> AM audio much more understandable (pleasant) on the FM filter, the extra 1 > KHz helps. >
To those who feel that AM reception with the 6 kHz filter is not very understandable: I had that same impression the first day or so after assembling my K3. Then I discovered that, with my small hi-fi speakers, excessive bass was the culprit. It appears that broadcast AM transmissions are balanced to sound pleasant with a wider receiver passband. The 6 kHz filter removes some highs, so to restore balance some of the lows need to be cut. This was easily achieved with the K3's receive equalizer. Of course, if you are using a speaker designed for communications, this is not likely to be needed. Anyway with the equalizer cutting off frequencies below 200 Hz or so, and some attenuation at 400 Hz, I found AM receive quality on voice to leave little room for improvement, and better than good SSB (assuming no ESSB). For music the FM filter would be a significant improvement of course, but when I listen to SW broadcasts, music is not generally what I am looking for, so I haven't been able to justify a 13 kHz filter. Incidentally, I find a similar situation with the surround sound system in my living room. When the tuner is set to AM, I need to adjust controls to cut some bass, probably because the manufacturer takes pride in a deep bass response. The car radio and small portable radios don't seem to have that problem, perhaps because the manufacturers expect the products to be actually used for AM, and of course in many cases less bass means lower cost of manufacturing. 73, Erik K7TV ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
