[hpsdr] ALEX - Call for comments - Protection devices.

[Dominik Bugmann]

What about the Elecraft K2 solution: R67 (1k5) and R68 (226R) against
ground.
Or in the KPA100: RF Choke of 100uH against ground.
 
In HB9 we run the "National Mountain Day" contest every July. 
It's a /p 80m CW event over 4h and max. 6 kg for the whole station (without
OP).
In 2002 a big thunderstorm with lightning crossed HB9 and damaged several
rigs. 
Surprisingly more transistors in the PA were damaged compared to the RX
frontend. 
The simplest solution found were: 50-100k against ground or 1-2.2 uH against
ground (It's 80m only).
 
73 de Dominik, HB9CZF 
 
PS: in case you read German I can scan 10 pages with many more details.
 
>A high value resistance to ground to prevent static buildup (100K to 1 
>Meg) in parallel with a spark gap offers no distortion and clamps 
>induced surges (not direct hits by lightning, of course).  Caps in the 
>front end filters should be rated somewhat higher than the spark gap - 
>you don't want to use 25V caps in a 70V-protected system!
> 
>Try searching Digikey for "surge arrestor gastube" for EPCOS' offerings. 
>  The lowest voltage ones ought to be suitable.
> 
>73,
> 
>Lyle KK7P

 

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