++++++++++++++++++++++++++++++++++++++++++++ Date: Sun, 25 Mar 2001 10:19:06 -0600 From: "Jay Henson" Subject: [Elecraft] Problem Discovered and Being Fixed I haven't posted to the list in a while but I religiously read it every day. I thought I'd pass this on under the heading "General Info" just in case someone else can benefit. During an FP net a few weeks ago, a couple of my friends reported that my K2 signal had a buzz on it. The last thing that I want to do is be labeled "BUZZ". I have disconnected the computer, station ground, used a car battery in lieu of my Alinco DM340MV PS (I know, 30 amp PS for a K2 is a bit much), etc. I have even received help from Dick (K2JQ in NY) and Jim (K4ZM, builder of many K2's and a K1) trying to figure out what has happened to my K2, S/N 1073. This morning, while listening to 10 and 15 meters, the signals sounded like they had a hum/buzz. My first thought was the Alinco has a bad filter and that is the root cause of all this. I get the car battery from the garage and take it to the shack. I figured I'd get on a strong signal with the pronounced hum and disconnect the Alinco and hook up the battery to see if the humm goes away. As I pull the K2 out to disconnect the PS wire, the hum goes away. HUH! I slide the K2 back and the hum is back. Bad connection???? Out/back. Same thing. Durn!!!!! Quite a while back, a similar problem was discovered by another K2 owner and posted to the group. The K2 can NOT be located close to a 30 amp linear PS. In my case, they sit right next to each other. The power transformer in the PS produces a very strong magnetic field that will produce all manner of evil in the K2. I am now in the process of re-routing power lines, coax, etc. so that the K2 and Alinco are separated by as much distance as possible. Be aware. Thanks to Jim for his help yesterday. See you on the radio. Jay AJ4AY Mobile, AL FISTS #7917 ARCI #8131 SOC#220 FP# - 115 +++++++++++++++++++++++++++++++++++++++++++++++++ Date: Sun, 25 Mar 2001 10:29:44 -0800 From: "Ron D'Eau Claire" Subject: RE: [Elecraft] Problem Discovered and Being Fixed Jay wrote: "The K2 can NOT be located close to a 30 amp linear PS. In my case, they sit right next to each other. The power transformer in the PS produces a very strong magnetic field that will produce all manner of evil in the K2." About a year ago I finished my K2 and put it on the air to immediately get a 587 report with very pronounced hum on the signal. After some fiddling around I realized that the hum appeared when I set it on my transformer power supply. I was using an 11-amp transformer supply with just about the same 'footprint' as the K2 and so, naturally, I set the K2 on top of the power supply. The field from the power supply was modulating the VCO in the K2. Wayne or Eric said that they'd put a warning in the future manuals for the K2 that you can't put it too close to a power transformer. I haven't seen a more recent manual and perhaps it never got inserted. Ron AC7AC K2 # 1289 +++++++++++++++++++++++++++++++++++++++++++++++++++ Date: Sun, 25 Mar 2001 12:32:30 -0800 From: Vic Rosenthal Subject: Re: [Elecraft] Problem Discovered and Being Fixed Jay Henson wrote: > Durn!!!!! Quite a while back, a similar problem was discovered by another > K2 owner and posted to the group. The K2 can NOT be located close to a 30 > amp linear PS. And if it is next to a rotator control, it will buzz while you rotate your antenna. I find this useful as it makes the signal stand out in a pileup! 73, Vic, K2VCO Fresno CA ++++++++++++++++++++++++++++++++++++++++++++++++++ Date: Sat, 09 Jun 2001 14:46:00 -0700 From: "N7LQ" Subject: Re: [Elecraft] Buzz on RX audio That was it Tom. Its sitting on my Astron RS-70.... On Sat, 09 Jun 2001 15:57:30 -0500, Tom Hammond N SS wrote: >This is definitely NOT normal... do you, by change, have the K2 on, or >close to a fluorescent light or ppossibly a P/S with a hefty xfrm? The bus >may be induced from nearby external equipment. ++++++++++++++++++++++++++++++++++++++++++++ Date: Sat, 9 Jun 2001 20:56:09 -0700 From: "Ron D' Eau Claire" Subject: RE: [Elecraft] Buzz on RX audio N7LQ wrote: > That was it Tom. Its sitting on my Astron RS-70.... > That reminds me that a year ago when my K2 was first on the air I got several T-6 and T-7 reports with comments about a very obvious hum on my signal. It turned out that I had placed my K2 on top of my transformer power supply and the a-c field around the transformer was FM-ing the VCO in the K2. Wayne or Eric commented that a warning was going to be put in the Manual but maybe it never made it. Ron AC7AC K2 # 1289 +++++++++++++++++++++++++++++++++++++++++