[RFI] Cordless Phone

Jim Brown jim at audiosystemsgroup.com
Mon Dec 6 18:56:39 PST 2010


On 12/6/2010 5:01 PM, rick darwicki wrote:
> Before I try more/different ferrite, is there anything I should do to the handset or phone base?

Hi Rick,

It isn't clear whether the phone is having problems or is generating RFI.

Your choke is tuned for the lower HF bands, and seems to be working well 
there. What you need is one or more chokes tuned to 10M. Usthe measured 
data for various chokes in http://audiosystemsgroup.com/RFI-Ham.pdf   as 
a guide. Something like 3-4 turns through a typical clamp-on should be 
about right for 10M. You may need several of them  in series to get a 
high enough impedance. Put these chokes closer to the phone than the 
bigger choke.  #43 material is fine for 10M.

73, Jim K9YC



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