This session seemed to be a little less robust than the previous few sessions here in Texas. Perhaps it was the morning noise in the Montana, Wyoming, and Dakotas region that the receive antenna was steered into overnight. Or perhaps it was the spike of the Kp prior to sunset after a number of quiet reporting periods. Its hard to say. Domestic reports were good with a number of CW levels, particularly on the East / West paths. Doug, K4LY / WH2XZO, reported good CW levels between his station and mine around 0230z. Had I been watching more careful during that time frame we might have completed a CW QSO during this session. Doug reported moderate noise in South Carolina as thunderstorms, many related to the system associated with the category-4 hurricane in the Atlantic, so there will be other, better times in the future for another CW QSO.
Geomagnetic conditions were beginning to return to quiet levels for persistent periods until another spike to the Kp was observed during the late afternoon in North America. The Bz had been near unity during the day but pushed to the South and has only in the previous few reporting periods returned to the North, near unity. Solar wind velocity had decreased to the 400 km/s range but has recently peaked above 500 km/s once again.
Doug, K4LY / WH2XZO, submitted the following details from South Carolina:
“Over 1000 spots of WH2XZO by 25 stations and 235 spots by XZO of 6 stations. East-west conditions were very good with 5 spots from WH2XCR, the first ones since April, I think. I believe he was using his TX antenna which seems to receive very well.
The strongest decode of the night was remarkably, WH2XXP, SNR -1 at 2835 km. WG2XXM was not transmitting and WG2XIQ had many single digit SNRs. John and I will try CW soon.
North-south conditions weren’t very good, and finally after days of geomagnetic storm level activity, WD2XSH/17 decoded Europe again.
If only there were 630M WSPR activity in Brazil and Atlantic coast Africa, I think east coast stations might have similar results to the west coast-VK path.”
WD2XSH/17 reports DK7FC for the sole decode on the trans-Atlantic path which continues to be reeling from the recent geomagnetic storm conditions:
Roger, VK4YB, issued a “code-3” for the morning trans-Pacific session with lots of QRN and propagation that dropped off as sunrise approached in North America. There were no QSO attempts and Roger reports that he left the antenna directed to the Northwest overnight. Roger indicates that good weather conditions are forecast for the upcoming sessions. He was decoded by three JA’s, including 7L1RLL_4, JA1NQI-2, and JH1INM:
Larry, W7IUV / WH2XGP, reported down conditions in eastern Washington state. He was testing two-way simultaneous receiving at his station and reports that it was a bad night to try to perform this test. He decoded six WSPR stations on the East antenna and seven on the West antenna, including VK4YB (under W7IUV call sign). He was decoded by 39 unique stations including VK4YB and VK2XGJ and indicated that VK9NZ operating from Norfolk Island on 160-meters was weak and challenging to work this morning. I was listening to the pile up as well and only heard a few bits from VK9 today.
Ward, K7PO / WH2XXP, was decoded by 50 unique stations including four VK stations:
Rick, W7RNB / WI2XJQ, also reported down conditions. He decoded six WSPR stations and was decoded by twenty unique stations:
Jan, LA3EQ, reporting these statistics for the overnight session on the RSGB-LF reflector:
Mike, WA3TTS, reported at 0224z in the ON4KST chat/logger that he was “RX on NW EWE 630m wspr2 9 stns decoded past 3hrs.”
It was noisy this morning and made my CW session challenging at best. No additional QSO’s were complete except for my morning CW sked. Propagation seemed good but down somewhat from the previous session although I decoded five WSPR stations, which can be seen here and was decoded by 39 unique stations, which can be seen here.
There was a lot of band activity during this session with 101 WSPR stations observed on the WSPRnet activity page at 0100z. Toby, VE7CNF, reported two new listening stations: N7DTP and VE6EGN. Welcome aboard!
Regional and continental breakdowns follow:
There were no reports from the trans-African path.
Eden, ZF1EJ, reported stations in the southern US during this session in spite of high storm QRN in the Caribbean, including WG2XXM who was absent over night but decoded late in the previous session.
Laurence, KL7L / WE2XPQ, continues to be impacted by high absorption from the recent geomagnetic storms. The trans-Equatorial path never developed as far as Alaska so there were no reports from VK but Laurence was successful with decodes of WH2XCR:
Merv, K9FD/KH6 / WH2XCR, shows that the East / West path was good for a few periods with a record seven JA stations reporting his signal. He also shared two-way reports with VK4YB and reception reports at VK5ABN and VK2XGJ. As previously reported, WH2XZO received Merv for the first time this season and was the easternmost station to report Merv during this session.
