Re: [Elecraft] magnetic fields and phase noise?
Worked Vic, K2VCO this morning on 40m CW. His K2/100 was absolutely clean with no clicks and no noise on his CW sidebands while he was running barefoot. When he ran ran QRO to his Alpha 87A, There were still no clicks, however there was noise on his sidebands extending out +/- about 1 kHz from center frequency. I honestly expected it to be worse than that, but he apparently also has the same problem with the magnetic field from the magnetic field from the HV xfmr in his amp getting into his K2. I was using my IC-756Pro3 with a 50 Hz bandwidth. Tuning off to either side of Vic's CW signal where the tone disappeared, you could still copy him due to the noise on his sidebands. Anyone with a K2 driving a linear amp can easily check for this by listening on a separate receiver using the narrowest bandwidth available by tuning the signal just out of the receiver passband while transmitting on the K2 with amp. It sounds like noisy sidebands on the transmitted CW signal. With my K2, the problem occurs on all bands. It doesn't occur when I use any of my other transceivers (IC-756Pro3, FT-1000MP, TS-830S). 73, de Earl, K6SE ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
RE: [Elecraft] magnetic fields and phase noise
Alan, G0HIQ, wrote: Reading the magnetic field and phase noise saga makes me think of earth loops. If moving to another power socket- as in moving to another room cures it. How about using mains isolation transformers so only connection K2-linear really is the coaxial feeder. Or battery power K2. - Good points! Has everyone chasing he noise problems at least isolated the house mains from the rig for RF with a ferrite choke? Since the K2 uses an external power supply, I use chokes on the 13 vdc supply lead where it leaves the K2. I don't have your problem to contend with, so I can't say what difference it might make. On HF, I currently use a balanced antenna fed with open wire line through a balanced ATU, so rig grounding isn't a big concern, but on general principle I like to isolate my rigs for RF to avoid unwanted noise getting in and to avoid unwanted RF grounds from occurring in the house wiring. Ron AC7AC ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
Re: [Elecraft] magnetic fields and phase noise?
Earl W Cunningham wrote: Worked Vic, K2VCO this morning on 40m CW. His K2/100 was absolutely clean with no clicks and no noise on his CW sidebands while he was running barefoot. When he ran ran QRO to his Alpha 87A, There were still no clicks, however there was noise on his sidebands extending out +/- about 1 kHz from center frequency. I honestly expected it to be worse than that, but he apparently also has the same problem with the magnetic field from the magnetic field from the HV xfmr in his amp getting into his K2. My K2 is about 4 feet from the Alpha 86 (not 87A unfortunately) and it's on the side near the hypersil transformer. If this is indeed caused by the magnetic field, I suspect that there is a particular component or components that are affected, and perhaps it would be possible to shield them. I rarely run more than 100 watts, but there are times that I would like to do so, so I'll be looking for a solution. -- 73, Vic, K2VCO Fresno CA http://www.qsl.net/k2vco ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
Re: [Elecraft] magnetic fields and phase noise?
Sorry, I had to post twice. Geoff GM4ESD - Original Message - From: Geoffrey Mackenzie-Kennedy [EMAIL PROTECTED] To: Earl W Cunningham [EMAIL PROTECTED] Sent: Sunday, March 20, 2005 7:41 PM Subject: Re: [Elecraft] magnetic fields and phase noise? Earl, How strong was Vic's carrier at your Pro3 when he was QRO with the 87A, and how far down were the sidebands? Not thinking of Rx problems at all, just trying to get an accurate pictue of Vic's QRO signal. 73, Geoff. GM4ESD - Original Message - From: Earl W Cunningham [EMAIL PROTECTED] To: [EMAIL PROTECTED]; elecraft@mailman.qth.net Sent: Sunday, March 20, 2005 6:13 PM Subject: Re: [Elecraft] magnetic fields and phase noise? Worked Vic, K2VCO this morning on 40m CW. His K2/100 was absolutely clean with no clicks and no noise on his CW sidebands while he was running barefoot. When he ran ran QRO to his Alpha 87A, There were still no clicks, however there was noise on his sidebands extending out +/- about 1 kHz from center frequency. I honestly expected it to be worse than that, but he apparently also has the same problem with the magnetic field from the magnetic field from the HV xfmr in his amp getting into his K2. I was using my IC-756Pro3 with a 50 Hz bandwidth. Tuning off to either side of Vic's CW signal where the tone disappeared, you could still copy him due to the noise on his sidebands. ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
Re: [Elecraft] magnetic fields and phase noise?
Fraser Robertson wrote: Interesting Earl, the non exhaustive tests I've done indicate that it is not due to magnetic fields. But if indeed that is the case, there must be a relatively easy, if perhaps not elegant, way of significantly improving this. Has anyone else investigated this? I have an Alpha 86 which is about 3 feet from my K2. I have performed tests in which someone listened to my signal at 100 watts and 1.3 KW without noticing any difference in quality. I'd be glad to sked Earl or anyone else who wants to try this (unfortunately I am in the process of working on my 160/80 meter antennas, so it would have to be 40 meters or higher). -- 73, Vic, K2VCO Fresno CA http://www.qsl.net/k2vco ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
