Topband: 1/4 and 3/8-wavelength vertical radiators: From: W2SH@aol (W2SH@aol) Date: Wed, 19 Jun 2002 15:21:28 EDT: I should like to revisit the subject of 3/8 wavelength antennas which brought several interesting postings on 17 May. I had long thought that it was best to get the point of maximum current in a vertical radiator as high as ...
This results in λ/2 (0.5 wave) spacing. If the reflection image is perfect, the theoretical maximum possible gain would be about 1.8dB over an antenna without any ground reflection gain. 1.8dB would be the gain of a λ/2 vertical or vertical dipole over a λ/4 vertical (quarter wave) with …
135 – Collinear Vertical Antenna 6dB-Gain for 2m, 1.3m, 73cm. 136 – Bi-Loop Antenna for 20m. 137 – Wire Beam 6dBd-Gain for 10m. 138 – Sloping Diamond Antenna 4dB-Gain for 40m. 139 – Twisted Loop Antenna for 160m. 140 – DX RX Loop Antenna for 160m. 141 – Hentenna 3dB-Gain for 10m, 6m, 2m.
2 METER SSB SQUARE LOOP From N4UJW 2m Quagi By W5UN 2M Yagis a Bunch-- From The Antenna Elmer 2M Quadix-- from Ross W1HBQ 2m 8db collinear for portable use.M3FVB 3 element 2-meter Yagi-- From The ARRL 5 element 2-meter Yagi-- From The ARRL 2M 9 Element Yagi 5/8-WAVE COLINEAR "OUTSIDE PVC" 2-METER 146 MHz FM J-POLE Via KB1DIG & KB1GTR
Jan 20, 2013· 20m Elevated Vertical Antenna – G8ODE NOTE: - The antenna wire is cut to the length calculated by the formula ; 1/ 4 . λ = 234 / F MHz (Feet) or 1/4 . λ = 75/F MHz (metres). The counterpoise wires are cut 5-10% longer than the antenna wire, and are used to support the antenna. Graphics by G8ODE DEC 2010 iss 1.3 . Plan View . 2m tall wooden ...
The SWR match for coaxial cable was 1.01 for 3- radials, 1.07 for 4-radials, 1.13 for 6-radials and 1.16 for 8-radials. This suggests that a perfect match to coax can be found for any number of radials by adjusting the vertical/radial Ratio. A confirmatory study for 8-Radials at 20° found a 50 ohm match at a vertical/radial Ratio of 0.522.
New 7 in. W x 6 in. H Slate Rubber Vertical Planter (3-Pack) Model# MT1005176CM $ 39 98 $ 39 98. Free delivery with $45 order. Set your store to see local availability Add to Cart. Compare. Worth Garden 18 in. Self-Watering 3 Pockets Vertical Wall Garden Plastic Planters Model# 4190 $ 14 75 $ 14 75 ...
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antenna projects for 10 meters band category is a curation of 77 web resources on , DIY 4 Element Yagi, A 10 metre EH Antenna, The 10 Meter Loop Antenna. Resources listed under 10 Meter Antennas category belongs to Antennas main collection, and get reviewed and rated by amateur radio operators.
The 2-meter 3-DFL The 2-meter 3-DFL is a great addition to any HT and provides several dB of gain over a rubber duck, but it costs only five dollars. In addition to being more efficient, the 3-DFL can be placed away from the operator to reduce RF at the operating position. And, the antenna is small enough to be placed on a table or a bookshelf.
The Hustler 4-BTV is a four-band trap vertical antenna providing an omni directional pattern. The 4-BTV is designed as a self-supporting vertical to provide optimum operation in the 10, 15, 20 and 40 meter bands. It can also be adapted to operate in the 75 meter band. This antenna is designed for installations with restricted space.
Had a home made duel band "J" Pole antenna up about 30 feet, was just using with a 2 meter radio. Feed line was about 60 feet of mini 8. Purchased the GP 3 and 100 feed of low loss coax. Installed the GP 3 at 20 feet for testing and comparing. Even through the GP 3 was 10 feet lower, it was 2 S Units better on any repeater within range.
The question is, how long should the horizontal wire section be. I suggest keeping the vertical section the same length as the original design, but add a horizontal wire of length 12.2m or 27.2m long, to make the total length of radiating element either 1 9.2m or 34.2m.
