Topband: Nasty QRM From ??

[Jim Brown]

On 1/24/2020 9:39 AM, Stephen Hawkins wrote:
> I have two new Chamberlain Garage Door openers that have cheap Chinese 
> switching supplies in them that use the wires to the switch at the 
> people door and the wires to the sensors at the bottom of the roll up 
> doors as antenna. Despite toroids and bypass caps they wipe out 160m.   
> When I know we are in for the evening I power them off at the circuit 
> breaker panel.

The better solution is to simply replace those nasty power supplies with 
old-fashioned LINEAR power supplies, cutting the cable for both the new 
and old power supplies and splicing the Linear supply to the cable going 
to the garage door openers. Details on my website, in the app note about 
building contest scores by killing receive noise.

73, Jim K9YC