Antenna location opinions

EC-7 · Post by **EC-7** » Wed Jan 23, 2002 8:46 pm

I am installing a VHF radio in my brother's car. He doesn't want a big visible antenna on it. What would you suggest to put on it. My options are, a 1/4 wave mag mount on the left of the trunk, or a through the glass on the top center of the window. I know that height is important, but I don't trust through the glass antennas. No roof mount! No holes! 30 watts out of radio.

Glendale Radio · Post by **Glendale Radio** » Wed Jan 23, 2002 9:50 pm

I Prefer A Diamond Mag-Mount, Better On The Center Of The Trunk, Side Does Not Matter Some. Never Did Like Thru-The Glass Either! My 2 Cents. Glen

EC-7 · Post by **EC-7** » Wed Jan 23, 2002 10:46 pm

I was thinking the side, because the rear window is taller than the antenna. I would mount it to the far back of the trunk, above the bumper. He only wants a 1/4 wave because of it's height. I personaly would go with a 5/8 x 2 Diamond through the roof, but it's his car.

N4UMJ · Post by **N4UMJ** » Wed Jan 23, 2002 11:09 pm

A picture is worth a thousand words.

This one really helped me.

http://www.larsenantennas.com/products/ ... ileant.gif

Larsen also makes some fine commercial and amateur antennas.

And yes .. my 2000 Toyota Camry now has a hole in the trunk lid (with an antenna in it of course).

Last time I traded my used 1990 Camry they had a problem with what the odometer read, not how many holes the car had in it. So, this time around I took the plunge and drilled a hole. Not too concerned about the impact to the trade in value since I keep my cars till they drop.

Eddie

EC-7 · Post by **EC-7** » Wed Jan 23, 2002 11:35 pm

Thanks, I guess where I was going to put it would be the worst spot.

Tom in D.C. · Post by **Tom in D.C.** » Thu Jan 24, 2002 5:18 am

Mark: A thru-glass antenna works fine. The glass is a capacitor of sorts, and a capacitor passes an AC signal and blocks DC. The RF is an AC signal so it goes through the glass. Tune it correctly and be sure it's got a ground connection. Thru-glass works fine for cellphones on 800 mHz and also on 440 and 2M.

Mag mounts sometimes fall off and can ruin the car's paint finish. A hole in the car is best, of course, but I would vote for a 3 db gain glass antenna if I couldn't cut a hole in the car somewhere. My Honda Accord wagon has a hole in the roof for an NMO mount which was installed by the Motorola dealer.

Tom, W2NJS
...in D.C.

jim · Post by **jim** » Thu Jan 24, 2002 12:42 pm

I've tried several different glass mounts on the VHF band and they all sucked.

I'd just use a trunk-lip mount with a 1/4 wave.

Another option that I've used on some unmarked cars is the "decal" antenna that TESSCO carries. It's just a decal that sticks to the inside of the window and you don't even see it. The do work better than the glass mount "cellular lookalike", but not by much.

Jonathan KC8RYW · Post by **Jonathan KC8RYW** » Thu Jan 24, 2002 1:46 pm

Imagine that: the place that exposes the operator to the least amount of RF also provides the best gain.

The center of roof wins hands-down in my opinion.

N4UMJ · Post by **N4UMJ** » Thu Jan 24, 2002 2:47 pm

If you do go with a glass mount do choose one that is rated for the proper amount of power. (I once smoked a Cellular 3 watt glass antenna mount with a commercial rig but that is another story...Live and learn!)

Be sure that your mounting location for the glass mount does not have any defroster wires in its path. And also ... I have heard that some of the windows with the defroster wires built that you can hardly see (gold in appearance) that can create problems too so keep this in mind.

If you do decide to drill a hole there is a special hole saw intended for this. I have heard of some using Greenlee Metal Chassis Punches too but this requires access from both sides. I try to stay away from those.

For reference my 3/4" Antenna Hole Saw Kit is made by Cablematic and the Model number is HSK-19.

If you place a large antenna on a Mag. Mount be prepared for the worst. I had one fly off the trunk when a Semi passed me going in the opposite direction on a two lane road. I ended up dragging the antenna behind my car for a while before I stopped. Not too good!

