We have reached the point for the first time this pre-season that I need a really long title to tease much of what happened overnight. These are beginning to be exciting times on medium wave not just because Fall and Winter are approaching but because we are a step closer to the solar minimum, which may prove to be rather prolific this time. As Steve, VE7SL, noted yesterday in the ON4KST chat/logger, “…it will only get better and better over the next few years and if experts are right, even longer!”
The bulk of the storm noise appears to have been with me and stations in the southeastern US. I struggled to null the QRN that was 200 miles to the South which proved problematic in the later evening but this morning was extremely quiet as the storm system burned itself out for the night.
Geomagnetic conditions are a bit confusing today. The Kp has ranged from quiet to very quiet but the Bz is currently reported at -14 nT, which is often observed under disturbed conditions. Is there a technical glitch or is the magnetic field just on a bender? Perhaps a hole has developed in the magnetic field but solar wind is so low that it does not matter. Protons were elevated to high levels through a number of reporting periods and are currently elevated in the low category. Solar wind is averaging 365 km/s, but appears to be on the increase. DST values strongly suggest that band conditions may be good:
I called CQ on JT9 after 0400z and was pleased to hear reports that Eric, NO3M / WG2XJM, and Larry, W7IUV / WH2XGP, were calling me. In fact there were a number of stations “in the peanut gallery” that were hearing one or more stations in the fray. Both Eric and Larry were visible in the WSJT-x waterfall but I struggled to null the QRN. I was able to “squeak out” a QSO with Eric but he was running pretty much all he had so that I could decode him. He was hearing well, however, and reported little noise on his end but did indicate that the QSB had a period of about 20 minutes.
Larry indicated that he decoded my signal on every transmission in spite of high noise in his area. Unfortunately he and I did not complete the QSO this time. Interestingly enough, this morning Larry and I were hearing each other at easy JT9 levels prior to local sunrise here in Texas for extended periods. Noise makes the difference every time.
Also of note this morning, Roger, VK4YB, called CQ on JT9 on 475.425 kHz during even minutes. Steve, VE7SL, was hearing Roger on WSPR and I fully expected that they were going to try for a QSO (NOTE: I initially believed that Steve and Roger were hearing each other but found that this was only a only way path after reading the chat transcript. Steve indicates that he has yet to be heard in Australia at 60-watts TPO). Steve indicated during this period that WH2XCR was at -13 dB S/N and Roger reported that WH2XGP was being received at -21 dB S/N. Roger’s noise floor was reported at -82 dBm and no QRN although storms to the West, still in full daylight, would cause an increase in noise as the evening progressed in Australia.
Roger had a very strong night with stations in North America, decoding WG2XXM, two-way reports at WH2XGP and reception reports at VE7SL.
This morning’s CW session didn’t yield anything new but I didn’t expect that it would. I am getting back into my routine of daily activity in hopes that random QSO’s will become normal again as they did last year. I am going to try to be up by 0900z this winter in hope of catching some of the guys on the East coast when noise is lowest and propagation is typically most favorable. I also had an opportunity this morning to observe the transition of WG2XXM’s signal from sky wave to ground wave. I would encourage everyone to take a look at nearby signals as they make these transitions. Today’s change in Ken’s signal began about 20-minutes before my sunrise and was characterized by rapid flutter and rapid decreases in signal on the broadside loop. The flutter was also observed on the probe. I will make a recording some morning and share it here.
While the loop was the noisier antenna in the late evening, I decided to steer it to the Pacific Northwest for the overnight period and I was not disappointed. Splitting the difference between the azimuth of WH2XCR and WH2XGP, I decoded both a number of times in addition to WG2XSV, VE7SL, VE7BDQ. Steve and Larry were particularly strong this morning.
Ken, K5DNL / WG2XXM, also reported good propagation to the Pacific Northwest and low QRN. He decoded five WSPR stations and was decoded by thirty unique stations including VK4YB and ZF1EJ, the latter providing 118 reports, best at -10 dB S/N. Ken also reported decodes from Laurence, KL7L / WE2XPQ, best at -15 dB S/N and Andy, KU4XR, at +16 dB S/N.
