Remembering The EME Years

This is one of a series of “Notes” I published on Facebook. Since Facebook has discontinued the Notes feature, I am publishing that series here on my blog.

As I watch the moon sinking low in the southwestern sky, shimmering through the trees I am reminded of an evening long ago. It was May 29, 1988 and I was running a two meter EME (Earth-Moon-Earth, or “moonbounce”) schedule with W7IUV in Arizona. The moon was in about the same position it is now, my single CushCraft 4218XL yagi looking at it through the trees, and I was pumping about 1000 watts of CW into the antenna, alternating two minute periods transmitting, two minutes listening. Perhaps I should emphasize listening. During receive periods I was tuning up and down through a narrow range of frequencies, about one kilohertz total, hoping to find some hint of a very weak CW signal at the noise floor. Eventually I did find it, and from time to time could even copy it. Back and forth we went, exchanging callsigns, signal reports and acknowledgement of information received according to a special format. I completed the contact with Larry that evening for my eleventh station worked via the moon. My first EME contact had come six months earlier when I worked superstation W5UN on December 26, 1987. That was the beginning of the most exciting phase of amateur radio I ever experienced.

I had started on 2 meters in the summer of 1986, after picking up a used all mode radio at a hamfest. I made a lot of contacts on the terrestrial propagation modes: troposcatter, sporadic E, aurora, meteors. But I was reading everything I could get my hands on about VHF DXing, and I knew EME was king. While the terrestrial modes allowed contacts to a distance of 1400 miles on occasion if one was lucky, the whole world was within reach by bouncing signals off the lunar surface. EME was all CW in those days and it required quite a bit of power. I could have probably worked W5UN with 100 watts or so, but I knew if I was going to work more than one or two of the very big stations it was going to take more. I set about collecting parts to build a kilowatt amplifier.

By the fall of 1987 the new amplifier wasn’t quite ready yet but I had upgraded the antenna a couple of times, now having the 29 foot long CushCraft on a 40 foot tower. I could not elevate the antenna above the horizon, but I listened at moonrise during the ARRL EME Competition in October and November of 1987. I heard several stations including YU3WV. Wow! I was hearing Europe on two meters! I couldn’t wait to make my first EME QSOs!

I am not sure how I survived the first contact with W5UN, because I don’t think I breathed during that schedule! Dave had the largest EME antenna in the world at the time, a truly massive structure comprised of 32 long yagis stacked four high and eight wide. That first contact was followed the next day by working N5BLZ with his array of 12 long yagis. A few days later I worked K1WHS which was interesting because we were just 150 miles apart. Pointed at the rising moon I could hear Dave’s tropo signal quite strongly off the back of my antenna. He was hearing me direct as well. But from time to time, shifted some 350 Hertz higher by the relative motion of the moon to our antennas (doppler shift), the EME signal rose just above the noise floor. It was bizarre. Not only was the lunar echo shifted in frequency, but it wad delayed by almost two and a half seconds. That is how long it takes a radio signal to traverse the half million mile round trip to the moon and back. Dave was literally QRMing himself! Instinctively we both began to send two or three letters and then pause for the echo to return. This was to prevent the tropo signal from overwhelming the weaker moon echo and give the other guy a better chance to copy the wanted signal. After all, we were trying to complete a QSO by way of the moon, not tropo! It was easy to tell one signal from the other by the frequency.

Left: “The Ugly Kilowatt” pair of 4CX250Bs’s, with all-mode 2 meter rig sitting on top; Right: Amplifier with three 4CX250B tubes that never did work quite right. In the middle, Kenwood TS-820S with Microwave Modules transverter which I was using on EME at this point in time.

A month later I worked my first two Europeans on 2 meters, SM7BAE and UA1ZCL. I had worked Europe on two meters! EME became the thing to do. Several others followed, and by the spring of 1988 I installed a receive preamp at the top of the tower, just below the antenna itself. This would allow me to hear the very weak EME signals a little better, and it paid off. I soon worked the smallest station to date: four yagi station KI3W. All told, I worked 16 different stations off the moon with my single yagi. I was hooked.

By October, when the EME Competition came around again, I had completed construction of a real EME antenna: 16 four-element quads which I assembled from strips of wood and wire from the local hardware store and lumber yard. There was no stopping me now! This antenna had 19 dB gain, or about 5 dB more than the CushCraft yagi. It made a huge difference. EME contacts were now much more numerous and I could elevate the thing so I was no longer limited to short windows at moon rise and set. For the first time I could hear my own lunar echoes come back. That in itself was a thrill!

The 16 quad array

The first amplifier, a pair of 4CX250B tubes, gave way to a legal limit-capable 4CX1000A. The KLM Multi-2700 transceiver got replaced by a Microwave Modules transverter in conjunction with my Kenwood TS-820S HF rig. The antenna was upgraded to 24 of the little quads, producing about 20.5 dB gain. As operator skill and confidence grew and the station slowly improved, running pre-arranged schedules gave way to what we called random operating. In other words, calling CQ and working whoever you could get. Or tuning the band looking for other stations calling CQ. By the end of 1994, 520 different stations had made their way into my two meter EME log. After a period of inactivity due to changes in living arrangements, I returned to EME in 2000. My final two meter EME QSOs were made in 2006 just before leaving the band. By then, digital modes had largely supplanted CW and EME via digital wasn’t much of a thrill. My two meter EME “initial” count, or number of different stations worked, had risen to 610. I also had a brief stint on 70cm (432MHz) EME, first with a single 22 element yagi, later an array of eight 21 element yagis. I worked 33 different stations via the moon on that band but never liked it as much as two meters. I made one and only one EME contact on 6 meters.

A later version of the station. Left to right: HF amplifier with four 811A tubes; “Ugly Kilowatt V2” 2 meter amplifier using a 4CX1000A; Kenwood TS-820S and transverter; Color Computer II running MoonTrak. Mounted on the wall above the Kenwood, azimuth and elevation controller for the EME antenna

EME also led me to take up computer programming. I wrote three programs for tracking the moon. First a very simple azimuth-elevation calculator for the Radio Shack PC-3 Pocket Computer; next, MoonTrak real-time azimuth and elevation tracker with polarization calculation for the Color Computer II; finally Z-Track for the IBM PC. For a time I sold copies of the latter to fund my EME addiction. My EME software was the first to incorporate calculations of “spatial” polarization offsets between stations and take into account the implications for EME scheduling. Later I collaborated on a rewrite of the EME scheduling database software used by the Two Meter EME Net.

Z-Track software. Note the year, 1996. This software was running under the MS-DOS operating system!

There is no way to describe what EME meant to me. The sheer thrill and excitement of it cannot be conveyed. It was the ultimate challenge, the ultimate DX, the ultimate accomplishment. Nothing I have done in ham radio before or after EME can compare. Not a day goes by that I don’t miss it. Ultimately it was the collapse of CW on EME that led to me leaving VHF for a decade, returning just this summer. If I wasn’t so constricted by budget I would no doubt build a large antenna array and return to two meter EME for the few CW QSOs which can still be had occasionally.

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