4087 km on 2m (The history of first VHF contact between W and KH6 in 1957)

The array that turned the trick at KH6UK is made up of four Gonset “Big Berthas” spaced two wavelengths each way, mounted on an 80 - foot pole. Location: Kahuku, on the northern tip of the Island of Oahu.

West Coast to Hawaii on 144 Mc.!
W6NLZ and KH6UK Shatter
2-Meter Record

On July 8, at 2130 PST [1957], W6NLZ listened, as he had nightly for more than 9 months, for the 144-Mc test by KH6UK, 2600 miles away at Kahuku, on the Island of Oahu. The signal was in there!

The 5-minute transmission seemed hours long. How could a miracle like this be expected to last through 5 minutes? But it did, and much longer. W6NLZ replied at the appointed time, shaking with excitement, and the 7-year 1400-mile record was broken by a margin beyond most 2-meter men’s fondest dreams.

Both stations run kilowatt rigs. The antenna at W6NLZ is a 24-foot Yagi, 35 feet above a fine location at Palos Verdes Estates, with a clear view out over the Pacific. KH6UK has a large multiple-Yagi array. Signals were good c.w. copy, and when W6NLZ concluded his telephone call to W1HDQ at 0150 EST, KH6UK was still riding through. Tape recordings were made by both participants. More details next month!

QST August 1957

BEYOND - THE - HORIZONT work on 5 meters as early as 1926 - the discovery of tropospheric bending in 1934 - sporadic-E DX in 1935 - auroral propagation in 1937 - world wide DX on 50 M.c. in 1946 - tropospheric propagation on 144 Mc at distances beyond 1000 miles in 1950 - aurora work on 220 Mc. in 1954 - these are some of the high spots in vhf. history that can be seen in retrospect by leafing through a QST file. They and other v.h.f. firsts came about, in many instances, because hams were willing to try things that more learned people would have said were impossible.

Practically every known form of long-distance vhf, propagation was first discovered in this way, often by accident. The important factor was a willingness on the part of hams to try anything! The formula still works, and no better example has ever turned up than the feat that we reported in brief last-minute fashion last month: two-way communication on 144 Mc across more than 2500 miles of Pacific Ocean. Nobody in his right mind would have given it a chance!

John Chambers, W6NLZ, aid Ralph Thomas, KH6UK, first worked on 14-Mc. c.w. on October 20, 1956. From that day on they made regular tests on 144 Mc. From early November to July 8, these averaged better than six per week - all without the slightest indication of signal either way on the higher frequency. For several months the tests had been the same: a short QSO on 14.095 and then a 5-minute test on 144.000 Mc by KH6UK. Results were always the same - nil. But the true ham never gives up. The tests started after the best of the fall inversions had passed, and the period did not include the king of all the meteor showers, the August Perseids. The summer inversion season and the Perseids shower held out two admittedly forlorn hopes.

Ralph E. Thomas, KH6UK, cuts a tape for use in his automatic keyer. At the far left of the picture is seen the 1 kW rig with a pair of 4-125A’s in the final, that has served both W2UK and KH6UK on 144 Mc. Receiver, center, is an SX-88, with a W2AZL 417-A converter for 144 Mc. Note prized QSLs from W6NLZ and W6NTC in the speaker grille.  (source DL-QTC 12/1958 tnx 1VR)

The evening of July 8 [1957], the inversion layer was clearly visible over the curving coastline from W6NLZ’s escarpment location, 910 feet [277m] above sea level at Palos Verdes Estates, at the southern end of Santa Monica Bay. It was a long way to Hawaii, to be sure, but at least the West Coast end looked good. Weather information indicated that a highly stable inversion had been building up for several days. At Kahuku, on the northern tip of the Island of Oahu, the afternoon of July 8 was like any other summer day in Hawaii. Nothing showed that tonight would be any different from the more than 200 others when the 144-Mc tests had been made. Tommy had given up listening on 2 long ago. The transmitters of RCA Communications filled the band with birdies, and he had seldom heard any 2-meter signals, anyway. But the transmitting tests still were made, and the W2AZL converter and SX-88 were ready to go, if anything happened.

The 2130 PDT sked was like all the rest: the exchange on 14.095, and the transmission on 144.000. But this time, as soon as W6NLZ got his 75A3 on frequency with the 417A converter - there was KH6UK! “Can it be? Is somebody pulling my leg? Am I getting if, feed-through? Am I dreaming?” All these and other thoughts raced through John’s mind and then came a wait that seemed an eternity, while the automatic transmission from KH6UK droned on. Would the guy never stand by?

No hurry about turning the thing off, Tommy thought, and the test ran on for some seven minutes before he heard W6NLZ calling him frantically on 14.095. Then came the quick change, the breathless moments, the fumbling sending, as two old c.w. hands who ragchew easily at 40 w.p.m. fell all over themselves in a rush of buck fever that is familiar to any ham who has tottered on the brink of a really big break. But the two-way worked - and good!

Signal reports were exchanged, and a few fumbling attempts at felicitation, and then on to see what else could be done while the rare opportunity still held. Tape recordings made at KH6UK tell the story. A period of birdies from the RCA transmitters, and then after some delay, a rather halting c.w. sig calling. A slow (this time) “QRZ de KH6UK” is followed by a call from W6NTC. Would this be someone a few miles east of W6NLZ, ready to claim the record, now that John had done the heavy spadework? Tommy replied with mixed feelings - and then learned that W6NTC is Mrs. W6NLZ, who was called in to run the rig while John placed a telephone call to W1HDQ.

