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Author Topic: Buzzing/helicopter-type sound on SW (Tecsun PL-880)  (Read 6385 times)

AC8HF

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Buzzing/helicopter-type sound on SW (Tecsun PL-880)
« on: August 14, 2017, 02:20:46 PM »

A while back I bought myself a Tecsun PL-880 for SWL, as well as for its excellent FM performance (I love listening to baseball--Go Detroit Tigers!).  Alas, it sat unused for the last year or so, until the recent tension with North Korea got me thinking about shortwave again.  So, out came the '880, and I started scanning the bands.

What I notice is that I get a very strong buzzing or "helicopter" sound on every SW frequency, oftentimes louder than the static between stations, and always louder and more pronounced than the stations themselves (regardless of station reception).

The noise is not present on FM or AM -- both bands are crystal clear and a joy to listen to.

I don't recall hearing anything like this when I used to toy around with my ham radio with wideband receive.

I was about to declare this a problem with the hardware, when I remembered I have an emergency radio with SW receive, a Kaito Voyager.  It too has the same sound on SW.

Makes me wonder -- what kind of local interference could cause this sort of phenomena?  I live just a couple of miles from a major airport; perhaps that's the issue?  Is there any way to mitigate the problem?
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KAPT4560

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RE: Buzzing/helicopter-type sound on SW (Tecsun PL-880)
« Reply #1 on: August 14, 2017, 02:35:55 PM »

 It may be more local than the airport. Possibly a nearby switching power supply (like within 100' of you)?
If you walk outside or around the house, do you still hear it or does it change?
What it is may not be as important as where it is. Locating the source of RFI is the first step.
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RENTON481

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RE: Buzzing/helicopter-type sound on SW (Tecsun PL-880)
« Reply #2 on: August 14, 2017, 06:22:40 PM »

My first thought is RFI, just like KAPT4560 mentions.

Especially with it 'covering all HF frequencies'.

The fact that it's louder than all the stations is a clue that it's something in your immediate vicinity.

Perhaps a CFL bulb is starting to go.... they can still put out light, but also put out lots of hash over the airwaves before the electronics give out. I had one do this, although it wasn't on HF I had the RFI problem, but the low Medium Waves.

Either way, my guess is that your signal is RFI of some type.
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WA8ZTZ

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RE: Buzzing/helicopter-type sound on SW (Tecsun PL-880)
« Reply #3 on: August 15, 2017, 02:03:34 PM »

Ditto on the RFI/EMI especially since you hear it on both radios. 
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AC8HF

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RE: Buzzing/helicopter-type sound on SW (Tecsun PL-880)
« Reply #4 on: August 15, 2017, 03:04:25 PM »

Well, I took the Tecsun to work — a modern office building — and didn’t hear the same interference (though I also didn’t really pull in any stations, though not a surprise).

So, definitely something local to the house.
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