Last night was a much better session in spite of a cluster of Atlantic storms that must have made listening challenging along the eastern seaboard. Even so, a single trans-Atlantic report was recorded. It was a very quiet night here in Texas. The band seemed very strong early on, particularly on the path to northward to Wisconsin where a number of stations have recently joined the fray and providing strong WSPR reports.
The geomagnetic field was quiet and stable through the session, with the Bz pointing north. Solar wind diminished to levels below 400 km/s.
In Europe, there were a number of reports of JT9 activity, as many stations work towards making last weekend’s activity night a regular occurrence. A station named “Vinny” (no call sign included, but appears to be from Germany) posted a report on the RSGB “blacksheep” reflector of hearing SV8CS, LA3EQ, YO2IS, OM1II and 9H1BT. Other reports include activity from DC1RJJ, DL6II, SV3DVO, F4DTL, DG3LV and ON7YD. Hopefully additional stations will join the action and this can continue to be a weekly or monthly activity.
The WSPRnet activity page reported 86 MF WSPR stations at 0140z. I suspect the number was much higher as I was active on the band but not reported in the list. A number of new or newer returning stations were active last night, including W0AEW, VE6ZC, AB4DF, WW7Y, WF7T, WB0VAK, WD0AKX, and NX0P. While there was daytime activity, no data was gathered as I was attending a hamfest.
Regional and continental WSPR breakdowns follow:
My neighbor Jim, WB5WPA / WH2XQC, and Brian, W1IR / WG2XPJ, returned to air on 630-meters last night. Both stations did exceptionally well and it my presumption until I hear otherwise that Jim is using the “Edginton” resonant loop that fits in a suburban backyard while Brian is using a full-sized dipole approximately 2-meters high in virtual “loop” mode.
I had a bit of insomnia around 0700z so I called CQ for a bit on JT9 near 1200 Hz while getting some work done. No QSO’s were recorded as most normal people were asleep or if they were awake they had projects that gave them a good reason to be. My WSPR waterfall was quite active as the following screen capture indicates:
Vasily, UA0SNV, and Michel, FR5ZX, were present on the band during the session but had no reports in the WSPR database.
In spite of stormy weather in the Atlantic, Dave, AA1A / WD2XSH/17, was able to receive Stefan, DK7FC, for a single report during the session:
In the Caribbean Eden, ZF1EJ, sees a return of the path to Merv, K9FD/KH6 / WH2XCR, in Hawaii:
In Alaska, Laurence, KL7L / WE2XPQ, had what appears to be a relatively typical session with reports in the western US and Pacific Northwest as well as Hawaii. KL7L was once again designated for receive-only.
In the Pacific, Merv, K9FD/KH6 / WH2XCR, had two-way reports as far east as WG2XJM in western Pennsylvania. The path to JA, which has been open so regularly, was not open during this session but the path to John, VK2XGJ, returned. While the path from KH6 to KL7 appears to have been somewhat degraded, the reciprocal path was quite active, with in excess of 100 reports from WE2XPQ at WH2XCR.
Additional anecdotes, comments, statistics and information follow:
Larry, W7IUV / WH2XGP, reports that his antenna is iced up again and he will be QRT until further notice.
Joseph, NU6O / WI2XBQ, reports antenna testing at 500-watts TPO. In previous tests, arcing occurred. No reports of arcing in the most recent test.
Neil, W0YSE/7 / WG2XSV, reports that he spotted Laurence, KL7L / WE2XPQ, 17 times through the session with -22 db S/N as best report.
Jim, W5EST, provided the second part of his comments on transmit antennas on 630-meters:
“PART II. VIEWPOINT: 630M TRANSMIT ANTENNA TOP HAT
Without some top hat capacitance, a 630m vertical may spark like a big Tesla coil. Using a top hat means fewer loading coil turns too. So 630m ops may use one to four top hat wires spreading horizontally from the top of the vertical. A Marconi-T uses parallel top hat wires.
Separate the top hat conductors well away from tree branches and leaves in all seasons to avoid starting a tree fire. Make top hat wire diameter generous and wire-ends bulbous to resist needle sparking. Later, visually doublecheck antenna with binoculars at night with TX powered up. Keep its voltage below breakdown field 33KV/cm. Reduce power or QRT in rain and fog.
Estimating air breakdown voltage itself is difficult, very roughly Vbreakdown ~20,000 volts. Measure antenna RF current I with an RF ammeter if available. Total resistance R includes all ohmic resistances Rground+Rcoil+Rvertical+Rtophat+Rradiation. Resistance R = P / I2 ranges from many tens of ohms (poor) down to ~10 ohms depending on construction. At 475 KHz run transmit power level P and antenna RF current I (rms amperes) that avoid antenna sparking.
Vtophat = L I 2π 475 sqrt(2) = L sqrt(P/R) 4200 volts < Vbreakdown
Since Q = (2π 475)L/R, that also means Vtophat = 1.4 Q P / I < Vbreakdown.
Adjust the loading coil tap or variometer for 1:1 SWR. V is voltage, L coil inductance in milliHenry units as used at 1:1 SWR, P is TX forward power watts. At best, reflected power is power stolen from antenna, so zero it! At worst, reflected power means a broken antenna system.
So much for theory. Tell us your real transmit antenna story!”
Additions, corrections, clarifications, etc? Send me a message on the Contact page!