The W6NTC - KH6UK QSO was still going on as John passed along the hot news over the landline at 0150 EDT, to your very sleepy conductor. But it was the last QSO over the 2540-mile circuit. Though John called several of the local 2 meter fraternity, none could be found at home with the necessary combination of gear, antenna and location to grab the plum that was waiting to be picked. KH6UK stayed on, calling CQ for three hours, but nothing more was heard but the RCAC birdies, and no other reports have been received of reception of Tommy’s signal on the West Coast.

The 2540-mile 2-meter QSQ across the Pacific did not "just happen.” There were superb stations, big antennas and capable operators at both ends. Above, left, John and Maureen Chambers, W6NLZ and W6NTC, smile happily over their DX record. Transmitter (in front of John) is modified KWS-1, that runs 1 kW on s.s.b. and c.w. on 144 Mc and lower bands. Receiver just visible between the operators is a 75A3, used with a crystal- controlled 41 7A converter on 144 Mc. Communicator serves for local work on voice. The Chambers station comes as close to being “all-band” as any you’re likely to see, there being facilities ready for all low frequency bands, plus 50, 144, 220, 432, 1215 and higher microwave assignments. Location, Palos Verdes Estates, is 910 feet above sea level, overlooking the Pacific.

How did it come about? The evidence points toward tropospheric propagation. Tape recordings from both participants show the signal to be essentially steady, with only the slow, typical tropospheric fade. There are no bursts; no wild excursions in signal strength that would almost certainly characterize meteoric or ionospheric reflections. The locations at each end are close to ideal, and the equipment the best obtainable. KH6UK uses the old W2TJK rig with 1 kW. to a pair of 4-125As. The antenna is 4 long Yagis in box formation, with 2-wavelength spacing each way, 80 feet above ground. W6NLZ runs 1 kW to a modified KWS-1, feeding a 24-foot Yagi 35 feet above a location where height above ground is of substantially no importance. His view out over the Pacific and northward along the curve of Santa Monica Bay is incomparable.

But other hams have good locations and fine equipment, and not a few are good operators. W6NLZ and KH6UK have earned undying fame in the annals of amateur radio because they had all the technical wherewithal - plus a willing ness to try something that gave every indication of being a lost cause before they started, and to keep on trying it, again and again, in the face of almost certain failure! The job is just started, however. The feat of July 8 showed that it can be done. It remains, now, to show how it came about, and to determine how often it might happen again. Does working across the Pacific mean that a QSO across the Atlantic is within the realm of possibility? Can equal distances be worked over land areas? We won’t know until we try!

QST September 1957

"It Seems to Us..."


At the recent ARRL National Convention in Chicago some of you heard President Dosland make a strong plea for more amateur awareness of PICON - a Washington-style term for “public interest, convenience or necessity.” Our President emphasized organization for emergency purposes, and well he may have, for such work makes news that can be appreciated by the public at large.

But another kind of hamming has been equally important in establishing the worth of amateur radio, even though your TV-viewing neighbor may never have heard of it. Many important and influential people do know about it, and more will be learning as a result of our IGY Propagation Research Project. Amateur contributions to the advancement of the radio art were recognized as far back as 1911, when a famous scientist testified before a congressional committee that amateur work had aided scientific investigations even before that time.

The amateur record in opening up the world above 50 Mc has been especially impressive. Moving into what seemed then to be wholly useless territory, hams working on 5 meters discovered tropospheric bending, sporadic-E skip propagation and reflection from the auroral curtain. This was in the middle 30’s, years before there were plans for using the vhf, range for commercial or military communication.

Following World War II, 50-Mc. enthusiasts turned up what is now known as transequatorial scatter, a phenomenon being given concentrated scientific attention during the IGY. They demonstrated that early postwar pre dictions for F2-layer maximum usable frequency were far too low in many areas of the world. Pioneering work with reflections from meteor trails in the early 50’s paved the way for development of means for long-distance communication with secrecy, a prime target in current work with meteor propagation. Scatter techniques, once thought to be usable only with very high power levels, are now being employed effectively by ham stations running less than 100 watts.

Hams have been able to augment scientific investigations mainly because of our unique character. We are everywhere. We operate largely without preconceived notions as to what will or won’t work. We try anything, even when better minds than ours have al ready figured out that what we are attempting is impractical. No better example of this emulation of the bee (theoretically incapable of flight, but doesn’t know it) has appeared in many a day than the recent but now historic 144 Mc QSO between W6NLZ and KH6UK. Nobody outside of amateur radio would have bothered to try such a thing even once, let alone attempt it nightly for nine months!

But John Chambers and Ralph Thomas were v.h.f. crazy from way back. They had seen the “impossible” done before, and they were game to keep on trying this one, even after 250 nightly attempts had given them not the slightest sign of encouragement. Then, on the night of July 8, the curtain of background noise parted a bit, and the 144 Mc test trans mission of KH6UK was heard, bending its way across more than 2500 miles of Pacific Ocean. A few minutes later they were at it two-way, and one of amateur radio’s greatest moments was written into our history. The contact broke the amateur record by more than 1100 miles, and it exceeds by some 25 per cent the greatest distance over which signals of any thing like this frequency had ever been received before.