I have always like the trunk lip mounts(with the "L" angle bracket that screws in), but with todays cars sometimes it is difficult to squeeze the coax through the smaller crack between the trunk and the car body.

Good Luck whichever mount you choose,

Eddie

radioEd · Post by **radioEd** » Thu Jan 24, 2002 4:24 pm

I'll just agree with Eddie above! Since I've been thru pretty much the same! Were replacing the Glass mounts on patrol cars! Cause of problems! Bottom Line!!! Put a hole in it! my 2 cents... Ed

RadioSouth · Post by **RadioSouth** » Fri Jan 25, 2002 8:52 pm

Ya gotta put the hole in the roof- works so
much better. Took me over a year to drill my
Nissan Maxima, the mag mount was scratching
the heck out of the car, should have drilled it from the get go. When I trade it I'll
put a cell phone rod on the NMO mount, don't think that will upset the trade. Someone mentioned about interior RF concerns with a
roof mount- take a look at the Hirschmann line they make a fully shielded NMO mount specifically addressing this. For VHF the
1/4 wave works well, being I'm a 90% highway
driver I stay away from the 5/8 type as it would be flying in the area of a 45+ deg. bend most of the time-has to be serious de-tuning at this angle. Yes, I-95 in FL really
moves at times.

radioEd · Post by **radioEd** » Fri Jan 25, 2002 9:42 pm

If you think about it..RF will find ya all the time. from a TV set, cell phone, (how would you like to sit and work a radar gun)? I don't think you can hide from it anymore. Just try to keep it at a minimun

Jonathan KC8RYW · Post by **Jonathan KC8RYW** » Fri Jan 25, 2002 9:45 pm

On 2002-01-26 00:42, radioEd wrote:
If you think about it..RF will find ya all the time. from a TV set, cell phone, (how would you like to sit and work a radar gun)? I don't think you can hide from it anymore. Just try to keep it at a minimun

I still wonder if they make RF shielded under-shorts? Anyone know?

Flametamer · Post by **Flametamer** » Fri Jan 25, 2002 9:58 pm

This is not directly related to this post but, has anyone ever heard of or tried the Untenna? http://www.untenna.com

Just curious
Darrin

radioEd · Post by **radioEd** » Fri Jan 25, 2002 10:51 pm

On 2002-01-26 00:58, Flametamer wrote:
This is not directly related to this post but, has anyone ever heard of or tried the Untenna? http://www.untenna.com
Just curious
Darrin

You'll find them in the ARRL books, some articles (for me) as far back as the 1970's ..been around awhile.[nope never tried one]Ed

EC-7 · Post by **EC-7** » Sat Jan 26, 2002 12:07 am

I think that the UNTENNA is UGLY! I think my brother would rather have a mag-mount on the roof than one of those. The RF is no big deal, it's only 30 watts, and talking to a repeater in town. Coverage/signal isn't a huge deal in this case. I think I'll just install a 1/4 wave trunk mout in the center of the trunk.

jim · Post by **jim** » Sat Jan 26, 2002 7:54 am

The untenna would be ugly on the roof of this car, but.....

I have used these mounted to the underside of the trunk-floor of several unmarked cars (underneath the car, that is) and it worked surprisingly well! Just make sure you seal it well! Sure beats the hell out of the performance of any glass mount.

radioEd · Post by **radioEd** » Sat Jan 26, 2002 8:12 am

On 2002-01-26 03:07, EC-7 wrote:
I think that the UNTENNA is UGLY!

I don't care what it looks like! I'm only interested in results/performance. That's what counts when you rx/tx on the radio.

Post by **alex** » Sat Jan 26, 2002 9:52 am

I have had very good luck with 3 trunk mount antennas, just with the simple lip mounts. I haven't measured SWR with them, or anything like that, but they work well, and haven't had a problem hearing or talking 1/2 way across the county.

I paid like $15/ea for the mounts, and another $10/ea for the antennas @ dayton.

-Alex

penstar · Post by **penstar** » Sat Jan 26, 2002 1:36 pm

You've probably heard it all, but just my 2 cents. Roof mount hole with 3db gain antenna is my first choice, hole in center of trunk with same antenna second.

