KP4AO Arecibo EME 16 April 2010
The recent 70CM EME activation of the Arecibo Radio Astronomy dish by KP4AO inspired me to reassemble the antennas I used nearly 30 years ago for both terrestrial and EME. The same az/el rotors also installed but not connected to the control boxes. So the array was manually positioned. After discovering I had printed out the tracking position for the sun instead of the moon :( I went searching for KP4AO's signal. The moon was not visible since it was so close to the sun but I had a general idea where to aim. I had no problem finding a much weaker than expected CW signal form KP4AO so I thought I must have them on a side lobe but I could not get their signal any stronger. I could hear them making contacts but thought it would be futile to call them with just 100 watts since their signal was weaker than I had heard years ago from some home EME stations. But I did anyway and was surprised to get a reply. Since they heard me well I assumed I had a receive problem but was pleased to get my call on their log. A few hours later I read some email messages stating KP4AO was only running 20 or 30 watts due to a power amplifier failure. So they were probably hearing me 10 dB better than I was hearing them considering the power difference and questionable NF of my receive system.
(dead air time between exchanges due to path delay edited to reduce file size)
4 X 19 element K2RIW antennas initially used at a previous location from 1980 to 1985
Antennas have been laying in the weather since 1986 with RG-213 phasing lines attached.
A very heavy spool of fiber optic cable was used as a quick mount.
Equipment used for the QSO:
Yaesu FT-897D (no added filters)
25+ year old 100 watt Mirage amp
PAG-432 Lunar preamp
Astron power supply / modified
Happy operator after success with a quickly thrown together station.
Update 17 April 2010
KP4AO's signal with their power amp back online was Q5 S5 SSB copy with the four yagi array. So I pulled an old 27 element KLM from the antenna pile to see how the copy would be with a single Yagi connected to a FT-817. I could copy KP4AO at times but not Q5 with the stock FT-817. I then inserted an ARR P432VDG preamp in line. Then copy was Q5. I recorded them working Jimmy, W4ZRZ, with this single Yagi system. Their signal was slightly in a fade during this exchange. I was glad to catch my microwave friend Jimmy making the QSO.