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Author Topic: Mag mount versus lip mount pros and cons for two meters +  (Read 269 times)

KK4GMU

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Mag mount versus lip mount pros and cons for two meters +
« on: January 26, 2023, 07:59:53 AM »

I'm shopping for good mobile 2 meter+ antenna for my 5 watt Kenwood TH-F6A HT.  I want to hit repeaters within 12 miles.  Trees but no significant hills or buildings inbetween.

My limiting factors are: 

SUV with sunroof
2' clearance in my garage
No drilling
Use would be infrequent, primarily EmComm related.

I'm considering three options:

Mag mount, foldable
Lip mount, foldable or
Stubby CompacTenna-type option.

A few things I don't know:

What minimum antenna gain should I seek?

Does the fact that lip mounts need to be mounted at the side or rear EDGE of the vehicle compromise the SWRs or gain of the antenna, and to what degree, typically, compared to mag mount that can be mounted near the CENTER of the roof?

Does the foldable mount compromise antenna performance?

The stubbies are are "compromise" antenna, but to what extent since ALL antennas are a "compromise" to some extent.  The tradeoff is between convenience and appearance versus performance and price.
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K9RJ

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Re: Mag mount versus lip mount pros and cons for two meters +
« Reply #1 on: January 26, 2023, 08:14:34 AM »

I have used mag mounts and lip mounts on an SUV. Both work well. Given your 2' roof clearance use the 19" whip that works on 2m and 70cm.
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WB6BYU

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Re: Mag mount versus lip mount pros and cons for two meters +
« Reply #2 on: January 26, 2023, 09:39:49 AM »

Part of the answer involves the height of the
repeater antennas above local terrain.  Having
it a few thousand feet on a hilltop makes a
big difference compared to an antenna on a
10’ mast beside someone’s garage.


I’ve used mag mounts for decades, with various
types of antennas on them, and I keep coming
back to a 1/4 wave whip.  If you also want 440,
get the kind with a small coil formed of the same
material as the whip, without any added joints.

Sure, the taller antennas may give you a bit more
range or signal strength at long distances over
flat terrain, but for local stuff the 1/4 wave whip
works well - I leave my mobile rig on the lowest
power setting most of the time.

Rather than worrying about a fold-over mount,
I just take off the mag mount when I go in a
parking structure where it bangs the ceiling.
But that isn’t a problem as often as with a
longer antenna.  If you are only using it
occasionally, just leave it inside your car
until you need it.

K1KIM

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Re: Mag mount versus lip mount pros and cons for two meters +
« Reply #3 on: January 26, 2023, 09:53:39 AM »

Trees but no significant hills or buildings in between.

How do you know if you are mobile whether there will be obstruction in line-of-sight unless you live and will only travel in a 12 mile radius of the repeater in flat terrain?

That being said, I've used mag mounts, permanent mounts and shoot through the glass mounts. All worked well and were under 19" other than the Comet CA-2X4SR.

I have an HT on my office desk in the house that with a 19" whip and 1.5W I hit the local repeater 10+ miles away with full quieting.
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K5LXP

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Re: Mag mount versus lip mount pros and cons for two meters +
« Reply #4 on: January 26, 2023, 10:13:21 AM »

Practically speaking I don't think it will matter much.  A quarter wave that's most anywhere on the vehicle will "work".  No reason not to have both in the kit, that way you're covered for any scenario.

Mark K5LXP
Albuquerque, NM
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KK4GMU

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Re: Mag mount versus lip mount pros and cons for two meters +
« Reply #5 on: January 26, 2023, 10:32:39 AM »

Just as I suspected - I'm over-thinking this. :P
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K6CPO

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Re: Mag mount versus lip mount pros and cons for two meters +
« Reply #6 on: January 26, 2023, 12:09:52 PM »

A mag mount antenna was a direct causative factor in my truck being broken into and a radio, GPS and some other items being stolen. I subsequently drilled a hole in the roof of the truck for an NMO mounted antenna. On another vehicle, I used a lip mount. I still have a couple of mag mount antennas in my possession but they haven't been used in years.
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WA8NVW

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Re: Mag mount versus lip mount pros and cons for two meters +
« Reply #7 on: January 26, 2023, 12:58:46 PM »

A Lip Mount on the hood near the driver's door works well.  If you use a 19" whip you shouldn't need to worry about breaking fluorescent lamp tubes along the ceiling of the garage. Easy to remove to go "undercoverr" and store inside the cabin under the drivers seat.
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WA3SKN

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Re: Mag mount versus lip mount pros and cons for two meters +
« Reply #8 on: January 26, 2023, 02:07:36 PM »

Mag mount will work fine for 2m and above.  They capacitively couple to the metal below.  They work fair for 6m and work fairly poorly for HF... just not enough coupling.
With the lip mount you need to crack the paint layer and get good metal-to-metal contact, usually adding some grease to keep down possible rusting.  Assuming a trunk mount you could be able to use a 5/8 wavelength antenna.
With your height limit of 2 ft, I would assume a mag mount with a 1/4 wavelength (19 inches) would be the way to go.  Most any antenna should get you 12 miles to a repeater, except a rubber duck.

-Mike.
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K4VBX

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Re: Mag mount versus lip mount pros and cons for two meters +
« Reply #9 on: January 26, 2023, 04:45:48 PM »

A quarter-wave mag-mount is the (slightly) better choice. The capacitive reactance of the magnetic attachment is so low at VHF that you are taking an imperceptible hit on efficiency. The lip mount on the other hand will give you some directionality, but it's also likely imperceptible. I've used a quarter-wave on the roof on a mag mount and a halfwave on a lip mount on the hood. There was little difference in receive levels (I tested both at the same time for a while), but my QW on the roof consistently suffered less fading on the move and physically shielded me from transmission RF. Also consider an antenna like the Diamond NR72BNMO. The coil made it much easier to remove than a $10 QW whip with nothing to lever up a strong magnet. It was also a little shorter, which is a factor in a low-clearance garage (your own and parking garages). I'm also suggesting, by extension, avoid the fold-over antennas.
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N5CM

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Re: Mag mount versus lip mount pros and cons for two meters +
« Reply #10 on: January 26, 2023, 07:51:26 PM »

...If you also want 440,
get the kind with a small coil formed of the same
material as the whip, without any added joints...

This is what I use.  Works pretty well.  As I understand it it's a quarter wave on 2m.

If I put the antenna on my vehicle, and if I'm going to be parked in a public place and away from the vehicle a while, I put the antenna inside until I'm ready to leave.
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KK4GMU

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Re: Mag mount versus lip mount pros and cons for two meters +
« Reply #11 on: January 27, 2023, 09:52:54 AM »

Problem solved.  I had a Tram dual band, 19" hanging around that I wasn't sure would work well.  I installed it on the mid-roof of my SUV and tested:  SWR=1.1  Yesterday I communicated on a net repeater 12 miles away with my 5 watt HT and they heard me and I heard them clearly with only a slight hiss in the background on each end. One inch of the tip hits the top of the garage door opening, but clears everything else.  I'll go with that.

No worries about the type of mount or spending more $$$.  Thanks, all.
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