Is a external antenna really necessary?

mmckenna

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In my opinion, ranked from best to worst:

#1:
em wave on a mag mount on the sorta middle of the roof.

Skipped #2 through #36 to help make the point that #1 is a MUCH better option than the rest by a long shot.


#37, because at least it's up on the roof, where antennas belong, but you need to use the correct NMO mount, or subtract lots of points:
ditch light mount on the roof rack (either towards the front of the roof rack or rear) with the em wave 700-800mhz antenna you linked.

Skipping #38 through #192 to make the point that trunk lip/hatch mounts are a bad idea.

#193. Just in case it's not clear, trunk lip/hatch lip mounts are a bad idea:
Motorola haf4013 on a lip mount on the hatch (still on the roof probably most aesthetic looking mount).

#276. Below the roof line with a lopsided ground plane. And I doubt you'll see much difference between the two antennas. Decrease rank to #594 if you use the incorrect NMO mount.
fender lip mount with the em wave 700-800mhz antenna. Another is to do fender lip mount but with the Motorola.

#1,352. Lopsided ground plane with a bracket that hovers the antenna up above that lopsided, plus getting the cable pinched in the hood, plus trying to route it into the cabin with the connector installed, and probably not using the correct NMO mount exposing the coax to the weather/road salt/oil/general nastiness.
ditch light mount on the fender using the Motorola haf4013.


Seriously, you are stuck in what we call "Analysis Paralysis". If you want this to work well, the antenna goes on top of the vehicle, with sufficient ground plane directly under the antenna. Since drilling a hole is out, the magnetic mount is your best option. All other choices pale in comparison.

If looks are more important, do whatever you want and live with the reduced performance. It's still going to work better than the scanner sitting in the cupholder with the stock antenna on top.


Here's my honest opinion. Go online and order these items and enjoy your scanner:

Magnetic mount, Silver?

Or Black? You decide:

For 800MHz, this antenna:
 

lcat06

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In my opinion, ranked from best to worst:

#1:


Skipped #2 through #36 to help make the point that #1 is a MUCH better option than the rest by a long shot.


#37, because at least it's up on the roof, where antennas belong, but you need to use the correct NMO mount, or subtract lots of points:


Skipping #38 through #192 to make the point that trunk lip/hatch mounts are a bad idea.

#193. Just in case it's not clear, trunk lip/hatch lip mounts are a bad idea:


#276. Below the roof line with a lopsided ground plane. And I doubt you'll see much difference between the two antennas. Decrease rank to #594 if you use the incorrect NMO mount.


#1,352. Lopsided ground plane with a bracket that hovers the antenna up above that lopsided, plus getting the cable pinched in the hood, plus trying to route it into the cabin with the connector installed, and probably not using the correct NMO mount exposing the coax to the weather/road salt/oil/general nastiness.



Seriously, you are stuck in what we call "Analysis Paralysis". If you want this to work well, the antenna goes on top of the vehicle, with sufficient ground plane directly under the antenna. Since drilling a hole is out, the magnetic mount is your best option. All other choices pale in comparison.

If looks are more important, do whatever you want and live with the reduced performance. It's still going to work better than the scanner sitting in the cupholder with the stock antenna on top.


Here's my honest opinion. Go online and order these items and enjoy your scanner:

Magnetic mount, Silver?

Or Black? You decide:

For 800MHz, this antenna:
What do you mean by correct nmo mount how would it be incorrect
 

mmckenna

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What do you mean by correct nmo mount how would it be incorrect

Most through hole NMO mounts are designed to go through the roof of a vehicle and seal the hole. The underside, where the coaxial cable attaches, is designed to be inside the vehicle where it's protected and dry. Often there is a little plastic cover that protects the coax from coming into direct contact with anything else, but does not seal the connection.

When you put an NMO mount through a fender bracket or "ditch light bracket" and the underside is exposed, the water/moisture, road salts, oil and all that other stuff is going to get to the underside of the mount and corrode the exposed electrical connection and likely wick up the inside of the coaxial cable, destroying it. The antenna/mount will work fine for a while, maybe a few years depending on your location, and then eventually performance will degrade and over time, fail completely.

The correct type of mount to use is one where the underside is properly protected. Usually the mount encloses the coaxial cable connection inside the body of the mount. I recommend using those, and then using a piece of marine grade heat shrink tubing over the point where the coax enters the NMO mount to add an additional layer of protection.


