My Subaru Forester Low Impact Installation

Discussion in 'Mobile Radio Systems' started by KN3O, Feb 19, 2016.

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  1. KN3O

    KN3O Ham Member QRZ Page

    I wanted to provide, for reference, my VHF installation of a VHF Mobile installation. The vehicle is very new, a 2015 Subaru Forester Base Model, with stick shift transmission. Hopefully this will give other hams some ideas or options for a similar vehicle. I had some difficulties finding good examples of other mobile installs in the latest Subaru. My goal was to upgrade from my current HT in the car to a proper mobile, with minimal to no permanent alterations to the vehicle.

    The Equipment Installed:
    Kenwood TM-261A (Thanks QRZ for your classifieds, where this radio was purchased!)
    Diamond NR770HB NMO Mobile Antenna (1/2 wave on 2m)
    Comet CP-5 NMO Mobile Lip Mount

    I'll work from Antenna to Battery

    First, the antenna was chosen due to it being a half wave on VHF. Since UHF is non-existent in my local area, I could care less about the UHF properties of the antenna. The 1/2 wave does not require a ground plane, eliminating the solid electrical contact needed with the vehicle. The NMO mount was chosen due to its wider base and more sturdy design. Here is the positioning of the antenna on the hatch:


    The coax was routed along the passenger side floor. The grocery net keepers make great helpers for this:


    The radio is help in place on the passenger side of the center console using command strip Velcro strips. These actually do a decent job, but if you don't mind something a bit more permanent (but still without drilling holes) my backup was Scotch Brand Extreme adhesive Velcro or something along those lines.


    I did not take a picture of the ground side of the power connection, but I will tell you how it was done. We pulled out the plastic trim around the bottom of the passenger door, and routed the lead to that point. A ring terminal was attached to the end of the lead, and then a single screw was sent through the body, with the ring terminal acting like a washer between the screwhead and the car body. If someone really needs pictures of this please ask and I will go through the effort.

    Obtaining a picture of the grommet used to get power through the firewall was difficult so I'll post the best I have. The easiest way to get your lead through is to approach from the engine compartment side, using an old antenna whip or coat hanger to puncture the grommet and see where it comes out. You can also pull your lead into the engine compartment using the same coat hanger.

    IMG_0945.JPG IMG_0947.JPG

    Zip ties were used to route the wire in the driver compartment and keep it out of harms way:


    The radio was then attached to the car battery using the following method, including a ring terminal and a fuse, meaning both sides of the firewall were fused.


    The setup works as intended. The antenna shows an SWR of around 1.15-1.2 at resonance in the middle of the VHF band. I hit all the repeaters I could before, plus a few new ones, thanks to the higher power, the additional antenna gain, the higher antenna placement, and by getting the antenna out of the vehicle. All this with only one hole in an unseen location, and a few bite marks from the antenna mount.

    Thanks everyone for the help with this!

    P.S. Excuse the salty, dirty vehicle. She went on a 6 hour ski trip yesterday.
    KX4O likes this.
  2. K0BG

    K0BG Ham Member QRZ Page

    Since you apparently posted this to ask for input....

    Well, you did a couple of things wrong with the wiring. First, you bypassed the battery monitoring system. Eventually that will cause you issues. And, you used the chassis for a ground return.
  3. KN3O

    KN3O Ham Member QRZ Page

    I posted this because I had not seen good information about installing a mobile radio in my model of vehicle and want to show people who may have me model of vehicle how I did mine. Feel free to tell me why grabbing my power from where I did will cause issues and why the chassis is a poor ground return. And what would you recommend I do to fix it?
  4. K0BG

    K0BG Ham Member QRZ Page

    Just about everything you need to know is on my web site. If you have a specific question, email me.

    Oh! Make and model don't mean much at least in a general sense. In a specific sense, there may be a better way to pass power through the firewall, or route coax around. And of course, finding a safe pace to mount things away from airbags and vehicle controls.

    One more thing. The wire size you used is wholly inadequate for the land impressed.
  5. WA3GWK

    WA3GWK XML Subscriber QRZ Page

    I think the OP just wants to know what time it is, not how the clock works. There is a lot of info on your site, but I found it a bit difficult to get down to the practical nuts and bolts of how to properly wire the radio in the vehicle.
  6. W7CJD

    W7CJD Ham Member QRZ Page

    I like the antenna and the mount.

    I could use that on my Subaru Legacy Outback.
  7. NM9K

    NM9K Ham Member QRZ Page

    Two words: ground plane!
  8. N1EN

    N1EN Premium Subscriber QRZ Page

    One of the nice things about the Forester from a muggle's point of view is the nice big moonroof on most of the recent trims.

    That doesn't leave too many XYL-approved places to put an antenna on the vehicle.
  9. KN3O

    KN3O Ham Member QRZ Page

    Sorry to bring this thread back from the dead, but doesn't a half wave antenna not require ground in order to work properly? The radio is grounded to the chassis and the bottom of the antenna is level with the roof and as high as possible...

    For what it's worth I have had zero issues with this install for my purposes, as a repeater radio. I have a much greater range both receive and transmit than I did prior. Especially for times I'm a tail vehicle in the bike races we provide communications for, just having to use the hand mike vs hold an operate the HT has been great and much safer.

    This is not a VHF contest rover though, and I'm sure this is not the solution for those folks.
  10. WB2LBV

    WB2LBV Ham Member QRZ Page

    Since the thread was brought back up, I think it's worth addressing this.
    I'm not sure that thing on the positive terminal is a sensor/monitor. It does contain the main fuse (probably either 80 or 100A) and you generally wouldn't connect power for a rig to the fused end of that so direct to the positive terminal is correct. In older vehicles that fuse would be either in the fuse box or a fusible link to the alternator and thus nowhere near the battery.

    Here is a pic of my '15 WRX which has the battery sensor on the negative terminal (it also has the main fuse under the red cap)-

    15 WRX Battery1.jpg

    The sensor monitors current flow into and out of the battery as well as temperature.
    A problem can occur with these if you connect the ground wire from a rig or other accessory directly to the negative terminal rather than the output side of the sensor or chassis ground. Doing so effectively bypasses the sensor and this will set error codes and result in a check engine light. It may also prevent the charging system from working properly.

    One other Subaru-related note, their OEM batteries are underrated. I'd recommend that anyone installing equipment in a Subaru replace the battery with a good AGM that has a higher CCA and reserve current rating. I recently replaced the original battery in my '15 with the Bosch AGM in the pic.

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