Product Details:
This is the big brother of the SR-640 tuner listed below. They are functionally similar although this unit has more on-board status indicators and controls.

Factory rated at 1000 watts continuous, this unit can probably handle much more under minor mis-match conditions. This is the largest automated fixed channel antenna matching unit SRS produced.

This programmable, broad-banded full range HF tuner is a series inductance, shunt capacitance T network. It begins with a 200 watt / 1000 watt forward and reflected power meter followed by a motor-driven Johnson 229-203 0.1 to 28 µH series roller inductor. Next in line is a selectable bank of shunt capacitor values from 18 to 2090 pF in 15 pF steps. This is followed by a pair of motor-driven 0.1 to 28 µH roller inductors. To aid in low frequency operation there is a giant 0.1 to 84 µH motor-driven rotary inductor which may be set to include a pre-set inductance, the entire inductor or removed from the signal path. Last in line is an RF voltage sensor which controls onboard 6 kv and 7.5 kv warning lights. A 7.5 kv voltage at the output is considered a fault condition since as there is a 7.5 kV spark gap at the output connector. This voltage level is also considered the maximum allowable voltage in the unit before internal arcing can occur.

The recommended 200 watt tune up signal can be reduced by using a lower range relected power meter on the input. Initial matching settings are easily accomplished by following the step by step instructions printed on the inside of the cover. The manual for the unit includes preliminary settings for 25 foot, 32 foot, 35 foot and 80 foot vertical antennas as well as 75 foot and 150 foot longwire antennas. The final settings can be recorded on the inside cover for future reference.

This unit is designed to operate with any number of the Scientific Radio Systems transceiver/amplifier combinations. It can readily be adapted to other units by use of a simple 1 of 10 grounding switch for band selection. Also available is a key-inhibit signal which shuts down the transmitter when capacitors are being selected during initial setup and when the unit is changing bands/channels. Also available is a 'status' line which is used to key the transmitter when in the tune mode. A 19 conductor cable is required to fully utilize all external lines/signals available as well as power to the unit. Eleven conductors plus AC power is all that is required if optional signals are not untilized. The unit requires 115 / 230 vac power.

All this is contained in a 20" x 24" x 9-1/2" aluminum enclosure with hinged, weather-proof lid. Four mounting tabs on the back of the enclosure facilitate mounting. Provision for a padlock is included. Power and control signals are applied via 19 pin MS3102 connector (mating cable-end connector provided). AC power may be supplied via separate cable through its own entrance. RF in is via an N female connector and the output is on a 2-1/2" ceramic feed-thru on the top. Setup / troubleshooting / operating manual included with full schematics and parts lists. Weight 50 lbs.