The news traveled fast. Hams over the world heard of it the next day via W1AW. The public got it shortly after, through ARRL prepared news releases that made newspapers and radio and TV news broadcasts. Trade and scientific journals featured it in their next editions. Top people in the wave propagation world were informed through the cooperation of Dr. M. G. Morgan, W1HDA, a moving spirit in the USA National Committee of the International Scientific Radio Union (URSI).

At the XII General Assembly of URSI held at Boulder, Cob., in late August, QST’s v.h.f. editor found this work a prime subject of conversation with some of the world’s leading propagation authorities. From Dr. R. L. Smith-Rose of England, Vice-President of URSI, and Chairman of the URSI Commission on Ionospheric Propagation, on down, scientists of varying personal interests wanted to hear more of the event. There was much discussion of the nature of the signals, and of the ionospheric and tropospheric conditions that prevailed when the contact was made.

All agreed on one thing - the distance was well beyond anything in their previous experience for the frequency, by whatever means. Without exception, these highly-placed men of science were strong in their praise. They found it truly remarkable that amateurs would have the facilities, the know-how, and most important of all the infinite patience for such an achievement. To a man they expressed the hope that the work would continue, and that future results would be as carefully documented as has been the work to date.

The tests are continuing. Already, they have produced another break-through, as reported in our v.h.f. column this month. It is quite likely that more will have been recorded before this appears in print. But whether or not W6NLZ and KH6UK ever hear one another again on 144 Mc., they have done all of us a service of the highest order. They have made powerful friends for amateur radio in an area where backing could be mighty important in bearing out our contention that hams occasionally do more than think up better ways to interfere with television.

PICON has seldom been better served!


The record 144-Me, contact of July 8 between KH6UK and W6NLZ was repeated Aug. 18 [1957], under quite similar conditions. Tests made by KH6UK for other West Coast stations were first heard by W6NLZ at 2000 PST. Two-way communication was held from 2050 to 2114, and the signal remained audible until 2127.

Most of W6NLZ’s reception was weaker than during the first QSO. After some minutes of very low signal level at the start, reception improved so that the two-way portion was solid, though never reaching the peaks that marked the first success. KH6UK, on the other hand, recorded clearer reception of W6NLZ than during the July contact, probably the result of less interference from the hf. transmitters of RCA Communications, whose antennas are close by the big array at KH6UK.

When signals were at their best, W6NLZ tried his 144 Mc s.s.b. A tape recording received from KH6UK shows the signal at the threshold of voice readability at this time.

How were these contacts made? Evidence from the Los Angeles Weather Bureau, and scientific opinion gathered by your conductor while attending the URSI General Assembly at Boulder, Cob., point definitely to tropospheric propagation. While the 2540 mile path is some 25 percent longer than any previous proven reception of signals at 100 Mc or higher, some authorities on tropospheric propagation over ocean paths are of the opinion that the new record is far from unbeatable.

One well-known scientist expressed the opinion that conditions favorable to very long-distance work exist frequently in the Doldrums belt. He does not rule out the possibility of 144 Mc, work with Europe, even across the frequently turbulent North Atlantic.

QST December 1957

Will the 2540 mile 144 Mc record ever be broken?

When the previous record of 1400 miles was set back in 1950, it appeared highly unlikely that it would ever I extended by any great amount. The W5QNL - W6ZL QSO, like others made at the same time over slightly shorter distances, was deemed to have been the result of very dense E-layer ionization. Going much over 1400 miles by this means seems a remote possibility, and double-hop propagation (which might mean a haul of 2500 miles or more) would involve a fantastic combination of perseverance and good luck. Tropospheric propagation? We’d had some out to 1200 miles or more, but nobody gave it a chance to go farther.

Moonbounce techniques were then in their infancy. They’ve advanced some since, but we’re still a long way from substantial success in that department, at least within the amateur power limit. A newer technique, ionospheric scatter, may just work at 144 Mc., though it is far more promising at 50. Meteor scatter can provide communication of sorts, but like ionospheric scatter and sporadic-E skip, it appears to be limited to something under 1500 miles.

That tropospheric propagation, first-known of all v.h.f. DX phenomena, could provide communication over distances of record proportions was hardly suspected until July 8 of last year, when W6NLZ and KH6UK achieved their first success over the Pacific from the West Coast to Hawaii. But they did it twice, proving that it was no fluke. Can we do better? What will it take, if so?

People who should know say that the tropospheric conditions that made possible these 2540 mile QSOs can extend even farther than Hawaii - but where west of Oahu would you find another KH6UK? And as for the Mainland end, few 2 meter operators have the combination of location, equipment, operating savvy and per severance that characterize W6NLZ. Conceivably the record could be extended a few miles at either end, but what we’re talking about is some thing more significant than a mere stretching of the record.

There are other places in the world where favorable tropospheric conditions occasionally prevail over very considerable distances. We would look for these most often on long over water paths in the low latitudes, but coincidence of good 2-meter stations and the right conditions seems a slim chance at best, in latitudes near the equator. CT3AE, Madeira Islands, has expressed interest in trying, but he may be low on power. A remote chance, but perhaps one most worth bearing down on, lies over the North Atlantic. Here we at least have the stations, if not the conditions. Do we have the operators?

