I am the net manager of two NBEMS nets, one on 80m (PaNBEMS) and one on 40m (MidAtlantic NBEMS).
Both nets meet Sunday mornings: PA at 7:30 AM Eastern and MidAtl at 10 AM
Conditions are usually stable on 80m up to 9 AM when the D layer kills RF.
Conditions are variable on 40m at 10AM based on the solar cycle.
We are only interested in EMCOMM over the mid-Atlantic region, not DX
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For preamble and taking checkins, we use THOR22 (500 Hz BW and 80 wpm) at 22 tones/second (baud).
If conditions are marginal with QSB, sometimes a signal fades and we get no print, so we ask all stations to check in with their call TWICE, then name, QTH and traffic/no traffic ¡. ?and we ask for checkins to report the net control¡¯s S/N as reported in their FLdigi waterfall (lower left). ?That gives the net control a quick sense of propagation.
Both nets take over 30 checkins and sometimes up to 60 checkins, from PA/MD/DE and NY/NY and most of New England and as far south as VA and NC.
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As I watch and listen, often the print gets somewhat garbled at about -10dB with THOR22.
So when I am net control, I consider switching to THOR11 (a gain of 3 dB and still about 40 wpm).
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When we switch to traffic mode, we often move to THOR32 or MFSK32.
I know these both need a decent S/N or we get gaps in a FLMSG (bad file) or missing blocks (FLAMP)
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If we try THOR56, we often get many reports of missing blocks, so don¡¯t try Thor56 now.
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Because of QSB, the signal may vary on my S meter (radio) by TWO S-units, or about ?10dB.
So the trick is not to estimate the avergage copy S/N but rather to consider who will miss data during the dip in signal.
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Dave W1HKJ has charts that show the expected S/N levels but my experience on morning nets is that if the S/N of MY Fldigi is -5dB to +5 dB that I will likely copy 100%. ?When the signal drops to -10dB (average) I know I will miss a bit of data, which is frustrating since then RESENDS are required, which slows down the net.
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Does that help?
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A casual chat with THOR is very different from an EMCOMM net using THOR where we want copy of traffic with NO errors.
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Dave - where are you located and what is your FCC call?
We can run some tests if we have prop between our stations.
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de k3eui Barry
Pa and MA NBEMS nets from eastern PA
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K3EUI Barry