Tony, I do not have any real experience with weak signal VHF work, but I do have some comments about the K2 on a technical basis that may help in your decisions.
I would be interested to know what the filter width was in use that generated those comments as well as the serial number of the K2 that was being used for that evaluation. Some of those deficiencies have been addressed and corrected along the K2's migration progress. The facts as I know them - the K2 SSB filter has very little ripple in the passband. The filter crystal specs (for all the IF crystals) were improved between Elecraft and the crystal vendor and the improved crystals have been in K2s since SN 2560. Secondly, the variable width (CW) filter on the RF board presents a smooth single-nosed passband if the filter width is set to 1000 Hz or less. Wider passbands do tend to break up into multiple peaks which may be troublesome to some applications, but that is the downside to attemting to use a filter designed for best response in the 400 to 600 Hz width range at a very wide setting - it works OK for SSB voice reception, but it certainly is not an optimum filter shape. Yes, the K2 is limited to 10 Hz steps - that is just part of the design compromises that were deemed acceptable Even RIT does not circumvent this limitation - the firmware controls the steps and RIT works through the firmware. For Satellite work, several folks have previously commented that the biggest downside for the K2 is the fact that the frequency cannot be changed while transmitting. That may not be a factor in many situations but where the transmit frequency must be changed to compensate for doppler, all I can say is that the K2 was not designed to do that task. Maybe the K3 or K? (if it ever gets into the product plan) will address that problem. The 28 MHz bandpass is broader than the others, and could possibly be improved if designed for a more narrow passband, but for HF use, that bandpass filter must be rather wide - as it is now on the K2, the speced 10 meter band is 28.0 to 28.8 MHz rather than going up to 29.7, so some compromises have already been put in place. The one nice thing about the K2 is that it can be changed to better meet the needs of a particular group of folks if desired - the network is nothing more than a double tuned bandpass filter, and the filter components can be altered for a more narrow peak if that is desirable. 73, Don W3FPR > -----Original Message----- > > I am forwarding this partial email thread from the Moon-net list to > everyone here on the Elecraft list in hopes to generate a good > discussion (not a flame war!) on the use of the K2 for weak signal use. > I would appreciate hearing all responses to this subject because I was > considering using the K2 (or maybe the K3?) for weak signal work > someday. What are the major strengths/weaknesses of the K2 in this area, > and what can be done to improve this. > > There are some very knowledgable people on this list and your experience > in this area would be most appreciated. > > Thanks, > Tony K4YYZ > _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
