The 6m Discovery Amplifier.
Since the UK power restrictions were lifted on six metres last year, anyone who wanted to achieve power levels approaching the 400w PEP limit, had little scope for choice. Tokyo produce an amplifier using a pair of 4CX240B's for around £999 which delivers 400/500w output. The Henry 2006 using a 3CX800A7 and capable of 1000w can be ordered from Stateside but will set you back around £1600 with the present $/£ exchange rate, import taxes and 17.5% VAT.
More recently a new Company has appeared on the scene from the UK, namely Linear AMP-UK established by Peter Rodmell Communications. Most of you will be familiar with their HF range of amplifiers, the HUNTER and EXPLORER (formally marketed as Heatherlite products). Recently added to the range is the 6m DISCOVERY.The 6m DISCOVERY is designed around an Eimac 3CX800A7 high mu triode in the grounded grid configuration, using a Pi L network to give maximum harmonic rejection. The amplifier is fan cooled with an Airflow 33 BTFL fan which is quiet and very efficient. The 3CX800A7 must be allowed to properly warm up before operation, hence the fitting of a 3 minute start up timer, to protect the valve cathode. Once this is activated the ready LED will come on allowing PTT operation.
The fully protected power supply incorporates an ILP toroidal transformer which has been successfully used in the HUNTER amplifier for the past 5 years without one single failure. A voltage-doubler power supply board supplies 2300 volts. The toroidal also supplies the heater voltage of 13.8V at 3 Amps as well as the control voltage of 12 volts used for pulling in the Tx/Rx relay.
Full metering of Plate input and Grid current is provided on the front panel along with LED status lights to give present Tx/Rx mode.
400w output can be obtained with around 10w drive. Grid current runs at less than 10mA under these conditions and the resulting signal is very clean and low on inter-modulation. A maximum drive level of about 35 watts results in full power output of 900+ watts. Under these conditions grid current (after careful tuning) can be held at around 35mA. Take the grid current past 60mA and you will soon be looking for a new tube!
Linear Amp-UK can supply the amplifier with a top quality Japanese coaxial relay using N-type connectors, instead of a plug-in relay. After testing both versions, we would advise those interested in EME and weak signal working to order the coaxial relay.
To sum up, the 6m DISCOVERY is a no compromise design, good value for money amplifier using quality components. The added fact that it is British built and designed by a team who can provide friendly advice and full service back-up gives it a high recommendation.
|Power: 800 watts with 25 watts of drive||Max o/p: 1 kW with 35 watts of drive|
|Input:1500 watts input DC at 25 watt drive||Supply:
220 - 240 V AC (110V available)
50 - 60Hz @ 8 Amps
Further details. current prices, and delivery times can be obtained from:
Tel: (44) 1964 550921
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