever decided there was any real difference between that and a permanent NMO mount. But on 2M? You've given away most of the antenna theoretical performance.

NMO hole mounts are cheap. If you want, I'll send you one, free, with 15' of coax - install your own connector. I bought a hole saw three weeks ago for $6.95.

 

[03msc]

I wasn't going to join in, but I felt the urge to jump in anyway:
It isn't just the potential for paint damage that makes mag mounts a second or third choice. Getting one strong enough to hold whatever antenna securely isn't necessarily a problem either.

The 'ground' of a mag mount is essentially a capacitor between the mount and the vehicle body. The poly plastic or whatever that's supposed to protect your paint is an insulator - so there's no electrical connection to the ground plane of the vehicle. The area of the mag mount base doesn't amount to a hell of a lot of capacitance so as you go lower in frequency, the mag mount becomes less and less efficient the lower you go. I have used a fairly large area mag mount on 23cm mobile antennas and am not sure I ever decided there was any real difference between that and a permanent NMO mount. But on 2M? You've given away most of the antenna theoretical performance.

NMO hole mounts are cheap. If you want, I'll send you one, free, with 15' of coax - install your own connector. I bought a hole saw three weeks ago for $6.95.

Well said. Thanks for the input and helpful information for others. I do believe many don't understand.

 

[KK4JUG]

k7ng, your point is well taken but I'm afraid of what's underneath the metal roof. I have a 7-passenger SUV. While I don't use the back seats, there are still air bags on the side and god know what kind of wiring throughout the roof area for lights, air bags, etc. For that reason, I'm taking my car to the folks that maintain the city's cars.

 

[W9WSS]

I've been against magnetic mounts for PERMANENT installations for years. My present vehicle has 11 NMO-mounted antennas, all of which are connected to operating ham radio equipment, a scanner, and two VRS-750 cross-band repeaters. If I looked real hard, I *might* find a magnetic-mounted base, but I'm sure it's probably trash by now.

I've owned numerous vehicles in my driving career (51 years), and I have NEVER, I repeat, NEVER had one cent taken off the trade-in price of my previous vehicle(s) because of NMO mounts left, or rubber hole plugs in their place. Matter of fact, I sold one of the cars to another ham with all the antennas (and radios) still connected and mounted in the vehicle. I've had 3 people approach me, and inquire frequently when I'm planning to "dispose" of my current vehicle. I'm also considering leaving everything RF-wise intact with the sale of the vehicle to the next happy ham.

 

[KK4JUG]

Do people glow when they walk by your car?

 

[03msc]

And I thought my three was getting close to excessive... mine looks fine now

 

[danesgs]

The only issue I had with my Tercel was security folks having to ask "whats with all the antennas". I always got the same reply mostly when telling them I was a HAM. "My grandfaher was one of those people" or something along that reply. Made me instantly feel like Papa Smurf with a radio fetish.

 

[k7ng]

Last year, I had one of the moments most folks hope for... I had the right words at the right time...
I have three NMO mount antennas on my Honda Accord. A younger (20's) fellow walked up to me at a gas station and asked what the antennas were for: "What's with the antennas? You talking with aliens or something?" I just looked at him and smiled, saying "Yup. They're here, you know. Had coffee with a couple of them this morning." He backed slowly away...

 

[rescue161]

I would have told him that the antennas were for 5G transmitters, so everyone could have a better signal. I'd go one further and tell him that Verizon pays me $5,000 a month for the use of the real-estate on the roof of my car. I'd mention that the deal with Sprint fell through, but with the amount that Verizon is paying, I never missed Sprints offer.

 

[dlwtrunked]

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.

...

And I can show you my 2006 Toyota Corolla with over 400,000 miles that has always has 1 and sometimes 2 magmounts on the roof. Not a single scratch from them. Sap has damaged the paint elsewhere on the car. When you take them off, you cannot tell where they were. If using a good magmount, scratches come from dirt between the magmount and the roof. My last car only made it to 260,000 miles (a Ford Escort) with magmounts always on the roof - again no marks. Either you take care of the car or you don't--not the magmount's fault in my experience.

 

[03msc]

And I can show you my 2006 Toyota Corolla with over 400,000 miles that has always has 1 and sometimes 2 magmounts on the roof. Not a single scratch from them. Sap has damaged the paint elsewhere on the car. When you take them off, you cannot tell where they were. If using a good magmount, scratches come from dirt between the magmount and the roof. My last car only made it to 260,000 miles (a Ford Escort) with magmounts always on the roof - again no marks. Either you take care of the car or you don't--not the magmount's fault in my experience.

If you're keeping a vehicle that long, drill the dang holes and mount them properly. The performance improvement will be worth it alone, besides the damage and appearance improvements.

99% of the thread here disagrees with your post but to each their own. Nobody can make you do it differently, the point of his thread was to share some accurate, first-hand information on the topic. The thread has proven the point.

K0BG's website is a great resource.

 

[dlwtrunked]

If you're keeping a vehicle that long, drill the dang holes and mount them properly. The performance improvement will be worth it alone, besides the damage and appearance improvements.

99% of the thread here disagrees with your post but to each their own. Nobody can make you do it differently, the point of his thread was to share some accurate, first-hand information on the topic. The thread has proven the point.

K0BG's website is a great resource.

