It was another amazing night on 630-meters. Noise levels were very low here in Texas and this mornings storms in West Texas and New Mexico were not heard at all. It was dead quiet, just as it was yesterday when the band seemed to be very “long”. Steve, VE7SL, reported QRN but was unsure of whether it was coming from the Gulf of Alaska or somewhere to the West. Its possible he was hearing the storms down here as he was yesterday or perhaps the approaching storm system that will likely keep many in the Pacific Northwest off the air in the coming days:
The geomagnetic field hit G1 storm levels this morning, pushing the Kp to 6. The Bz has spiked to a moderately high -19 nT but solar wind has only increased to about 405 km/s at this time. Its sure to increase, although the CME triggering this storm was considered “only” a glancing blow. DST values showed the characteristic increase before “the bottom fell out”:
Starting in the East, Albert, PA0A, received multiple WSPR decodes from Vasily, UA0SNV, for a second consecutive night:
On the trans-Atlantic path PA3ABK/2 and WG2XKA were reported by Dave, WD2XSH/17, and Geoff, G0LUJ, respectively. These reports were probably perfectly timed, occurring just prior to the onset of the G1 storm although Geoff reports that conditions were not quite as good as yesterday, which may have had something to do with the storm conditions:
John, WA3ETD / WG2XKA, provided the following comments on the trans-Atlantic reports in addition to the other openings he experienced during this session:
“Last nights session was almost a mirror image of the previous. Over 1K spots were exchanged, with TP and TA reports exchanged with WH2XCR and G0LUJ. The PNW was again well represented. Noise levels were moderate as unsettled WX moves into the NE area. The number of stations active in the US continues to increase nightly.”
Sliding further West, Ken, K5DNL / WG2XXM, reports that he was decoded by 51 unique stations including four VK’s, Alaska, Hawaii and ZF1EJ. Ken reports 97 decodes from WH2XCR, best +2 dB S/N, and 119 decodes from ZF1EJ, best +10 dB S/N. His total number of decodes from VK during this session was 54.
This was a rather remarkable morning for the trans-Pacific path between North America and Australia, especially when the Kp-index was 5! Roger, VK4YB, was decoded by Bill, VE3IQB, and Eric, NO3M / WG2XJM in eastern North America and it is a remarkable feat by both stations. Eric reports that he was using the 8-circle array, pointing West, and that the array is currently in a state of disrepair, with a number of element potentially missing. Eric observed that VE3IQB’s reports were “3dB better SNR vs. my best (@-29), but only 1 spot vs. 3, interesting” referring to Bill’s single spot at a better S/N. UPDATE: Bill reports that this was his longest MF WSPR reception ever and indicated that he “… was using an omni-directional E-probe antenna up about 20 feet.” According to Phil, VK3ELV, the longest WSPR report ever recorded on 630-meter was VK1DSH to F6CNI at a distance of 16832 km on February 16, 2013 at 50W TPO. On March 24, 2016, VK3ELV was decoded by F6CNI at a distance of 16712 km.
If these things are happening this early in the season, what will December and January bring? Or the solar minimum?
Roger issued a “Code-7” this morning as he switched his antenna from North America to Japan. Steve, VE7SL, noted that it was as if Roger’s signal was a fire hose moving back and forth, from North to South. Roger reported that a CW QSO attempt may or may not have been possible as higher latitude paths were dominant and the “spotlight” was moving around. Steve added that often when VE7BDQ observes an opening to Roger, he is not heard at Steve’s QTH to the South in spite of being located in the same area. Roger’s additional statistics and details follow. He adds that his “… reports list station in distance order, number of spots, call, best s/n in brackets”:
“Rx 35*wg2xxm (-15) 2*wg2xiq (-27) 20*wh2xxp (-20) 1*va7mm (-31) 2*ve7cnf (-27) 6*wi2xbq (-24) 1*we2xpq (-29)
Tx 1*ve3ibq (-26) 3*wg2xjm (-29) 7*ve6jy (-25) 8*ve7bdq (-23) 5*wi2xjq (-24) 20*we2xpq (-22) 45*wh2xcr (-4) 1*ja1pkg (-27) 11*jh1inm (-21) 1*7l1rrl4 (-31)”
Ward, K7PO / WH2XXP, reported that one of his power supplies shut down around 0930z resulting in his signal being down a few watts ERP after that time. Nevertheless, he was decoded by 51 unique stations including five VK stations:
John, VK2XGJ, reported early, even visual decodes of WH2XXP in the 0800z hour:
In addition to his previous reports from this session at VK4YB, Joe, NU6O / WI2XBQ, was also reported by VK2EIK and VK2XGJ:
Phil, VK3ELV, received reports late in the previous session and in this session from JH3XCU and and JH1INM:
JA1PKG was transmitting during this session and received a single decode during the reporting period from VK2EIK. UPDATE: Phil, VK3ELV, reports that he believes that this is the first time a JA station has been received in VK:
Phil, VE3CIQ, has been consistently heard here and in KH6 over the previous few sessions. Its almost like someone flipped a switch. Phil provided the following comments:
“Pretty good turnout. Heard 13, was heard by a whopping 30. Farthest was being heard by WH2XCR. I see more VE’s than ever”
Doug, K4LY / WH2XZO, had a strong night into Canada and offered these comments:
“It was a Maple leaf night! Last night compared favorably with last season’s very best 630M conditions to VE7-land with VE7SL, VE7BDQ, VA7MM, and VE7CNF all in the log. Add VE6JY, VE3CIQ, VE3EFF, VE3IQB, and VE2PEP to her majesty’s electromagnetic magnificence.
