[Elecraft] KSB2 bandwidth - 1.9 kHz?

[Julian, G4ILO]

The KSB2 in K2 #392 has the original crystals, and therefore presumably the 
1.9KHz bandwidth (though I've never tried to measure it.) I have often 
received unsolicited reports of outstanding audio with it, and having 
monitored the audio on another receiver I would agree with that. It is 
clean, smooth, has plenty of punch with 3-1 compression, and is just what 
is needed for QRP operation. I have often considered that the K2 running 10 
watts on SSB has been as effective as previous radios I have owned which 
could run 100.

I don't really understand the use of the word "fidelity" in the context of 
amateur voice communications, nor why anyone would seek it. Surely the 
objective is for the guy at the other end to understand what you are 
saying? It seems to me that on a crowded, noisy band, and especially if you 
are running low power, that is best achieved by concentrating the power 
into the range of audio frequencies that carries the most intelligence, not 
wasting power on frequencies that will be heavily attenuated by the 
receiver's filter anyway.

Incidentally, I use a "Nissei" desk mic which is also sold under other 
brand names such as Alinco and Adonis. The audio is also excellent using a 
very solid Chinese made CB type fist mic, which suggests to me that the 
cost demanded for certain ham radio mics is a waste of money. The only mods 
I've done to the KSB2 are to increase gain (change a couple of resistors) 
and reduce IMD for PSK operation. So I think Elecraft got it pretty well 
right first time (though I wouldn't mind a bit more VOX sensitivity.)

73,
--
Julian, G4ILO. (RSGB, ARRL, G-QRP, K2 #392)
G4ILO's Shack: http://www.qsl.net/g4ilo

"Sverre Holm" <svholm2@broadpark.no> wrote:

I have seen recommendations for both the 2.2 and the 2.5 kHz bandwidths,
but so far no one seems to advocate the 1.9 kHz bandwidth - the one
which is closest to the original KSB2 design bandwidth. Is this a
correct observation? Is there too much punch and too little fidelity in
that bandwidth, even for QRP SSB?