Unusual Antenna Mounting Location

[Brts96]

On the way to work today, I saw a vehicle that had an antenna (looked to be a half wave 2 meter) mounted on the hood of a small SUV.

It was located about the center of the hood , closest to the firewall. Anyone else ever see this type of antenna mount on a vehicle before?

It's definitely new to me and I wasn't able to get a picture since I was driving.

 

[rescue161]

I've seen that done in Europe. Not sure why they do it. Most of the ones that I saw were off-road type vehicles. Some had the antenna centered on the front bumper/push-bar. Strange looking for sure.

 

[mmckenna]

I had a friend with an old beat up jeep with a bunch of radios in it.
By the time he got done mounting the HF gear, the only place he had for VHF was on the hood, so there it went.

 

[prcguy]

Mounting an antenna to the front hood area makes it more susceptible to spark plug noise on most cars. A metal car hood over the engine is a somewhat of a shield but not that great due to only a few poor grounding points.

HF and CB would be the most susceptible to spark plug noise but I've seen a few vehicles that really screwed up the VHF band from spark plug noise.
prcguy

 

[SCPD]

I have seen antennas mounted there- especially on Jeeps without metal roofs. In countries outside the US I have frequently seen HF antennas mount'd on the front bumpers of Land Rover's and other Ute's-- where they don't want the whips detuned by a close proximity to the vehicle's body.
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Personally, I kind'a like the look-- its certainly isn't a mounting site for the prissy....
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................CF

 

[DJ11DLN]

I know a guy who mounted an NMO 2M quarter-wave antenna in the middle of the hood of his pickup. He wanted a sunroof but he also wanted the antenna to do its job, so it went in the hood. It seems to work fine, but he gets teased about his "unicorn" a bit.

Seriously, on these new vehicles with glass roofs...where else would you mount an antenna with any hope for decent performance? And what about RF exposure through the windshield?

 

[SCPD]

Fiber glass tops?.....
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I took these two photo's this morning-- they show the quarter wave antennas on the fiberglass top on my 2014 Jeep Wrangler.
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One is for LMR, the other 2 metre's. And of course they need ground planes--- which are two separate sheets of double sided, glass based PC board: the very thin stuff of ~1mm thickness, -- cemented to the underside of the roof. NMO connectors pass thru that top (**Horrors!**, I know, but its My Jeep!) and these are each solder'd to the boards. Each represents as much of a quarter wave ground plane as I could/would aesthetically fashion.
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Yes, I am quite aware that this represents a bit of an RF field hazard- so the one directly over my head- the VHF- seldom sees more than 10 watts-- the UHF: 25. I seldom transmit anyway- so they aren't much of a worry..... though my passengers seem to complain a lot about getting headaches when I drive (but then you should see the goat trails here in the Rockies that pass for mountain roads... those are hardly radio induced pains.... )
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.SWR on both?.. 1.1 -1.5 on both--
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Laughing-- a Coyote's Credo: "Don't fear the circle cutter...."
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............................CF

 

[RFI-EMI-GUY]

I was going to comment about the flower aesthetic, but then I noticed a much smaller jeep was treading on the coax....

 

[DJ11DLN]

Fiber glass tops?.....

What I was making reference to are some of the new cars and SUV's that appear to have a glass roof. Can't at the moment recall make/models. Not just a sunroof but the whole thing is clear to the sky. I think I would hate that but different strokes etc. First time I saw one on a TV commercial, I thought, "Well, if you want to put an antenna on that thing and have it perform, you are kinda screwed." And then the "guess you could put it on the hood" thought occurred, followed quickly by the "how much RF would I get through the windshield" thought. Which should be immaterial or trunk mount antennas wouldn't be viable for more than a few watts...I've been told that I sometimes overthink things.

I've used your solution on fiberglass before, mainly pickup caps...also, a lot of farm machinery built since the mid '90s has composite cab roofs, I have installed antennas on some of those using thin sheet or even foil w/adhesive to create a ground plane. Works well and usually the entire top comes off (for A/C access), sometimes fairly easily, so it's not even that hard to get to.

 

[SCPD]

Hi DJ11.... !
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Yes, I realize that I was not on target with the glass roof's.. I had composed 90% of my post before I knew it wasn't going near the question-- but I'd already taken the pictures ....
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For me its rhetorical; Just how Do you place a whip on a car's glass roof?? I have no experience with cars like that, nor do I particular care to. I know some talent'd people who can drill a hole thru such glass- but Ye Gads ! .... why go that route? A car owner like that has higher priorities than roof mount'd antennas....
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There are the thru-the-glass mounts- and effective ground planes can be formed for them- but I am going to assume that all these glass tops contain a tinting metallic colloidal which precludes their use.
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Thru the body trunk mounts work well, if a permanent arrangement is desired. I think an imaginative mind can come up with a number of alternatives to the roof for their antennas with out resorting to the hood.... I'm thinking of how ridiculous that location looks....not to mention what a spouse would say!....
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RF coming thru the rear window? may- maybe not a issue-- remembering the possible effects of glass tinting etc.
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Me?, I have no suggestions... other than to not buy such a car if you want a roof top antenna. An interesting question all the same
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Whose up next to take a shot at it ??
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Cheers !
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...................................CF

 

[wrath]

When I was a motorist and installed an antenna someone asked me what if you sell the car ?
Pretty simple "it's a used car" i used it for me, you may use it differently . My dad was a ham also had a red early sixties mustang convertible with 21 antennas on the trunk and hood ,it was the very definition of rolling porcupine,my mother would not marry him until he gave up the car , and consequently amateur radio.

