Radio: it's not just a hobby, it's a way of life

Current Operating Frequency and Mode

OFF AIR but will be QRV on CW somewhere between 472.5 kHz and 475 kHz after dark

SCHEDULED ACTIVITY: CQ 474.5 kHz CW by 1030z through sunrise most days, WX permitting

Similar session to previous with a few surprises; Antenna comparisons at W0YSE/7 / WG2XSV; WG2XXM returns to air after lightning strike

– Posted in: 630 Meter Daily Reports, 630 Meters

The geomagnetic field was more active than in previous days with elevated Kp values and solar wind in excess of 450 km/s with peak periods above 500 km/s.  If the forecasts are to be trusted, it seems we are due for more storm levels over the coming days.

planetary-k-index 050716


Kyoto DST 050716


Australia 050716


I am of the opinion that this session was very much like the previous session, with extremely low noise levels and numerous coast to coast reports at CW levels.  What was interesting was that I neither decoded nor was decoded by WH2XCR.  Merv appears to have been active overnight but the path appears to have been impacted in some way.  Similarly, Neil, W0YSE/7 / WG2XSV, reported that he was performing some receive comparison test between his top loaded vertical and E-probe.  Neil reports that he decoded my on the vertical but not the probe during this session while decoding WG2XXM just 200-miles to the north on both antennas.  Merv also decoded Ken.  It seems some type of anomaly was present overnight that favored signals further North.  Neil provided some comments that he said I could include here from his test showing the data for my signal.  I am sure Neil will have further data to report on his test in the near future so watch his website for details.  Neil’s test data and comments are found below:

WG2XSV 050716


Phil, VE3CIQ, was also performing antenna comparisons during the session and offers the following comments:

VE3CIQ 050716a


VE3CIQ 050716b

VE3CIQ session WSPR activity


Regional and continental WSPR breakdowns follow:

NA 050716

North American 24-hour WSPR activity


EU 050716

European 24-hour WSPR activity


VK 050716

Australian 24-hour WSPR activity


JA 050716

Japanese 24-hour WSPR activity


There were no trans-Atlantic or trans-African WSPR reports during this session. UA0SNV was present during the session but no reports were found in the WSPRnet database.

Eden, ZF1EJ, reported WG2XXM and WG2XIQ during this session.

ZF1EJ 050716

ZF1EJ 24-hour WSPR activity


Laurence, KL7L / WE2XPQ, reported WH2XGP, VE7BDQ, and WH2XCR during this session.

WE2XPQ 050716

WE2XPQ 24-hour WSPR activity


WH2XGP WE2XPQ 050716

WH2XGP, as reported by WE2XPQ


WH2XCR WE2XPQ 050716

WH2XCR, as reported by WE2XPQ


VE7BDQ WE2XPQ 050716

VE7BDQ, as reported by WE2XPQ


Merv, K9FD/KH6 / WH2XCR, experienced what seems to have been a slightly down session compared to recent previous sessions.  Its possible that he did not operate for the entire session.  Nevertheless the openings to Australia continue.

WH2XCR 050716

WH2XCR 24-hour WSPR activity


WH2XCR VK4YB 050716

WH2XCR, as reported by VK4YB


WH2XCR VK2XGJ 050716

WH2XCR, as reported by VK2XGJ


In Australia, Roger, VK4YB, and Phil, VK3ELV, received reports from WH2XCR.  Roger also shared two-way reports with Merv.  Phil also received a report from JH1INM.

VK4YB WH2XCR 050716

VK4YB, as reported by WH2XCR


VK3ELV WH2XCR 050716

VK3ELV, as reported by WH2XCR


VK3ELV JH1INM 050716

VK3ELV, as reported by JH1INM


Jim, W5EST, expands on yesterday’s discussion with this offering, entitled, “LAUNCH ANGLE VS. GREAT CIRCLE DISTANCE”:

Let’s dig deeper into the launch angle feature suggested by a column of yesterday’s table of multi-hop long path information.

Launch angle (degrees) vs. great circle distance (km) follows a sawtooth-shaped relationship shown in the accompanying graphical Figure based on the Appendix below. So long as ionospheric reflection is mirror-like with one reflection altitude per concentric layer over the path distance, the sawteeth should approximate those shown for different exemplary reflection heights h. Moreover, each sawtooth would be relatively independent of each LF/MF/HF frequency that uses that reflection height h.  Also, TX launch elevation angle then equals arrival elevation angle at RX for a given path.

In the graph, two sawtooth curves—red for E, green for F—represent ionospheric region reflections at supposed altitudes 150km and 300km.  The graphs extend to 20,000km of path distance although, so far on 630m, nobody has exceeded the mid-13Kkm range, as far as I know.

With a little practice, you can use the E, F curves to identify possible mixtures of E and F reflections and their angles in case both E and F propagations are actually occurring.  For one example, at 6000km (“61” horizontal, DK7FC-xsh/17) 3-Ehop and 2-Fhop multihop might co-occur at 3° angle.  In another example, at 4000km (“41” horizontal, XKA-ve7sl) 2-Ehop 4° might coexist with 2-Fhop 10°.

I have ignored possible coexistence of two or more different E hop modes (or F modes) at a same path distance because I presume that more hops at same height will insignificantly add dB. If you think they’re important, then extend the curve of each sawtooth upward-leftward.

A foreshortened third curve (in blue) represents 75km reflection for single hop distances in case D-layer reflection  at LF/MF is responsible for daytime propagation when it occurs.

I have yet to become certain what reflective regions and propagation modes are truly responsible at 2200/630m for propagation over particular paths at various times of night/day and seasons. If you know a scientific paper or book that settles any such question, do send the citation.

The Angle vs. Distance graph may also be useful to compare with antenna pattern information to estimate some of the variation, as between different paths, of radiated power from TX antennas and received signal in RX antennas.  I’ll plan a further blog post on that.


Recall from yesterday that path elevation ANGLE to a 150km E layer was given by:

ANGLE(multihopE) ~=  56.0° [0.02354/θ  – 0.5118 θ]

where θ = “KM”/(2xHOPSx6371km).

KM is distance.  Number of hops is calculated by:

HOPS= ceil[KM/(Max km/hop)].

θ signifies great circle (g.c.) arc angle traversed by the RF signal, given by reflection height h divided by Earth radius Re = 6371km.

Max km/hop = 2 Re arccos(1/(1+h/Re), or 1945/2738/3836km/hop at h = 75/150/300km.

A specialized formula for multihop launch angle assumes angles < ~ 6° and for different heights:

ANGLE(multihop) ~= 57.3° [Eh/Re – (1+h/Re2/2 ] / [(1+h/Re)θ]

Since single-hop can involve higher launch angles, a general great circle angle formula is needed to cover single and multihop as follows. I used this for spreadsheet calculation of sawtooth curves.

ANGLE(hop) ~= 57.3° arctan{[-1 + (1+h/Re)cosθ] / [(1+h/Re)sinθ]}”


W5EST 050716



Additions, corrections, clarifications, etc?  Send me a message on the Contact page or directly to KB5NJD <at> gmail dot (com)!