I would replace the 2.7 with the 2.8, keep the 400 and be done with it. I did.
The purpose of the "roofing filters" (I hate that term) is to protect the 2nd mixer from overload. The wider filter is used on TX as well and the 2.8 has superior symmetry which helps opposite sideband rejection.
Most of the garbage you will hear, particularly on SSB is from the lousy phase noise and TX IMD (K3s include here) from adjacent signals falling in your RX passband. No amount of filtering on your end will fix this.
Wes N7WS On 3/8/2018 9:22 AM, Chuck Chandler wrote:
Right now I have the stock SSB and a 400 Hz filter in both main and sub rcvrs. I would like to add some a few at a time. My first priority is to add a couple to the main receiver, since it is the biggest chore to get to. I plan on a 250 Hz CW filter, but am going back and forth between the 2.1 and 1.8 kHz filters. I know that narrowing the DSP to 1.8 gives a really difficult to understand voice signal, while the 2.1 allows in more adjacent signals. However, the roofing filters may not behave in the same manner. For example, the 1.8 could be set to turn on at 2.1 to take advantage of skirt shape. I primarily DX, and operate in some contests as well. I know SSB contests really need a narrow SSB filter. Any suggestions on the matter from those who have gone this route before? 73 de Chuck, WS1L
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