Trunk Lip Mount vs. Hole Mount with the Phantom

[rmcclellan]

I currently have a PRO-2096 installed in my car and ONLY monitor an 800 MHZ Trunking System. I have no intentions of listening to any other bands. Reception is excellent with my existing mag mount whip style antenna. However, I do not like the looks of it and also I don't like having to remove it for carwashes.

I plan to purchase the Antenex Phantom low profile antenna due to positive reviews on this board as well as its "discreet" design.

I have never used a Motorola-style NMO mount and am looking for some advice:

1. Am I correct in assuming that a NMO mag mount for the Phantom would be less desirable (performance wise) than a trunk lip and permanent hole mount?

2. If properly mounted, would a trunk lip mount perform just as well as a permanent hole mount? If not, is the difference significant enough to drill a permanent hole in my car? (Please note that the mounting location on the vehicle would be exactly the same for either type of mount).

3. I am seeing a standard RG58A/U cable being supplied with these NMO mount kits. My run length would be no longer than 20 feet. Would you recommend that I use another cable type? If so, what cable type would be best?

Thanks in advance for any and all advice on this! I am pretty savvy with scanners...just not too much with antennas and this appears to be the place for answers.

Thanks again!

Rob

[mmartinfan]

I use a Phantom with a Trunk mount with what ever cable Waltel puts on the units. I love it for 800Mhz and UHF.

[blinddog50]

Don't drill if you don't have to.
Mag or trunk lip work just fine.
If you don't live in a metro area you need to center it as much as possible as your car will act as a low grade ground plane.
If you live in a metro area it won't matter do signals being so strong.

As for cable, check with your supplier and ask for cable with the most dielectric insulation.
Today's cars give off alot of electronic noise.
It will cost more but the results will be worth it.

[Al42]

Originally Posted by rmcclellan

1. Am I correct in assuming that a NMO mag mount for the Phantom would be less desirable (performance wise) than a trunk lip and permanent hole mount?

More important than the type of mount is where you're mounting the antenna. A mag mount on the roof has about 4-5db gain over an antenna on the trunk lid, even if it's a permanent hole mount in the trunk lid.

2. If properly mounted, would a trunk lip mount perform just as well as a permanent hole mount?

If properly mounted - that means the mount connected electrically (at 800 MHz) to the trunk lid and fender - not something you're likely to do. So the answer is that in a practical installation, at 800 MHz, a trunk lid mount is about as good as the rubber ducky on the scanner.

If not, is the difference significant enough to drill a permanent hole in my car?

Only you can answer that one, but a mag mount on the roof is better than a hole mount in the trunk lid, so why even consider a trunk lid mount - of any kind? Even an on-glass is better than an antenna on the trunk.

3. I am seeing a standard RG58A/U cable being supplied with these NMO mount kits. My run length would be no longer than 20 feet. Would you recommend that I use another cable type? If so, what cable type would be best?

Best? 3 inch dry-nitrogen-filled hard line. Practical? RG58. RG8X if you want a little less loss. RG58 has 2.8db loss at 800 MHz for 20 feet. RG8X is 2.4db loss. RG6 would be 1.7db loss. Really low loss LMR600 would be 0.5db loss, but the difference isn't really worth the price and problems (the others are a lot more flexible).

[rmcclellan]

I live in the center of a metro area (Columbus, OH)...so signal strength is not an issue at all.

Thanks for the advise so far!

Would you expect better performance from a trunk lip mount versus a mag mount? The reason I ask is because I remember reading something about an issue with mag mounts not being grounded or something like that???

Also, do the trunk lip mounts have a nice and professional appearance once installed?

Thanks!

[rmcclellan]

Oops...look like you pretty much answered my questions while I was typing mine

Just one more thing...what about the cable run on a roof mount? I dont like the idea of a cable running accross my roof

This is the reason I was leaning towards the lip mount...

Rob

[blinddog50]

If you're only going to listen to 800 mhz and want it centered as much as possible on your car and don't want exposed cable go with an on-glass.
Living in a metro area just put a celluar antenna on your back glass.

[bluesman905]

Hi Rob, I recently changed to the Phantom and used an NMO mount in the centre of the roof of an Aerostar (older so I wasn't concerned about the hole although I would do it to a newer vehicle too, very clean look). I would think that the roof is better than the trunk/fender mount for reception.The RG58A/U cable that came with it works fine for me (I'm mosly city use). Antenex has options for type of cable so order accordingly if you want a higher grade (and price).

[rmcclellan]

Thanks everyone! This site rocks!!!

I appreciate all your advice.

Rob

[Al42]

Originally Posted by blinddog50

As for cable, check with your supplier and ask for cable with the most dielectric insulation. Today's cars give off alot of electronic noise.
It will cost more but the results will be worth it.

The more insulation the more loss, which is why air dielectric cable is the lowest loss. But insulation doesn't eliminate noise, shielding does. RG6 quad-shielded is about the best shielded.

However, the best way to eliminate noisy signals in scanners is to eliminate the noise, not shield against it. Coaxial capacitors for all noisy primary leads, battery voltage taken right at the battery - not at the cables coming from the battery. (There are posts that can be drilled into the battery posts, something like lag bolts, to eleiminate picking up the noise dropped across the post-to-takeoff-point resistance.) Good resistance ignition cables, and replace them every couple of years. Wheel springs if you get wheel noise. Bonding all sheet metal.

Eliminating automotive noise is about as complex a subject as designing a scanner.

[w8prr]

I use low loss cable to a 1/4 wave nmo mount on the roff on my truck. With any mag mount you have no ground connection at the antenna and have exposed cable to cause problems. I listen to the Columbus system a lot and it is agood system. I'd use the trunk mount over the mag mount as it will hold up longer.

Rick W8PRR