A transatlantic 2-meter QSO won’t just happen, because a few tries are made, now and then. If it ever comes off, it will probably be the result of intensive long-term effort like that made by KH6UK and W6NLZ. There will be schedules, kept religiously and at all hours. There will be the ultimate in equipment, within amateur limits, at both ends. And there will also be phenomenal good luck!

At least a few stations have setups that offer some hope of success. At this side of the Atlantic there are plenty of kilowatts and big antennas. Presumably there are also operators - and probably these are most important. In Europe most countries have power limits that are discouraging, but some special IGY authorizations may help out. We know that at least one British station, GB3IGY, has a 1 kW authorization on a temporary basis, an excellent location and a first class operator, G5KW. From PA0AFN, now living in this country, we learn that PE1PL, a laboratory station operated by a group of people interested in propagation experiments, will soon have a high-powered 144 Mc station on the air. They have a fine dunes location near The Hague, with a view out over the North Sea. And in Germany, DL4WW, well known to American 2-meter enthusiasts as W3YHI, is on with the legal power limit, 500 watts.

There are undoubtedly many others who are eager to work on the possibility of pushing a 2 meter signal across the Atlantic. The Inter national V.H.F. Society tried it some years ago, and they could very likely be talked into giving it another go. A spot on the Irish Coast might be a very favorable site from which to try, too. The main thing would seem to be to try, and right now is the time to start.

QST June 1958

Pacific Duct Experiment on 220 and 445 Mc

The following information was received too late for inclusion in July QST, so the basic details were mailed to OES appointees vest of the Mississippi, and were put on W1AW and other bulletin stations. As the tests will he less than half completed by the time this issue reaches you, here is a more complete report than was possible in bulletin form.

The U. S. Navy is conducting a series of propagation tests between San Diego and Hawaii on 220 and 445 Mc, to study the trade-wind duct that was responsible for the record-breaking work of W6NLZ and KH6UK on 144 and 220 Mc. Amateur cooperation in this experiment is solicited. Four c.w. transmitters will be used, one of them airborne along the route between the terminal points of the radio circuit. San Diego will he on 219.987 Mc. with 1 kW and a 20 dB antenna having a beam width of 20 degrees. Oahu will use a similar antenna with 200 watts output on 220.012 Mc. The 100 kW transmitter and 40 dB antenna normally used for Navy moon-relay work on 445 Mc will aim its 1.8 degree beam at San Diego, and also track the aircraft in flight. The plane will carry a 200 W 220 Mc transmitter and a 10 dB antenna.

The three ground stations will be on the air for approximately 15 hours each test day, beginning at 1200 GMT July 9, 1500 July 12, 1900 July 16, 2200 July 22, 0300 July 26, 0500 July 30, 0700 Aug. 2, 1100 Aug. 6, 1400 Aug. 9, 1800 Aug. 13, 2100 Aug. 16, 2400 Aug. 20 and 0100 Aug. 24. Note that times are in GMT (PST plus 8 hours). This schedule may be altered for aircraft maintenance, in which case cur rent information will be available from Robert Hopkins, Navy Electronics Laboratory (Code 2222) San Diego 52, or David L. Ringwalt, International Hotel and Motel, 1804 Sycamore St., E. Segundo, Cal.

The first flight and alternate flights thereafter will be from San Diego to Oahu. Other days the flights will be Oahu to San Diego. The airborne station will start transmitting about 2 hours after the ground stations. The Oahu 445 Mc transmitter will beam on San Diego for the first 2 hours of the transmission period, and track the plane thereafter. Its 1.8 degree beam will illuminate about 80 miles of the West Coast at any one time, and its heading will depend on the position of the plane during the tracking periods.

Please send detailed reports of any long-distance reception of any of these stations at once to ARRL.

QST August 1960

As this department changes hands (see later comments) it might well change headings too, if this month’s headline news is any criterion. The World Above 420 Mc would be more appropriate. For our last effort in the field of v.h.f. reporting we could hardly have dreamed up a more exciting swan song than the two items handed to us within a few days of each other just before our last deadline!

First came the thrilling word of a coast to coast QSO on 1296 Mc via the moon, and then almost before we’d recovered our breath came news of a breakthrough on 432 Mc across the Pacific. The latter story is one of frustration as well as glory for KH6UK, for though his 432 Mc signal made it across the 2540 miles from Oahu to Palos Verdes, he was unable to hear W6NLZ to make it an authentic two-way record. Having set the propagation world on its ear twice by their transpacific QSOs on 144 and 220 Mc, John Chambers, W6NLZ, and Ralph Thomas, KH6UK, had been trying 432 Mc for some time. Procedure was similar to that which produced the results before: a liaison QSO on 14,095 kc followed by automatic transmitting tests on 432 Mc by KH6UK. At 2010 PST July 20, W6NLZ began to hear the u.h.f. signal weakly. It faded in and out of the noise at first, but built up slowly to an S8 level by 2300. It held strong for about an hour and then dropped off slowly, until by 0340, when John finally gave up, KH6UK was barely discernible in the noise.

Time and again as the signal built up, Tommy listened on 432 Mc for W6NLZ, but in vain. The signal was in again the following night at 1907 PST, and again at 2007, 2025 and 2100, though always weak. Still no reception the other way, and by the time the trouble was traced to a bad 416B in the r.f. amplifier at KH6UK, and a replacement made, the signal was gone for good. It remains now to see whether there will be another chance this year. The first 144 Mc QSO was made July 8, 1957. It was repeated Aug. 18 of that year. The 220 Mc break came on June 22, 1959.

