[TowerTalk] Interference to CO Alarm

[Jim Lux]

At 12:28 PM 11/6/2006, you wrote:
>Hello All,
>
>I have an RF problem with my Kidde
>Carbon Monoxide Alarm.
>The alarm goes off when I am transmitting
>on 40 or 20 meters.
>
>Any suggestions as how to filter the alarm?

Is it AC or battery powered?

If the former, try ferrites around the power lines

If the latter, enclose it in a shielding enclosure (obviously, with 
holes in it so you have air flow, etc.)  Spraying the housing with 
conductive paint may be all that's needed.  The conductive enclosure 
needs to be all encompassing and with no conductors penetrating the 
shield wall (but holes are ok).

For a temporary test, try wrapping it in aluminum foil.

At 20 m, you can have a HUGE hole in the enclosure and still be 
fairly well shielded.

Jim Lux