John, WA3ETD / WG2XKA, had an almost carbon-copy night of the previous session, including another transcontinental opening. John indicates that his noise is “general weekend noise”, probably from people that are home running their gadgets. The nearby farmer’s electric fence has been off since the most recent rains. John provided the following comments and map for his session:
“Conditions and activity definitely improving-however, the noise levels remain very high. WG2XKA was heard by VE7SL and heard WH2XGP on the NW transcon path. W4BCX in Florida spotted XKA at dusk here which is hopefully an indicator of things to come…”
After recent discussions about the September QST article by Roger, G3XBM, John provided some comments about measurements and observations that he has made with the same design, particularly with respect to low pass filtering between the mixer and squarer:
“Considering the number of semi-commercial, commercial, and homebrew transmit converters around today, there is often an overlooked, yet important circuit element ‘glossed-over’ : a proper low-pass filter between the mixer output and subsequent stages.
Looking at common designs using an IF frequency in the 80m band at 3.2 MHz, the output of the mixer contains the desired DIFFERENCE product at nominally 475 kHz as well as the SUM at ~6.875 MHz. Clearly, the sum product must be stripped while passing the desired LF/MF frequency. Failure to properly do so will impact the performance of subsequent PA circuits, often causing excessive heating and lower than expected power output, ESPECIALLY with a Class E PA.
Having built multiple transmit converters over the past four years I have observed these issues. For example, a popular homebrew design recently published in QST Magazine employs a 10nF capacitor at the output of the mixer as the LPF. With a LO frequency at 3.2 MHz, it marginally works; however the HF sum frequency can be observed slightly modulating the desired 475 kHz waveform. With a LO at 4.0 MHz the effect is reduced, as the reactance of the cap at HF decreases, causing an increased ‘shorting effect’ of the undesired sum component. With a 10 MHz (GPSDO) LO, the 10nF cap does a reasonable job as a LPF.
On a specific test rig here, I found that when using a LO of 3.2 MHz, a popular choice, the power output increased from ~19W to ~24W by using a PROPER mixer post LPF…device heating was dramatically reduced as well.
The choice of post-mixer LPF is critical when using a DDS derived f0 as well – many DDS designs are shockingly dirty! (I have several cheap DDS boards available on ‘Epay’.)
An examination of the DDS derived f0 signal in the commercial JUMA 500 kHz rig reveals a very aggressive post DDS LPF consisting of 2, 3-pole filters in series!
All that being said, in my design I use a crude but highly effective post-mixer LPF consisting of a 3-pole Chebyshev , consisting of a 15uH series element and two, 6800pF shunt elements. With this filter there is essentially no HF component passed on to subsequent stages…my two cents.
Larry, W7IUV / WH2XGP, pointed the flag to the west for the session in hopes of hearing VK4YB, which he was successful a total of four times, best -24 dB S/N. Larry decoded ten WSPR stations and was decoded by 28 unique stations including three VK’s and ZF1EJ/1. The VK4YB reports have been previously presented. VK2DDI and VK2XGJ reports follow:
Steve, VE7SL, reported a “nice night”, decoding twelve WSPR stations including VK4YB. His signal was decoded by sixteen unique stations and he indicates that there were quite a few eastern stations in the mix as well. Steve decoded WH2XCR 48 times with a session best report of -8 dB S/N. Steve’s VK4YB reports were previously presented.
John, W1TAG / WE2XGR/3, current operating from Maine reported that Steve, VE7SL, decoded his WSPR signal. John also indicated in another discussion that Stefan, DK7FC, was active on 630-meter WSPR last night but its unclear about his power level at this time. Perhaps trans-Atlantic reports will begin soon as a result of his activity.
