Info: Homebrew copper loop by DK3SS. Two turns; frequency is adjusted by varying the spacing between the turns.
Conductor: Copper tube 10mm.
Capacitor: Ceramic Disc Capacitors.
Environment: On a table in the middle of an attic apartment room, non-conductive building materials.
Thanks: Many thanks to Arno for answering my many questions by email.
| Band | 80m | 40m | 30m | |
| Frequency f | MHz | 3.650 | 7.100 | 10.100 |
| Intrinsic bandwidth Bint | kHz | 6.7 | 24.2 | 39.9 |
| Source of Bint | Q webpage | |||
| Loop diameter D | m | 0.860 | ||
| Conductor diameter d | m | 0.010 | ||
| Loop count n | 1 | 2 | ||
| Inductance L | H | 7.32e-06 | ||
| Capacitance C | pF | 26 | 68.6 | 33.9 |
| Unloaded Q0 | 1 | 545 | 293 | 253 |
| Damping resistance RT | Ohm | 0.308 | 1.115 | 1.836 |
| Radiation resistance RR | Ohm | 0.000925 | 0.0133 | 0.0544 |
| Loss resistance RLoss | Ohm | 0.307 | 1.101 | 1.782 |
| Power to antenna Pfwd | W | 10 | 10 | 10 |
| swr_min | 1 | 1.00 | 1.00 | 1.00 |
| etaSWR_ant | % | 100 | 100 | 100 |
| Power antenna load Pload | W | 10 | 10 | 10 |
| Antenna efficiency η | % | 0.300 | 1.19 | 2.96 |
| Loop current I rms | A | 5.70 | 3.00 | 2.33 |
| Loop voltage Uloop rms | V | 957 | 978 | 1084 |
| Magnetic dipole moment m | A m² | 6.619 | 3.480 | 2.711 |
| Link to calculator | calculator | calculator | calculator | |
The fixed capacitors are doorknob type. Important: there are different quality levels. For a magnetic loop, it is
important to choose low-loss types that are suitable for high frequencies.
The spacing between the turns is varied automatically, which tunes the frequency.
The coupling is adjusted via a variable tap on the gamma match.
Info: Homebrew copper loop by DK3SS. Two turns; frequency is adjusted by varying the spacing between the turns.
Conductor: Copper tube 10mm.
Capacitor: Ceramic Disc Capacitors.
Environment: On a table in the middle of an attic apartment room, non-conductive building materials.
Thanks: Many thanks to Arno for answering my many questions by email.
The bandwidth values used for the calculations were measured earlier by DK3SS and published on his website. It is unclear whether the measurements were made with or without a feedline cable.
This homebrew magnetic loop is a very nice DIY build.
The measured efficiency is not outstanding. This is probably also due to the indoor measurement environment, which attenuates the antenna.
The creativity seen in homebrew antennas is impressive. Anyone searching for DK3SS will find many contributions on the internet.
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.