Dear Alan,

I can hear, and copy, most of the signals on 136 with a 2.5KHz SSB filter,
................
carrier of DCF39 is only 60dB down, and I get a light trace of the signal

on

the waterfall display.

I have been "listening" to the NewZealanders on 181.4 Khz for a few months
now (is about 2500 km toVK) and find that Spectrogram is much happier if I
use my wide SSB filter. If I use my narrow CW filter it rings badly to the
everpresent QRN. This ringing is very visible on Spectrogram.

I am looking for a definitive article or text which explains which is the
best FILTER TYPE (shape, phase response, inpulse response, etc) to minimise
ringing from QRN. Can any body help please?

regards .............. Zim .............. VK3GJZ