Well,
You defenitely need those filters in the K3.
When signals are strong and the band is busy, signals coming through the
roofing filter (line S9+20dB) is said to pump the hardware AGC, even if
you have the DSP filtering set to a small BW. Anyway, you can certainly
hear that.
Try it on CW, on 40m in the evening when there's a contest. You'll love
the 400Hz roofing filter.
73
Arie PA3A
Al Lorona schreef op 11-5-2014 23:03:
What determines the bandwidth you hear at the loudspeaker? It's not your
roofing filter, despite a continuing notion that it is.
Dave Hachadorian's point in a post a few weeks ago was that you don't need a 1.8 kHz filter to get a 1.8 kHz bandwidth. You're free to set whatever bandwidth you want with any filter.
Before rigs had DSP we got used to the idea that your crystal filter sets your
bandwidth. That's not true any more. It sets your *maximum* bandwidth. You then
have the freedom to narrow and position a bandwidth arbitrarily using the DSP
controls [SHIFT and WIDTH or HI and LO].
Here's a true-false quiz:
1. I'm a contester, so I need a 1.8 kHz roofing filter in the K3.
2. I should purchase the 400 Hz filter if I like to operate CW with bandwidths of 300 - 400 Hz.
3. For SSB, the 2.7 and 2.8 kHz filters are 'too wide'.
4. I have the 2.7 kHz filter installed, so for best results I should set my WIDTH control for a passband of 2.7 kHz.
5. I can use my 2.7 kHz filter in CW mode with my LO=0.30 and HI=0.50 (that is, BW=0.20).
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