A pretty simple yet effective design. Measurements are not too critical, if you're +/- an inch or two it will still be well within the 88-108 MHz FM band.
It;s not necessary to build a radome if it's to be used indoors or in the attic, but it does make it easy to install with simple plastic pipe clips. Those can be found in the hardware store with patio misting system supplies.
The peskiest part can be securing the matching transformer through the end cap. It works best to locate one with a longer thread on the type-F jack so there's enough thread to pass through the end cap, accommodate a skinny nut and still have enough to connect the coax.
In the drawing I spec'd a short stub of pipe coming off the T to give a little extra space to fit the transformer (or to wind your own, for the more adventurous type). Otherwise it's a tight fit squeezing it all into the T (although it looks clean). You can also use nylon hole plugs instead of end caps for a cleaner look.
The folded dipole design is somewhat directional perpendicular to it's length. Best results usually come from mounting it on a wall facing the transmitter.
Some time ago I was assembling these units for sale and got a lot of positive feedback. Given the time & costs involved it's honestly best to build your own at home. Let me know how yours works out.
-Ken
No comments:
Post a Comment