If
someone wanted to validate the Lev Antenna, begin with
the parameters of my circuit board that have been shown
to work. On the Phoenix board touch your frequency
counter probe at screw A on the T1 terminal in the 3 x 3
section.
* Use the proper spring coil with a max of ˝” (13mm)
stretch.
* The LC tuning on earlier models was necessary, but
now… not always?
* Operate your pitch oscillator at 875 kHz.
* Use Hartley oscillators made with NPN bi-polar
transistors or vacuum tubes.
* Use ferrite oscillator inductors instead of air core.
* Oscillator LC capacitor = 47pf for 875 kHz
* Use a good earth ground!
I prefer
an un-stretched coil measurement end to end outside coil
edge
of 15 3/4"
There
seems to be a 3/8" (10 mm) variation in spring
lengths from different vendors.
The washer
size is 6 mm, slipped within the ends of the antenna
spring to place the internal dowel or 3/8" PVC pipe
against, this is to expand the spring for the needed
1/2" or less stretch. This more for insulating the
coil turns from one another even though there is a
slight insulating coating already. A bit larger than 6 mm
would be
nice. (7 mm) 8 mm is too large and stick out the side of
the spring preventing insertion into the outside clear plastic tube.
Materials
for the Lev Antenna
Lowes Spring =
Hillman/Resorte 9/16" x 16-1/2" x
.054"
(This
is the Antenna)
Zinc Plated, add a stretch of 1/2" or "about" 16
turns per inch.
My Lowes still had this as of 2013 for $4.97
Century Extension Spring
C-253 $4.97 usd 9/16" x 16-1/2" x .054"
(14.3 mm x 419.1 mm x 1.372 mm) Bar Code 3859? 00253
16 turns per inch (approx. 252 turns at a ˝"
I.D.diameter)
Amazon
has something that might work.
Walmart
maybe $7.87
I have seen
them at Home
Depot
on the nuts & bolt isle near the metal rods. Verify
the dimensions! 9/16" x 16-1/2" x .054"
For
the best look as seen above, use 5/8" thin wall clear aquarium
pipe on the outside and a 3/8" inside PVC pipe
or wood dowel against two small washers on each end
of the spring to get the
1/2" stretch. Use fine emery cloth to clean
the contact area between the spring loops for the
washer. The RF connecting wire solders to one of these
washer. Use (Lowes) PVC mounting
brackets to hold the antenna to the outside of your
enclosure.
Or use:
5' PVC pipe 1/2 x 5' 98 cents -
Use the full length of the PVC until your ready to mount it. This way you can stand it on the
floor while experimenting. Use an alligator clip connected to the
brass screw on the Lev Antenna that
holds the spring in place.
I would
also recommend 5' PVC pipe 1/2 x 5' High
Pressure PVC
which can be found in the plumbing section of a hardware
store. This has a slightly larger inside diameter and will
fit snugly over the coupling nuts like those used on the
EtherWave Standard elbow.
Use a 1/2"
(ideal) on the spring in the PVC pipe as seen in the picture to the left next to the brass screws. This gives you about 15 turns per inch. To
much stretch the outside low octaves could become
"narrower" than the inside high note octaves.
Hold your un-stretched spring next to the PVC pipe to get
your screw markings.
You need two 1" brass screws and nuts to hold the spring stretched in the PVC
pipe, or
use two 2" brass screws and have your spring
mounted on the outside of the PVC.
"With
the Lev Antenna tuning it is possible before adjustment
that the octave next to the antenna could be "wider" than the outside lowest octave, this is one of the interesting antenna phenomenon's."
|
