Comet Giacobini-Zinner. Wikipedia photo. By Alexander Vasenin – Own work, CC BY-SA 4.0, 

We previously reported about how the phenomenon of meteor scatter was discovered in 1944, through the distant reception of short bursts of signal from FM broadcast stations on the 42-49 MHz band.  And 80 years ago tonight, hams got their first taste of what meteors were capable of.

The night of October 9, 1946, saw a spectacular astronomical show. While much of the Eastern Seaboard had cloudy conditions, areas with clear skies witnessed a meteor shower from the passage of the comet Giacobini-Zinner. For example, the Nogales (AZ) International for October 11 reported, “many Nogalians saw a spectacular display Wednesday night when hundreds of falling meteorites from the comet Giacobini-Zinner flashed across the sky. The display was said by astronomers to have been one of the greatest ever witnessed.”

Prompted by the 1944 discovery of the phenomenon, hams were ready to see what it had in store for them. And for those who tuned the six meter band that evening, they were not disappointed.

Ed Tilton, W1HDQ, wrote about that night in the World Above 50 MC in the December 1946 issue of QST:
https://www.worldradiohistory.com/Archive-DX/QST/40s/QST-1946-12.pdf

We thought we’d seen everything! We’ve lived with temperature inversions and sporadic-E skip for years, aurora effect, with its fuzzy c.w. and unintelligible ‘phone is becoming widely recognized; the possibility of long-distance work via F2 skip is well known, and countless v.h.f. workers are on the lookout for it – but then along comes old Giacobini-Zinner and we have “ionization by cosmic dust” as a new means of v.h.f. propagation.

The display of meteors, forecast for October 9th, had been well publicized, and v.h.f. enthusiasts were on the lookout for unusual propagation conditions throughout the evening. By about
8:30 P.M. a peculiar rumble was noticeable on all 50-Mc. signals coming from beyond the horizon. Signals from points in a range from 200 to 1200 miles began to fill the 6–meter band, causing a degree of QRM never before experienced in this normally wide-open space.

Shown here 70 years ago, in the March 1956 issue of Popular Electronics, is CHU station staffer J.P. Henderson making an adjustment to one of the  timing devices in use by the station at the Dominion Observatory in Ottawa.  The voice announcements were recorded on the soundtrack of 35 mm film, and a system of cams was used to start the correct announcement of station ID, hour, and minute.

The magazine noted that during the summer months, the observatory was open to the public for astronomical viewing on Saturday nights.  During each session, there was also an open house at one of the observatory’s divisions, meaning that radio fans had a couple of opportunities each year to visit the radio station and see it in action.

Since January 1, 1955, the station had been on the air giving the exact time on its then frequencies of 3330, 7335, and 14,670 kHz.  Many North American hams, like me, undoubtedly used the 7335 signal as a means of making sure their 40 meter receiver was in calibration.  These days, the 40 meter frequency has moved to 7.85 MHz, but the other two frequencies remain in operation.

Shown here, on the cover of the March 1953 issue of QST, are W4AO and W3GKP, carefully aligning the W3GKP antennas in preparation for bouncing their 144 MHz signals off the moon.

The feat had been accomplished by the U.S. military a few years earlier, but it was much more challenging with amateur power levels of 1000 watts. The first echoes came in 1950, but the two hams kept the early results under wraps and continued until a definitive echo was shown, which happened in early 1953, on 144 MHz.

The details of the operation were carried in that issue of QST. That first EME (Earth-Moon-Earth) or “Moonbounce” signal required a great deal of technical expertise, but both technical innovation and collective experience have made the feat much more achievable, with many stations logging more than 100 countries. For an idea of the relatively minimal amount of equipment now needed, see W5RZ’s 2016 article about portable EME from a park, in which he made contacts with Europe by bouncing signals off the moon from an antenna strapped to a charcoal grill.