G4HDU    20 Apr 2014 : 11:00
 None    Construction

How I solved the problem of not making holes in the car!

Back in December 2011 Sue, my XYL, and I decided that we no longer needed the Kia Sedona as there was now only two of us at home number one daughter, Jane, having left for university. A trip to Thorntrees Garage up in Leyland resulted in us purchasing an adapted wheelchair accessible VW Caddy.

Obviously I wanted to continue to have my mobile operation with my FT-8900 but didn't want to drill holes in the vehicle. I also wanted to add the provision for HF mobile operation with my FT-897D and therefore wanted two antenna fixings. Due to the modifications to the vehicle I didn't think that a hatch back mount would work or indeed any of the other similar mounts. A mag mount for HF is too cumbersome and so I had a look at the roof.


Obviously I wanted to continue to have my mobile operation with my FT-8900 but didn’t want to drill holes in the vehicle. I also wanted to add the provision for HF mobile operation with my FT-897D and therefore wanted two antenna fixings. Due to the modifications to the vehicle I didn’t think that a hatch back mount would work or indeed any of the other similar mounts. A mag mount for HF is too cumbersome and so I had a look at the roof.

Sirio Mount

To my surprise I found that there were four screws strategically placed for mounting roof bars and roof racks on the vehicle. Removing one of the screws proved that a secure fixing could be made to these mounting holes and so I went in and started to check out ebay for antenna mounts. I found a suitable antenna mount from Truck King Radio (who are now sadly defunct).



Cable assembly
Also from the same place I picked up a matching SO239 cable assembly. This is a single hole mount with a length of coax connected to it and a PL 259 on the end. The quality is not over marvelous, crimped connection at the SO239 end and will allow water ingress. Some clear sealant soon put a stop to that problem. The order was duly placed and the goods arrived two days later

Naturally the bracket was the wrong shape to just go straight on to the roof, the plates have ridges in them for mounting on roof bars and so a short period in the garage with a blowtorch and a lump hammer straightened out one plate. An extra hole to clear an M8 threaded machined screw was drilled into the plate and a small piece of plastic cut out to go between the bracket and vehicle roof to prevent damage to the paintwork.

Painted brackets
So that the brackets look more aesthetically pleasing I painted them with some silver Hammerite paint which matches the car and just happened to be lying around in the garage. The SO239 mount was mounted on the bracket along with a short length of braided wire to go under the penny washers for the mounting screw.

Cheese Head Screw
The original screws provided by VW are made from a softish material and are not very long. Exploring the Screwfix website I tracked down some hex socket set screws which were the correct length and made from stainless steel.

 

Mounted bracket
The complete bracket was then mounted on the car ready for the installation of the 4 band whip (covering 10m, 6m, 2m and 70cms) and a matching bracket was mounted on the near side ready for the HF aerial. Currently this is just a simple multiband whip but a lovely treat by the XYL has now seen it upgraded to an ATAS 120A.

Update
Since this article was written I have transferred the FT8900 to the shack and purchased an FT857D. This is permanently mounted in the car and is covered in a separate post.

 

Overall Installation
Front View
VHF Aerial
Rear View




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