This session was very good on domestic paths. While some areas reported high noise from storms that exited the central US earlier in the session, it was a quiet night here. Doug, K4LY / WH2XZO, in South Carolina reported noisy conditions once again but he managed to decode eight WSPR stations and was heard by 46 unique stations, including many stations in the West where noise was very low. Some nice and surprising openings were observed on the trans-Atlantic path and while the trans-Pacific path seemed less reliable than previous sessions for some, there were also some nice peaks in the morning in spite of storms to the East of Brisbane. Roger, VK4YB, only issued a “code 3” for this session, however:
G1 storm levels are in effect with G2 level expected in the coming 24-hours as a coronal hole becomes geoeffective. The Bz is pointing to the South and numerous reporting periods at consecutive storms levels have now pushed solar wind velocities to an average of 530 km/s. DST values are negative, suggesting disturbed band conditions:
WD2XSH/17 was the sole station to receive stations on the trans-Atlantic path from Europe, which is not surprising given the current state of the geomagnetic field. Most notable of the four stations decoded, IK0VVE, reports that he was using 50 mW ERP. Location is everything!
Ken, K5DNL / WG2XXM, reports that he decoded nine WSPR stations and was decoded by 46 unique stations in 12-hours of operation including VK4YB:
Larry, W7IUV / WH2XGP, reports that he decoded eleven WSPR stations using the omni antenna, including VK4YB and some eastern stations which have otherwise been a challenge recently. He was decoded by 44 unique stations including VK4YB, VK2XGJ, ZF1EJ and a number of eastern stations. Larry indicates that he was hearing VK4YB quite a bit earlier than he was being heard and first decodes came near sunrise:
Joe, NU6O / WI2XBQ, reports “Good prop to E, TP not as strong as last night. Low noise, overall very good condx. 4QR 612khz jumped up to +30, and spotted by vk4yb, so maybe TP is peaking now.”
Neil, W0YSE/7 / WG2XSV, provided the following statistics and comments:
Roger, VK4YB, reports the session started out very average with improvements later as the QRN subsided. He posted the following statistics on the ON4KST chat / logger:
“Rx 1*wg2xxm (-26) 4*wh2xgp (-20) 26*wh2xxp (-15) 3*wi2xbq (-24) 17*wh2xcr (-17)
Tx 10*wh2xgp (-22) 9*ve7bdq (-22) 1*wi2xjq (-28) 18*ve7sl (-23) 7*w6xy (-22) 6*wd2xsh/20 (-18) 6*we2xpq (-22) 4*wh2xcr (-25)”
Phil, VK3ELV, was reported late in the previous session by JH1INM and JH3XCU:
Ward, K7PO / WH2XXP, was decoded by 53 unique stations including four VK’s in what he described as “Good conditions from AZ overnight”:
Rick, W7RNB / WI2XJQ, reports “…I think the activity was down, on RX, but TX went quite well from what I see in the spots. Appears to me that the band is changing. Was very happy to see VK4YB in again, probably becoming consistent and was spotted by KU4XR…”:
Larry, WD0AKX, in Minnesota, posted a comparison video of his impressions of the PA0RDT E-probe compared to an 80-meter dipole. I believe that he has been using the dipole very successfully for 630-meter receive over the last year:
Domestic conditions were very good here in Texas with many persistent CW-level reports across North America. Low noise helped tremendously. I operated JT9 for a few minutes near sunset in the Pacific Northwest in hopes of being detected by WG2XSV’s remote JT9 receiver to no avail but I was decoded in the lower to mid -20 dB S/N in the early evening. This morning’s CW session yielded no additional QSO’s but my morning CW sked at 1030z was easy listening. After QRTing from the sked I spent some time on 160-meters. Pacific signals were poor and there was only a minor peak on H44GC 10 minutes before local sunrise. It was not enough for a QSO. This behavior seems to be a common theme for many stations on the Pacific path during this session on 630-meters as well. My 630-meter receive report can be viewed here and my 630-meter transmit report can be found here:
WSPR activity was very high overnight, with 105 MF WSPR stations observed at 0200z on the WSPRnet activity page. KK4MBI was observed as a new receiving station. Welcome aboard!
