70cm DISCOVERY LINEAR AMPLIFIER (with GS – 31) Operating Manual WiMo Antennen und Elektronik GmbH Am Gäxwald 14, D-76863 Herxheim Tel. (07276) 96680 FAX 6978 http://www.wimo.com e-mail: info@wimo.
INDEX 1. 2. 3. 4. 5. Specifications Introduction Installation Operating Controls Operation CAUTION There are dangerously high voltages inside the amplifier when the power is switched on. DO NOT remove the covers unless the power has been disconnected and sufficient time has elapsed for the capacitors to discharge. NOTE The 70cm Discovery is capable of a greater power than the CW rating shown in the specifications.
1. SPECIFICATIONS Function……………….The 70cm Discovery is a desk top linear RF amplifier with a nominal output of 800W covering the range 430-440MHz for amateur radio use. Type of emission…………………………………………………SSB/FM/CW/RTTY Dimensions………………………………….……14in wide x 9.75in high x 17in deep 360mm x 250mm x 430mm Weight……………………………………………………………………………..25kg Output power…………………………………...…………………….800W CW/SSB Gain……………………………………………...………………………11dB nominal Power requirements………………………………..
2. INTRODUCTION The 70cm Discovery is a high quality linear amplifier, which is designed around a GS 31 medium mu triode in grounded grid configuration. The amplifier is forced air cooled to give you the ability to operate at full output power for as long as you wish. The recommended maximum drive is 100Watts. The new model of the Discovery features a specially designed Triode control board by G3SEK.
3. INSTALLATION SETTING UP a) Unpack the amplifier and check that it is undamaged. The carton should also contain a power cable, operating manual, phono plug (for relay switching lead) and spare fuse. Please retain the packing and box should it be necessary to ship it or move it to another location. b) Ensure you have a reasonable airflow around the site you have chosen to install your amplifier. Do not enclose the cabinet or restrict the airflow in any way.
4. OPERATING CONTROLS FRONT PANEL CONTROLS ON/OFF SWITCH…………………………………………....Mains power on and off STBY/TX……………………………………….…………Amplifier standby / operate PLATE METER……………………..0 – 1.5A, monitors the plate current of the valve GRID METER…………………………...0 – 400mA, monitors the grid current which should not rise above 300mA GRID / RF OUT…………………..switches the grid meter to monitor relative RF O/P NB. On the 70cm Discovery there is no relative RF O/P, so the switch only operates in the GRID position.
REAR PANEL CIRCUIT BREAKER…………………………………………….10A, press to re-set MAINS……………………………………..IEC connector for mains cable, 230VAC TX………………………N – type connector, coaxial INPUT to amplifier from driver ANT…………………….N – type connector, coaxial OUTPUT to antenna through a suitable power meter PTT…………………………………….……Phono connector for relay switching lead WiMo Antennen und Elektronik GmbH Am Gäxwald 14, D-76863 Herxheim Tel. (07276) 96680 FAX 6978 http://www.wimo.com e-mail: info@wimo.
5. OPERATION SET-UP Connect all the cables as previously described in the manual, then double-check. When you are satisfied that everything is correct and the STBY/TX switch is on STBY, switch the amplifier on. The WAIT light should be on. After approximately 3 minutes the WAIT light should go out and the READY light should come on, indicating that the valve has warmed up and is ready for operation. Now put the STBY switch to TX, which puts it into the operate mode.
OPERATING PRECAUTIONS To ensure safe and reliable operation please regard the following precautions:HIGH VOLTAGES CAN BE LETHAL. Never try to operate your amplifier with the covers removed. If it is necessary to work inside the cabinet, always disconnect the Mains supply and allow the capacitors to discharge fully. Never operate the amplifier into a load or antenna with an SWR greater than 2 : 1. Always tune the amplifier for resonance using low drive at the operating frequency.
