Try switching to a linear supply?
Sincerely, Frank Krozel t: 1-630-924-1600 [email protected] BSEE, AASEET, FCC Lic.# PG-18-19178, KG9H Electronic Instrument Associates - Central, Inc. ...since 1971 w: www.electronicinstrument.com d/l our linecard at http://www.electronicinstrument.com/lc.pdf > On Apr 26, 2019, at 9:46 PM, Nicklas Johnson <[email protected]> wrote: > > Before I forget, thank you to everyone who has responded thusfar with ideas > and suggestions. This one is a real head-scratcher, and I appreciate > everyone bouncing ideas around with me. > > If the problem is in fact originating with power line neutral distortion, > what, if anything could I actually do about it, beyond what I've already > done in running on battery power? I can't really move my 'shack' in this > case. > > I did find the "squeaky wheel" at least. It was the end of one of the > aluminum straps of an antenna mast chimney mount brushing against a copper > ground wire in the wind. A pair of tin snips solved that problem. This > bit was kind of fascinating-- if I held a copper wire against the aluminum > strap, and position the antenna of the KX3 nearby, I could receive some > broadcast AM station on the 51.123 MHz carrier I was transmitting from > inside the house (it's pretty close to a multiple of 810kHz, so if I had to > guess, it was likely KGO I was getting). > > I also found the noise gets a hell of a lot louder near the back gutter of > the house (which runs parallel to the power lines that run through the back > yard), though this could just be because the antenna of my KX3 was coupling > to it. > > Yet to be determined is whether the noise is a local thing only affecting > reception (e.g., some kind of passive intermod), or if in fact it becomes > part of the signal I'm sending up to the ionosphere. To really figure that > one out, I probably will need to make an actual distant AM contact and ask > someone to tell me how it sounds... this may be no small feat with the way > the sun is behaving lately, but I'll keep trying. > > Nick > >> On Fri, 26 Apr 2019 at 19:18, Bob McGraw K4TAX <[email protected]> wrote: >> >> I think Jim's concern, expressed earlier, about power line neutral >> distortion components is valid. And it may be originating in "the big green >> transformer" in the yard. >> >> Bob, K4TAX >> >> >> Sent from my iPhone >> >>> On Apr 26, 2019, at 8:53 PM, Nicklas Johnson <[email protected]> wrote: >>> >>> Sorry for the additional email, but this is particularly interesting: it >>> occurred to me that I'd never tried the reverse setup, so I put the KX3 >> in >>> transmit mode and 0.1W on AM in another room, and set the K3S on receive. >>> And sure enough, the K3S immediately started picking up S40 of buzzing >>> noise. However if I tune the K3S to an AM broadcast station or WWV, no >>> buzz. So either both the K3S and KX3 are being affected on transmit in >> the >>> same way (which seems implausible but not impossible), or possibly >>> something else is going on at my QTH. >>> >>> On the P3, I definitely see the noise when the KX3 is transmitting from >> the >>> other room. >>> >>> Now I wish I had a scope so I could see what the AM carrier generated by >>> the KX3 and K3S looks like so I could tell if this is something that's >>> happening inside the transmitter, or something that is happening because >> of >>> some outside influence mixing powerline noise with the AM carrier. The >>> important thing to me is that the carrier I'm putting out there is >> clean... >>> if there's some local mixing that happens that means I can't listen to my >>> own transmission without a buzz, I can live with that. >>> >>> One kind of curious thing is that there's also a superimposed "squeaky >>> wheel" sound at random intervals detectable when the KX3 is transmitting >> an >>> AM carrier, and not otherwise, and also not when listening to WWV or AM >>> broadcast, which vaguely seems to correlate with how windy it is at any >>> given moment. Could all of this be a "rusty bolt" effect from something >> in >>> the vicinity? >>> >>> Nick >>> >>> >>> >>>> On Fri, 26 Apr 2019 at 18:11, Nicklas Johnson <[email protected]> wrote: >>>> >>>> A few more data points: >>>> >>>> Changing TX EQ, including cutting the first 4 bands all the way down to >>>> -16 had no effect on the received signal. >>>> >>>> Plugging in some headphones, turning the TX Monitor up all the way, I >>>> don't detect the hum in the TX monitor signal either in TX test mode, >>>> transmitting into a dummy load, or even transmitting into the antenna >> with >>>> very low power. If I turn up the Line In level, I just hear expected >> white >>>> noise on the TX monitor. So at least as far along the path as the TX >>>> monitor, there's no hum or buzz introduced. >>>> >>>> Switching the receiver (a KX3) to USB mode and using one leg of a >>>> buddistick as an antenna so I can walk around, the noise received around >>>> the house and outside is around S4 when transmitting about 100mW into >> the >>>> antenna, though it varies some as I walk around. >>>> >>>> I do have a set of power lines running through my back yard, and where I >>>> live in San Mateo, you're always near somebody's wiring for something, >>>> unfortunately... my neighbor's south wall is possibly as far as 8 feet >> away >>>> from my north wall, etc. >>>> >>>> It looks like two phases running along the top, then a transformer to >> two >>>> phases and a neutral along the bottom, to which people's houses are >>>> connected. >>>> >>>> We also have underground utilities on our street, including a big green >>>> transformer that sits in the corner of our front lawn. >>>> >>>> I think the next test will be to take the K3S and the KX3 some distance >>>> away from all of these things and see if the hum goes away, and if it >> does, >>>> then figure out what thing the K3S needs to get away from in particular. >>>> If it's the powerlines in my back yard or the transformer in my front >> yard, >>>> then that'll be a difficult problem. >>>> >>>> Nick >>>> >>>> >>>> >>>> On Fri, 26 Apr 2019 at 17:28, Bob McGraw K4TAX <[email protected]> >>>> wrote: >>>> >>>>> Yes but the EQ is in the digital path. The EQ should be done there, >>>>> preferably after the MIC input. The AM BW does not attenuate the end >> like >>>>> the SSB filter. >>>>> >>>>> I suggest -16 dB on the first 3 bands. >>>>> >>>>> Bob, K4TAX >>>>> >>>>> >>>>> Sent from my iPhone >>>>> >>>>>> On Apr 26, 2019, at 6:38 PM, Nicklas Johnson <[email protected]> wrote: >>>>>> >>>>>> Flat, except I turned the first one down a few notches, which doesn't >>>>>> really do much in my case because both the microphone and mixer that I >>>>> use >>>>>> (when they're actually connected) roll off below 150 and 80 Hz >>>>>> respectively. It had previously been suggested to me that rolling off >>>>> low >>>>>> frequency cruft is a good idea for AM and SSB. >>>>>> >>>>>> Nick >>>>>> >>>>>>> On Fri, 26 Apr 2019 at 15:57, Bob McGraw K4TAX <[email protected]> >>>>> wrote: >>>>>>> >>>>>>> I recall commenting earlier. What TX EQ values are being used for >> AM. >>>>> ? >>>>>>> >>>>>>> Bob, K4TAX >>>>>>> >>>>>>> >>>>>>> Sent from my iPhone >>>>>>> >>>>>>>> On Apr 26, 2019, at 5:48 PM, Nicklas Johnson <[email protected]> wrote: >>>>>>>> >>>>>>>> My desk in this case sits adjacent a wall, and there's only a shower >>>>> on >>>>>>> the >>>>>>>> other side of that wall. I did turn off everything in the vicinity >> of >>>>>>> the >>>>>>>> desk and all the lights in the room (I've in fact heard a very >> similar >>>>>>> hum >>>>>>>> from the switching power supply for my