Two things conspired to cause trouble with early K2 SSB. Steve touched on one of them about variations in crystals.
The original K2 SSB filter was purposely designed to be as narrow as possible to give the signal more "punch", especially for weak-signal/QRP operation. The narrower the bandwidth of a signal at a given power, the louder it sounds at the receiving end. So the SSB filter was designed to be just a tad over 2 kHz. That's about the minimum for good "communications quality" SSB. As Steve, W2MY observed, the variations in crystals from the manufacture meant there was a wide variation in SSB filter bandwidth. For example, mine was barely 1800 Hz wide at 6 dB down! There was no way I could get good-sounding SSB out of it. Several years ago Elecraft changed the filter design for a wider bandwidth *and* employed more consistent crystals in the kit so there was less variation from rig to rig. That seemed to put an end to all issues with the filter. When I put new crystals into the filter, I opted for the wide bandwidth mod since my use of SSB is very casual anyway. That fixed the audio quality problem. As Don pointed out, it is true that the K2 requires a fairly high output microphone. That's especially true on 10 meters where the transmitter has the least overall gain, so low audio will show up as less-than-full output if you're trying to run the full 10 watts PEP with a QRP K2 or 100 watts PEP with a K2/100. Ron AC7AC _______________________________________________ Elecraft mailing list Post to: [email protected] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