QST September 1960

California to Hawaii on 2 Meters 1976 Edition

That radio rainbow has just made its second showing within three years.

By Wayne Overbeck, K6YNB

Everyone from amateurs to the US. military considered it an impossible feat until the late John Chambers, W6NLZ and Ralph Thomas, KH6UK, did it in July, 1957, after some 10 months of daily scheduling. The same pair repeated their incredible accomplishment on 220 MHz in June, 1959. But after that, it was 14 years until the next W6-KH6 QSO above 144 MHz. We recall the spectacular five-day-long 1973 opening and compare it with the shorter but, equally dramatic opening this summer.

Most temperature inversions have gradual changes with height. However, the one that ducted 2-meter signals 2500 miles across the Pacific Ocean had a very abrupt boundary as seen here on June 29,1976, near Santa Maria, California.

Ever since those five warm, summer days in late July, 1973, Californian and Hawaiian hams have been waiting, hoping, wishing and praying for more of those thrilling days when vhf signals miraculously span 2500 miles of ocean to make each other sound like locals on 2 meters.

Sure enough, it happened again on another hot, summer day - June 28, 1976. Conditions were the same in many ways, but different in others. For some vhfers the latest opening was better, but frustrating for others be cause it failed to last as long or travel as far north as the previous spectacular. The basic mechanism that makes those line-of-sight signals cross an ocean on such rare occasions is a tropospheric duct. It might be likened to an enormous, flat, elongated pipe conveying vhf signals thousands of miles close to the earth’s surface. Unlike typical E- or F-layer ionospheric propagation on lower frequencies, the ducted signal never rises to any great height or bounces back down. Thus, sporadic E and F2 signals can rise over mountains while the tropospheric duct can be blocked by any large terrestrial object along the way.

Usually, the duct is fairly low at the California end, rises as it moves west and ends at both shorelines. The east elevation is less than 1500 feet while the Hawaii side lies between 5000 and 8500 feet above sea level. That means Californian stations with a clear shot to sea at modest heights have a big edge or their side of the path and Hawaiian mountain toppers, or mountainside repeaters, have the advantage there.

Characteristics of the Modem Openings

Stations in the shadow of hills or islands had no success even with a kilowatt and large antenna arrays such as the author’s, shown here.

The original mainland-to-Hawaii duct was first worked by Jerry Gastil, K6DYD, on July 28, 1973, when he keyed the 16/76 repeater at the 8300-foot level of Mauna Loa - 13,011 feet high. His kilowatt rig fed an 80 element Yagi array at his home 300 feet above the sea on Point Loma near San Diego. Since that day Jerry has maintained a daily morning ritual of attempting to key it again. Finally, his perseverance was rewarded at 1657 UTC on June 28, 1976, when he hit the Hawaiian repeater and quickly worked nine KH6 stations.

A difference this time was that I Mauna Loa repeater had changed to 22/82, a fact which made it much more difficult for California stations to won through it. There are busy 22/82 repeaters all along the California coast that covered the weaker Hawaiian signal. To their credit, though, most W6 repeater operators were very courteous during the opening.

An even more notable difference was that the tropo duct neither lasted five days nor moved all the way up the coast to San Francisco. Predictably, it moved to Santa Barbara within a few hours allowing WB6OBB to repeat his 1973 success by working numerous Hawaiians through the Mauna Loa repeater and at least two mountaintop mobiles on 146.52-MHz simplex. But the duct never extended much further north. Another 100 miles up the coast in Morro Bay, WB6PYD was the northernmost station to make a Hawaiian contact.

Worse still, this opening was alarmingly short. After the excitement of June 28, it was all but over. Jerry and a few others heard the Mauna Loa repeater until about 2100 UTC on June 29, but that was it. If the 1976 opening didn’t move on up the coast and didn’t last long, neither did it produce direct QSOs between urban Hawaii and California. Apparently, those in the islands worked the mainland only through the repeater or from a high elevation. Un fortunately, no Hawaiian station was readily equipped for the higher bands.

Getting Across

On the positive side, the highlight had to be a mini-mountaintop expedition by Al Pacheco, KH6IAA, with a 10-watt Multi-2000 and four-element beam. It was good enough for him to put a potent signal into California and work dozens of W6s on 145-MHz ssb. Thanks to Al’s multi-mode rig, more vhfers made a simplex ssb QSO with Hawaii during that one evening than the entire five days of the 1973 opening. Then, only a few simplex QSOs were made into the islands, including a handful in low-level urban areas.

This is not to say that mainland signals never made it below the Hawaiian mountaintops the second time. During one peak period on June 28, K6YNB/6 at Malibu Beach was working a string of Hawaiians through the Mauna Loa repeater when Chuck Niernann, KH6IOR, broke in with a report that the direct signal was S5 at Hickam Air Force Base near Honolulu. The installation is 200 miles northwest of Mauna Loa and near sea level about 10 miles behind the Koolau range, which has peaks over 3000 feet high.

Hindsight says K6YNB should have dropped everything and tried to make direct contacts into Honolulu right then and there. Because of the previous experience, it was easy to assume the opening would last for days, affording plenty of time for that later. He kept working through the repeater unaware that the Hawaiian signals would fade into the noise so soon.


