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Author Topic: Hatchback Antenna Mount  (Read 8470 times)
pmraiders

Posts: 47




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« on: April 30, 2013, 12:32:22 PM »

I am trying to find a reasonable mount for the back of my vehicle that will offer decent performance in a package or mount style that will not scratch up the paint on my vehicle.

My car is a 2012 Subaru Impreza WRX. Here is a picture of the back of the car.

http://photos.leftlanenews.com/photos/cars/subaru/big-images/2011-subaru-wrx-sti-hatchback-10_653.jpg

I looked at lip mounts, but the glass on the rear window goes to and is the edge of that portion of the trunk.
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K0BG
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« Reply #1 on: April 30, 2013, 01:34:28 PM »

That leaves just about everything out! If it were mine, I'd just drill a hole in the trunk lid, mount an Larsen, NMO2/70, and never look back.
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K5LXP
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« Reply #2 on: April 30, 2013, 02:17:45 PM »

Are we talking a mount for a 2M quarter wave, ball mount with low band whip, or an HF screwdriver antenna?

Mark K5LXP
Albuquerque, NM
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pmraiders

Posts: 47




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« Reply #3 on: April 30, 2013, 04:42:53 PM »

Unfortunately I don't want to drill into the outside surface of the car. I would consider doing an L-Bracket style mount that drills into the inside portion of a body panel.

Mark, I'm not entirely sure what I want yet! I am a brand new ham (just got my call sign an hour ago) and I am still finding out what I want to install, if anything, on my vehicle. Correct me if I'm wrong, but aren't antenna mounts generally universal and can work for a variety of vertical antennas for different frequencies (hf, vhf/uhf)?

Thanks for your replies,
Jordan KG7DBM
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K7AAT
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« Reply #4 on: April 30, 2013, 06:47:21 PM »


  Your URL Link did not work for me but I went to the web for a picture of the rear of your car.  It looked to me like it had a tiny trunk.    If so, and assuming you are just looking for a basic 2M antenna,   I'd highly recommend a small trunk lip mount such as available from Antenex,  their model  TM8 ( ~$30)  or if you want black, the TMB8 ($38.) .   It is very small profile....about as tiny a mount as you can get,   is no holes mount on the lip of your trunk edge,  and takes any NMO type antenna base.   I'd also recommend you get a nice 2M whip made by  St-co,  their  flexi-whip which is also about $30.   It is ultra thin and flexible....low profile visibility and won't hurt anything if you bump into it as it is so flexible like the ones available for HTs too.

Ed   K7AAT
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K7AAT
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« Reply #5 on: April 30, 2013, 06:53:11 PM »


  After reviewing the only pictures I could find of the original poster's car I see that his hatchback does NOT have a trunk of any sort,  so the comments I made above would not apply unless he wants to use it on the hood lip....which would work well too.
  For an antenna mount for the hatch back rear I can only suggest that Diamond makes a very complete series of antenna mounts just for such vehicles and I am certain that one of the extensive model line mounts would work well for this car.   Unfortunately he would need to do his own research as to which would work best.  It would be best to have an actual product in hand to view as every hatchback has a bit different construction and design.

Ed   K7AAT
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pmraiders

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« Reply #6 on: April 30, 2013, 11:24:33 PM »

Yup, nailed the problem. I am still researching a solution while investigating repurposing the FM antenna location on center rear of the roof to be used for HAM. I have ipod/pandora hooked up and never use FM.

Thanks for the help, I will definitely check out Diamond.
Jordan KG7DBM
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M6GOM
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« Reply #7 on: May 01, 2013, 08:24:28 AM »

Repurposing the existing FM antenna hole is pretty much the only option on that car. You're not going to be really using any other kind of mount. Beware that the roof is thin though so you're not going to be wanting to put anything large on there but it should take something like a Larsen NMO dual band antenna quite happily.
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pmraiders

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« Reply #8 on: May 01, 2013, 08:50:01 PM »

I spoke with a local operator who suggest a screwdriver antenna for HF usage and also mentioned that I could use a rubber/foam pad on the bottom of a mag-mount. I am going to try his mag-mount suggestion, and I was considering using the factory tow hook location on the rear of the vehicle to have something custom fabbed to hold a screwdriver antenna off the rear.

Thoughts?

