MT Arecibo

From Stu2
Jump to navigation Jump to search
Hi-tech Elevation Sensor

I was one of about 200 stations world wide to complete a CW EME QSO with KP4AO on 432MHz on April 17th, 2010.

My station was a simple 432 UHF yagi based on the K1FO design. WB7SZM and I built the yagi in the early 90's to support our VHF/UHF contest activities. The elements are insulated from the boom using the protective endcaps from hypodermic needles. (His wife was a nurse and these things were just the right size!) The elements were super glued in place and expected them to fall out, after all these years. But they stayed in place!

After many contests, I knew the yagi had a clean pattern. The night before the first session, I replaced one of the pieces in the T match. The antenna presented a 1:1 load to the transmitter and I was able to copy the 200mW beacon from HO-68. (Peaked at S2 when the satellite was 15 degrees above the horizon.)

Day 1

W7IY (r) Trying to explain to the gang why things weren't working as expected.

I attempted to make a QSO was during the W4AD tower removal activities. My station was set up on the old picnic bench built by W4NF. While they toiled away removing antenna parts, I tied like mad to get one last EME contact from W4AD's backyard.

KP4AO was weak with a lot of QSB and I never heard any USB. They switched to CW about 1/2 hour into the operating period and I was able to copy partial CW transmissions for the remainder of the operation. However after many, many calls - no luck.

I shut down at the end of their published operating period. If the signals would have been strong enough, I think I would have been able to provide an opportunity for several other EME first contacts. But still - just to hear a signal bouncing off the moon is very cool. Think about it. The signal has to travel from Earth through some 238,000 miles of space, reflect off the moon and travel back to earth - where some guy standing in his back yard can copy it - all with inexpensive ham radio gear.

Day 2

432MHz EME Station

The next day, I set up in my backyard in Stafford and used a very short feed line. The signal was definitely stronger the second day. (Their amp was back!) I was able to copy about 40-60% of the USB transmissions, with QSB at all the wrong moments. I continued transmitting CW to increase my chances of being heard. KP4AO was working about one QSO every 2-3 minutes. Still - no luck.

About an hour into the operation, they changed operators. The operator's accent changed and so did the operating style. After about another 1/2 hour I heard the announcement they were switching to CW. A few minutes later, I could hear their CW signal. This helped. My copy rate increased to about 80%. I continued to call. I tried moving my TX frequency from .056 to .059. Nothing.

Just when things were looking bleak, I decided to moved my TX frequency to .052. and try again. After a couple more calls, I thought I heard a reply. I sent W7IY twice again. Sure enough - I copied my call sign and the exchange. Signals were very clear! I sent RRR's and a report. No response - gave them another set of RRRs and a report and finally copied their RRR's and 73's. Good QSO! My first ever 432MHz EME contact at 16:25 4/17/2010 local time.


The station was a Kenwood TS-2000, TE 432AMP (175W), 23 element K1FO yagi (from the handbook), 10' RG-213, SSB Electronics 432 Preamp, MFJ 45 amp power supply and homebrew, manual Az-El mount. I used a compass and a protractor with fishing line to measure the antenna angle. My antenna was mounted on a Dayton army pole special and held in place with a concrete brick.

If the KP4AO ops ever see this page - please accept my thanks! I have one other EME contact (W5UN) on 2M, which I completed under the mentoring of W4AD(K4HWG) over 20 years ago. This contact was every bit as exciting and one of my ham radio highlights!