Question on mobile antennas and 1 other question...

[SoccerDad]

I want to get a mag maount antenna for my ford explorer. The only concern I have with a mag mount is the magnet scratching the paint. Is there a way to help prevent or reduce the possibility of scratches?

Also, the length of cable that normally comes with most antenna is not enough for me to run from the back roof up to the front of my vehicle. Does anyone know where I could purchase cable with a bnc male plug on one end and a bnc female plug on the other?

 

[K5MAR]

Most mag mounts come with a non-scratch surface on the bottom. I haven't had any problems with the various ones I've used over the years.

Female inline BNCs are kinda scarce. However, you can get dual-end female barrels (in other words a female to female BNC). this will allow you to connect an extension cable. However, I'd suggest that you bring the cable in through one of your passenger doors rather than through the back hatch. Keeping the cable run as short as possible is always a good idea, especially at the higher frequencies.

You might consider this, rig a mount to clamp to the Explorer's luggage rack and use a regular antenna, such as the Larsen NMO-150/450/800. Bring the coax in through the door seal of one of the rear passenger doors. Larsen (and others) make a nice little right angle bracket that will easily bolt to the luggage rack and take the mount of your choice (NMO for the Larsen antenna). And the Larsen NMO mounts come with 17' of cable, you can cut it to the length you need. Easy to attach BNC connectors are available at Radio Shack.

Mark S.

 

[oregontreehugger]

Some magnet mount antennas come with a protective rubber boot over the bottom to reduce scratches. Antenex is one manufacturer that comes to mind.

Still, I wouldn't expect such a product to not damage your paint or scratch it.

As far as an added length of cable, you might be able to buy an antenna mount with a longer cable run. I just looked at Antenex's web site and they mention to call for a custom cable length on their mobile magnetic mounts. Or as you mentioned, buy a short run of cable with the right connectors.

Another option is not getting a magnet mount at all, but buying a suction-cup antenna holder. I've got one and it works great (not as great as an outside dedicated antenna, though). Picked mine up at Radio Shack a few years ago, not sure if they still carry them. Below is a link to the exact thing I have:

http://www.batteriesandgadgets.com/site/814130/product/20-022

With the suction-cup antenna holder you mount a portable/HT antenna on the end (BNC), wet the suction cups and attach to an out of the way inside window, run the cable to your radio and you're good to go. Inconspicious and out of sight. Works great on the inside windshield, over to the right side near the pillar trim. Out of the way and more or less upright.

That's for only receiving, though. If you are looking to transmit you'd do better to stick with an outside mobile antenna.

 

[twolf816]

the rs mag-mount antenna that ive been using for years is still 100percent functional and has made 0 scratches or anything else for that matter on the roof

 

[JohnWayne]

The Antenex mag mounts can be had with a rubber boot that slips over the bottom. This will greatly help to prevent scratches on your vehicle. However, I do NOT recommend any mag mount for any type of permanent installatio since they will leave a ring after a while of sitting on the roof. There is a reason permanent mounts are made.

As far as the coax, I am an authorized Antenex dealer, which means I can order custom mounts for you. I get customers all the time wanting mag mounts with 20' or 30' of coax. If you're willing to wait two weeks for the custom order, then it is no problem.

Fell free to email me at jeff@waltel.com or call me at 1-888-803-5595 to talk about the best solution for you.

Thanks,
Jeff

 

[jhooten]

Take a piece of kitchen wax paper cut it to fit the mag mount and put it under the antenna. When you take the antenna off you will have a nice bright shiney spot of paint under it. Change it everytime you take the antenna off or every couple weeks and your paint will be in good shape for a long time. Just don't let the magnet pick up any metal particles or you will have a large mess in no time.

 

[imcleish]

Suggestion 1: go with an nmo mount antenna, to the roof rack or front fender. Rain caps are available if you want it removed and are in expensive.

Suggestion 2: Go to your local vinyl graphics business and ask for a scrap piece of the adhesive 1 side vinyl (3M products are best), or purchase some if you need larger or they will not give you scraps. With the left overs (if you got clear), cut some custom size pieces for your cell phone display, scanner display, or any other displays you can think of (not reccommended for flat screen tv's of computer monitors).

Enjoy the 3M quality that rubs off with a finger when removed (like the slime on the back of a new credit card).

 

[bsavery]

You might consider this, rig a mount to clamp to the Explorer's luggage rack and use a regular antenna, such as the Larsen NMO-150/450/800. Bring the coax in through the door seal of one of the rear passenger doors. Larsen (and others) make a nice little right angle bracket that will easily bolt to the luggage rack and take the mount of your choice (NMO for the Larsen antenna). And the Larsen NMO mounts come with 17' of cable, you can cut it to the length you need. Easy to attach BNC connectors are available at Radio Shack.

Mark S.

How well would that work considering the rack isn't grounded though? Say compared to the same antenna except mounted to an angle bracket by the hood?

I'd been thinking of doing that very thing myself. I've seen a Jeep around here with the mount still attached. Looked like a mirror mount with just longer bolts.

Bob

 

[Al42]

You might consider this, rig a mount to clamp to the Explorer's luggage rack and use a regular antenna, such as the Larsen NMO-150/450/800.

How well would that work considering the rack isn't grounded though?

Considering that the scanner antenna is mostly totally mismatched to the cable at any particular frequency? I'd worry a lot more about the loss in even 15 feet of RG-58 at 800 MHz than I would about lack of ground under the antenna. (The roof rack is a counterpoise anyway, so there's no lack of ground.)

 

[K5MAR]

You might consider this, rig a mount to clamp to the Explorer's luggage rack and use a regular antenna, such as the Larsen NMO-150/450/800.

How well would that work considering the rack isn't grounded though?

Considering that the scanner antenna is mostly totally mismatched to the cable at any particular frequency? I'd worry a lot more about the loss in even 15 feet of RG-58 at 800 MHz than I would about lack of ground under the antenna. (The roof rack is a counterpoise anyway, so there's no lack of ground.)

Let's see, RG-58 has an attenuation of 16.5 db per 100 feet at 900 MHz, so 15 feet would have 2.48 db attenuation, or slightly less than 1 S-unit. Not a major amount, but something to keep in mind. If you are going to make up your own cable, use LMR-195. It's the same size as RG-58, but only 9.9 db per 100 ft., that's half an S-unit with 15 feet. And it uses the same connectors as RG-58. The coax information is taken from the RF Parts website.

In answer to your question, bsavery, height is important. Getting the antenna up in the clear will help more than the marginal loss due to using RG-58. Also, you might want to check, some luggage racks are grounded, some aren't. And a ground strap can be easily added, if desired.

Mark S.

 

[gen3led]

Just take....

the discone and place it on the 3/4 measurement, after that if you have any problems I would run it along the rf slurped and contraint. Interference? maybe...but it's a good tryed and true radio method.
Let me know if this helps.

 

[gen3led]

Yes....

First of all don't worry about scratching the paint. In order to save money whcih I feel you desire to do, simply extend the wire with a little copper and electrical tape. The mag mount for rf connector is $20 at radio shack and the modulator for the copper and taping job with cost about $100.

Enjoy and stay safe.