Jim, W5EST, talks loops today with this presentation, entitled, “STRUCTURAL OPTIMIZATION OF MULTITURN LOOP ANTENNA”:
“Steve VE7SL and John WG2XIQ both have experience with multiturn loops. They replied to my questions, edited for this post into three-way dialog form:
Jim W5EST: How did you pick the materials for your octagonal loop? http://members.shaw.ca/ve7sl/loop.html
Steve VE7SL: I’m a long-time wood worker, not an engineer so I (initially) chose the material most familiar to me. Red Cedar was used for its strength, light weight and superb weathering capability. California Redwood has been used by others but Fir or Pine would not be suitable due to weight issues (Fir) and weathering (Pine).
Jim W5EST: Would you comment on the type of shape you decided on?
John WG2XIQ: I built my loop so it would fit in the available space and turn without hitting tree branches. No further optimization was done. The square shape was out of convenience and ease of building with thin wall PVC reinforced with wooden dowels. It’s been up for at least two years and seen near 100-mph winds on a few occasions without any problems. I painted the PVC with a few coats of Krylon® spray to minimize UV impact. I use thin wall PVC because thick wall PVC fails early because its heavy. Many don’t treat the PVC for UV, so it gets brittle. I imagine cold may be an issue up North. No issues here yet.
I can see the octagon being an advantage in that you increase the aperture. If I could do it, I would use a larger aperture. I would also locate it higher, maybe 20 feet, but that might also impact survivability in wind.
Steve VE7SL: As John points out, the octagonal shape was chosen mainly for maximum aperture but it also produces a stronger, heavier structure. These latter two features go hand-in-hand when it comes to wooden frames when exposed to storms. I’m here on the open ocean, where very strong and prolonged storms pound the antenna with their sudden, high intensity gusts.
Jim W5EST: What other stations have put up this 630m receiving loop so far?
Steve VE7SL: My first design of the wooden frame octagonal loop appeared in a mid-’80s Lowdown (http://www.lwca.org/) and was on the front cover. Over the years I have heard from many dozens of those that have reproduced the design.
Jim W5EST: What tradeoffs confront this 630m receiving loop?
Steve VE7SL: Strength (cross-section of frame elements) versus wind load area. Stronger structures unfortunately also produce higher wind loads and higher stresses on the frame. This includes adding gussets (triangular inserts) to further brace the frame. I struggled to raise the 10-footer’s frame myself and was able to manage it. Anything larger is out of the question unless one has additional help.
Jim W5EST: Where is the structure most likely to fail in a storm?
Steve VE7SL: These half-lapped frames are strong, even the smaller ones. From my one blow-down, this loop’s weak point instead is the ABS pipe to mount the structure. I’d say reduce UV degradation of the tubing. Repetitive flexing and UV from years of winter wind blasts and contributed to the 10-footer’s demise. Wooden bracing around the pipe at the top of the mounting post prolonged its life but did not prevent eventual failure. I went to an 8-foot loop.
Jim W5EST: If you had stayed with 10’ loop, what could have kept that support tube from breaking in a storm again?
Steve VE7SL: A nested central 2” ABS pipe and a 1.5″ inside it. And some annual spray painting to reduce UV damage.
Jim W5EST: How does one decide how big or small to make those gusset triangles?
Steve VE7SL: They were just a tradeoff between bracing benefit versus wind loading.
Jim W5EST: John, do you have anything you’d do different with your square loop antenna?
John WG2XIQ: I give it a thumbs up. I use a W7IUV preamp and LPF (ahead of preamp) in the shack. No issues…only changes would be getting it higher in the air and larger aperture. 73!
Jim W5EST comments: As we know, mechanical engineers (M.E.s) optimize physical structures so that the weight or cost is minimized while resisting failure modes–like breaking under tension, and buckling and breaking under compression by lateral wind forces. The antenna must withstand forces from all directions in the plane of the loop and also perpendicular to it. Static balancing the antenna can help reduce continual lateral bending torques by the antenna’s own weight, but wind gusts remain in the picture. If antenna wires are optimized thin (this blog, Sept. 29), the structure must prevent wire snap by sudden gust forces.
Can a reader point me to any M.E. structure optimization software that might apply to a loop antenna of this type? I’ll continue with more from Steve and John in a further blog post.”
Additions, corrections, clarifications, etc? Send me a message on the Contact page or directly to KB5NJD gmail dot (com).