I'm launched on experiment to put K1 on 10 meters -- using 26.170 MHz xtal at Wayne's suggestion (and generous contribution). This should make the whole project easier with lower frequency crystal and more premix output, but I've run into a snag and seek some advice.
Instrumentation here is pretty crude -- RF probe and HF receiver. RF probe uses 1N914 vice 1N34A and that makes a difference in readings for low level signals. 10 meter filters are built as Band 1 on a KFL1-2 board with 80 meters working like gangbusters as Band 1, my basis for comparison -- acknowledging potential difference in freq response for the probe. The premix filter is same as for 17 meters, peaks nicely and right mixing product verified with HF receiver. Bandpass filter and RF board mods follow design by Stephanie Maks, VA3UXB. This includes change to R11 on RF board and absence of L-section at output of BPF. For now, the output filter is jumpered across - just seeking raw output into dummy load. Best I can achieve is a hair under 200 mW output. That level does peak with slugs in L7 and L8 very near all the way down. No problem hearing low level 10 meter signal generated in shack. Signal is dying either within the BPF or from mismatch at its output. Comparison with 80 meters yields 1.06 volts at test point TR1 for 10 meters vs 0.28 volts for 80 meters. The 80 meter signal drops to 150 mV at test point BPF, but the 10 meter signal drops like a stone to 16 mV at the same point, so difference in RF probe freq response cannot be an issue. I'm stumped over great difference from Stephanie's results. Caps in the bandpass filter are high quality from Elecraft. My only immediate source for filter changes, however, is limited to Radio Shack - grand variety and questionable quality. Anybody else been down this path and have ideas? Bill Cunningham K4KSR _______________________________________________ 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
