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Saturday, November 01 2014 @ 02:32 AM GMT+4

Lightweight Portable UHF/VHF/HF Antenna

Experiments / ProjectsBy WB2LUA, Dr. John A. Allocca -- The Smith-Victor 10 foot aluminum light stand extends to 10 feet high and weighs only 3 pounds. It collapses to 32” and easily fits into a 36” light stand case. The top section has a diameter of 5/8”, which is suitable for most mounting clamps....

The Maldol AX-75 Dual Band Mobile Antenna was selected because it is a 1/2 wave, 30”, antenna that will easily fit into the 36” case. The Smith-Victor 10 foot light stand uses plastic connecting parts, which are not conductive. Therefore only the top section will conduct and it will provide the 1/2 wave 19.6” ground plane counterpoise required for UHF/VHF mobile antennas.
A dipole hamstick configuration can be used with the Lakeview # 901 dipole mount. The dipole configuration is heavier than the AX-75 antenna and therefore should not be used during moderate to high wind speeds without guying. The Pro Am Valor hamsticks are recommended because they can be tuned prior to use. Then the antenna can be taken apart without tools and without affecting the tuning. The Pro Am Valor is not currently available for 60 meters. Fully assembled, the hamsticks extend to 8 feet long. With two hamsticks in a dipole configuration, there will be a total length of 16 feet. Disassembled, the length of the hamsticks will be 49 inches. Hamsticks come with a plastic carry case. Hamsticks are available in all frequencies including the new 60 meter band (Lakeview brand, which requires a tool).’
The light stand will not provide enough ground plane area for a vertical HF antenna. If a vertical HF antenna is needed, a counterpoise braided cable will be required. Near Vertical Incident Sky wave (NVIS) is accomplished using horizontal dipole configuration for communications at distances from 200 miles to 800 miles. A 25 foot or more length of RG8X cable will be required. Hamsticks need to be tuned with an antenna analyzer or bridge.


Parts List:
  • Smith-Victor, RS10, 10 ft. Aluminum Light Stand, Folds to: 32 in., Footprint: 47 in., Weight: 3.0 lbs. - $45
  • Davis & Sanford, DATC Tribag, 36”, Padded Tripod Case - $20
  • Diamond, C211, SO239 mount with RG8X extension cable for 16.5 feet total - $50
  • Diamond, CRM, Right Angle Bracket with U Bolts - $17
  • Maldol, AX-75 2m/70 cm, 1/2 wave, Dual Band Mobile Antenna, 30” - $60
  • Two Pro Am, Valor PHF20, Valor 20 meter 8', 3/8-24 whip (1/4 wavelength) - $24
  • Two Pro Am, Valor PHF40, Valor 40 meter 8', 3/8-24 whip (1/4 wavelength) - $24
  • Lakeview, # 901, dipole mount - $19 + 3/8-24 5/8” bolt, 1-1/8” spacer, 3/8” washer, shorter u-bolt
  • Two (one for UHF/VHF and one for HF) Cable Xperts, CXP08XC25, 25 FT RG8X CABLE W PL259S - $26
Above prices effective as of 5/2/07

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