Upgrade ! your Watkins Johnson Receiver

(A4) Pre-selectors suitable for WJ-8711 & WJ-8712 Series Receivers

The A6A2 (A4) Sub-octave Pre-selector option filters unwanted out-of-band signal energy from the RF signal that is applied to the WJ-8711/12 Digital HF Receiver. The A6A2 (A4) option uses eleven pre-selector filter bands to improve second and third order intercept performance helping to eliminate unwanted intermodulation products. The WJ-8711/12 series receiver digitally selects the required pre-selector filter based on the receiver's tuned frequency. The A6A2 (A4) Pre-selector also features two RF overvoltage protection circuits. An overvoltage relay circuit disconnecting any input greater than 1 Watt and a GDT device that will ground away any signal greater than 75V. Power sensing at the Pre-selector RF Input protects the receiver from unwanted high level RF signals and stops any damage to the receiver.

EPROM A2U12 contains the internal control software necessary for the WJ-8711/12 series receivers to use the A6A2 (A4) Pre-selector. WJ-8711/12 A2U12 software releases earlier than 1.4.0. (do not support Pre-selector operation) and new software will have to be installed.

11 RF filters are digitally selected in line with the tuned frequency being used. During normal usage the Sub-octave Pre-selector continually monitors the RF input for an overload condition. If an overload condition occurs then the RF signal will be disconnected, grounded to earth and an Overload message will be displayed in the “Memory / Scan” LED front panel. To reset you have to press the clear button. The A6A2 (A4) Sub-octave Pre-selector offers an in circuit insertion loss of less than 2.7dB.

Each A6A2 (A4) Sub-octave Pre-selector unit is "brand new" and hand assembled . I offer a money back guarantee if not delighted with the product or performance.

Contact: sales@a6a2.co.uk

A6A2 (A4) Sub-octave Pre-selector Performance Test details:

Upgrade your receiver with essential RF protection and the elimination of unwanted RF signal energy.

For pricing and availability please contact:
sales@A6A2.co.uk

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