-Ed-

PETNRDX · Post by **PETNRDX** » Sat Jan 26, 2002 5:58 pm

Best is NMO & qarterwave in roof.
2nd NMO & quarterwave on trunk.
3rd NMO to a stainless steel L bracket that goes down inside along seam of trunk lid or hood. That way the two or three holes left by the screws are under the lid when removed. Put the screws back in the holes after the bracket is removed, paint them with the "brush in the cap" touch up paint and no one ever sees them on trade in.

Gives better ground (counterpoise) when transmitting compared to Mag mount. Also doesn't scratch the paint. Most of the name brand antenna manufacturers make the L brackets for about 3 to 7 bucks. Already drilled for NMO.

I have used this about 100 times for those who lease cars and can't drill holes. Works great.

jonatl · Post by **jonatl** » Sat Jan 26, 2002 9:19 pm

Hey... Speaking of low profile antennas.... what would you guys recommend for an 01 expedition. I dont want tall antennas. I have a clearance problem already... i'd prefer something short and 'low profile'. I will be needing 3.. VHF, UHF, 800. Anyone suggest anything worth investigating?

Thanks!

Post by **HumHead** » Sat Jan 26, 2002 9:48 pm

YOu may want to check out the antenex "Phantom" and "Discadoo" (for 800) lines. (http://www.antenex.com

I haven't personally used them, so I can't speak for the RF performance, but they're sure low profile.

<font size=-1>[ This Message was edited by: HumHead on 2002-01-27 00:55 ]</font>

RadioSouth · Post by **RadioSouth** » Sun Jan 27, 2002 7:39 am

Had the same (3) antenna's on my '98 Exped.
As long as your not operating on the outer fringes quarter waves are compact- about 3"
for the 800, 6" for the UHF, about 16" for the VHF. In almost 3 years the only one
that was hit was the VHF- would recommend the
whippy VHF type like the Motorola- I needed
to straighten it a couple of times but the
rigid mast 1/4 waves like some companies make
(better performance at high speed due to not de-tuning when it flexes) would have damaged
the roof.

jim · Post by **jim** » Sun Jan 27, 2002 12:26 pm

Don't even THINK about using Antenex's VHF low profile unless you want to change it every month. I used many of these and changed them all- more than once. They did redesign it and it still sucks. The new one is de-rated to 60W at 60 seconds and they still regularly burn up from a M1225 and CDM radios. I had about a 75% failure rate with them.

The UHF, 800 and the "Discadoo" work great and I have never had a problem with them. Too bad they can't get the VHF working.

I tried Comtelco's VHF antenna that looks identical to the Phantom and they either fill up with water or the "cup" breaks off of the base plate. I had a 100% failure rate with them.

The only low profile VHF that I've used so far with no problem is the Untenna. So far, the success rate is 100%

Post by **alex** » Sun Jan 27, 2002 12:35 pm

What about these? They come in most of the bands V,U,800...

I've seen them mostly on ambulances, and other vehicles.

Oppinions?

http://www.antennaspecialists.com/lm_cat/lmrpg21.html

Looks this might solve most of the problems.

-Alex

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<font size=-1>[ This Message was edited by: alex on 2002-01-27 15:36 ]</font>

FireCpt809 · Post by **FireCpt809** » Sun Jan 27, 2002 2:11 pm

Anyone had any problems with the patch antennas? If your not familiar with them they are a black decal about 3"x5" and have a cable and tuning pot. I forget who makes them at the moment. They are advertised as " discrete" antennas I know you can put atleast 50w VHF through them. They are avalible in VHF UHF and 800 Commerical and celluar

Next time im at the shop I will get the exact name and manufactuer

April · Post by **April** » Wed Jan 30, 2002 1:16 am

The "patch" antennas NOT realy an antenna, they SUCK big time.
Not to mention that they fail to meet OSHA regulations on radiation and operator exposure to high RF feilds.
Get a god old quarter wave "motorola" type antenna, on the vhf antenna remove the ball so it will not catch in garage doors and at the Jack in the Box drive thru!!!!
I would rathe replace a bent up whip for $5 than fix the roof and replace the mount.
A freind of mine once got his lowband base loaded ASP268, it has a 49" whip and spring, caught in the garage door and it pulled the door down on the top of the Jeep Cherekee and the antenna mount right out of th Jeep's roof.
It pucckered the roof.