This was a really weird session on a number of accounts, particularly when compared to recent overnight periods. QRN was generally low although there were nagging storms in New Mexico and the Panhandle of Texas and Oklahoma that slightly impacted signal-to-noise. Oddly the noise was less of an aggravation on the transmit vertical than on the receive loop which has historically been the “go to” noisy night antenna, at least so far this season. A large number of very good CW-level reports were received from around North America and there were a large number of very good decodes reported here so the band was open. The path to KH6 was imbalanced again and two-way reports were less robust than in previous session at my station. In Australia, Roger, VK4YB, reported very poor domestic and trans-Pacific propagation. Were these propagation variations the result of the reports of “Low latitude AU Alert” that was posted in the ON4KST chat/logger? I’m used to seeing the high latitude warning and the impact to Northern stations, particularly WE2XPQ but this was one of the first times I noticed a low latitude warning.
Geomagnetic activity was quiet but elevated compared to the previous session and the Bz was pointing to the South. Solar wind velocity is mostly unchanged from the previous session, averaging near 360 km/s. DST values were variable and near nominal levels.
John, W1TAG / WE2XGR/3 was decoded by G0LUJ for the sole trans-Atlantic report of the session. John reports that it was a good night, being decoded by 25 unique stations including VE7SL and G0LUJ and decoding thirteen WSPR stations including 33 reports of VE7SL.
Phil, VE3CIQ, and Steve, VE7SL, completed their first JT9 QSO together during this session. Phil reports that the QSO was spread over two hours but took only 12-minutes to complete the QSO once solidly underway. The band was opening briefly on this path about once an hour. Phil provided the following screen capture from his station:
John, WA3ETD / WG2XKA, also had a strong session with transcontinental reports:
“Very low noise levels here resulted in the best session so far this season. XKA was heard by 31, including a spot from WH2XCR. The VE blocks on both sides were well represented this evening. XKA heard 11 uniqueson the LNV.”
Roger, VK4YB, issued a “code one” at 1046z, reporting poor domestic and trans-Pacific propagation, with the band opening very late. Roger adds that storms from New South Wales moving towards Queensland my have contributed to the problem. Roger’s unassociated report details follow:
“Rx 4*wh2xgp (-23) 3*wh2xxp (-24) 3*wh2xcr (-21)
Tx 2*wh2xgp (-24) 1*ve7bdq (-29) 1*ve7sl (-28) 2*we2epq (-26) 7*wh2xcr (-11)”
Steve, VE7SL, reports excellent East / West propagation, evidenced by the JT9 QSO with VE3CIQ. He decoded fourteen WSPR stations including VK4YB and was decoded by 44 unique stations:
Larry, W7IUV / WH2XGP, indicates a bad night for reporting at his stations due to rain increasing his SWR and shutting down the transmitter. He added that due to operator error both stations were reporting under WH2XGP. He used WSPR4 as the decoder and reports that he had no multiple decodes as he had in the previous session but several of the very loud stations were missing last night. Larry had a few decodes of VK4YB but North American signals dominated during this session:
Ward, K7PO / WH2XXP, was decoded by 56 unique stations including VK4YB and VK2XGJ:
Doug, K4LY / WH2XZO, reports “Good conditions! Spotted 11 and was spotted by 30 stations, both best of season. The SuperKaz maiden voyage was successful. It’s a little better than the loop.”
Rick, W7RNB / WI2XJQ, decoded eight WSPR stations and was decoded by 37 unique stations. Rick adds, “It appears that conditions were pretty good from this station — Had a great time seeing where my transmitter was going to next.”
Mike, WA3TTS, enjoyed a good night of transcontinental openings:
Neil, W0YSE/7 / WG2XSV, submitted the the following log from his join.me screen sharing receiver session showing the QSO between VE3CIQ and VE7SL in addition to other activity:
It was a good night of domestic reports around North America. Signal reports were strong in spite of the QRN from the West and many CW levels were registered for my station. The morning CW sked was nominal but no additional QSO were logged. I opted to QRT for the daytime session for now and restart again in the mid-afternoon. Daytime propagation has really not developed yet so I will revise my plan to be QRV 24/7 as of October 1 to actively re-evaluate the start date and tentatively plan on November 1. Let me see some afternoon reports and that will help me make the decision to keep the station running during the day. My transmission reports can be found here and my reception reports can be found here.