Jordan
KG7DBM
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K7AAT
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« Reply #9 on: May 01, 2013, 09:43:23 PM »


 I would be very cautious about using padding of any sort on the bottom of a mag mount.  Other than a very thin piece of plastic,  it does not take much to significantly reduce the holding power of a mag mount,  and even though HF antenna mag mounts are much stronger,  so is the torque applied to that mount by HF antennas.

Ed   K7AAT
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pmraiders

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« Reply #10 on: May 01, 2013, 10:29:09 PM »

The mag-mount is a VHF/UHF and I was thinking a small patch of clearbra (think invisible shield for your car) on top of the vehicle where I place the mount.
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AC4RD
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« Reply #11 on: May 02, 2013, 04:25:30 AM »

...and I was considering using the factory tow hook location on the rear of the vehicle to have something custom fabbed to hold a screwdriver antenna off the

Jordan, I've been using a tow-hook mount for several years now.  Seems to work pretty well for me.  I found I still needed braided straps from the antenna mount to the car's chassis; the tow-hook to chassis alone wasn't a good enough RF connection to let the antenna work well.  There are some photos:

  http://people.duke.edu/~kuzen001/ac4rdmobile.htm

 ... that same antenna is on a different car now, on an aluminum bracket bolted to the towing eye beneath the rear bumper.  The shot showing the tow-hook mount on the little red car is higher resolution than you see on the web, so you can zoom in.   Feel free to email me if you want to discuss further.  GL 73!  --ken
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K5LXP
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« Reply #12 on: May 02, 2013, 07:26:39 AM »

Unfortunately I don't want to drill into the outside surface of the car.

Sorry, can't help you there.  I introduce Mr. Hole Saw to Miss New Car pretty much on the first date.

You really do limit your options this way.  I like your idea of the protective plastic on the panel below the mag mount but you still need to address the issues of coax entry to the vehicle.  You're either drilling a hole or perforating a door or window gasket somewhere.  Then you have to secure the coax somehow so it doesn't move, or wherever it touches the paint will get scratched.  Mag mounts are great for testing things out or interim solutions but long term I'd be looking at something permanent.

Quote
I would consider doing an L-Bracket style mount that drills into the inside portion of a body panel.

Baby steps.  Sure, that can work OK.  Kinda looks like an AM/FM antenna on the cowl if you put it in front.


Quote
aren't antenna mounts generally universal and can work for a variety of vertical antennas for different frequencies (hf, vhf/uhf)?

Depends on the mount you pick.  A 3/8-24 mount can support quite a variety of antennas as you describe, from (small) HF sticks to V/U whips.  Some mounts are better suited to some antennas more than others.  Even a 3/8 mount can't hold a screwdriver without additional support, and you'll find a better selection of V/U antennas that use NMO mounts, the standard for V/U installations.

You easily solve the problem by installing all the mounts you need for all the various antennas you'll have.  Put 2 or 3 NMO's in the roof for V/U plus maybe a ball or bracket mount for HF on the back, and you can accommodate any scenario going forward.

Check out K0BG's site to get some ideas of what's out there.  A stroll through the parking lot at a hamfest can also net some creative (and sometimes humorous) ideas.


Mark K5LXP
Albuquerque, NM
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pmraiders

Posts: 47




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« Reply #13 on: May 02, 2013, 03:34:00 PM »

Thanks for the replies!

AC4RD, did you obtain a compatible chunk of stainless and have a bracket custom welded so you could mount an antenna mount onto it?

Jordan
KG7DBM
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AC4RD
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« Reply #14 on: May 03, 2013, 04:11:40 AM »

AC4RD, did you obtain a compatible chunk of stainless and have a bracket custom welded so you could mount an antenna mount onto it?

No, Jordan, that would have been a better way to do it, I imagine.  :-)  What I did was to pop out the little plastic cover and screw the towing eye into the socket in the chassis.  Then I used a standard aluminum bracket meant to take a 3/8x24 antenna mount on one end, about 6" long, and stuck it on the towing eye with U-bolts.  The antenna connector was in the middle of the eye itself.  :-)  If your browser lets you zoom in on the photo of the little red car, you can see what I'm talking about.

My current car didn't have a towing eye that screws in--it has a loop coming off the chassis, under the body.  The loop is vertical (the old setup was horizontal) and I've got a piece of aluminum bolted to the towing loop, and the antenna mount bolted to the other end of the aluminum.  I'll take a photo if you want.   Strictly improvised, but it seems to work well.

Hope this helps!  Mobile HF is a lot of fun!  73!  --ken
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