Loop on Ground Antenna for RX
The Loop on Ground (LoG), popularized by KK5JY, is an exceptional receive-only antenna for the lower HF bands (particularly 160m, 80m, and 40m). It seems counterintuitive to lay an antenna directly in the dirt, but its location is exactly why it works so well. Please note that it is no good for TX. What I have noted here on 80m and 160m is that the noise is very high with my usual antennas. Net control right from my city is able to hear me 5,7 on 80m morning net while I am unable to copy the net control!
The Magic of the Dirt
By placing the wire flat on the ground, the earth absorbs a massive amount of signal energy, making it a very “lossy” antenna. However, the ground attenuates local electrostatic noise and man-made QRM much faster than it attenuates incoming skywave signals.
Your absolute signal level will drop significantly, but the Signal-to-Noise Ratio (SNR) skyrockets. It frequently pulls highly readable signals out of what sounds like a completely unusable noise floor on a standard dipole or vertical.
Construction Breakdown
Building a LoG is a highly rewarding, fast project. Resonance does not matter here — the antenna is intentionally broadband.
| Component | Specification |
| Wire | 60 feet total, any insulated hookup wire. |
| Layout | 15 x 15 foot square, staked flat to the earth. |
| Transformer | Galvanically isolated, wound on a #73 binocular core. |
| Feedline | 50Ω or 75Ω coax, run flush with the ground. |
The Feedpoint
The antenna is fed at one corner. You cannot connect the coax directly, and you should not use a standard autotransformer (unun). You need a galvanically isolated transformer to completely decouple the coax shield from the antenna wire. If you don’t isolate them, your feedline simply becomes a noisy ground radial, defeating the entire purpose of the loop.
- Core: A Fair-Rite #73 material binocular core (like a BN-73-202) is ideal for 160m–30m operation.
- Turns: Typically 5 turns on the antenna side and 2 turns on the coax side.
Preamplification
Because the LoG delivers such low voltage to the feedline, you will need to engage your transceiver’s internal preamplifier. If you are feeding this into a direct-sampling SDR or a homebrew receiver block, adding a clean, low-noise outboard preamp right after the antenna’s transformer can help overcome the coax loss on the run back to the shack.
Directivity
While largely omnidirectional, a 15×15 foot LoG does exhibit two broad main lobes pointing off the sides (broadside to the feedpoint), with slight nulls off the front and back corners. VU24DX mentioned that he is using a loop on ground by KK5JY design with good low noise RX. I am on the look out for a space and components to try it out!