During peak conditions of the tropospheric duct, modest installations such as this could work Hawaii from selected places with S9+ signals. Those hot spots were easily determined by monitoring with the rooftop whip antenna while driving along the California coast.

But the consolation had to be the quality of signals during those few hours on June 8. After K6DYD opened the band more San Diego stations, including W6BLK, WA6OIL, WB6ROP, K6UA and others had the thrill of working numerous KH6s through the Mauna Loa repeater. As the duct moved up the coast, W7VQQ/6, WB6RIV and other Los Angeles stations joined the fun. Soon KH6IAA was mobiling up the active volcano with his ssb-ready rig. At first there was nobody to talk to on ssb, so he worked fm on 146.52-MHz simplex and killed time by trying to key the San Diego 04/64 repeater which he could hear. Meanwhile, K6YNB drove along the Malibu coast and monitored Mauna Loa with a 19-inch whip. Frantically, he broke in announcing a spot where signals were the loudest and worked KH6IAA/KH6 on simplex with full quieting signals both ways. They switched to 145.010-MHz ssb and immediately exchanged 59-plus reports. Other Southern California ssb stations began to hear Al weakly at first, then more and more loudly, especially after he switched to horizontal polarization of his little beam. In one experiment, K6QEH reduced his kilowatt in steps down to an estimated 0.25 milliwatt and still maintained contact with KH6IAA/KH6. Al’s signals peaked between 0500 and 0700 UTC, about local sunset over the path, but by 0900 he was gone and it was all over.

Meanwhile, K6YNB rushed home from his hot spot on Malibu Beach, determined there were no detectable signals 20 miles up the coast and hurriedly put together his camper-mounted portable station, capable of a full kilowatt on bands through 432 MHz and scrambled back to Malibu. However, the signals were gone by then (local midnight).

On the following morning K6DYD and WB6PYD, 250 miles apart, worked into the Mauna Loa repeater simultaneously showing how broad this short-lived duct had become just before its demise. By 2100 UTC that day, stations in the best coastal areas were hearing the Hawaiian repeater for the last time.

In the Right Place
At the Right Time

Although its short life and failure to move up to San Francisco were big surprises, the June, 1976, duct confirmed the 1973 observations. Again, the absolute necessity of a clear shot to the open ocean was proven on the California end. Stations that were only one range of hills inland had almost no luck, regardless of their power level, while stations with low power and modest antennas near the coast were very successful. Even the Channel Islands off California’s coast proved in surmountable barriers although they are less than 2500 feet high. Several Oxnard stations on the beach, but behind the Islands, heard nothing. At the same time, others along the coast and clear of island obstructions copied Hawaiians above S9.

Like someone shouting into the end of a long pipe, one must aim directly into the duct with no obstacles in the way to get to the other end. In California that meant a clear view to sea at a low angle. In Hawaii, the right height was necessary. Neither the Haleakala repeater at 10,000 feet, nor the Diamond Head repeater at 400 feet, were directly heard in California. They are 100 and 200 miles northwest of Mauna Loa, respectively, to form a linked triple-repeater chain.

By Tuesday night, June 29, no elevation or signal angle produced anything anywhere along the California coast. How do we know? We know because after the Hawaiian signals completely disappeared from K6YNB’s Malibu hot spot, he and WB6RIV wasted three tanks of gasoline and a long day driving up and down the California coast. They tried site after site in a futile quest for the California end of the elusive trans Pacific tropospheric duct. If it was there, it was well hidden.

1 “World Above 50 MHz,” QST, September, 1973.
2 “The Cabover Kilowatt,” QST, August, 1971.

QST September 1976

Tropo z KH6 do W6,W7,XE2 1998/2007       
K6QXY-@   50000.0 KH6HME/B    144.170 tropo!!!! cm88> bk29  2203 14 Dec 1998
K6QXY-@  144170.0 KH6HME/B    S5 CM88> BK29                 2335 14 Dec 1998
K6QXY-@  144170.0 KH6HME/B    144 432 1296  all Q5 S1 ---9 C0433 15 Dec 1998

KG7FU-@  144170.0 KH6HME/B                                  1754 09 May 1999
K6QXY-@  500000.0 KH6HME/B    TROPO 144& 432                0432 27 May 1999
K7JA-@   144169.7 KH6HME      Beacon BK29 to DM03 S-6       1929 08 Jul 1999
K6ODV-@  144170.0 KH6HME/B    HAWAII Beacon into DM13       2337 08 Jul 1999
K7JA-@   432077.5 KH6HME      SSB BK29 into DM03            0552 09 Jul 1999
K6KLY-@  144171.0 KH6HME      BK29 to CM87 two meter SSB    0631 09 Jul 1999
N6CA-@   144170.0 KH6HME/B    & 432 still in West coast     1612 16 Jul 1999
K7JA-@   432077.7 KH6HME      Loud Beacon BK29 into DM03    0209 17 Jul 1999
N6CA-@   144170.0 KH6HME      & 1296 & 3456 MHz SSB         0315 18 Jul 1999
K7JA-@   144170.0 KH6HME      Beacon BK29 into DM03 S-7     0243 17 Aug 1999
K7JA-@   432077.7 KH6HME      Beacon BK29 into DM03 S-3     0244 17 Aug 1999
N9JIM-@  144170.0 KH6HME/B    bk29 to cm88 (K6QXY) TROPO    2213 15 Dec 1999
N9JIM-@  432000.0 KH6HME/B    bk29 to cm88 (K6QXY) also 144 2213 15 Dec 1999