From here, the 13 unique decodes and 40 decodes by others also compared favorably to last season’s best. WH2XCR hears so very well this year, decoding me every night, and finally last night a single decode of Merv on my KATZ antenna, which supposedly favors northeast, but decoded all the above! The loop, on a different receiver, was down, as that computer crashed early, not noticed until this morning. Great activity guys. Thanks.”
I wonder if he has room for a west-facing KATZ. I have asked that question.
Neil, W0YSE/7 / WG2XSV, had a very strong night of transmit and receive from his station in Vancouver, Washington:
Rick, W7RNB / WI2XJQ, decoded fifteen WSPR stations and like many stations in the Pacific Northwest is reporting the approach of a big storm system that will likely have him and others in the region off air in the coming days.
Mike, WA3TTS, submitted the following comments and comprehensive report details:
“John: No T/As on 630m last night although I had the EWE antenne pointed NE until 0500 or so. VO1NA was strong on 137.777kHz QRSS tho to the NE last evening. However, the NW and W path was very good on 630m after 0600, with 21 XCR captures overnight on the NW EWE transformer and split IF receiver setup”
Andy, F6CNI, posted his plans for activity during the evening in Europe on the RSGB-LF reflector:
“Hello dear friends.Just for info : this evening and beginning now, I am receiving QRSS3 in the window 476.130 to 476.230 to copy an other F station who be active in balise mode.Later, begining at 2200 TU, I’ll send some CQ using JT9 with my QRPP TX 1 Watt out : QRG 474.200 USB dial and AF modulation between 1000 to 1400 Hz, just below the WSPR window.73 @++ Andy”
“Hello everyone, my QRSS3 beacon with 50W will be active tonight on 476,200 kHz from 2100 GMT and all night long.
You can see some pictures of this little transmitter on: http://www.lfiste.fr/viewtopic.php?f=40&t=5313Reports are welcome
F4DTL Nicolas JN18FP“
It was another good night here at my station. As previously reported, there were no hints of any noise from the storms along the Texas / New Mexico border and WSPR signals were very strong as were the reports being provided for my signal, in many cases at CW-levels. I was pleased to receive two reports from Roger, VK3YB, in addition to Merv, WH2XCR, and Eden, ZF1EJ. This morning’s CW session was normal. My daily sked was good conversation and at 1100z I returned to CQing until sunrise. I did note a few “phantom ditters” out there so someone reading these reports has a good sense of humor… It also lets me know that someone is listening and hopefully soon enough another QSO can take place. My WSPR transmit reports can be found here and my receive reports can be found here.
It was another busy WSPR session with over 100 MF WSPR stations reported at 0230z on the WSPRnet activity page. W4ATV, K6JQ, and N6LQB are new or newer receiving stations for this season. Welcome aboard!
Regional and continental WSPR breakdowns follow:
There were no reports from the trans-African path.
Eden, ZF1EJ, continues to provide reports to the eastern two-thirds of the US. Interestingly, there were no reports from the Pacific Northwest during this session:
Laurence, KL7L / WE2XPQ, reported a K of 7 overnight with this stunning picture of the aurora and the “ACESHIGH” probe hanging in the center:
Laurence was able to share two-way decodes with VK4YB and WH2XCR and even decoded WG2XXM during this session.
Merv, K9FD/KH6 / WH2XCR, experienced another exceptional session which is becoming the “new normal”. Activity in JA and VK has really sky-rocketed and I believe that Merv’s activity is directly related to a significant part of that interest. He recently asked about the BX2ABT in Taiwan. There seems to be a noise problem there, which is common in and around Asia and in China, in particular. It seems Merv has set his sights on being heard there this season so I hope Hans will continues to listen and improving his situation to make this possible. While this morning’s path to Texas was pretty good, it did not seem stable enough for a CW QSO attempt, particularly in light of the observations made by VK4YB and VE7SL on whether they should make an attempt today. Its early in the season – we will find the right night to get it done. Merv had a strong signal across North America and was hearing well, with reports for WH2XZO, WG2XKA and VE3CIQ among others that are about as far away as you can be in North America.
