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Hand wound, 1:1 current balun, using 20 feet of RG/58u coax (RS) on a 4" PVC
pipe about 6" long. After winding the coax a single layer of
½ lapped
electrical tape was added under tension. Holes were drilled at an angle
for entrance and exit slightly larger than the coax plus 2 wraps of tape for
protection from the edge of the PVC. Before taping run your hands
around and around in the direction of the wrap to tighten the coil.
Good
air core balun
discussion.
Device: 1:1 Current coax balun
Manuf: NE8R
Feed: PL-259
The wood stake holds the string that was fed through the window-line and
tied to the center insulator for strain relief. Electrical tape is
used to gently hold the window-line to the stake so the solder joint to the
coax moves very little.
HF scan - 2 to 30 MHz into a 54.6Ω resistor
Comment: Wish I had saved the previous scans leading up
to the above scan. The first showed a wild response - dirt in the
PL-259. The second showed a high impedance at low frequency - bad
solder joint on the resistor. I could imagine all of these occurring
during Field Day.
The bandwidth of the balun well in excess of 1 to 180 Mhz.
If you have any graphs that could be added to
this site please send them along. I'll post and credit your
information. |
