Bob,
I am going to build my coil much like the coil you built and feature on your website.
What was the length of the 2 inch pvc pipe you used?
If it's close to what I already have here on hand then that means I don't have to run to town for the pvc.
Thanks
Barry of Blue Bucket Radio 89.7 FM
The windings ended up about 12" long. A couple inches was left on each end beyond that in order to glue on the reducers.
As I recall I started with a 24" piece, wound the coil and then cut to fit.
Thank You MRAM 1500
I have little over a foot of pvc here which will be part of the coil assembly.
Also the ground radials are going to be fanned out and anchored by..... brace yourselves!
A hub or rotor I just replaced on my Jeep Grand Cherokee, it already has the holes in it.
It is fairly heavy so it will stay in place, what more can you ask for?
Oh and the Blue Bucket from Lowes will house the transmitter and the antenna will be on the side of the bucket.
After I built mine and found the coil needed a few more windings. The radials (like a top-hat) were added to resonate the antenna as it was already 10 feet long. Of course there is much discussion as to whether or not that is counted as part of the antenna length.
A possible mod would be to purposely exceed the calculated number of windings and use taps to set the resonant point. That would also accommodate moving to a new frequency if needed.
I used what amounts to plastic insullated hook-up wire for the coil. Enameled wire would reduce the length of the coil. Depending on which type is used will affect the number of windings among other characteristics.
I think I will be splitting the difference with this antenna. Not sure how it's going to turn out but worth a try. After all experiementing is what this hobby is all about.
My plan is to have a driven element cut to 4 1/2 feet and a grounded element at roughly 4 feet. I don't think it will actually be grounded but it will have a coil in the center.
Haven't really tried to figure it up on paper yet, but the idea is to have a compact antenna that is as close to effiecent as possible.
As i mentioned earlier in this thread, I will be using a brake hub from my Jeep which i guess is re-purposing the hub for another use? Here is the hub that hasn't been mounted to the other wheel which is new just to give you an idea what I will be using for the ground radials.
It was easier to grab this one for a picture.
Just imagine wires wrapped around the lug holes and then stretched out like spokes on a bike wheel. This should work pretty well.
Too soon to be sure.
My wife helped me wrap 102 feet of wire to this pipe then we wrapped it with electrical tape to ensure it stays tight and doesn't seperate. Tape will probably come off after the antenna is completed.
Once I put the reducers on each end the coil stayed in place just fine.
Like any of these very short antennas, tuning is critical. Changing the coil a half turn can put it way off. Even changing the length slightly and away goes the peak! We're talking about fractions of an inch...
If the coil is close on then it's easy to change the radiator length for tune up assuming it doesn't go over the 10 foot limit. In my case the coil was a turn or two short so I added the capacity hat.
Be patient when it comes to tuning it up. It can be frustrating as every time you move away from the antenna the tuning will change a little.