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Re: [wsjtgroup] contest skeds wanted de K9ZF SOLP EM78cq

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  • Joe Taylor
    Dan -- Sorry to say, I never heard you during the contest. Hope you didn t have a major failure of some sort. Another time! -- Joe, K1JT
    Message 1 of 18 , Sep 14, 2005
      Dan --

      Sorry to say, I never heard you during the contest. Hope you didn't
      have a major failure of some sort. Another time!

      -- Joe, K1JT

      Dan K9ZF wrote:
      > Joe Taylor wrote:
      >
      >
      >>Dan --
      >>
      >>Here's a last-minute request for a contest sked. Let me suggest 1030
      >>UTC on Sept 11. Start on 50.285, and when we are complete, QSY to
      >>144.113. Send grid for report. Please confirm if this will be possible
      >>for you.
      >> -- 73, Joe, K1JT -- FN20
      >>
      >>
      >>
      >>
      >>
      >>
      >
      > Will be looking for you Joe. 10:30 is fine.
      > Dan
      >
    • zenithfan
      I m puzzled by some local interference (at least I think it s local). See the two attached photos of the waterfall. The interference is multi-frequency and
      Message 2 of 18 , Apr 15

      I'm puzzled by some local interference (at least I think it's local).  See the two attached photos of the waterfall.  The interference is multi-frequency and spreads at the start, it then collapses at the end.  Radio is on 20M at 14.076.   Happens several times an hour.


      Bill WB9KPT

    • Gary
      See if that coincides with your air conditioner cycling on/off. I live in a condo here with an attic antenna, and I see several of these things of varying
      Message 3 of 18 , Apr 15

        See if that coincides with your air conditioner cycling on/off.  I live in a condo here with an attic antenna, and I see several of these things  of varying strengths  The strongest one comes from the condo next door, where a new central air conditioner unit was recently installed.  My own AC unit does not produce this noise.  It is over 12 years old.  Seems something in the newer units generate this noise.  The worst problem for me is on 17m, but I get it on 20 and 15 too.

         

        I know of no way to easily rectify this problem.  Just another case of manufacturers producing junk with no regard for the RFI it produces.  It just keeps getting worse and worse with no end in sight.

         

        73 de Gary – W9BS

         

         

        From: wsjtgroup@yahoogroups.com [mailto:wsjtgroup@yahoogroups.com] On Behalf Of wb9kpt@... [wsjtgroup]
        Sent: Saturday, April 15, 2017 9:23 PM
        To: wsjtgroup@yahoogroups.com
        Subject: [wsjtgroup] What is this? [2 Attachments]

         

         

        [Attachment(s) from wb9kpt@... [wsjtgroup] included below]

        I'm puzzled by some local interference (at least I think it's local).  See the two attached photos of the waterfall.  The interference is multi-frequency and spreads at the start, it then collapses at the end.  Radio is on 20M at 14.076.   Happens several times an hour.

         

        Bill WB9KPT


        Virus-free. www.avast.com
      • zenithfan
        Thanks Gary, it s probably from one of my neighbors, but I will check to see if it s from our furnace. Not yet running AC here in the Mountains outside of
        Message 4 of 18 , Apr 16
          Thanks Gary, it's probably from one of my neighbors, but I will check to see if it's from our furnace.  Not yet running AC here in the Mountains outside of Denver.  As you point out, even if that is the case, it will be hard to remedy...

          Bill WB9KPT
        • Kai
          Newer air conditioners achieve very high efficiency, but to do that they use PWM (pulse width modulated) power supplies on the air handler motors. That creates
          Message 5 of 18 , Apr 16
            Newer air conditioners achieve very high efficiency, but to do that they use PWM (pulse width modulated) power supplies on the air handler motors. That creates a ton of RFI!  Very difficult to get rid of. That put my indoor attic antenna out of commission, but my summer power bill was cut in half here in southern Florida. So it was a choice "cool" or "radio".  We opted for "cool", and now I operate form our club station, or during the winter months.

            There was a recent QST article on curing RFI on window-mounted units,  search the QST archives.
            73,
            Kai

            On 4/16/2017 01:42, 'Gary' w9bs@... [wsjtgroup] wrote:

            See if that coincides with your air conditioner cycling on/off.  I live in a condo here with an attic antenna, and I see several of these things  of varying strengths  The strongest one comes from the condo next door, where a new central air conditioner unit was recently installed.  My own AC unit does not produce this noise.  It is over 12 years old.  Seems something in the newer units generate this noise.  The worst problem for me is on 17m, but I get it on 20 and 15 too.

             

            I know of no way to easily rectify this problem.  Just another case of manufacturers producing junk with no regard for the RFI it produces.  It just keeps getting worse and worse with no end in sight.

             

            73 de Gary – W9BS

             

             

            From: wsjtgroup@yahoogroups.com [mailto:wsjtgroup@yahoogroups.com] On Behalf Of wb9kpt@... [wsjtgroup]
            Sent: Saturday, April 15, 2017 9:23 PM
            To: wsjtgroup@yahoogroups.com
            Subject: [wsjtgroup] What is this? [2 Attachments]

             

             

            [Attachment(s) from wb9kpt@... [wsjtgroup] included below]

            I'm puzzled by some local interference (at least I think it's local).  See the two attached photos of the waterfall.  The interference is multi-frequency and spreads at the start, it then collapses at the end.  Radio is on 20M at 14.076.   Happens several times an hour.

