++++++++++++++++++++ Date: Wed, 17 Jul 2002 17:51:39 -0400 To: elecraft at mailman.qth.net From: Dudley Chapman Subject: [Elecraft] 40m Rasp My K2 #2522 seems to have no functional problems that I can see. However, I have noticed a kind of "rasp" on the rx of cw signals. I haven't had a chance to characterize if it is band specific or not, however. Funny thing happened last night regarding this problem. I answered a CQ from a VE last night and he came back to me with a signal report saying "rst 589 on your fb K2 rig", before I had even made my first xmtn in the qso. Took me aback, to say the least, so I asked him if we had QSO'd before. he said he no, but he could identify a K2 on 40m the moment he hears one, due to the distinctive raspy note. He QSOs with a K2 owner buddy frequently and has learned to identify them easily. I am wondering if this is only a 40m problem and if it is related to some of the mods and alignment techniques that have been suggested for the vfo on 40m? Does anyone have any insight into this? Regards, Dudley, WA1X ++++++++++++++++++++ Date: Wed, 17 Jul 2002 15:07:06 -0700 From: Vic Rosenthal Organization: Transparent Software To: Dudley Chapman Cc: elecraft at mailman.qth.net Subject: Re: [Elecraft] 40m Rasp Dudley Chapman wrote: > > My K2 #2522 seems to have no functional problems that I can see. However, > I have noticed a kind of "rasp" on the rx of cw signals. I haven't had a > chance to characterize if it is band specific or not, however. If it is within 18 inches (46 cm) of a generator of AC magnetic fields, such as a linear power supply or an antenna rotor control box, the magnetic field may be modulating your transmitted and received signals. It was suggested that the BFO coil was sensitive to such fields. I personally find this fascinating and like to think about it, but most guys just say "so move the power supply". 73 Vic K2VCO ++++++++++++++++++++ Date: Wed, 17 Jul 2002 18:24:14 -0400 From: "Mark J. Dulcey" To: Dudley Chapman Cc: elecraft at mailman.qth.net Subject: Re: [Elecraft] 40m Rasp Dudley Chapman wrote: > My K2 #2522 seems to have no functional problems that I can see. > However, I have noticed a kind of "rasp" on the rx of cw signals. I > haven't had a chance to characterize if it is band specific or not, > however. The first thing to check is whether your K2 is close to your power supply, or anything else with big transformers in it. The K2 is susceptible to nearby magnetic fields. +++++++++++++++++++++ Reply-To: From: "Ron D'Eau Claire" To: "'Dudley Chapman'" , Subject: RE: [Elecraft] 40m Rasp Date: Wed, 17 Jul 2002 15:52:08 -0700 My K2 #2522 seems to have no functional problems that I can see. However, I have noticed a kind of "rasp" on the rx of cw signals. I haven't had a chance to characterize if it is band specific or not, however.... Regards, Dudley, WA1X IF the "rasp" might also be called AM or FM Hum and if you rig is near the power supply, then Vic has the right answer. When I first put my K2 on the air I plopped it on top of my linear power supply and immediately got reports of hum on my signal. Taking it off of the supply fixed the problem immediately. It was easy to hear on an outboard receiver as well. In my case, the ops thought that the hum was just a result of my call. I've worked a couple of dozen K2's - maybe more - over the past three years and I've yet to hear one that didn't have an absolutely clean CW note. Indeed, I even suggested that we have the firmware include some user-selectable amount of "chirp" so we could make them stand out a bit on the bands. Ron AC7AC K2 # 1289 ++++++++++++++++++