Hi Mike,
I too did FFT using both my oscilloscope and a software based audio
oscilloscope and will post them on a website and share it with the group in
just a little bit. I also did it on a known power line RFI source that’s
arcing 2 times per half cycle for comparison.
Standby.
Don wd8dsb
On Wed, Nov 26, 2025 at 7:40 AM Michael Carter via RFI <rfi@contesting.com>
wrote:
>
> I generated a FFT spectrum estimate of Jeff's 'Noise 1a 20 kHz BW' audio
> file and attempted to post it to the reflector, forgetting of course that
> this reflector doesn't allow image content embedded in posts. I sent that
> email direct to K9YC and W4DD, and hope that Jeff can add it to his Google
> Drive page.
>
> For anyone wishing to generate their own spectrum estimate, I used
> Audacity with FFT size 8192 points, Hann windowing. The 60 Hz line and its
> harmonics are prominent.
>
> 73,
> Mike, K8CN
> ________________________________
> From: RFI <rfi-bounces+mike.carter=unh.edu@contesting.com> on behalf of
> Jim Brown <jim@audiosystemsgroup.com>
> Sent: Tuesday, November 25, 2025 11:12 PM
> To: Rfi List <rfi@contesting.com>
> Subject: Re: [RFI] RFI Signature
>
> CAUTION: This email originated from outside of the University System. Do
> not click links or open attachments unless you recognize the sender and
> know the content is safe.
>
>
> Can you do an FFT of this, Don?
>
> Jim
>
> On 11/25/2025 5:09 PM, Don Kirk wrote:
> > One is the oscilloscope display of your noise which I called "RFI
> > being investigated" when you were using 20 KHz bandwidth. T
>
>
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