Greetings everyone
In the past I have made my own base insulator for R-25 towers. To do so, I
drilled three 1"-diameter holes in
the HBP-25 in which I inserted some machined insulating spacers. These spacers
insulated the mechanical
connection between the base-plate and the hold-down bolts embedded in the
concrete base. Separating the
bottom of the HBP-25 and the concrete, I used several thick sheets of
insulating material (if I remember
correctly, it was either several thicknesses of 1/2" plexiglas or ABS
sheet-stock salvaged from a plating
tank.
The insulated base made it a simple job to feed the antenna. The only
excitement it ever produced was a
significant local fire around the base of the tower when the plastic-box
housing the antenna tuner assembly
caught fire. Boy, did I do some fancy foot-stomping shortly after noticing the
amplifier started behaving badly!
There-after, I kept the area around the tower free of dried grasses and used
more robust components in the
new tuner.
HBP-25 Assy.
|<-------- ~2" -------->|
|---------------------------|
| O O | The 3 "O's" are the added
|-----------. .------------| Phenolic material
| /\ | 1"-holes drilled in the
|------| . . |-------|
| / \ | base-plate
| . . |
| / \ |
|----. .----|
| / \ |
| /----------------\ |
Insulating Spacer
| O |
|---------------------------|
73 de Dick - W7WKR CN98pi
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