mixer, and my first thought >>>>> was it >>>>>>>> was this that was being picked up), but I didn't turn off the >>>>> computer on >>>>>>>> the other side of the room. In this case it will be easier to move >>>>> the >>>>>>> rig >>>>>>>> outdoors with a battery than it will be to turn that computer off >> for >>>>> the >>>>>>>> moment. It would have to be an impressively/obnoxiously strong >>>>> magnetic >>>>>>>> field from that side of the room to influence the transformers >> inside >>>>> the >>>>>>>> rig 8 feet away, but it's worth trying and simple enough to rule it >>>>> out. >>>>>>>> >>>>>>>> Nick >>>>>>>> >>>>>>>>> On Fri, 26 Apr 2019 at 14:51, Don Wilhelm <[email protected]> >>>>>>> wrote: >>>>>>>>> >>>>>>>>> In addition to operating from a battery isolated from the solar >>>>> system, >>>>>>>>> I would recommend that you do a quick test - remove all cables from >>>>> the >>>>>>>>> K3S except the power cable and a coax to a dummy load. Power down >>>>> all >>>>>>>>> power supplies in your station, including any desk lamps. >>>>>>>>> Go into Transmit by tapping the XMIT button. >>>>>>>>> Is the hum still present? If not, then start connecting things to >>>>> your >>>>>>>>> K3S one at a time, doing the same test after each thing connected. >>>>>>>>> >>>>>>>>> Of course, if the hum is present with nothing connected, contact >>>>>>>>> [email protected] - but I cannot imagine a hum with harmonics >> of >>>>> 60 >>>>>>>>> Hz being induced if you take away all the 60 Hz operated sources in >>>>> the >>>>>>>>> area. >>>>>>>>> >>>>>>>>> 73, >>>>>>>>> Don W3FPR >>>>>>>>> >>>>>>>>> -- >>>>>>>> *N6OL* >>>>>>>> Saying something doesn't make it true. Belief in something doesn't >>>>> make >>>>>>> it >>>>>>>> real. And if you have to lie to support a position, that position is >>>>> not >>>>>>>> worth supporting. >>>>>>>> ______________________________________________________________ >>>>>>>> Elecraft mailing list >>>>>>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>>>>>>> Help: http://mailman.qth.net/mmfaq.htm >>>>>>>> Post: mailto:[email protected] >>>>>>>> >>>>>>>> This list hosted by: http://www.qsl.net >>>>>>>> Please help support this email list: http://www.qsl.net/donate.html >>>>>>>> >>>>>>> >>>>>>> >>>>>> >>>>>> -- >>>>>> *N6OL* >>>>>> Saying something doesn't make it true. Belief in something doesn't >>>>> make it >>>>>> real. And if you have to lie to support a position, that position is >> not >>>>>> worth supporting. >>>>>> ______________________________________________________________ >>>>>> Elecraft mailing list >>>>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>>>>> Help: http://mailman.qth.net/mmfaq.htm >>>>>> Post: mailto:[email protected] >>>>>> >>>>>> This list hosted by: http://www.qsl.net >>>>>> Please help support this email list: http://www.qsl.net/donate.html >>>>>> >>>>> >>>>> >>>>> >>>> >>>> -- >>>> *N6OL* >>>> Saying something doesn't make it true. Belief in something doesn't make >>>> it real. And if you have to lie to support a position, that position is >> not >>>> worth supporting. >>>> >>> >>> >>> -- >>> *N6OL* >>> Saying something doesn't make it true. Belief in something doesn't make >> it >>> real. And if you have to lie to support a position, that position is not >>> worth supporting. >>> ______________________________________________________________ >>> Elecraft mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:[email protected] >>> >>> This list hosted by: http://www.qsl.net >>> Please help support this email list: http://www.qsl.net/donate.html >>> >> >> >> > > -- > *N6OL* > Saying something doesn't make it true. Belief in something doesn't make it > real. And if you have to lie to support a position, that position is not > worth supporting. > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