Sent from my SM-T810 using Tapatalk

 

[bharvey2]

I've come face to face with the full glass roof. A few months ago we bought a Ford Edge for my wife. From the inside, it looked like a typical sun roof. From the outside, the roof was all black. I didn't pay a lot of attention to it and just thought it was a typical color scheme for the car.

A few days after getting it home I thought I'd prepare for future road trips and plan for antenna mounting. Behold: a roof made entirely out of glass! No metal surfaces whatsoever. As this is my wife's daily driver, any antenna options would need to be low key as she doesn't share my love of radios. A hood "Unicorn" look would never fly. (She knows where I live and sleep) A 1/2 wave antenna with an adjustable hatchback style mount was of the few options available.

 

[jonwienke]

A glass mount antenna might work, IF the window doesn't have metallic tinting. If it doesn't, performance will be OK but not awesome. If it does, then performance will be horrible. But OK performance might be better than nothing.

The only other option is to get a 3/4" diamond hole saw of the sort used for cutting holes in tile, install a NMO mount, and attach a dipole antenna to the mount that doesn't need a ground plane.

 

[sfd119]

On the way to work today, I saw a vehicle that had an antenna (looked to be a half wave 2 meter) mounted on the hood of a small SUV.

It was located about the center of the hood , closest to the firewall. Anyone else ever see this type of antenna mount on a vehicle before?

It's definitely new to me and I wasn't able to get a picture since I was driving.

Could be a Pyramid Vehicle Repeater antenna.

 

[RFI-EMI-GUY]

A glass mount antenna might work, IF the window doesn't have metallic tinting. If it doesn't, performance will be OK but not awesome. If it does, then performance will be horrible. But OK performance might be better than nothing.

The only other option is to get a 3/4" diamond hole saw of the sort used for cutting holes in tile, install a NMO mount, and attach a dipole antenna to the mount that doesn't need a ground plane.

I don't think you can drill tempered glass. At least that is what the glass man told me when I bought glass for my shower enclosure. They sent all the requirements to the glass factory, and drilled holes before tempering. I had a huge side window on my 15 passenger van break spontaneously while driving it. It took all of 0.05 seconds and all that was left were 10 million cubes 1/16 inch on a side. I was told, all it takes is a scratch...

 

[jonwienke]

It can be done, although it requires tooling specifically designed for making holes in glass or tile.

Tempered glass isn't any more prone to breakage than normal glass, it is just designed to break into relatively harmless small pieces, rather than jagged sharp shards. Look up how a glass gutter works--it merely scores the glass along the cut line, and the piece must be broken along the score line (which is just a scratch in the glass) to complete the operation. There is a risk of breakage when making the hole, particularly if too much pressure is used. Making some practice holes in pieces of scrap glass would be advisable.

 

[prcguy]

Small round holes like an NMO mount needs are almost impossible to make in glass without breaking it. Some vehicle windows are two plates of glass with thin plastic glued in the middle and you can't cut that with a scoring type glass cutter.
prcguy

It can be done, although it requires tooling specifically designed for making holes in glass or tile.

Tempered glass isn't any more prone to breakage than normal glass, it is just designed to break into relatively harmless small pieces, rather than jagged sharp shards. Look up how a glass gutter works--it merely scores the glass along the cut line, and the piece must be broken along the score line (which is just a scratch in the glass) to complete the operation. There is a risk of breakage when making the hole, particularly if too much pressure is used. Making some practice holes in pieces of scrap glass would be advisable.

 

[jonwienke]

I know that a scoring-type glass cutter will only work for straight line cuts (actually controlled breaks) in non-laminated glass. A diamond-grit hole saw will work, if care is excercised to not apply too much pressure.

 

[bharvey2]

I've done some cutting with diamond core drills in porcelain tile. - Much harder than glass (There are glass tiles too) I imagine that given enough patience and technique (slow speed, lots of coolant and low pressure) that drilling a hole in a glass auto roof could be done. Given the size of the glass roof and the suspected cost to replace it, I'd never try it though.

Even if I could get it done, driving into a covered or underground parking structure and whacking an antenna wouldn't be near as forgiving as it would be with a metal roof.

 

[RFI-EMI-GUY]

If you read complaints about the Ford Edge glass roof, you will find there are a lot of complaints of spontaneous breakage. Repairs up to $2000 with labor. The dealers blame rock damage. I don't think you want to be drilling/cutting/looking at that glass while under warranty. They won't cover it.