-
You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.
Band pass filter
- Thread starter nfsus
- Start date
No. Band pass filter is for stopping harmonics above a certain frequency from being radiated by the antenna system. Or for only letting a certain range of frequencies be received and/or transmitted.
Lightning crashes are very very very wideband, covering from longwave way up into VHF, so there's no real way to filter them........
DSP can help to some extent though.
Lightning crashes are very very very wideband, covering from longwave way up into VHF, so there's no real way to filter them........
DSP can help to some extent though.
No it works. Trying to knock out lightning, local electric noise and just atmospheric noise in general.
local electrical noise & other local types of RFI can almost always be dealt with by using an MFJ-1026, or similar phase-cancelling device. Pretty much impossible to reduce lightning or atmospheric noise though..........
I have the MFJ unit and it will easily take 9 S units of power line arcing noise down to 1 S unit or less.....
I have the MFJ unit and it will easily take 9 S units of power line arcing noise down to 1 S unit or less.....
Think of a lightning stroke as the most broad-banded pulse of RF energy on the planet. Literally from DC beyond visible light to X-ray light and everything in between. Any small slice of the electromagnetic spectrum contains only a small percentage of the gigaWatt pulse energy, but that still adds up to a lot.
That energy will be found within the passband of any filter, just like the signal you want to hear but can't because of the lightning crash.
Wish I knew more DSP programming. Always suspected that if your DSP was listening to a "quiet" frequency as well as the frequency you want to hear, it could correlate the lightning waveform from the "quiet" (lightning pulse-only) channel and subtract it from the voice channel.
And that's as far as I have ever gotten with the idea. Kinda like a noise blanker, but in the frequency domain, not just the amplitude domain.
73
That energy will be found within the passband of any filter, just like the signal you want to hear but can't because of the lightning crash.
Wish I knew more DSP programming. Always suspected that if your DSP was listening to a "quiet" frequency as well as the frequency you want to hear, it could correlate the lightning waveform from the "quiet" (lightning pulse-only) channel and subtract it from the voice channel.
And that's as far as I have ever gotten with the idea. Kinda like a noise blanker, but in the frequency domain, not just the amplitude domain.
73