K7JA     144170.1 KH6HME      BCN S7 INTO DM03              0208 02 Jun 2000
N6YM     144170.5 KH6HME/B    bk29>cm88 559                 0409 17 Jun 2000
K5KT     144170.0 KH6HME/B    Q5 IN PALOS VERDES            1745 17 Jun 2000
K6CCC    432077.5 KH6HME/B    Solid copy in Glendora, CA    1952 17 Jun 2000
AJ6T-@   144170.5 KH6HME/B    BK29>CM87 539 mobile          0530 18 Jun 2000
K6NPS    144200.0 KH6/K6MIO   into cm96                     0623 18 Jun 2000
K7JA     144170.3 KH6HME      Beacon S9 into DM03           1643 23 Jul 2000
K7JA     144170.1 KH6HME/B    Bcn BK29 into DM03 S-9        0543 02 Aug 2000
K7JA-@   144169.8 KH6HME      Beacon BK29 into DM03         0210 12 Aug 2000
KH7E-@   144170.0 KH6HME      Listening VHF/UHFand UP Has wo2235 12 Aug 2000
K7JA     144170.5 KH6HME      Working San Diego stns.       2249 12 Aug 2000
K7JA-@   144170.5 KH6HME      Paul, S5-S7 into DM03         2340 12 Aug 2000
K7JA-@   144170.5 KH6HME      Paul S5-7 into DM03           1751 13 Aug 2000

K7JA     144170.0 KH6HME      Beacon BK29 539 into DM03     0051 23 Apr 2001
K7JA-@   144170.0 KH6HME      Beacon BK29 S3 into DM03      0120 05 May 2001
K7JA-@   144170.1 KH6HME      Worked at 0045, BK29 to DM03  0221 18 Jun 2001
K7JA-@   144170.5 KH6HME      Paul S9 into DM03 04Z         0407 18 Jun 2001
XE2EED   144170.0 KH6HME/B    BK29 HI. all day into         0511 23 Jun 2001
K7JA     144170.3 KH6HME      Beacon BK29 S9= into DM03     0117 11 Aug 2001
K7JA-@   144170.1 KH6HME      Beacon BK29 S9 into DM03      0123 30 Aug 2001

N6HY     144170.0 KH6HME      beacon                        0213 28 Jun 2002
K7JA-@   144170.2 KH6HME      Beacon S9 into DM03           0042 26 Jul 2002

N6PEQ    144170.0 KH6HME/B    BEACON STILL INTO DM13        0240 21 May 2003
N6PEQ    432078.0 KH6HME/B    LITE INTO DM13                0245 21 May 2003
N6HY     144170.0 KH6HME      beacon                        0313 21 May 2003
N6PEQ    144170.0 KH6HME/B    > DM13 LITE                   2155 21 May 2003
N6PEQ    144170.0 KH6HME/B    S9+ > DM13\                   2141 22 May 2003
N6HY     144170.0 KH6HME      beacon                        0133 23 May 2003
N6PEQ    144170.0 KH6HME/B    LITE INTO DM13                0010 16 Jun 2003
KH6DV-@   50061.5 KH6HME      kh6 beacon                    0348 10 Jul 2003
KB6NAN   144170.3 KH6HME      first 2m dx                   2221 13 Jul 2003
N6HY     144170.0 KH6HME      s9                            0206 14 Jul 2003
N6HY     440000.0 KH6HME      slow scan tv                  0208 14 Jul 2003
N6HY     222100.0 KH6HME      s1                            0251 14 Jul 2003
N6HY     144169.8 KH6HME/B                                  0200 16 Jul 2003
N8WWM-@   50125.0 KH6HME      599 to EN81 and if ya believe 0428 16 Jul 2003
KB6NAN-@ 144170.0 KH6HME/B    strong                        1645 16 Jul 2003
N6HY     144170.0 KH6HME/B                                  0217 18 Jul 2003

N6XQ-@    50000.0 KH6HME/B    144.170 bcn into calif        2339 03 Jun 2004
XE2HWB-@ 144170.0 KH6HME/B    VERY STRONG IN DL44           0238 04 Jun 2004
XE2ED-@  144170.0 KH6HME/B    559 in to DM12km              2250 04 Jun 2004
XE2ED-@  432078.0 KH6HME      Hawwaii 559 in to DM12km      2338 04 Jun 2004
WA6LIE   144170.5 KH6HME      USB Paul on Mountain wrking Ca0201 06 Jun 2004
KH6SX-@  144200.0 XE2HWB      Hrd DL44 to BK29 !!!          0609 07 Jun 2004

ZP6CW-@   50061.7 KH6HME/B    579                           0250 17 Feb 2005
K7JA-@   144170.0 KH6HME/B    Beacon into DM03 S5           0033 18 Jul 2005
K7JA-@   144170.5 KH6HME      Paul QRV S5 into DM03         0205 18 Jul 2005
K6QXY-@   50061.0 KH6HME/B    TROPO 144 432 & 1296 in also  1924 26 Jul 2005
WA6LIE   144170.0 KH6HME/B                                  0029 28 Jul 2005
WA6LIE   432078.0 KH6HME/B    432 best at this time into CM90031 28 Jul 2005
K6OYY-@  144170.8 KH6HME/B    S3 in DM04 at 1357z           1442 28 Jul 2005

