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The Loop Antenna Amplifier ++ contains all the electronics needed for home DIY construction of an active loop (magnetic loop) low noise receiving antenna.

The amplifier consists of two units, a weatherproofed outdoor head unit for connection to a suitable loop and a bias tee unit to provide DC power up the coaxial cable to the outdoor unit. The head unit can also be used on it's own powered by the internal bias tee inside a SDRPlay receiver.

The outdoor unit is housed in a polycarbonate box with stainless steel antenna connections and a BNC socket. The bias tee unit is a PCB with two BNC connectors and a DC socket to take DC power from a battery or power supply.

Like our other active antenna products it has RF overload protection to allow it to be used very close to transmit antennas without damaging the amplifier or the attached receiver.

The loop depends on what the user has available. We have tested it with simple wire loops or deltas, coax loops and an alloy loop made from a bicycle wheel rim. We supply a 2.5m m (8 ft) length of wire as a simple loop to make a first loop for testing.

The Bias Tee unit is intended for use with a 12 V feed which allows the head unit amplifier to have a greater dynamic range than with the 5 V available from a SDRPlay receiver. The components in the internal bias tee inside a SDRPlay receiver limits the minimum frequency to 500 kHz. Using our bias tee unit allows the antenna amplifier to work over it's full range. This is ideal for fixed station operations with high quality loops and high performance base station receivers or transceivers.

Specifications:

Frequency range (Loop Antenna Amplifier ++ V4): 90 kHz to 55 MHz
Frequency range (Loop Antenna Amplifier ++ unfiltered): 50 kHz to 150 MHz
Frequency range (Loop Antenna Amplifier ++ NYLA HF only): 1.8 MHz 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 15V from a bias-tee feed via the coaxial cable

Supply current (head unit fed with 5 V from bias-tee ): 30 mA

Supply current (head unit fed with 13.8 V from bias-tee): 40 mA

Loop antenna outdoor unit connectors: Two M6 stainless steel threaded studs and BNC female (RF out 50 ohms)

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)

We can supply three versions of the Loop Antenna Amplifier ++. The first version is the V4 version of the amplifier is used in the HF Active Loop Antenna V4.

This has high and low pass filtering in the amplifier covering a frequency range of 90 kHz to 55 MHz. We recommend this amplifier for installations where the antenna is used for HF monitoring operating 24/7 unattended in all weathers.

This version is supplied as standard.

The second version is the unfiltered version.

This covers 50 kHz to 150 MHz.

The third version is the "NYLA HF only" version. This amplifier has high and low pass filtering in the amplifier covering a range of 1.8 MHz to 55 MHz.
One feature of this version is that the rejection of the VHF FM broadcast band is very high, typically over 70 dB.

It was originally designed for customers who live in New York and Los Angeles where megawatt class broadcast stations are line of site on high buildings or mountains.

The filtering allows HF reception in those conditions where HF receivers are overloaded by the strong VHF signals.

The NYLA HF only version is also suitable for applications such as Coastguard use where VHF transmitters are on the same site as the HF receiver.

Add a note with the order or send an eBay message to request the unfiltered or NYLA HF only version otherwise the standard V4 version will be shipped.