Helical Antenna - L-Band

General

Created this helical antenna for L-band and to detect  OH radiation from supernova CAS A. 
can be used on balcony without reflector. Antenna center frequency is 1665 MHz, bandwidth is around 1550–1780 MHz. Printed in sections of 4 turns for required gain and beam-width. 

N = 4, 8, 12, 16, 20 turns using the standard Kraus formulas  

Build

1. Print parts using colorless PLA (avoid pigment affecting Er and Loss) 
2. Add bolt and nut on bottom part
3. Glue together and align for foil path
4. Add foil
5. Add cable and connector 
6. Tune triangular transformer using VNA if necessary. 
7. Prime with some epoxy primer and paint with polyurethane paint. If epoxy it can take a week before full performance.
8. Mount using bolt and add LNA close to antenna. 
9. Optionally make a cover for antenna to not upset your surroundings. 

Bom

• 3D Printed:
  • Bottom Plate
  • Segments
  • Top hat
• Short coaxial cable
• 10mm copper tape for helix
• 50 mm copper tape for reflector
• Coaxial connector (SMA or N)
• Threaded rod M10
• Nut M10
• Primer (spray)
• White paint: water based polyurethane 
• Glue
• Isopropanol to clean surface

Tools

• Soldering iron
• Scalpel
• Scissors
• Brush for painting 
• Soft cloth to apply copper tape