Subaru Outback Antenna Installation

This is information I received from Dennis, N6KI regarding installing an antenna mount on a 2000 Subaru Outback.

“A friend forwarded your query to me and I believe I have one of the best methods for mounting an ATAS-100/120 antenna that will also give it a good ground.

I tried the trunk/hatch mount on the hatch of my 2000 Subaru Outback and could not get an effective ground, even after scraping thru paint so the set screws would make better contact.

Here is a pix of what I came up with. Problem is you will need to know a contract a machinist/metal worker to fabricate and install though but you will have a better mount than anything you can buy. Most vehicles that have a minimum of a 3/16" space between body parts can accommodate this scheme.

As you can see I took advantage of the using the space between the hatch and the body of the vehicle. I also had a friend who used the space between the tail light and body of a minivan to make a similar mount. 1/4 inch angle aluminum was used as bracket material.

The bracket is held in place by using a nifty fastener called a Pem Stud Insert that can be mounted into a blind hole if the body part you mount the bracket to does not allow you to reach behind and use a nut and lock washer to secure the mounting bolts. Pem Stud Insert can be purchased thru most ACE Hardware stores I believe.

Local Subaru dealer told me it was OK to install and use radios on vehicle as long as I ran my power DIRECTLY to battery and fused it at battery. I run 40 thru 6 mtrs plus 2 mtrs, 220 mHz and 70 cM and no problems except that the computer in the Subaru emits annoying tones on 20 thru 10 mtr bands every 15 to 20 kHz and also engine electrical gets hash into 2 mtrs... go figure.

73, Dennis N6KI”

“I bought the "Thread-Sert" by the "MARSON Corp"., http://www.marsoncorp.com/ which are the inserts that accept standard 1/4-20 bolts (and other size bolts/screws), from a local specialty hardware store that sells machine tools and supplies and is a kind of "SUPER" hardware store so I don't know that you can get these at Home Dept etc. They are made to mount in a blind hole. As long as the area on the body of the car (door jamb etc) has at least 0.900" of space for a bolt to protrude into it should work fine. Call me before you decide to drill any holes if you use these blind inserts as there are some idiosyncrasies I want to tell you so you don't have an installation failure as the hole size they recommend drilling initially caused me a problem!!!

On my store receipt the Threadsert is listed as Marston Part # 47850 but I cannot find it at the web site. When I go to this page: http://www.marsoncorp.com/threadsert.htm They list the 1-4" Aluminum Threadsert as Part # 57950 ...hmmmmm don't know what the heck that is all about so maybe you will have to call Marston.

Now they sell a fancy expensive insert tool but the THREADSERT I installed only uses a 3-16" Allen wrench (supplied) and a 1/4-20 X 1.75" length Allen socket head screw to do the install and a 6 sided Spacer (Supplied).

Now they say that your material thickness must be 0.0937 thickness minimum so even though the thickness of the body sheet metal where I installed these was less, the Threadsert still held ..... I didn't know all this info until this evening when I went to Google and figured out that Marston made these.

I did one installation on another vehicle where one of the Threadserts did slip and spin a bit when I install the bolt holding the antenna bracket so maybe I got lucky.

What I would do in future to meet minimum material thickness is to use a thin stainless washer under the head of the Threadsert to make up the difference if car body material is less than 0.0937....”

“While I was designing this bracket I bought an antenna lip mount from either Diamond or Comet and mounted the antenna on the lip of the hatch back. That got me by but I could not make the antenna see a good ground because of the hinges but it did tune and work on some bands.”