Neil, W0YSE/7 / WG2XSV, was one of the many stations from the Pacific Northwest that I decoded overnight. Neil presents the following statistics and comments:
Phil, VE3CIQ, reports a good session but he continues to seek reports in excess of 2000km. He recently performed antenna upgrades that reduced more of his loading requirements:
Rick, W7RNB / WI2XJQ, reports high noise that is endemic to his area and he expects that the noise won’t begin to subside until the rains come. Rick had a solid session and provided the following WSPR statistics for this station:
Ken, SWL-EN61, in Indiana reports a good session where it was nice to hear West coast stations. This was Ken’s second session running his decoder under Linux. After his first session he had the following comments:
“I noticed that the audio level bar in wsjt-x would vary with the amount of audio fed in but…
The level didn’t seem to vary with, let’s say, lighning pulses that would increase the rx volume. So I thought the system was just getting audio feedback from somewhere and not really seeing the radio output.
Apparently, there is some sort of AGC action going on that I was unaware of. What I did was just set wsjt-x to 30db audio level and leave it. Again… fluctuating QRN audio doesn’t change the wsjt-x level but in spite of this situation, wsjt-x does decode spots. I proved that by logging 20m wspr again.”
After his second night of testing, Ken provided the following comments:
“The only thing I have to add is that the ” agc anomaly” of the audio level bar in wsjt-x may just be a matter of a setting (that I can’t find) in audio properties concerning my internal sound card. At this time, I don’t know why the audio level indicated in wsjt-x doesn’t vary with varying audio input (from changing band noise), but it doesn’t seem to affect the decoding of spots.”
Don’t forget that the WWROF will be sponsoring a free webinar by Carl Leutzelschwab, K9LA, on August 23 at 9 PM EDT (August 24 at 0100z) entitled, “Solar Topics – Where We’re Headed”. This is a citrix-based webinar and registration is required at https://attendee.gotowebinar.com/register/4583976502814826243 . Much of Carl’s focus is on the low bands and his information may be helpful in what we do.
K9ANF was reported as a new WSPR receive station during this session or returning for the first time in many months. Welcome aboard!
Regional and continental WSPR breakdowns follow:
There were no reports from the trans-Atlantic, trans-African, or trans-Equatorial paths. UA0SNV and 8P9EH were present but no reports have been filed at this time.
Eden, ZF1EJ, reports that he operated two receivers and antennas during this session. ZF1EJ was configured as the FT-991 and log periodic antenna while ZF1EJ/1 was configured as the FTDX-3000 and magnetic loop. Since this was a comparison I typically like to present all of the individual data points, when possible, but there were so many reports for WG2XXM and WG2XIQ on both systems that I will exclude those here, instead showing only the report of WH2XGP that was decoded by ZF1EJ/1. Larry’s report seems to be the most valuable in this comparison as his reports have been absent for many sessions:
It’s interesting that there was only a single decode for WH2XGP at ZF1EJ/1 because the report was -18 dB S/N, hardly a detection limit report. It seems that QSB continued to be very active as late as 0730z.
Laurence, KL7L / WE2XPQ, reports that the probe designated as “Talktomegoose” and configured for KL7L and KL7L/1 has been lowered from 22-meters to 10-meters above ground during this session. All of the antenna configurations worked well with reports of VK4YB, WH2XCR, stations in the Pacific Northwestern region of North America, and the south central US at WG2XXM and WG2XIQ:
Merv, K9FD/KH6 / WH2XCR, had a hot session, scoring the first JA decode of this pre-season and being decoded by WG2XJM in western Pennsylvania for the most distant reception of Merv’s signal in North America in many months. He was also decoded here which has been a rare treat this summer. Two-way reports with VK4YB continue in spite of Merv’s receive dipole laying on the ground and reports from the very faithful VK2XGJ and VK2DDI continue. Reports were also received from EJTSWL who may or may not be portable at the moment:
Additions, corrections, clarifications, etc? Send me a message on the Contact page or directly to KB5NJD gmail dot (com).