Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Adjustable Ground Plane Antenna

356 views

Published on

Ground Plane Antenna
Adjustable Ground Plane Antenna
144MHz - 174MHz VHF
by 4S6GGS

Published in: Engineering
  • Login to see the comments

Adjustable Ground Plane Antenna

  1. 1. 1 | P a g e 4s6ggs C Right
  2. 2. 2 | P a g e 4s6ggs C Right adjustable ground plane antenna designed primarily as a VHF base station antenna when a high gain antenna is not required or justified. As it is adjustable over the entire VHF high band 144 to 174MHZ The antenna is constructed of an aluminium mounting tube with the radiating element enclosed by a UV stabilis,piece design. The antenna is DC grounded for lightning protection and reduction of static noise. omnidirectional unity gain adjustable ground plane quarter wave radiating element with the radials acting as a counterpoise. Specifications  Impedance at resonance: 50 ohms  Resonant Frequency: 144-174 MHz (adjustable)  Frequency range with SWR below 1.1.5 MHz (adjustable)  Power handling capability: greater than 200 Watts  Radiation Polarity: vertical  Directionality: omnidirectional  Angle of maximum radiation: approximately 45 degrees from horizontal Materials  1120mm length of 38mm T2mm Aluminum pipe, cut to resonance 1Nos. Radiator  137mm length of 38mm T2mm Aluminum pipe, cut to resonance 1Nos Radiator  1131mm length of 19mm T 2mm Aluminum pipe, cut to resonance 2Nos Radials  38mm Aluminum pipe end cap 1 No’s  38mm I.D. compression pipe clamp 2 no’s for Radials  RG-8 or RG-213 50 ohm coax cable 980mm 1Nos feed point matching  RG-8 or RG-213 50 ohm coax cable 1500mm 1Nos feed point fat tx rx  PVC tube ID 38mm T 3mm L152mm insulator
  3. 3. 3 | P a g e 4s6ggs C Right Construction The antenna is constructed around a standard 38mm diameter aluminum radial elements have been attached with 19mm diameter elements The radiating element is fitted to coax center pin and positioned with two part coax matching Marine grade silicon to make to assembly water proof.
  4. 4. 4 | P a g e 4s6ggs C Right
  5. 5. 5 | P a g e 4s6ggs C Right
  6. 6. 6 | P a g e 4s6ggs C Right
  7. 7. 7 | P a g e 4s6ggs C Right
  8. 8. 8 | P a g e 4s6ggs C Right
  9. 9. 9 | P a g e 4s6ggs C Right
  10. 10. 10 | P a g e 4s6ggs C Right  RG-8 or RG-213 50 ohm coax cable 980mm 1Nos feed point matching  RG-8 or RG-213 50 ohm coax cable 1500mm 1Nos feed point fat tx rx Joint cox
  11. 11. 11 | P a g e 4s6ggs C Right The actual impedance of the antenna at its center feed point varies with frequency and antenna height. The transmission line is a balanced conductor pair with a 50-Ω impedance. Coax cable with a 50- Ω characteristic impedance (Zo) Coax is an unbalanced line since RF current will flow on the outside of the coax shield, creating some undesirable induced RF in nearby devices, although the antenna will work well enough. The best feed method is to use FEED POINT FOR TX /RX Cox center FEED POINT FOR TX /RX Cox Outer
  12. 12. 12 | P a g e 4s6ggs C Right
  13. 13. 13 | P a g e 4s6ggs C Right Feed for TX /RX Feed for Machine Machin Feed for TX /RX center Feed for TX /RX outer Feed for Mac outer Feed for Mac center Feed for Mac center
  14. 14. 14 | P a g e 4s6ggs C Right Feed for Mac center Feed for Mac center Feed for TX /RX center
  15. 15. 15 | P a g e 4s6ggs C Right
  16. 16. 16 | P a g e 4s6ggs C Right
  17. 17. 17 | P a g e 4s6ggs C Right

×