Reports from individual operators suggest that last night was a much improved session compared to the previous in spite of more stations being off air due to storms. I was fortunate to be able to receive for a few hours during the evening as storms approached from the Northwest. The broadside multi-turn receive loop did a nice job eliminating a significant portion of the noise during the evening here and I was able to decode WSPR signals from WG2XXM, WD2XSH/15, WH2XZO and WH2XXP before shutting down around 0400z. Other experienced similar improved results, including Phil, VE3CIQ, who decoded six WSPR stations and was decoded by ten unique stations including WH2XGP and WH2XXP, both of which have not been seen in more than a week. Phil is using a new E-probe and has been making some very good observations which can hopefully be detailed here in the near future.
Solar and geomagnetic conditions were quiet during the session although several periods of elevated solar wind velocity were observed, up to moderate levels above 400 km/s. The Bz was generally pointing to the North, in many cases strongly. Elevated protons were observed in the late afternoon during this session.
Neil, W0YSE/7 / WG2XSV, was one of the stations that was not transmitting during the session but he was able to receive during the session using an E-probe and provides these statistics and details:
Neil also notes that he remeasured his base current which is reporting 1.55 Amps for 1.4-watts ERP or just over 2-watts EIRP. He attributes the increase to improvements in his ground system and additional power from the amplifier as he drives it a bit harder.
Larry, W7IUV / WH2XGP, received a report from John, VK2XGJ, during the session.
Ward, K7PO / WH2XXP, reports that he was decoded by thirty WSPR stations including decodes from VK2XGJ and VK4YB.
Neil and Steve, VE7SL, also brought to my attention a shake-up with the WSPRnet system. It seems that Bruce, W1BW, who is the site owner and primary administrator, has decided to step aside and is soliciting volunteers with the appropriate skill set and time to help maintain the site. I think this has been a long time coming and there is nothing wrong with getting some help to maintain a system that has become so important to many of us. I do have some strong opinions related to what led up to this decision for change. Some very rude comments were posted on a number of email reflectors about the most recent outage. Frankly, I am embarrassed as an amateur, a human, and a WSPRnet user that some people would make such uninformed, off-the-cuff statements about the system, that experienced a 12-hour outage this past Saturday – ITS A FREE SERVICE TO USERS, OPERATED BY VOLUNTEERS WHERE USERS HAVE NO RIGHT TO ANY EXPECTATIONS! The system has experienced 100% uptime since Bruce made significant improvements to the capacity of the system in January. We don’t know what the outage might have been caused by. It could have been a power or Internet problem at the server farm which would be completely out of Bruce’s control, yet people treated Bruce like he is some kind of monster because the system was down. We see this insanity with other facets of society as well, including stereotypes related to social media down time. As a power user of WSPR data, I can say that the reliability has been exceptional since the upgrade that Bruce made in January and I want to apologize to him for some of the comments made by an insensitive, uninformed “mob”. The formal statements from Bruce, provided both Steve and Neil, are provided below:
Regional and continental WSPR breakdowns follow:
There were no reports from the trans-Atlantic or trans-African path. UA0SNV was present but no reports were found in the WSPRnet database. Eden, ZF1EJ, was also reported as present but no reports were found in the WSPRnet database. Its possible that this may have been an upload problem as this has happened recently.
Laurence, KL7L / WH2XPQ, continues to operate a receiver from Hawaii while on work assignment and is transmitting and receiving from Alaska. The high latitude paths don’t appear to be terribly poor after all of the recent geomagnetic activity.
Merv, K9FD/KH6 / WH2XCR, continues to do well, with two-way reports at VK3ELV and VK4YB, and reception reports at VK2DDI and VK2XGJ. Eric, NO3M / WG2XJM, is the eastern-most station in North America to report Merv during the session.
In Australia, Phil, VK3ELV, and Roger, VK4YB, continue to see two-way reports with WH2XCR. Phil received late reports from JH3XCU from the previous session but at the time of data gathering for this report no additional reports from Japan have been received.
Jim, W5EST, continues his recent thoughts with this discussion, entitled, “PART 3: ENERGY IS COMMUTING BETWEEN YOUR ATU AND ANTENNA”:
“The last couple of days I’ve talked about displacement current in your antenna capacitance and displacement current in your radiated signal. Recall that an MF/LF antenna system is like an RLC circuit that your transmitter drives. “C” is the antenna system capacitance. “L” is the loading inductance of the antenna tuning unit (ATU). “R” combines the ohmic resistances—earth ground and any radials, plus antenna conductors and a little MF/LF radiation resistance.
