How to make a magnetic loop antenna

This antenna has 70cm diameters loop which is aluminum board of 5cm width × 0.3mm thickness and guide of 2mmφ aluminam line

This anetnna has 70cm diameter element with 150PF paralled with 10PF VC and coxial condencer for 40m band, which works on 7MHz to 28MHz band.

Small loop for impedance matching is on the top of antenna and VC for adjusting frequency is on the bottom of antenna.

This antenna have 3 VCs and coxial condencer which is on 40m band. Only 30PF VC is adjust frquency on 18MHz to 24MHz Just 10PF VC is for 28MHz band

Please pay attention strongly!! It is very important to prevent shock of RF voltage which is very dangerous for people especialy kids even 5W output.

Each parts

2mmφaluminum line for guide of aluminum element    0.3mm thickness aluminum element    Complete magnetic loop antenna

150pVC and case  coxial condencer for  7MHz band Parts of antenna  before package

Complete loop antenna with guide of aluminum line in the antenna element and small loop for impedance matching (up)

Loop antenna and YS33 bike with DC moter at Chihaya-akasaka village   HT-750 tranceiver with small key and PC

HT-750 has 3W output power and 3 bands (7/21/50MHz bands) made by Tokyo hypower.     HT-750 is one of vintage QRP tranceiver which is very nice and light weight    HT-750 has 3W output power and 3 bands (7/21/50MHz bands) made by Tokyo hypower.   .

Result

This antenna has less noise than dipole antenna. But this is very critical to adjust frequency and almost spot frequency operatin. It will takes about 1 hour to complete antenna system and disassemble. This antenna is very inconvenience without remote control system.