Mine is experience over several cars. I take that over anyone's post. They have worked fine. If one does not keep their car clean and waxed, there will be problems with magmounts and other things. Doing it now is in the same line as the people telling me to trade in this dependable car for an untested new one. (I have always had the tools and parts to do the permanent install.) Additionally, using a magmount gives me the flexability to try different antennas and pick the best one (which I do)--something sometimes not possible the other way. I suspect doing that comparison and tests likely gives me better performance that just picking an antenna and installing it permanently--and comparisons with others on 2m using simplex over decades of commuting shows that I do at least as well. The only negative I have found is about every >5 years having to replace the rubber liner where the coax passes through (neglegible cost) and being careful when I shut that door and careful attention to the cables tension so that it does not rub the roof. Rest assured, if performance were an issue, I have have ditched the magmount long ago. Anyone with scratches like that is the result of not taking care of their car--not the magmounts fault. When I wash and wax my car, I take the magmount off and make sure the area is clean. Over those 400,000 miles, one cannot not tell where I put the magmount and I have to take time to re-center it when I put it back on. It is true that the car has outlasted 1 or two magmounts that I chose to replace. And my information is from 30 years of first hand using magmounts. Nothing wrong with a permanent mount if you just want a couple antennas and want to do that work but the attack on magmounts is exaggerated by extreme examples that could be equally countered by people showing botched effects of permanent mount installing.

 

[rescue161]

I consider your care for a vehicle to be extreme as most people don't baby their vehicles the way that you do. I let the rain wash my vehicles. Mechanically, they are top notch, but I do not spend a second with washing and waxing. There is no carpet in my truck and I use it as a 4x4 truck. It is a tool that merely helps me perform work. It mostly has to do with my Dad having us help wash cars on the weekends. I hated it when I was a kid and I hate it now. Based on the number of clean vs. dirty cars that I see on the roads and in parking lots, I can conclude that most people don't baby their cars, so a mag mount in their case would cause the damage that everyone is talking about.

 

[03msc]

Mine is experience over several cars. I take that over anyone's post. They have worked fine. If one does not keep their car clean and waxed, there will be problems with magmounts and other things. Doing it now is in the same line as the people telling me to trade in this dependable car for an untested new one. (I have always had the tools and parts to do the permanent install.) Additionally, using a magmount gives me the flexability to try different antennas and pick the best one (which I do)--something sometimes not possible the other way. I suspect doing that comparison and tests likely gives me better performance that just picking an antenna and installing it permanently--and comparisons with others on 2m using simplex over decades of commuting shows that I do at least as well. The only negative I have found is about every >5 years having to replace the rubber liner where the coax passes through (neglegible cost) and being careful when I shut that door and careful attention to the cables tension so that it does not rub the roof. Rest assured, if performance were an issue, I have have ditched the magmount long ago. Anyone with scratches like that is the result of not taking care of their car--not the magmounts fault. When I wash and wax my car, I take the magmount off and make sure the area is clean. Over those 400,000 miles, one cannot not tell where I put the magmount and I have to take time to re-center it when I put it back on. It is true that the car has outlasted 1 or two magmounts that I chose to replace. And my information is from 30 years of first hand using magmounts. Nothing wrong with a permanent mount if you just want a couple antennas and want to do that work but the attack on magmounts is exaggerated by extreme examples that could be equally countered by people showing botched effects of permanent mount installing.

You are certainly an exception to the rule, then. You've also shown that you don't fully understand how an NMO mount works - you can change antennas everyday if you want to. I change antennas on mine fairly often for the same reason - try different ones. You just unscrew one and screw on another to the NMO mount. Easy. No unsightly coax running around, etc. Everything nice and hidden and all the flexibility in the world to try different antennas...and with better performance than mag mounts (regardless of what you say) because of the difference in how the mounts function electrically/RF-wise.

They may perform "fine" for you but it is common knowledge that the manner in which mag mount antennas operate (RF-wise) makes them subpar performers in comparison to NMO antennas. If you want to use mag mounts and are fine with the performance then that's up to you, but making claims that most of us know aren't true doesn't help you prove the point you're trying to make.

YES, damage on the vehicles shown in this thread is from the mag mount antenna - if it hadn't been on there, the damage wouldn't be there. 100% the fault of placing a mag mount on there...

I do not expect, nor is it really my goal, that we can change your mind or convince you otherwise, but much of your paragraph there actually goes to support the spirit of this thread and not the point you're trying to make; we read between the lines. We have much experience, too. I've used mag mounts! I've then changed to hole mounted NMOs and saw the improvement first hand. My experience and the experience of many others.

It's not an "attack" on mag mounts, as you say - it's sharing factual information to help others (the true spirit of a ham operator), in hopes that they will take it to heart and do things better than the easy, ugly way that won't perform as well. It's up to each person to decide, though. You seem to have made up your mind and that's fine...but, I would hope you'd be open to at least learning something new.

I strongly encourage you to at least click the following link and read the 3 or 4 short paragraphs (take you 90-120 seconds tops) that are presented in that section, that's it. It's just some simple information that you, and everyone in this thread, should know. Especially paragraphs 3 and 4. Here's the link: http://www.k0bg.com/antmount.html#mag

Have a good one!

 

[slowmover]

And, . . not everyone lives in San Diego.

Try it in Cleveland.

 

[dlwtrunked]

You are certainly an exception to the rule, then. You've also shown that you don't fully understand how an NMO mount works - you can change antennas everyday if you want to. I change antennas on mine fairly often for the same reason - try different ones. You just unscrew one and screw on another to the NMO mount. Easy. No unsightly coax running around, etc. Everything nice and hidden and all the flexibility in the world to try different antennas...and with better performance than mag mounts (regardless of what you say) because of the difference in how the mounts function electrically/RF-wise.
...

I understand NMO mounts perfectly--but many of my antennas are Type-N and even some SMA spectial mounts for microwave and I have magnetic mounts for all of these and also with SO-230 for HF/LF/VLF.

 

[jmaack]

learned that years ago running an old magmount k40. never again.