The Link L3070/L3030 is a downconverter and filter combination used within Vislink (formerly Link Research) wireless camera systems, commonly associated with the L1500 series and similar broadcast setups. 

Key Components & Functionality
L3070 Downconverter: Designed to allow the remote placement of antennas from the receiver. It receives microwave signals (e.g., from an ENG antenna) and converts them down to a lower IF (Intermediate Frequency) for processing by the receiver.
L3030 Input Filter: Supplied as a filter unit to work alongside the downconverter, designed to select specific frequencies and reject out-of-band signals, preventing interference.
Application: These components are generally used in live broadcast and event production, enabling high-quality, long-distance transmission for cameras. 

NOTICE: These units are untested. There are also 2 antennas attached with part numbers L3520.

Location: 3J1

Quantity of 4. 2 antennas. 

Photo is for example but similar condition.