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Just hooked up an oscilloscope to my HF antenna feed line and it looks like I'm getting a large ~1 MHz signal from the antenna before being filtered in the transceiver to receive 14.074 MHz.
@neptune22222 The image shows a digital oscilloscope screen displaying a waveform. The oscilloscope is a RIGOL TD model, as indicated by the text at the top of the screen. The waveform is a blue, sinusoidal pattern, oscillating around a zero voltage line, which is marked at the center of the screen. The vertical axis is labeled with voltage values, and the horizontal axis is labeled with time values. The voltage scale at the bottom of the screen shows a range of 20.00 mV per division, and the time scale shows a range of 1.000 µs per division. The frequency of the waveform is indicated as 2.000 MHz. The screen also shows a cursor at the peak of the waveform, and the voltage at this point is displayed as 0.00V. The background of the screen is dark, with a grid of dots to help measure the waveform's amplitude and period.
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@neptune22222 local AM broadcast station?
Good point. Yes, I found a right wing AM radio station with very strong signal at 1.08 MHz. Ads about buying gold and besthotgrill.com. AM1080 Santa Cruz.
@neptune22222 KSCO has a fair bit of poke, 10kW day, 5kW directional at night. That'd induce a bit of voltage on your HF dipole!
@weezmgk Ah thanks.
Looks to be just under 80 mV p-p from about 4 miles away on my 23.5 foot vertical, half dipole.
@neptune22222 that's about right. Your antenna is working fine, if that's any consolation. If their xmtr is in good shape, without any significant spurs, it shouldn't bother you
@neptune22222 @weezmgk You might try an AM band notch filter, they are cheap
Edit: also not hard to DIY https://www.dxing.com/tnotes/tnote06.pdf
@mntn Shouldn't need to filter AM band, it's the harmonics from an AM BCB xmtr which would cause grief on amateur bands. Possible to see trash on the 80m band if the AM BCB xmtr was filthy, but I can't imagine any self-respecting US broadcast engineer to let that happen (I was one for 25 years). FCC would have you (and the broadcaster license) by the short & curlies. @neptune22222
@weezmgk @neptune22222 True, but some receivers (especially cheap ones) can be overloaded by nearby strong signals. I had a similar issue with an SDR. Real world example from someone: https://vk3il.net/projects/broadcast-band-filter/