Mounting a Mobile Antenna

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Dennis David
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Mounting a Mobile Antenna

#1

Post by Dennis David » Mon May 10, 2010 6:43 pm

I have a Maldol EX-107B Dual Band mobile antenna that I am using with a Comet CP-5M lip mount. The mount uses set screws. It also comes with two steel shims. Should I use these or scrape the paint off and use the set screws. Does it make a difference? Is this antenna trying to use the car body as a ground plane?
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cruiserlarry
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Re: Mounting a Mobile Antenna

#2

Post by cruiserlarry » Mon May 10, 2010 7:47 pm

The set screws do not have to make metal to metal contact; In fact, those shims are used to protect the inner lip of the body from damage from the set screws. Place the shims between the inner side of the panel lip, and the mount, and tighten the set screws into the shim. You usually won't have to crank the set screws tight - they get a pretty firm grip and the pressure keeps the mount from moving...
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DennisDawg
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Re: Mounting a Mobile Antenna

#3

Post by DennisDawg » Mon May 10, 2010 8:16 pm

Use locktite on all the set screws on the mount and antenna. I use blue for this.
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Dennis David
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Re: Mounting a Mobile Antenna

#4

Post by Dennis David » Mon May 10, 2010 8:44 pm

Thanks guys. I wanted to get something pretty stealthy. I'm still not fully out of the closet as far as radios go. :lol:
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xtatik
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Re: Mounting a Mobile Antenna

#5

Post by xtatik » Mon May 10, 2010 9:27 pm

cruiserlarry wrote:The set screws do not have to make metal to metal contact;
True for FM, but they do work better grounded. On Diamond's website they also include instructions for grounding the K400 (same). You definitely need to ground for an HF antenna. The antenna needs its other half (the car body) connected to the shield in order to create a counterpoise.....and the closer to the feedpoint of the radiator the better. It's a vertical, but think dipole.
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cruiserlarry
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Re: Mounting a Mobile Antenna

#6

Post by cruiserlarry » Mon May 10, 2010 11:35 pm

DennisDawg wrote:Use locktite on all the set screws on the mount and antenna. I use blue for this.
I've never had the set screws back out, so I don't use loctite on them - keep in mind any connection that requires electrical contact will no work with loctite isolating the threads from the contact point....
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Re: Mounting a Mobile Antenna

#7

Post by DennisDawg » Tue May 11, 2010 11:04 am

cruiserlarry wrote:I've never had the set screws back out, so I don't use loctite on them - keep in mind any connection that requires electrical contact will not work with loctite isolating the threads from the contact point....
I have not had any issue with Locktite on the antenna set screws or the mount. The set screws are not key to the return path in this case as you presented earlier in the thread.

We go on long trips and tough trips at times. The vibration, over time loosens everything not Locktite ‘ed (and sometimes stuff that is). In truth, I didn’t even think about Locktite but the helpful guys at HRO in Anaheim, who deal with a lot of desert folks I guess, recommended that from their experience with Race Radio users.

The "blue" came from me.
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Re: Mounting a Mobile Antenna

#8

Post by unwiredadventures » Tue May 11, 2010 1:12 pm

cruiserlarry wrote:The set screws do not have to make metal to metal contact; In fact, those shims are used to protect the inner lip of the body from damage from the set screws. Place the shims between the inner side of the panel lip, and the mount, and tighten the set screws into the shim.
I've had two of these mounts on my truck installed just like this for over 2 years. No blue Locktite and they have not yet loosened up.
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DennisDawg
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Re: Mounting a Mobile Antenna

#9

Post by DennisDawg » Tue May 11, 2010 3:02 pm

unwiredadventures wrote:I've had two of these mounts on my truck installed just like this for over 2 years. No blue Locktite and they have not yet loosened up.
Okie dokie . . . but me, blue locktite to be 99.72% sure. :D
Local Repeaters On Which You Might Find Me (K6DOB):
  • Big Bear K6BB 147.330+ PL: 131.8 - Keller Peak KE6TZG: 146.385+ PL: 146.2 - Sierra Peak KD6DDM 146.610- PL: 103.5

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