Julian, G4ILO wrote: >I think it was me who used the term "ghost" signals when referring to the harmonically related CW traces >I could see on the CW Skimmer display.
Julian, About 6 months ago I found a similar situation with another radio and another program. In that case the distortion was definitely caused by the sound card input being overdriven, not by the radio. I am not saying that that is happening for you, only that it CAN happen with certain equipment. Here are the details if you want to know. I was building a new interface that lets me operate PSK-31 and other modes (including pactor 2) with switching between any of two radios and any two hardware modems and soundcard. It is also designed to work with both my desktop computer and my laptop (HP ZT-3000) by manually moving the cable. Serial port was switched along with the modems. The radios were FT-1000D and TS-570, both interfaced through the connector on the back. The 1000D (now sold to finance K3) has a single fixed output level, the 570 three selectable levels. I selected the level most closely matching the 1000D. The software was MixW running on the HP laptop. I found that I could not only see a give station in two places, but copy their PSK-31 in both places! The second frequency was outside (above) the filter cutoff, but the signal was about as strong as the one in the passband. I don't remember the actual frequencies, but there was a big difference in them, such as double or triple. I didn't determine if the ghost was created as a harmonic or by mixing, but it was good copy and strong. (Hmmm,... wonder if PSK would be copiable on a harmonic?) My interface has a volume control for the output (as well as input) of each radio. When I turned down the output at the interface (not touching the radio), the ghost went away. On a tangent topic: I had previously run the 570 with the laptop using a much simpler interface, and somewhat marginal results (did not run into any ghost, was probably using a lower output level selected on the radio). That interface had short audio cables. The new interface has long cables for flexibility in placing the equipment around the shack. When I first tried to transmit, there was a horrible hum on the signal. I had tied together the 3 grounds of the 570 at the aux connector. I solved the problem completely by running separate 3 grounds from the 570 to the interface box with its transformers. The 1000D had no such need, maybe because its PSU was built-in) but I implemented both radio cables with separate grounds to be prepared for future radios. I should be covered for the K3, whether it behaves like a 1000D or like a 570. I wonder though if the K3 is more similar to one or the other in its grounding scheme... 73, Erik K7TV KX-1 T-1 K3 on order -- View this message in context: http://n2.nabble.com/K3-Harmonic-Distortion-tp797780p832903.html Sent from the Elecraft mailing list archive at Nabble.com. _______________________________________________ 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