Wrong style mount for bracket/ditch light bracket mounts:

Correct style mount for those applications:
 

lcat06

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okay so basically ive found out that i can have one mag mount on the center of the roof and one comproimise mount (lip mount) which antenna should go on which? scanner em wave antenna on the mag mount and ham on the lip mount on the hood or vise versa
 

mmckenna

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okay so basically ive found out that i can have one mag mount on the center of the roof and one comproimise mount (lip mount) which antenna should go on which? scanner em wave antenna on the mag mount and ham on the lip mount on the hood or vise versa

Here's how to answer that question yourself:

Center of the cab roof is the location that is going to work best.
Bracket off the fender is a serious compromise.

Which radio do you want to work better?

Answer to that question tells you which antenna goes on the center of the roof. The other antenna goes on the compromise mount where performance will suffer.
 

lcat06

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Here's how to answer that question yourself:

Center of the cab roof is the location that is going to work best.
Bracket off the fender is a serious compromise.

Which radio do you want to work better?

Answer to that question tells you which antenna goes on the center of the roof. The other antenna goes on the compromise mount where performance will suffer.
Roger, if ham antenna is on fender will the directivity of the ground plane effect reception… same with scanner
 

mmckenna

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Roger, if ham antenna is on fender will the directivity of the ground plane effect reception… same with scanner

Yes. So will the presence of the cab, A pillar, etc. Add in proximity to all the RFI generators under the hood.
 

lcat06

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Yes. So will the presence of the cab, A pillar, etc. Add in proximity to all the RFI generators under the hood.
will I have to aim the car for the ham antenna? What abt the scanner?
 

mmckenna

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will I have to aim the car for the ham antenna? What abt the scanner?

Same for both. Lopsided ground plane is a lopsided ground plane. That's the reason you'll see antennas on most public safety vehicles mounted centered on the roof with sufficient ground plane under them. There's no magic way around that.
 

lcat06

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Same for both. Lopsided ground plane is a lopsided ground plane. That's the reason you'll see antennas on most public safety vehicles mounted centered on the roof with sufficient ground plane under them. There's no magic way around that.
Roger, found a old mag mount hustler cb antenna. Could I cut that to a certain length for ham?
 

lcat06

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It also can remove the whip part of it from the mag mount not nmo not sure what it is just below the hex key
 

G7RUX

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I’m getting a sds100 and I am wondering if I need a external antenna on my vehicle. I have good recommendations for external antennas but I don’t really know if it is completely necessary to have one in the first place. I live in Jefferson County, AL and the stock antenna on the sds100 works well enough in my home county but, for when I’m travelling should I get an external antenna or not? What are some very low profile antennas that would do this (I like the shotgun shell design) and cheap stico recommendations would be good too.
Yes.
 

kc2asb

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Roger, found a old mag mount hustler cb antenna. Could I cut that to a certain length for ham?
Possibly. Depends on what bands you want to operate on. Some CB antennas can be cut to work on 10 meters (28-29MHz)

It also can remove the whip part of it from the mag mount not nmo not sure what it is just below the hex key
I don't know. Could be a loading coil to make an electrically short antenna resonant. Knowing the model # of the antenna you are dealing with and having the manufacturer's instructions would be helpful.
 

mmckenna

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Roger, found a old mag mount hustler cb antenna. Could I cut that to a certain length for ham?

I think you were talking about the 2 meter and 70 centimeter bands in one of your earlier posts. If that's what your plan is for this antenna, then, no, it's not going to work to take an old CB antenna and cut the whip. The base coil is designed for CB and you won't get it to work correctly on VHF and UHF.

It also can remove the whip part of it from the mag mount not nmo not sure what it is just below the hex key

Don't waste your time. Get a proper NMO mag mount and a good dual band antenna if that's what you plan on doing with this.
 

lcat06

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What would be better performing in mtn brook Alabama, the mlpv700 or laird qw760 let’s say its front hood lip mounted
 

mmckenna

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What would be better performing in mtn brook Alabama, the mlpv700 or laird qw760 let’s say its front hood lip mounted

No idea. Purchase both, try them, and then get back to us.

Seriously. There's no way we can answer that question for you. The quarter wave is less than $20. Take the gamble.
 
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