Jim, W5EST, presents, “PART 4: PREAMP NOISE FIGURE IN ACTION ON 630M “
“Let’s say you know your receiver noise figure. Christoph DK6ED’s September QST article stated a 6.8dB RX noise figure example on low bands. That means the receiver generates 3.8 (noise factor 4.8 minus 1) times as much receiver noise power as thermal noise power Nthermal produced by a resistor matched to the receiver’s input. That might sounds terrible, but it really isn’t, because thermal noise power is relatively small compared to 630m band noise.
If one preamp has a 2dB lower noise figure than another preamp, does that mean 630m SNR will be 2dB better? NO. First convert the datasheet receiver noise factor by multiplying it by thermal noise to get receiver noise power itself. Add 630m band noise power N630m from the antenna to get total noise power. Then find RX noise factor with reference to 630m noise by then dividing by the sum of thermal noise and the actual 630m noise power input:
FRX630 = [(FRX Nthermal + N630m ] / (Nthermal + N630m).
Let noise power ratio R = N630m / Nthermal and simplify things to give:
FRX630 = (FRX + R) / (1 + R).
This formula suggests a reason why we don’t talk about noise figure on 630m as much as we might. Since 630m band noise far exceeds the -140dBm (2.5KHz b.w.) thermal noise level kTΔf, the 630m-noise-based noise factor FRX630 tends toward unity 1.0, considering 630m band noise and the good performance of most modern receivers! That is hyperbole, but you get the idea. And lest I leave the idea that 630m band noise is terrible, let’s not forget that 630m ham stations have communicated between Canada and Australia! Now, back to the point:
EXAMPLE 1: PREAMP DOESN’T HELP
Suppose R=20, meaning 13dB of 630m noise over thermal noise. Then the example receiver noise factor 4.8 becomes, for 630m purposes:
FRX630 = (4.8 + 20) / (1 + 20) = 24.8/21 = 1.18.
The effective receiver noise figure (dB) for 630m purposes is:
FRX630(dB) = 10log10(1.18) = 0.7 dB.
There’s only 0.7dB of noise figure to improve upon because noise figure by definition can’t go below zero dB.
A preamp that has noise factor Fpreamp = 1.4 relative to thermal noise would have 630m noise factor Fpre630m = (1.4+20) / (1 + 20) = 1.019 and Fpre630m(dB) = 0.082dB. Suppose the preamp has a gain of 10x or 10dB. System noise factor Fsystem = Fpreamp + (FRX -1)/Gpreamp.
Fsystem = 1.019 + (1.18 -1)/10, so F = 1.037 and F(dB) = 0.15dB.
In other words, the preamp of this example makes an imperceptible half-dB improvement in 630m SNRs (0.7dB – 0.15dB) regardless of how strong or weak a desired 630m long-path signal buried in that noise happens to be. Also that preamp might introduce intermod noise that would mask the improvement or even make things worse in this case.
If your antenna is already delivering 630m band noise that’s at least ten times the receiver noise power referred to its RX input, then probably you don’t need a preamp. http://njdtechnologies.net/100716/ That’s because even a poor receiver noise factor under a thermal noise definition still adds relatively little noise in proportion to 630m band noise.
But if you are working with a physically convenient small-size one-turn loop, 630m band noise may get comparable to or even less than receiver noise.
EXAMPLE 2: PREAMP HELPS
Let’s say you have a small one-turn loop that delivers excellent signal-to-noise ratio, but both the signal and band noise level from this loop are less than, say, R=2 or twice the thermal noise power kTΔf. Suppose further a 630m receiver with 10dB datasheet noise figure relative to thermal noise. You obtain a preamp with 1dB noise figure F=1.26 and 20dB gain G=100. Now the receiver noise factor for 630m purposes is: FRX630 = (10 + 2) / (1 + 2) = 12/3 = 4.0.
The effective receiver noise figure (dB) for 630m purposes is: FRX630(dB) = 10log10(4.0) = 6.0 dB.
There’s 6dB of 630m noise figure to potentially improve upon, with goal to make system noise figure approach zero dB for 630m purposes.
A preamp that has noise factor Fpreamp = 1.26 (1 dB) relative to thermal noise would have 630m noise factor Fpre630m = (1.26+2) / (1 + 2) = 1.087 and Fpre630m(dB) = 0.36 dB. Suppose the preamp has a gain of 100x or 20dB. Then get system noise factor from its equation.
Fsystem = 1.087 + (4.0 -1)/100, so F = 1.117 and F(dB) = 0.48dB.
The preamp improves 630m SNRs by 5.5 dB (6.0-0.48dB). Naturally, in this low-signal loop situation a preamp becomes useful and highly desirable on 630m paths. Especially this matters on 630m long paths where every dB counts both to decode WSPR and to get from WSPR SNR to JT9 SNR levels!
So much for this 4-Part introduction to noise figure. If you have a 630m design or an operating experience where noise figure directly played a part in your efforts, e-mail us for this blog!”
Additions, corrections, clarifications, etc? Send me a message on the Contact page or directly to KB5NJD gmail dot (com).