> Has anyone heard of this happening with a SignalLink sound card > before?
Yes. Did your friend change computers, connect Signalink to a different port, add (or remove) an externally powered hub? Signalink has documented design issues - it lacks the V/2 regulator for the codec as recommended by the chip vendor, has a severe lack of bypasses on the 5V bus, insufficient filtering on the USB power (which becomes the 5V bus) and no regulation. If the computer's USB power becomes noisy/unstable, that noise is imposed directly on the audio output of the codec *and* is further modulated on the audio via bias to the op-amp audio stages. See documentation of the defects (and modifications to fix some of the shortcomings - including schematics) here: http://www.frenning.dk/OZ1PIF_HOMEPAGE/SignaLinkUSB-mods.html If one wants a higher performance interface at a lower cost that will do everything that a Signalink will do and is willing to melt a little solder see: http://www.g4ilo.com/usblink.html 73, ... Joe, W4TV On 2014-06-30 3:45 PM, David Cole wrote:
Hi, I have a friend who lives about 1/2 to 3/4 of a mile from me. He is running a 706 MK2G, at around 10 watts. In the past, while using a Pro III, when he came on, I was able to copy and see signals using JT65, and work stations right next to him. After getting the K3, I believe I was able to do this as well, or better... Suddenly his signal is sprayed across the entire audio spectrum to the point, I can't even tell what frequency he is on... I get a solid white block using WSJTx. He and I enlisted a third friend, to insure it was not just me that is seeing him as very wide. The third friend lives about 4 to 5 miles from both of us, and is line of site to my friend with teh 706 MK2G. When the 706 MK2G lets loose, I see the spray, but my friend does not... He sees a nice tight signal. It looks and sounds like phase noise... However... If he just does a Key down for CW at 50 watts, I can copy stations right next to him... It is as if his sound card, (Signal Link with internal sound card), is adding a low level hiss to the audio, I see it due to proximity, and my friend does not again, because he is much further away... This has started suddenly, and the owner of the 706 can not pin a change to it... We swapped in a different 706MK2G, and the same problem still happens... Has anyone heard of this happening with a SignalLink sound card before?
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