Feed Point Preamp BOX

This is unique product for RX antennas. It combines universal transformer, preamplifier, simply Low Pass Filter, Bias Tee, front-end protection and common-mode output filter. The transformer allows you to set three ratios: 1:4, 1:9, 1:16. This alows the Feed Point Preamp to be connected to most RX antennas: Beverage (classic or BOG), RX loops like K9AY, DHDL, flag etc. The input is isolated from the coax ground.

There are many RX antennas (RX loop, K9AY, Flag, etc.) that have negative gain. Inserting a coaxial cable between the antenna and the amplifier can induce unwanted signals and further attenuate desirable ones - in addition to common-mode current problems. Therefore, in this device the signal is amplified immediately at the feed point of the antenna.

There is also the possibility to include a Low Pass Filter with a limitation below 11 MHz, between the transformer and the preamplifier, besides the RF limiter. Thanks to this filter, the preamplifier will not be bothered by nearby signals from the transmitter in the bands 20m and above.

The preamplifier has a maximum gain of about 18 dB. Behind it is a variable ATT, which allows you to control the overall gain as needed.

The preamplifier can be powered via coaxial cable (internal Bias Tee) using an external Bias Tee in hamshack or via a cable connected directly to the box via a gland.

There is common-mode choke at the output of the box. This provides additional isolation between the antenna and the coaxial output.

The Feed Point Preamp is sold in two variants: the preamp box alone (only preamp version) and then in a version with a universal terminator.

Universal Terminator is a small box designed to terminate RX antennas like beverages, K9AY and other loops. This terminator allows you to change the value in three ranges: typ. 900, 450, 230 and 320 Ohms with the possibility of adding +50 Ohms to each value. The terminator is designed for a continuous RF load of approximately 3 W. It includes current (power) overload protection as well as voltage protection using GD and Neon lamps at approximately 80V AC.