Guess this thread needs a new title... Paul's LWPC interface is here: http://abelian.org/lwpc/ It seems that the broad midday maximum appears consistently on different medium-range VLF paths, also on
Paul, Thanks for making the 12-month plot of NAA - Todmorden diurnal amplitude (and for the effort that went into a year of quality data capture). After Markus mentioned the broad midday maximum I se
Paul, Thanks; as always, great data and analysis. After reviewing the six (including 1 previous) plots, I scrolled back and forth through them; in sequence they make a compelling picture. The prognos
Paul, With each piece of data (your NAA/WH2XBA 3-day amplitude below) this becomes more interesting. Summarizing some previous discussion and thoughts: NAA amplitude and phase are stable and repeatab
"Antenna current is essentially constant during the transmission with negligible tuning adjustments" "Some little shift of phase and amplitude of the modes involved, altering the interference pattern
Alan, Good point regarding a possible additive process that could disproportionately affect a small signal; and I agree with all of your points regarding phase, and add that the repeatability of NAA
Some real good work Paul!-Bob > Date: Mon, 10 Mar 2014 22:07:43 +0000 > From: [email protected] > To: [email protected] > Subject: Re: LF: Daytime 29.499 kHz > > A better signal last nig
Paul, Thank you for the data and analysis. The WH2XBA/1 and WH2XBA/1 - NAA phase and amplitude plots are fascinating. Thanks to you and Bob for providing this valuable information (and great SNR!). T
Paul; Wonder what effects soil conductivity changes has on the propagation at these VLF freqs?? Temperature here this pasted week has been and averaged 4-8 F degrees. Yesterday and last night temp cl
Paul; It is not only the ground but the air temp has great influence and maybe much more than the shallow depths of the ground freezing-Bob > Date: Sat, 8 Mar 2014 17:06:09 +0000 > From: vlf0403@abel
Bob, Some information below on the effects of above-freezing and below-freezing temperatures on various VLF losses, including (a) ground-wave losses, (b) near-field ground effects losses and (c) skyw
Jim, I use to receive SAQ from Grimeton on 17,2kHz here in southern Germany in winter always significantly stronger (I really mean signal strength, not SNR) than in summer. Distance is a bit less tha
Markus, I found a typo: At 30kHz, ground-wave loss in non-frozen soil of poor conductivity (10^-4 mhos/m) might be 20dB greater (20dB more loss) than in non-frozen soil of fairly good conductivity (1
Clemens, Not necessarily; two possibilities come immediately to mind: trapped surface wave and a change in the modal interference pattern (from phase changes due to ice and/or frozen soil, a change i
Markus, Thank you for the feedback. I have a feeling that with discussion, the group might make particularly quick progress on electrically short VLF antennas for long-range paths. It’s an area
Dumb question but just in case: was the quick phase change of 120 degrees corrected prior to integration? Jim AA5BW I think the propagation at 29.5 has changed, even though NAA looks normal at 24kHz.
Some plots of NAA amplitude and phase for the recent few days http://abelian.org/vlf/tmp/naa140301.png http://abelian.org/vlf/tmp/naa140302.png http://abelian.org/vlf/tmp/naa140303.png http://abelian
