[Elecraft] K3 Roofing filters

[Don Wilhelm]

Paul,

The roofing filters protect the A to D converter input from strong 
adjacent signals, so choose your CW filter according to your operating 
habits.  If you do CW contesting or DXing in pileup situations, you will 
want a narrow filter.

If you are using the K3 as an SWL receiver, you would want either the 13 
kHz or the 6 kHz roofing filter installed.  The DSP audio bandpass will 
go out to about 4 kHz, so if you want full fidelity, choose the 13 kHz 
filter for that - AM bandwidth is double the audio bandwidth.

The DSP width is displayed as the audio passband, the roofing filter is 
at the IF, so for AM double the audio bandwidth.

73,
Don W3FPR

On 10/10/2013 6:06 AM, Paul Barlow wrote:
> Dear Elecrafters,
>
> I've been using my K2 for a dozen years and I'm thinking I might go for a
> K3. I have a question about RX filtering I'd like to get straight. Is the
> widest bandwidth available to the receiver the width of the widest roofing
> filter? I was wondering about getting the general coverage receive filter
> board, but I wanted to know if I'd be as well to get the AM (6kHz) roofing
> filter as well - or could I dial out beyond the stock 2.7 kHz?
>
> My usual mode is CW, so I know I'd want a narrow filter to help with -
> although I realise that the DSP does the filtering, the xtal filters provide
> roofing.
>