Noise at 10 Mhz...

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kd5ywa

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I have a noise issue, at 10 Mhz. I tune to this regularly because of the WWV time clock station. But now I have noise... quiet noise, doesn't sound like static...sounds like someone has an open mic. Yet my signal meter is not showing any signal strength. It saturates from 9800 kHz to 10500 kHz, and is prevalent all day long. I have also notice around the house too that cell reception is terrible with static and Verizon has told me to turn on my wireless calling. (all of which may be unrelated) Yet... this all started several months ago, and has become annoying.

I have a Yaesu FT-897 with an Alpha Delta dipole. The noise is also heard upstairs with my little Grundig shortwave radio.

FYI... a large solar farm about five miles from here has been build yet is not online. It consist of about 125,000 300Watt solar panels. The construction on it started in April of this year.

Anyone have any trouble shooting ideas?
 

ka3jjz

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Your little Grundig could be used as a rough direction finder, Fully collapse the whip and see if you can walk around and find where the noise is coming from. Wear some light gloves so your hand capacitance doesn't skew your results. You may need to turn on the attenuator (if it has one) to further limit the signal, since the AGC in these little radios (if it has any at all) might make it rough to try to find the strongest direction

Mike
 

kd5ywa

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I will do that... I have a lot of land too, and I will go all over it to start looking for it. Also for kicks, this is a pic of the waterfall.
 

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jonwienke

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It could be a harmonic of the switching transistors in the solar panel controllers. If so, the noise will probably be more prominent on sunny days.
 

bharvey2

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A birdie comes to mind. Does your radio have an IF Shift knob? That might attenuate the noise a bit.
 

ka3jjz

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Good thought but it's unlikely that exactly the same birdie would show up on precisely the same frequency on 2 very different radios. Possibly, but highly unlikely

Mike
 

bharvey2

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I missed that it was showing up on two radios. Yeah, unlikely its a birdie. Might try powering down things in the house and go hunting with the Grundig on batteries.
 

bharvey2

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It occurred to me that I should have explained this. Superheterodyne receivers have oscillators that are part of the receiving stages/circuits. In some cases, your receiver is hearing those internal oscillations. If you do any scanning and were to scan a frequency range, your scanner will often park or stop on those signals. You can consider them to be phantom signals that aren't generated from an outside source such as a radio transmitter. Often they appear as a dead carrier so at first blush, that is what I thought you were describing. Since you had the same problem with two different radios, it is unlikely that this is the cause, While not impossible, two radios, especially for different brands and designs wouldn't likely have birdies on the same frequencies. I hope that clears things up.
 

kd5ywa

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I took the little shortwave radio out into the country about five miles and I could hear the wwv signal on 10 Mhz, but that was when I raised the little antenna up all the way. Otherwise with the antenna lowered... I hear much of the same as I do at home. Yet only for a moment did it appear to get worse when I pointed it in the direction of the solar farm... What in my home could be producing a harmonic hum that wipes out all signal for a 1000 kHz bandwidth range? I have a house full of kids and a husband. I would love to kill the power to the home and see if I can find it, but I may have to wait till everyone is gone! hee hee..
 

ka3jjz

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See message 4 of this thread. A royal pain, to be sure, but it sounds like it's possible that solar farm that's being built is the cause of your issue, especially since it's stronger when you pointed the radio in that direction. And of course, that signal would propagate just as any other HF signal would, so I can see where you'd hear it even at some distance.

Fortunately WWV transmits on 5 Mhz which you can hear at night, and 15 Mhz during the day

Mike
 

kd5ywa

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Ok...one more goofy question, (because I just know that everyone knows and I don't) why would I have this "quiet" noise, that has no sound, very little static, like an open mic, ... have a strong visual harmonic signature on the waterfall, yet no S meter reading? If it is that strong, what is it not registering on the S meter?

I plotted it with my Radio Sky Pipe program for 24 hours and the graph show where it detected changes in the noise floor. It also detected spikes which I am hoping was the WWV. The only really problem with the program is that it detects changes in the sound cards audio levels... and since the noise is not very noisy there was very little change. Plus some of those spikes could just be AC draws within my house from the fridge or my water pump.

And one more question, anything I can do to be rid of it if it is the solar farm?
 

a29zuk

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The MFJ-1026 noise canceller works well for eliminating unwanted signals.
You will have to put up a second antenna for a noise aerial, though. Once you receive the unwanted noise on both antennas equally the unwanted signal can be phased out.
It works very well at my location.
I believe Timewave still makes a similar noise eliminator too.
They both have gotten good reviews on eham.net

Good Luck,
Jim
 

majoco

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why would I have this "quiet" noise, that has no sound, very little static, like an open mic[unquote]

Exactly that. It's just a carrier with no modulation. The carrier brings up the AGC voltage which makes the noise reduce. A good receiver does not necessarily raise the "S" meter on a low signal level, but will reduce the noise before it gets to S1. It does seem strange that your signal is on 10Mhz and it's harmonics - almost like a crystal calibrator is running somewhere.

What I do find strange is that there are no other signals at all - where are the signals that I would have expected to see in the 19m band? What local time was this waterfall recorded?
 

kd5ywa

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The waterfall looks like that all the time. The "noise" as of right now measures from 10.600 Mhz to 9.600 Mhz.
 
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