Re: Determining best roofing filter with DSP??

Posted by Bob - W0GI on Feb 25, 2010; 12:00am
URL: http://elecraft.85.s1.nabble.com/Determining-best-roofing-filter-with-DSP-tp4629030p4629479.html

I ordered mine with a 250Hz 8-pole, and with it punched in, close signals disappear. That said, I will probably add a 1500Hz and 500Hz later on.

Now that I have played with the DSP, I am thinking that either a 500Hz or 400Hz is plenty good enough, as the roofing filter protects the DSP from close signals, but it will still go down to 50Hz brick wall with the DSP.

I really can't say what my preference will be, until I try them. The K3's use of roofing filters is much different the the Mark-V, where I have a 500 on the 455kHz IF, and a pair of 250's on both the 8.2mHz IF and the 455kHz IF. Even then my K3 just blows the Mark-V away blocking close signals.

I have a feeling that the K3 with the 500Hz 5-pole filter performs better then just about any other receiver.

Good luck, as you may have to flip a coin. :>)

73, Bob