Regional and continental WSPR breakdowns follow:
There were no reports from the trans-African path.
Eden, ZF1EJ, had a strong and identical session on both of his active receivers with reports into eastern Washington and British Columbia:
Laurence, KL7L / WE2XPQ, experienced relatively consistent reports for WH2XCR and VK4YB during this session compared to the previous session in spite of the K-index spiking to 5+. He also seemed to have a relatively successful session in the western areas of North America, both hearing an being heard by others:
Merv, K9FD/KH6 / WH2XCR, experienced another strong session of East / West propagation with strong reports into the eastern US, including WA3TTS in Pennsylvania and SWL/EN61 in Indiana. The trans-Equatorial path yielded good results to VK in spite of the storm levels, even being reported by VK7TW in Tasmania:
Jim, W5EST, continues yesterday’s discussion with “PART 4B: 630M RX MAG LOOP CALCULATOR TABULATIONS”:
“Yesterday’s blog suggested optimizing a mag loop limited by conductor weight to get turns and wire size.
Today, to get some background information to inform such an optimization procedure on another day, I simply entered some dimensional values into the DG0KW loop calculator (blogged Sept. 19). That way gets us some estimated values of radiation resistance* designated Rrad , and metal resistance** Rmetal . For a single wavelength like 630m, Rrad depends only on the loop area A (or diameter if circular) and the number of turns N. Rmetal further depends inversely on conductor diameter d. In the TABLE, I’ve assumed copper conductor of circular cross-section for the wire or tubing. Loop diameter 2.6m equals 8 feet.
The first five entries involve tubing, and the second five entries include wire sizes as listed. The wires are all spaced across a width of 102mm (4”), which the DG0KW calculator calls coil “Length.”
I’ve assumed that tubing can be represented on the calculator by solid conductor using the same diameter as of tubing. Either way, there’s probably comparable resistance because of the skin effect. Resistances are stated in milliohms (.001Ω = 1mΩ).
The Ratio column is equal to self-resonant frequency of the coil divided by operating frequency (all squared). Large ratio values mean that the self-capacitance*** Cself desirably fails to shunt much current from the antenna output.
The capacitive reactance between the turns needs to be high to avoid shunting current from the inductive reactance of the turns away from the loop output and uselessly back into the internals of the loop coil. Probably above about 8 turns, 630m performance of a loop antenna starts trading off with current-shunting by its self-capacitance unless one makes the loop width very wide to sufficiently space the turns.
* Radiation resistance of a magnetic loop Rrad=~ 0.312 [NA/λ2]2 milliΩ where loop area A=πD2/4 (m2) . Express operating wavelength λ in hundreds of meters, here 6.3; and N is number of turns. See Equation 12.10 at p. 3 of this white paper (Nikolova 2014).
**Metal resistance is RF ohmic resistance including skin effect.
Rmetal ~ (ND/d)sqrt[ρ2πf μ0/2] Ω. On 630m, Rmetal ~ 178(ND/d)milliΩ in copper. Use:
Diameter D(m) of a circular loop with N turns, diameter d of conductor(mm), and signal frequency f =0.4755 MHz. Rho ρ is DC resistivity of the metal. For copper Cu, ρCu=1.68×10-8 Ω-m and ρAl =1.58 ρCu. μ0=1.257uH/m free space magnetic permeability.
Compare the above formula with the metal resistance formula (scroll 70%) in:
*** Let the self resonant frequency fself = 1/[2π sqrt(LCself)]. The 630m operating frequency is given by f = 1/[2π sqrt(LC)]. Use the resonating capacitance C and self-capacitance Cself values from the TABLE. (f/fself)2 = C/Cself .
Self-capacitance is discussed and estimated in a G3YNH white paper, see p. 39.
Additions, corrections, clarifications, etc? Send me a message on the Contact page or directly to KB5NJD gmail dot (com).