Mar 06, 2016· ̅ = 3.2m Hydrostatic force ̅ = 0.85x9810x(1.2x1.2)x3.2= 38424N CP of F M.I. about CG 0.1728m4 Vertical distance of CP of F1 from free surface ̅ ̅ = 3.209m Vertical distance between the hinge and F = 3.209-2.9 = 0.309m Taking moment about the hinge P = 19788N R+P=F R = 38424-19788 = 18636N R CGCP F P 30 0 24Kpa Gate (1.2mx1.2m) P Hinge oil ...
GP 3 Vertical 2m/70cm: COMPACtenna: 6m/2m/440 6m, 2m and 440 MHz Antenna: 10m/2m/440 10m, 2m and 440 MHz Antenna: 20m/2m/440 20m, 2m and 440 MHz Antenna: HamR-7 40m, 20, 10m, 6m, 2m, 220 and 440 MHz Antenna: Cushcraft: A270 6S Beam 2m and 440 MHz: A430 11S Beam 440 MHz: Vertical Antenna Chart & Index:
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3 elements on 2m 5 elements on 70cm 144-148 mHz 440-450 mHz 9.5 dbi on 2m 11.15 dbi on 70cm 125 Watts 50 Ohm FB ratio more than 12db Boom length 44.5" Longest element 41.1" Connector N female Mast size 1.25" to 2" Weight 2 lbs Wind load less than 1 square ft Optional Accessories
Jan 13, 2012· Its vertical component is 3.2 x sin(25) or 3.2cos(75) 0 0 0. Login to reply the answers Post; Still have questions? Get your answers by asking now. Ask Question + 100. Join Yahoo Answers and get 100 points today. Join. Trending Questions. Trending Questions.
It is found that a 3/4 wavelength vertical element provides a good match, and therefore one solution for providing a good impedance match for the 5/8 wavelength vertical antenna is to make it appear as a 5/8 radiator but have the electrical length of a 3/4 element. In this way it radiates like a 5λ/8 radiator, but has the impedance of a 3λ/4 ...
Aug 05, 2018· Comet GP-15 Tri-Band VHF/UHF Base Vertical Antennas provide good gain figures on the 6-meter, 2-meter, and 70-centimeter bands in a compact 7.9 foot package. These superior-quality base station antennas feature a one-piece, heavy duty, UV-stabilized fiberglass radome for many years of reliable service Find Comet GP-15 Tri-Band VHF/UHF Base Vertical Antennas GP-15 and get Free …
Horizontal is only used (on 2m) for ssb/cw on the low end of the band, very little activity there (virtually none). You’ll lose a lot of signal if you run a 2 meter antenna horizontal. On HF it doesn’t matter so much but on 2-meters it does. Stay vertical if you wanna hear repeaters and such. 73, —kv5r
This is the ideal antenna for FM operation on 6 meter, 2 meter, and 70cm bands. Similar in construction to the X200A dualband, the V2000A has an additional counterpoise radial – adjustable for 6m (52-54 MHz only). With 6m activity, enjoy the freedom of 3 bands in one compact antenna. ...
The vertical wire was secured to the mast with nylon ties and run down to a point 12.41 feet/3.78 meters above the ground. The six radial wires were attached to their pvc posts. The 450-ohm feed line was attached to the base of the antenna (12.41 feet/3.78 meters above ground).
Jun 27, 2011· Total moment of inertia = MOI of rod about hinge + MOI of mass about hinge = ML²/3 + 2M(2L)² = ML²/3 + 8ML². Initial potential energy = (M + 2M)gL = 3MgL. Energy at the vertical position = (1/2)Iω² + Mg(L/2) (Because, 2M mass reaches the bottom while the Centre of mass of rod is still L/2 above the assumed zero potential)
Adrian PA0RDA and I once bought a bunch of glass fibre masts with a length of 12.5 meters to do experiments with vertical antennas. After a successful experiment with a 1/4 wave vertical for 40m we wanted to build a vertical for 20m too. The fibre masts are just tall enough to hold a 5/8 vertical for 20m, the idea of building a 5/8 was born.
Optimum number and length of radials for a vertical antenna on 80 meters (3.75 MHz) operating over very poor soil (conductivity = 0.001 Siemens/meter and relative permittivity = 5). Total Wire Optimum Number Optimum Length Peak Gain Length (ft) of Radials of Radials (ft) (dBi) 250 7 35.71 -3.48 500 11 45.45 -2.72 1000 17 58.82 -2.00