The -30+ loop antenna is a popular broadband antenna Perfect for shortwave listeners () and amateur radio amateurs (HAM) in urban balconies, rooftops, etc.This portable shortwave indoor loop antenna is a simple kit that includes all the necessary kits. Modular design, easy to install in limited spaces such as balconies and roofs.Excellent directivity can help you reduce noise and improve signal-to-noise ratio; you can simply change the orientation of the antenna to align the virtual point of the antenna with the interfering signal, thereby minimizing specific near-field interference for best results .Noise suppression is up to 30 dB compared to longline antennas. It can dig out weak signals that are overwhelmed by noise. The 8-shaped pattern provides deep virtual dots to further reduce interference.Do not connect to the transmitter as this will damage the preamplifier.Listening to shortwave radio is an exciting hobby, but for city dwellers, the experience is often disappointing. We could hardly receive any useful signal, even for more powerful radio stations. Signals hide in all the different types of interference. Why is this happening? Urban radio frequency interference (RFI) has increased dramatically, and all kinds of poorly designed electronic devices have been found in every corner of the city. Interference is generated by LCD , WiFi routers, poorly designed power adapters, WiFi extenders, EV chargers, etc., all of which combine to cause interference in the shortwave spectrum. If there is a suitable place to set up an outdoor long-line antenna, the situation may be different. But when living in an apartment or condo, there is no roof to set up a long wire antenna. That's when you need the -30+, a magnetic loop antenna for balcony setups.Small, compact, low profile and barely noticeableValid ra: 500kHz to 30MHzPowered via USB, super convenient. A feeder is included for easy setup.No manual adjustment requiredColour:As ShownMaterial:plasticPackage Contents:1 x Antenna amplifier1 x Stainless steel vibrator1 x Bias power supply1 x USB cable 0.8m(Random color, don't accept the specified color.)1 x 60cm SMA jumper2 x Stainless steel set screw1 x 3.5mm connectorOnly the above package content, other products are not included.Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.