WiMo GS-31 Operating Manual

6m DISCOVERY

LINEAR AMPLIFIER

(GS – 31)

Operating Manual

WiMo Antennen und Elektronik GmbH

Am Gäxwald 14, D-76863 Herxheim Tel. [phone] FAX 6978

http://www.wimo.com e-mail: [e-mail]

INDEX

1. Specifications

2. Introduction

3. Installation

4. Operating Controls

5. 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 6m Discovery is capable of a greater power than the CW rating shown in the
specifications. In order to achieve the stated PEP output, the amplifier must be
capable of operating CW at the same level for short periods. Do not try to operate the
amplifier at greater than the recommended level.

If the amplifier is operated for long periods at levels greater than the recommended
ones, then damage may occur. This applies particularly to the GS 31 valve, so great
care should be taken not to exceed 1Amp plate current or to drive with more than
100W continuous wave drive. Also, care should be taken not to exceed 1.5 : 1 SWR.

WiMo Antennen und Elektronik GmbH

Am Gäxwald 14, D-76863 Herxheim Tel. [phone] FAX 6978

http://www.wimo.com e-mail: [e-mail]

(1)

1. SPECIFICATIONS

Function………………….The 6m Discovery is a desk top linear RF amplifier with a

nominal output of 1000W covering the range 50 – 54MHz 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…………………………………...…………………….1000W CW/SSB

Gain……………………………………………...………………………12dB nominal

Power requirements………………………………..………230V AC at 15A, 50/60Hz

Duty cycle………………………………………Full O/P with normal amateur service

Cooling………………………………..……………………….……Forced air cooling

Frequency coverage………………………..……………………………..50 – 54 MHz

Input impedance……………………………..…………50 Ohms with tuned I/P circuit

Valve……………………………………….………………………single GS 31 triode

Harmonics………………………………….…………3rd harmonic: better than –45dB

Plate voltage……………………………………..……………………SSB: 2800V DC

Cabinet……………………….……………chassis – Zintec steel, covers – aluminium

RF compartment – aluchromed aluminium

Antenna relay…………24VDC antenna relays automatically transfer the driver to the

antenna when in STBY or OFF. Standard in-built are coaxial
O/P relay and short throw I/P relay.
The amplifier requires a relay contact in the driver to key the
amplifier.

Metering………………………… ……………Plate current, Grid current and RF O/P

Protection………………………… …………..All power circuits protected by fuses

Grid protection circuit

(2)

2. INTRODUCTION

The 6m Discovery is a high quality linear amplifier which is designed around a GS 31
medium mu triode in grounded grid configuration. The amplifier uses a Pi – L
network in the output circuit and a tuned input circuit. 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 GS 31 must be allowed to warm up properly hence a 2 min. start up timer is
fitted. When the amplifier is switched on, the WAIT light will come on. After the time
has elapsed the WAIT light will go out allowing you to operate the PTT.
It is recommended that you use a Bird (or equivalent) power meter capable of
measuring 1500W at the correct frequency.
Please read the instructions carefully before operating the equipment. RF amplifiers at
this power level and frequency can be easily damaged by improper use. Please follow
the precautions on page 1 of this manual.

The Discovery is fully self-contained and has three separate voltages:-

1. HIGH VOLTAGE which is 2800V, the main voltage applied to the valve

anode.

2. HEATER SUPPLY which is 13V at 3A.

3. CONTROL VOLTAGE which is 12V used for the LED control condition

of the amplifier, 24V for pulling in the Tx/Rx relays.