Info: Rectangular loop, PVC pipe wrapped with aluminum foil. The frequency is tuned by sliding an aluminum-foil-covered tube back and forth in the upper segment.
Conductor: PVC pipe wrapped with aluminum foil.
Capacitor: Variable capacitor made from telescoping PVC pipes wrapped with aluminum foil.
Environment: Outdoor, details unknown.
Thanks: Many thanks to W6NBC (Silent Key) for the many publicly available contributions.
| Band | 40m | 10m | |
| Frequency f | MHz | 6.940 | 31.870 |
| Intrinsic bandwidth Bint | kHz | 200.0 | 700.0 |
| Source of Bint | SWR screenshot | ||
| Loop diameter D | m | 1.376 | |
| Conductor diameter d | m | 0.048 | |
| Loop count n | 1 | 1 | |
| Inductance L | H | 2.96e-06 | |
| Capacitance C | pF | 177 | 8.41 |
| Unloaded Q0 | 1 | 35 | 46 |
| Damping resistance RT | Ohm | 3.725 | 13.038 |
| Radiation resistance RR | Ohm | 0.0199 | 9.725 |
| Loss resistance RLoss | Ohm | 3.705 | 3.314 |
| Power to antenna Pfwd | W | 50 | 50 |
| swr_min | 1 | 2.70 | 1.10 |
| etaSWR_ant | % | 78.9 | 99.8 |
| Power antenna load Pload | W | 39 | 50 |
| Antenna efficiency η | % | 0.421 | 74.4 |
| Loop current I rms | A | 3.25 | 1.96 |
| Loop voltage Uloop rms | V | 421 | 1161 |
| Magnetic dipole moment m | A m² | 4.837 | 2.908 |
| Link to calculator | calculator | calculator | |
A video showed measured SWR versus frequency diagrams. I tried to estimate the corresponding bandwidths. This was reasonably possible for the 10 m band, but for the 40 m band it is only a rough estimate because the SWR was not tuned to 1.0, and from the measured values it is not clear whether the coupling is too strong or too weak.
Overview of all Antennas with filter/selection: compare page
Overview of all Antennas static: static compare page
2026 Peter Märki (HB9ISP). This project is created in my free time and has no commercial background. Provided without warranty of any kind. Feedback is welcome.