WA6FXL   144170.0 KH6HME/B    hrd by K6QXY tropo            2205 18 Jun 2006
N6HY     144170.0 KH6HME/B                                  0320 19 Jun 2006
N6HY     144170.6 KH6HME/B                                  0211 21 Jun 2006
WA6LIE-@ 144170.6 KH6HME/B    Hawaii beacon Q5 S1 into CM96 1847 25 Jun 2006
WA6LIE-@ 144169.7 KH6HME/B    BK29>CM96 Q5 S1               2055 25 Jun 2006
NA6XX-@  144169.9 KH6HME/B    ESP in/out of noise in CM97   2114 25 Jun 2006
WA6LIE-@ 144171.0 KH6HME      BK29>CM96 Paul at the Mic     2358 25 Jun 2006
WA6LIE-@ 432078.0 KH6HME/B    Q5 S1 into CM96 Paul on 144.170203 26 Jun 2006
N6ED     144170.0 KH6HME      CQing KH6 > W6                0229 26 Jun 2006
W7KKE    432078.7 KH6HME/B    BK29 > CN75 very weak         0244 26 Jun 2006
WA6FXL   144170.8 KH6HME      Q5, > CM89 path disappearing  0402 26 Jun 2006
WA6KLK   144170.0 KH6HME      CM89HI(TR>BK29 59 still in nor0534 26 Jun 2006
W7KKE    432078.7 KH6HME/B    BK29 > CN75 slow QSB peaks S1 1505 26 Jun 2006
W7KKE    144170.0 KH6HME/B    BK29 > CN75 slow QSB abt same 1519 26 Jun 2006
WA6KLK   144170.0 KH6HME/B    CM89HI(TR>BK29GO vry strong, 21608 26 Jun 2006
W7KKE    144169.9 KH6HME/B    BK29 > CN75 freq has drifted a1819 26 Jun 2006
W7KKE    144169.6 KH6HME/B    BK29 > CN75 S1 ocnl S3. Nil 701946 26 Jun 2006
W7KKE    144169.6 KH6HME/B    BK39 > CN75 S1. Nil 70cm      2127 26 Jun 2006
WA6LIE-@ 144171.0 KH6HME      Paul on the mountain CQing    2212 26 Jun 2006
KI6BPY-@ 177170.7 KH6HME      BK29 > DM12 5-2               2254 26 Jun 2006
KI6BPY-@ 144170.7 KH6HME      BK29 > DM12 5-2               2255 26 Jun 2006
W7KKE    432077.0 KH6HME      >CN75 s1 -                    2307 26 Jun 2006
WA6LIE-@ 144171.0 KH6HME      Paul will be on mtn til 2000 H2336 26 Jun 2006
K6KSY    432076.8 KH6HME                                    0049 27 Jun 2006
W7KKE    144170.6 KH6HME      BK29 > CN75  S1               0426 27 Jun 2006
W7KKE    144169.8 KH6HME/B    BK29 ( CN75 419               0358 28 Jun 2006
W7KKE    432078.4 KH6HME/B    BK29 ( CN75 weak with fades   0421 28 Jun 2006
WA6FXL   144170.0 KH6HME/B    USB 519 BK29go>CM89ob         0453 28 Jun 2006
N6HY     144170.0 KH6HME/B                                  0623 28 Jun 2006
W7KKE    144070.0 KH6HME      BK29 > CN75  559              1424 28 Jun 2006
W7KKE    432079.3 KH6HME/B    BK29 > CN75  519 (both r bcns)1425 28 Jun 2006
WA6FXL   144169.6 KH6HME/B    Drifted down BK29>CM89        0404 29 Jun 2006
K6QXY-@   50000.0 KH6HME      144 & 432 & 1296 beacons in   2129 04 Dec 2006
K6QXY-@   50000.0 KH6HME/B    TROPO 144, 432 & 1296 beacons 2211 05 Dec 2006

K6QXY-@   50000.0 KH6HME/B    144, 432, & 1296 beacons TROPO2102 02 Jan 2007
K6QXY-@   50000.0 KH6HME/B    144 beacon TROPO continues    1721 03 Jan 2007
K6QXY-@  500000.0 KH6HME/B    TROPO to KH6 144 beacon       2339 09 Jan 2007
K6QXY-@   50000.0 KH6HME/B    144 beacon in via TROPO       2343 09 Jan 2007
K6QXY-@ 5000000.0 KH6HME/B    144mhz beacon in via TROPO    2212 18 Jan 2007
K6QXY-@   50000.0 KH6HME/B    144 beacon via TROPO          2216 18 Jan 2007
K6QXY-@   50000.0 KH6HME/B    144, 432, & 1296 beacon very s0549 19 Jan 2007
XE2HWB-@ 144170.0 KH6HME/B    VERY WEAK INTO DL44uc         0821 09 Mar 2007




For OK2KKW web rewrited OK1TEH

More interesting links:


The California to Hawaii Attempt on 10 GHz http://www.cq-vhf.com/CalifornGordo%20Sum05.pdf