Hi Lars.

Can I suggest:

1) A 47k resistor across the input of your converter. The static will have a very high impedance and I've found 47k will remove it without increasing the noise figure of your converter.

2) For really severe cases. An inductor to ground. An 0805 or smaller device. Something that presents a couple of k ohms at the frequency of interest would be OK. Or perhaps a high pass filter designed for 50 ohms with an inductor to ground. Cut off frequency at 30% lower than 23 or 13cms

Thanks

David

In a message dated 05/08/2009 05:11:17 GMT Standard Time, lars.petersen@pobox.com writes:

Hello AMSAT list,

I have a problem caused by static electricity building up on my two helix antennas (23 cm and 13 cm). Two converters have already been zapped, so I have to do something about it.

What measure would you recommend to avaoid statics building up on helix antennas?

Does anyone have experience using the shorted quarter-wave-stub mentioned in "The ARRL Handbook 2008" pages 23.20-21?

Vy 73, Lars Petersen, OZ1BXM, AMSAT-Member 36222, oz1bxm@pobox.com