K1RA was observed as a new WSPR reporting station on 630-meters during this session. WQ5L was not new but I did not have him on my receive operator list so I will include him as well. Welcome aboard!
Regional and continental WSPR breakdowns follow:
There were no reports from the trans-African path.
Eden, ZF1EJ, once again decoded stations across North America. including VE7SL, WH2XGP, WG2XKA, and WE2XGR/3:
Laurence, KL7L / WE2XPQ, reports that he decoded eight WSPR stations and was decoded by seventeen unique stations. He received two decodes of VK4YB and was decoded by JH1INM in what he referred to as a “Short weak opening to JA.”
Merv, K9FD/KH6 / WH2XCR, shut down early after “reading the play” and seeing that there was nothing there (sports analogy) as sunrise approached. Merv shared in the very good domestic North American propagation with limited reports to VK. Will we actually see a long term decrease in VK openings and will JA fill the void?
Jim, W5EST, is talking noise in this discussion entitled, “PART 1: 630M NOISE FACTOR/FIGURE– CONFUSING? SIMPLE?”:
“Preamplifiers for particular 630m receiving antennas were mentioned in these blogs:
1-turn 2’ diameter loop; shack-tuned, shack preamp: http://njdtechnologies.net/092816/ .
Multiturn 8’ loop & 1-turn pickup, w/ or w/o outdoor preamp: http://njdtechnologies.net/100416/
1-turn 10’x20’ loop; outdoor preamp: http://njdtechnologies.net/100616/
You’ve probably heard about noise figure for preamps and receivers. Christoph DK6ED used noise figure reasoning to introduce JFET preamp designs for low bands in “Activate Your Loop Receiving Antenna” QST 9/2016, pages 36-38.
On 630m we often list long-path SNRs and tell about instances of high or low levels of 630m band noise. Where does noise figure come into all this? Why don’t we mention noise figure much?
While using the noise figure concept may be second nature to some, many of us like me may have found noise figure difficult to grasp and use. Especially for 630m. SNR, Noise Factor, Noise Figure, Gain, transformer turns ratio, input/output impedances, — they all seem intertwined like a big wad of yarns. Let’s use some blog space to try unraveling some of the confusion!
By SNR, I mean the ratio S/N of signal power S to noise power N at a given place in a circuit.
“(dB)” means 10log10 of whatever ratio, like SNR(dB)– 10 times the common logarithm LOG (not the LN) on your calculator. “dBm” means 10log10 of whatever power you’re talking about in watts divided by .001 watt (a milliwatt).
Noise factor F of a preamp stage is also a ratio—it’s the ratio of input signal-to-noise power ratio S1/N1 divided by output signal-to-noise power ratio S2/N2. Calling it noise factor is easier than saying “ratio of signal-to-noise ratios”! Noise factor is always 1.0 or more.
Noise Figure F(dB) is noise factor F turned into dB by calculating F(dB) =10log10F. Because of the way logarithms work, Noise Figure F(dB) is just the input SNR(dB) minus output SNR(dB) of a device or circuit such as a preamp or a receiver or even a transformer. Noise Figure is always positive dB, or at least zero dB, meaning that any real system element introduces some SNR degradation, however small. Zero dB noise figure perfectly maintains SNR. Ditto for 1.0 Noise Factor.
Product datasheets for preamps state their noise figure F(dB). But if noise factor F is simply a ratio of SNRs, and input SNR varies, how can a preamp have any one particular dB value of noise figure and what does it mean? If SNR can never get better (F>=1), how can a preamp ever do any good? Stay tuned for more in Part 2!”
Additions, corrections, clarifications, etc? Send me a message on the Contact page or directly to KB5NJD gmail dot (com).