[Elecraft] KX3 - Roofing filters

[Don Wilhelm]

Pierre,

The roofing filters may not necessarily help with such strong signal 
rejection as you would have had with 2 KX3s transmitting simultaneously  
on different parts of the same band.

The usefulness of the roofing filters is to protect the receiver front 
end from normal level signals that are within the passband of the 
roofing filter, but not within the passband of the DSP filter. The 
result is AGC Pumping by the stronger signal which may not even be heard 
because the DSP filter cuts it out.

73,
Don W3FPR

On 7/23/2012 10:34 PM, Pierre wrote:
> Hello to all.
>
> Maybe that I don't understand the real utility of the roofing filter but I observed this. Last saturday, we were on a SOTA summit using two KX3s about 40 feet appart transmitting CW at 5 W. And even with  the roofing filters on, we heard each other's sending as a diffuse noise. I know that changion RX shift to 8 disable the roofing filters, but we were not using that shift.
>
> So, am I missing something about the use of these filters? Are they designed for operations with operators near each other like SOTA activation on a crowded summit ?
>
> 73, de VE2PID KX3 S/N 190
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