Airspy Youloop Indoor HF Antenna

This simple, lightweight travel loop is quick to deploy and the perfect companion for Airspy and similar SDR radios!

Most of the problems were related to ineffective RX antennas that were too sensitive to the surrounding noise. So we decided to design a new Noise Cancelling Passive Loop (NCPL) to fix the noise problem.

The YouLoop is a generalization of the Möbius loop where a balanced electric shield is used as the centre of a multi-turn loop. The rest of the turns run inside the shield. To preserve this electric balance from alteration by the transmission line, a low loss miniature BALUN is used.

The more turns, the higher gain at the lower frequencies. Note that to preserve the electric balance, the number of turns increases by increments of two.

An aspect of this two-turns coax build is its response in VHF. The same HF magnetic loop can be used in the FM and the 2m HAM bands with a slight change of its core principle, it’s now a folded dipole. The feed point of the folded dipole is on the top and the actual legs are composed of the coax ground.

In order to further improve the impedance matching and flatten the frequency response, a high impedance external pre-amplifier can be used near the antenna to present a constant output impedance to the receiver.

This could be the best option for you if you do not want or cannot build the antenna from scratch. AS the only remaining action is to connect the SMA cables.

Specification

• HF Response: 10kHz to 30 MHz
• VHF Response: up to 300 MHz
• Maximum Power: 250 mW
• No Tuning required
• Low-Loss Wide-Band BALUN with 0.28 dB loss typ.
• Dimensions: H-31cm x W-24cm x L-17cm
• Weight: 0.5kg