dummy load to attenuator mod #dummyload


KEN G4APB
 

Hi all,
I have come up with a simple addition to the QRPLabs dummy load that turns it into a 26dB attenuator. It only requires the addition of a 56ohm resistor and a bnc connector.
This can provide a very useful protection between the QCX-mini and a signal generator when testing. I have managed several times to accidentally get it transmitting a message at full 5 watts into my sig gen while actually attempting to change the receiver frequency.
I have used 18x1k resistors instead of 20 to maintain the 50 ohm match at both ends. this gives a resistive source and load of 55.55ohms. Two of the 1k resistors are paralleled to give 500 ohms series R. The Pi network created gives 26dG attenuation.

Careful use of unused pads has been used to create a neat package. See my photos.

73 Ken G4APB

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