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+--- Thread: A delay when lightning shows up on 80 Mhz (/showthread.php?tid=3862)
A delay when lightning shows up on 80 Mhz - andrewalvarez - 2024-05-24
Why is their a delay when lightning shows up on 80 Mhz when detected by lightning detectors used at lower frequencies hosted online?
Stupid question because I think I know the answer but have forgotten it
I see lightning at Blitzortung.org but on RSP1a it shows up on 80 MHz 5 second later slope
RE: A delay when lightning shows up on 80 Mhz - cutty - 2024-05-24
(2024-05-24, 05:02)andrewalvarez Wrote: Why is their a delay when lightning shows up on 80 Mhz when detected by lightning detectors used at lower frequencies hosted online?
Stupid question because I think I know the answer but have forgotten it
I see lightning at Blitzortung.org but on RSP1a it shows up on 80 MHz 5 second later
First, how do you know your SDR system is indicating the same impulse chain event?
Second, VHF and VLF systems look for totally different energy characteristics.
Third, How are you correlating between the two types of reception?
Generally, your 60-80MHz receiver SHOULD be up to 20 seconds ahead of the VLF c-g stroke, captured and displayed by the Blitzortung VLF network, rather than 5 seconds behind, since the higher frequencies reflect low energy, very short duration inter-cloud cascades preceding the very high energy, long duration c-g ground discharge we locate using VLF and GPS time with TOA and TOGA. Some lightning detector systems suggest those VHF precursor cascades can occur 10, or more, seconds before an actual c-g impulse begins.
So, if you ARE receiving the same event, then your SDR and processing is horribly slower than, for example, the Blitzortung network, which typically will display on-line 5-10 seconds after the ground stroke. In fact, what you claim to observe could be actually 20 seconds behind what you are attempting to correlate. So, I suspect what you think you're seeing isn't reality, when compared to a VLF locating system, and if you're comparing to a VHF detection system, then you're simply slower.