Building a Window Mount for your Antenna Assembly by WB6JPI
The window mount allows the antenna to mounted to the car and operated by the T-Hunter without any modifications to the car. It has some advantages and some disadvantages. First, it requires that the car window be partially open. Second, it requires the operator to stick his hand outside in the real world. The advantages are that it doesn’t cost much and it seems to work rather well.
The unit is entirely made from ¾ PVC pipe and parts, and it is glued together using standard PVC cement. (not supplied). The unit is quite universal, fitting a very wide range of vehicles and front and back windows. It can be easily removed and stored in a small space leaving the window to its original purpose. The related antenna is designed to be independent of the vehicle and can be easily moved from one vehicle to another or one window to another, simply by having a mount for that location available. The mount is quite cheap and you may want to consider having several of them for different windows and different vehicles. You will need to build the antenna first. It will be used to align the mount and to insure that all of the clearances are as they should be as once you cement up the mount, it is fixed and forever in that configuration. You will need to assemble the mount parts dry, without any cement until you are sure it is aligned correctly. While it is still dry mounted in the window, mark each of the 11 joints as to their orientation and fit. This is essential as you cannot get it apart while in position and you have to get each part isolated to apply cement to the joints.Be sure that the joint between the central Tee and the antenna mounting tee has no gap as this is a major stress point and you need all of the cement and help to hold these two tees together.
Find the following parts: 3 large Tees, one smaller Tee. This is the antenna mounting tee and has been bored out to accept the antenna mast. 2 Elbows. Two 6-inch pieces of pipe with no notches or anything, 2 4-inch pieces of pipe with deep slots and two 1-ft. pieces of pipe with shallow notches on one end and shallow slots on the other. There are also three little 1 ½ inch pieces of pipe. Start with a large tee and place a 6-inch pipe in the two opposite holes of the tee. Place another large tee on the end of the 6-inch pipes such that long part of the tee is in line with the pipe. Put a 1 ½ inch pipe into the center tee and in each of inline other tees. Twist things around until the center tee hole is facing you and the other two tee holes are facing down.Put an elbow on each end and the 4-inch deep slotted pipes in the outside tees facing down. This assembly should look like the picture.
Next go to your vehicle window and raise the window until it is about halfway up. Put the 4-inch pipe notches over the window glass and rotate and wiggle until they are seated with the glass all the way into the notch. It doesn’t matter if the assembly is level as it will work just fine at an angle. The tiny pipe in the center tee should be facing into the vehicle. Now place the center hole of the short tee, the antenna mount tee, on this inward facing pipe and align it to face vertically in all planes, both front and rear and left and right. Don’t be too critical yet, we will get it better soon.
Lower the window until there is about an inch or less of glass showing under the lower end of the nearest notched leg. Move the entire assembly until the rear elbow is just touching the rear of the window frame. If you have no frame around the window, then adjust it with the door closed so that the elbow is about 1/8 inch from the closed door sill. The wind loading will tend to cause the entire mount to move to the rear until it hits something and this is a precaution to make sure that the mount is secure with this tendency.
Insert the antenna mast and make sure that you can rotate the antenna and that it is vertical in all directions. The mast should just clear the top of the window frame. If it is more than ¼ inch from the frame, then raise the window until it is about ¼ inch. Make sure that you have at least 4 inches between the mount and the top of the roof to get your hand in there to rotate the antenna.
Notice how the window is closed at the top. Is it outside of the door and up against a rubber molding or is it going into a rubber lined slot in the top of the door? Is it an innie or an outie? If it is an outie, then you will use the small slot on the upright and if it is an innie you will use the small tab to fit up into the slot on the uprights. The uprights have one on one end and the other on the other end, but you will only use one end, the other being either cut off or buried in the elbow joint.
Now take one of the uprights and pick the right end and stuff it into the rubber above the front elbow to see how far it will go, and then measure just where it comes on the elbow.. Add ¾ of and inch from the top of the elbow and cut.
Lower the window and insert the upright into the elbow and raise the window until the front upright is in place. Be sure that the lower legs are fully seated on the window and the whole assembly is against the rear of the window frame. Measure the rear upright and cut.
Install the rear upright and again check the alignment and wiggle the frame around. It should be quite secure. Realign the antenna mast and verify all is correct and remove the antenna very carefully not to move anything. The antenna has a tendency to move in the slightest breeze and change the alignment. Now with the mount still mounted in the car carefully mark each of the 11 joints. Now mark them again even more carefully to ensure accuracy as even a 1/32 of an inch misalignment of the joint will screw things up and you don’t get a second chance.
Carefully lower the window and remove the frame. Take the mount apart one joint at a time, clean both parts of the joint with the purple cleaner and when dry cement that joint working from one end. When installing the wet joint, keep the marks in full view and push quickly as the cement really hardens fast (in a couple seconds). Let it dry for a half hour or so before installing it back into the car.
Mark the frame with the car and the window so you won’t forget. You can paint the frame if you feel it is too ugly but it won’t make it pretty.