Steve WB6RSE wrote: > Anyone have any experience changing the K1 from > LSB to USB CW?
Steve, That's an interesting question. The K1 front end mixer injects the local oscillator (LO) signal ABOVE the incoming RF signal (high side injection), while the product detector injects the BFO signal BELOW the IF signal (low side injection). The result is the receiver functioning in LSB mode. One could raise the frequency of the BFO so that it is above the IF signal (high side injection), and you would have as a result a receiver operating in USB mode. The *only* positive attribute of going to high side BFO injection that I can think of would be a theoretical improvement in opposite sideband rejection due to the asymetrical shape of the IF crystal filter bandpass skirts. But the opposite sideband rejection of the K1 is already as good as one will ever need. The big negative to USB for me would be losing the ability to copy LSB phone on the lower 20 kHz of the 40m phone band on my K1 with a 170 kHz VFO span. One finds no USB signal worth covering on 30m unless it is military/utility outside the ham band, and nothing on 17m or 15m on USB within the K1 tuning range, nor are the foreign phone USB signals on 20m of much interest to me. The other operating characteristic that would change is that the AF tone of the received signal would lower as the VFO is tuned upward in USB mode. I like the LSB characteristic of the AF tone going up as I tune upward on the VFO. I'd be curious about the advantages that you see in a K1 LSB-to-USB conversion. 73, Mike / KK5F _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net http://mailman.qth.net/mailman/listinfo/elecraft You must subscribe to post. Subscriber Info (Addr. Change, Unsub etc): http://mailman.qth.net/subscribers.htm Elecraft page: http://www.elecraft.com
