Power Attenuator for 6 watts 20 - 10 - 7 - 3 dB by PA1B |

**Power attenuator**is

**fast in CW QSO's**, because

7 dB and 3 dB can be switched instandly..

The attenuator is also very accurate.

The large resistors are resistors of 2 watts. The resistors with 2 stars (**) are resistor of 1/2 watt and the resistors with 1 star (*) are resistors of 1/4 watt.

I built my attenuator with

The schematic goes from

Please notice that the layout on the switches, inside the box goes from

So you will find the the resistors of 150 ohm and 330 omh to the

**Power Attenuator**

All attenuator sections are designed for an continuous input power of 6 watts. To reduce the number of resistors, I chose for

**asymmetrical**sections in the attenuator.
The power resistors, with a lower ohmic value, dissipate

**most of the power**and an other resistor is added in parallel, to arrive

**accurately**on the wanted ohmic value.

The power attenuator sections of 20 dB and 10 dB are build with 7 resistors, since they must dissipate

**much more power**than the other sections.The large resistors are resistors of 2 watts. The resistors with 2 stars (**) are resistor of 1/2 watt and the resistors with 1 star (*) are resistors of 1/4 watt.

I built my attenuator with

**metal film resistors**of 2 watts, 600 mW (*) and 400 mW (*)

**Schematic**

6 Watt
Power attenuator built with resistors of 2 watts, 1/2 watt and 1/4 watt by PA1BClick to enlarge |

The switches on the front. 20 - 10 - 7 - 3 dB |

**Reversed order**

**left to right**.

Please notice that the layout on the switches, inside the box goes from

**right to left**.

So you will find the the resistors of 150 ohm and 330 omh to the

**right**.

Notice the reverse order with respect to the schematic |

R2 and R5 are also placed |