After 2 weeks of testing the Hairpin antenna for 40 m band (the light model with Cu wires), it’s time to build the regular prototype with Al tubes. But, first off all, let’s play with MMANA- GAL to see what are the limits.
The main differences between classic Hairpin antenna and this model are:
- The antenna is mounted on a metalic grounded mast.
- The spacing between arms is larger to obtain a wider antenna
Now, let’s play with parameters.
- Spacing
Aluminium tube diameter = 24 mm
Hairpin length = 3 meters
Height from the ground = 4 meters
Ground setup = 14 / 5
Q capacitors = 500
R =50 ohms (+/- 1)
jX = -1 /+1 ohms
Higher spacer, better gain and Bw
2. Aluminium tube diameter
Spacing = 24 cm
Height from the ground = 4 meters
Hairpin length = 3 meters
Ground setup = 14 / 5
Q capacitors = 500
R =50 ohms (+/- 1)
jX = -1 /+1 ohms
Higher tubes diameter, better gain and Bw
3. Q capacitor
Spacing = 24 cm
Height from the ground = 4 meters
Hairpin length = 3 meters
Ground setup = 14 / 5
Aluminium tube diameter = 24 mm
R =50 ohms (+/- 1)
jX = -1 /+1 ohms
Vacuum capacitor (High Q), high gain but narrow Bw
Regular air capacitors, lower gain but wider Bw
4. Height from the ground (grounded mast length)
Spacing = 24 cm
Q cap = 200
Hairpin length = 3 meters
Ground setup = 14 / 5
Aluminium tube diameter = 24 mm
R =50 ohms (+/- 1)
jX = -1 /+1 ohms
More height, more gain and Bw
5. Hairpin length
Spacing = 24 cm
Q cap = 200
Ground setup = 14 / 5
Aluminium tube diameter = 24 mm
R =50 ohms (+/- 1)
jX = -1 /+1 ohms
Height = 4 meters
Too short, less gain. Too long, you can not tune the antenna (value of Cv1 will drop to parasitic capacity, or to zero)