             

            Bill WB9KPT


            Virus-free. www.avast.com

          • zenithfan
            Thanks Kai. I m guessing its a neighbors furnace, since its not air conditioning season here yet... I guess the good news is that I m still able to receive
            Message 6 of 18 , Apr 16
              Thanks Kai.  I'm guessing its a neighbors furnace, since its not air conditioning season here yet...  I guess the good news is that I'm still able to receive JT65 signals on the affected frequencies.  Very few houses have air conditioning in our neighborhood because we are at 7300'.  We had a system put in a few years ago, and so far I have not noticed any issues.

              Bill WB9KPT
            • David Garnier
              Zenithfan, Before I retired I did compliance testing of medical imaging products, I worked in 10 meter TDK chamber and chased down these sorts of radiated
              Message 7 of 18 , Apr 18
                Zenithfan,

                Before I retired I did compliance testing of medical imaging products,
                I worked in 10 meter TDK chamber and chased down these sorts of
                radiated emissions (RE) issues to meet product compliance...
                We are all guessing to what this suspect is until you do some snooping
                in your environment with a HF handheld receiver...
                 
                My educated guess, this is some sort of switching power supply that's
                unloaded, (the electronic gizmo is off,) but the power supply is still
                energized.  The neat thing here, depending on your point of view,
                is a couple times an hour that supply supply quickly turns on to maintain
                it's -unloaded- output voltage and then shuts off and slowly decays...
                I also have one of these supplys in my house but it's -not- my variable
                firing rate furnace, but given how bright it's on your screen, your suspect
                maybe in your house...  Time to walk around the house with hand held
                receiver and start switching off circuit breakers to find this "screamer." 
                This may not be easy to find considering it energizes only a couple times
                an hour...  Look at all the wall warts power supplies in your house as being
                the possible suspect, this might be an interesting chase.

                73's & GL - wb9own

                --------------------------------------------------------------------------------------

                Sat Apr 15, 2017 6:23 pm (PDT) . Posted by:

                zenithfan

                I'm puzzled by some local interference (at least I think it's local). See the two attached photos of the waterfall. The interference is multi-frequency and spreads at the start, it then collapses at the end. Radio is on 20M at 14.076. Happens several times an hour.


                Bill WB9KPT
                Attachment(s) from
                2 of 2 Photo(s)



              • zenithfan
                I found the problem! I guess the good news is that it s from my house, not a neighbors. It s the motor on my (3 year old) Furnace/AC system. It cycles on
                Message 8 of 18 , Apr 20
                  I found the problem! I guess the good news is that it's from my house, not a neighbors.   

                  It's the motor on my (3 year old) Furnace/AC system.  It cycles on several times an hour to recirculate air in the house, even if the Furnace or AC is not running.  I had a chance to observe the cycle several times today, where the Furnace also comes on, which changes the nature of the interference.  I believe it is being coupled into my antenna system via some of the external control cables (at least I hope so), so I'm going to look at some clip on ferrite beads to see if that reduces the problem.

                  Thanks everyone for your suggestions.

                  Bill WB9KPT
                • Dave Cole
                  Hi, If you are going to the Eugene Swapfest Saturday, look me up. I will have a table there. 73s and thanks, Dave NK7Z http://www.nk7z.net
                  Message 9 of 18 , Apr 20
                    Hi,

                    If you are going to the Eugene Swapfest Saturday, look me up. I will
                    have a table there.

                    73s and thanks,
                    Dave
                    NK7Z
                    http://www.nk7z.net

                    On 04/20/2017 03:32 PM, wb9kpt@... [wsjtgroup] wrote:
                    >
                    >
                    > I found the problem! I guess the good news is that it's from my house,
                    > not a neighbors.
                    >
                    >
                    > It's the motor on my (3 year old) Furnace/AC system. It cycles on
                    > several times an hour to recirculate air in the house, even if the
                    > Furnace or AC is not running. I had a chance to observe the cycle
                    > several times today, where the Furnace also comes on, which changes the
                    > nature of the interference. I believe it is being coupled into my
                    > antenna system via some of the external control cables (at least I hope
                    > so), so I'm going to look at some clip on ferrite beads to see if that
                    > reduces the problem.
                    >
                    > Thanks everyone for your suggestions.
                    >
                  • Kai
                    Hi Bill, There are two main ways to reduce radiation from noisy wires, like power supply wires to a motor. (1) seek out a pair (plus and minus, hot and
                    Message 10 of 18 , Apr 21
                      Hi Bill,
                      There are two main ways to reduce radiation from noisy wires, like power supply wires to a motor. (1) seek out a pair (plus and minus, 'hot' and 'return') of the power supply wires to the motor, and twist them together as a pair, at about twist per inch if you can. Same with pairs of control lines/wires. (2) place a clamp-on choke at the source end of the twisted pair, possibly also on the 'sink' end of the cable pair. A third way is somewhat onerous; shield the entire assembly, or at least the power source, but that is usually not feasible.

                      Good luck,
                      Kai, KE4PT

                      On 4/20/2017 18:32, wb9kpt@... [wsjtgroup] wrote:
                      I found the problem! I guess the good news is that it's from my house, not a neighbors.   

                      It's the motor on my (3 year old) Furnace/AC system.  It cycles on several times an hour to recirculate air in the house, even if the Furnace or AC is not running.  I had a chance to observe the cycle several times today, where the Furnace also comes on, which changes the nature of the interference.  I believe it is being coupled into my antenna system via some of the external control cables (at least I hope so), so I'm going to look at some clip on ferrite beads to see if that reduces the problem.

                      Thanks everyone for your suggestions.

                      Bill WB9KPT

                    • zenithfan
                      Thanks Kai, I will look at my options (ferrite clamp on beads are on order) and report back to the group what success I end up having. Bill WB9KPT
                      Message 11 of 18 , Apr 21
                        Thanks Kai, I will look at my options (ferrite clamp on beads are on order) and report back to the group what success I end up having.

                        Bill WB9KPT
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