[RFI] Is a low pass filter necessary?

Hardy Landskov n7rt at cox.net
Thu May 10 21:48:43 PDT 2012

I have a 22KW BC station about 5.5 miles away from me and it turns the K3 
into Hamburger until Sundown. I talked to N6KR at Visalia and he said I was 
in a minority of people having this problem and putting additional filtering 
on the front end would solve the problem. He is right but my FT1000D never 
did it nor did my FT990. I have looked at the interior and IMHO it's just 
poor grounding. So all that "buckshot" you might be hearing is not you 
towers but the best radio ever made, did not do their homework very 

---- Original Message ----- 
From: "Kim Elmore" <cw_de_n5op at sbcglobal.net>
To: <rfi at contesting.com>
Sent: Thursday, May 10, 2012 8:52 PM
Subject: Re: [RFI] Is a low pass filter necessary?

> Even though I know that modern rigs don't need one and that modern
> amplifiers don't need one and that VHF TV is dead as a door nail (or
> is that coffin nail?), I anachronistically use one. The insertion
> loss is negligible in my case and it does no harm. Besides, if anyone
> has the temerity to complain about RFI, I can point at it and say
> "See? I'm doing my part. Proper filtering. Nothing here is broken!"
> Kim N5OP
> At 10:41 PM 5/10/2012, John wrote:
>>I was on an antennas reflector recently asking about the proper placement
>>of a low pass filter and several members asked why am I using one at all.
>>They said with the modern radios (I have an Icom 706 original) a low pass
>>filter really isn't necessary, that most modern rigs already contain one
>>and the spurrious emissions are already greatly reduced. So, what is the
>>opinion of list members-with a modern rig, does having a low pass filter 
>>line really help to solve any additional problems?
>>John AF5CC
>>RFI mailing list
>>RFI at contesting.com
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