The ATU loading inductance forces its energy into the antenna capacitance. A quarter-cycle later the antenna capacitance returns the energy into the ATU loading inductance. Then the ATU forces its energy into the antenna capacitance again but with opposite voltage polarity, and in another quarter cycle the energy is forced back into the ATU, whereupon a new cycle begins.
It’s like blowing up a balloon with one deep breath and then letting the balloon blow air back into you, and so on. Like your workday in miniature, the energy is shuttling or commuting back and forth from “home” in the ATU to its “workplace” in the antenna where something useful gets accomplished and then the energy returns “home” again!
Your transmitter initially energizes this repetitive process. In about 100 microseconds after transmission starts, the TX has “pumped up the LC swing,” so to speak. Thereafter, your TPO is simply making up for the dissipative losses and radiated power emission implicit in the resistance “R” of RLC.
How much energy? How much power are we talking about? The peak energy in the 110 pF example of MF/LF antenna capacitance is half the square of its peak voltage times the capacitance. Capacitive Energy= ½ CV2. In the MF/LF antenna example I used Jan. 15-16, this blog, the RLC antenna system resonated at 630m, consumed 200 watts TX power (TPO), stood 70′ tall, and featured 20 ohms, 1mH, 110pF, 3 RF amperes rms, Q=150, 13KV antenna peak voltage.
Energy = 0.5 x 110 x 10-12 farads x (13 x 103 volts)2 ~= 9 milliJoules.
Every half-microsecond quarter-cycle at 475 KHz, about 9 mJ are “commuting” to the example antenna. A quarter-cycle after that, the 3A rms RF antenna current has turned around and “charged up” the magnetic energy inside the 1 mH loading inductance: half the square of its peak current times the inductance. Inductive Energy = ½ L I 2. The 1 mH loading coil acquires a nearly equal energy:
½ x 1mH x (4.24A peak)2 = 9 mJ, minus some ohmic losses on the way.
In each quarter cycle that’s an average rate of energy transfer over 17,000 watts!
9 x10-3J / 0.52 x10-6 sec. ~= 17000 watts.
Believe it or not, that’s what the high antenna Q=150 entails in this example.
The shuttling of energy to and from the antenna capacitance is manifested in the changing electric field there. Current in the vertical antenna section is encircled in the inductive magnetic fields it makes. Displacement current corresponds to changing electric field as discussed April 19, this blog. Displacement current contributes a magnetic field too. There’s a radio wave in embryo, somewhere.
Out to a fraction of a wavelength —I calculate out to roughly 100-200 meters at 630m–the mixture of electric fields and magnetic fields arising in their various ways constitutes what’s called the near field. Meanwhile the antenna is radiating, which constitutes the far field more remotely.
The near field zone is a complex place that includes both non-radiative electric and magnetic fields as well as your RF signal power (TRP) getting launched. It’s an interesting place–if only because your shack and your home are tenuously immersed in it! For the most part, these fields are like those associated with any inductor and capacitor as well as boomerang “wannabe” electromagnetic waves that never get launched. The unradiated fields in the near field nevertheless harbor the vast majority of the energy that “commutes” and enters the MF/LF antenna system each half-cycle from the ATU.
You could say a 630m TX antenna develops an energetically “hot” hemispheric ball of inductive and capacitive energy within about 200m of a 70’ vertical, with or without top hat. This hemispheric, mostly-nonradiating ball of energy is close to the antenna because that’s where the strongest electric and magnetic fields are found. The ball of energy has an indistinct, fuzzy boundary where some of the energy “evaporates” and steams outward so to speak. That’s the RF signal radiation you constructed the antenna to send skyward. Only a few watts are radiated compared to the thousands of watts commuting to the antenna.
Since your antenna is probably electrically small, 70’ or less, how do all those fields in the near field come to be? In other words, how do the propagating radio waves of your RF signal ever get made? Let’s dig into the innards of the near field in another blog post!”
Additions, corrections, clarifications, etc? Send me a message on the Contact page or directly to KB5NJD <at> gmail dot (com)!