Cross Country Wireless manufacture a HF Active Loop Antenna with a frequency range of 90 kHz to 55 MHz.
The antenna can be used for all LW, MW and HF professional monitoring and short wave listening. It can be mounted vertically for bi-directional high angle NVIS reception or horizontally for low angle omnidirectional operation.
The antenna uses a double loop 350 mm or 14" diameter with a variant of our Loop Antenna Amplifier ++ with tight RF filtering to avoid overload of SDR receivers by signals outside the wanted long and medium wave and HF bands.
Careful design of the antenna has isolated the antenna loop from the amplifier so that it has minimal electric field pickup from the loop element. This allows the antenna to work as a true magnetic loop antenna with very deep nulls for interference rejection. It also reduces RF noise when used indoors. A common mode choke on the amplifier output also attenuates RF noise travelling up the coax cable to the antenna.
The antenna has a polycarbonate box housing the amplifier with antenna loops made from heavy coaxial cable with transparent polycarbonate spacers. An aluminium bracket allows the antenna to be mounted either vertically or horizontally to a supporting vertical mast or horizontal rail. The design of the bracket allows it to be used in horizontal mode mounted to a balcony rail on high rise buildings but we would recommend adding an additional safety restraint when used at height. The bracket can also be used to allow the antenna to be placed on a table top for casual short wave listening.
The antenna is ideal for portable operation from temporary listening sites with compact storage and easy installation in areas with restricted access.
A BNC female connector are used for the RF output port on the base unit. RF over-power protection on the antenna and the RF output allow the antenna to be used very close (>2m) to transmit antennas without damage. The antenna could be mounted on top of a rotatable HF beam as a low noise diversity reception antenna.
We can also supply this loop antenna with a HF Multicoupler with a bias tee built in to power the antenna. This provides 5 RF outputs for multiple receiver monitoring.
Specifications:
Loop diameter: 350 mm or 14"
Frequency range: 90 kHz to 55 MHz
Output impedance: 50 ohms
OIP2: >+70 dBm
OIP3: >+32.5 dBm
Gain (head and base units Loop Antenna Amplifier ++): 25 dB at 14 MHz
Noise figure: 0.79 dB
Supply voltage (head unit): 4.5 to 15 V from a bias-tee feed via the coaxial cable
Supply current (head unit fed with 13.8 V from bias-tee): 40 mA
Loop antenna outdoor unit connectors: BNC female (RF out 50 ohms and DC power input)
Loop antenna amplifier bias tee board connections: BNC female (RF input and DC feed to outdoor unit), BNC female (RF output to receiver), DC connector (for 4.5 to 15 V DC power input)