During second period of activity from ARECIBO Radio telescope I have recorded SDR files with this activity. Some pictures showing this traffic are here.

Joe K1JT explain parameters:


Lines 1 through 4 of the following table give reasonable parameters for antenna gain, transmitter power, system noise temperature, and self-echo S/N in 100 Hz bandwidth for three different stations:

- KP4AO on the Arecibo radio telescope

- typical "brick and Yagi" satellite-class station

- QRP station with 10 Watts and a 4 element hand-held Yagi


Lines 5 and 6 give reasonable estimates for S/N in 100 Hz BW for each of the other stations at KP4AO, and for KP4AO at each of the other stations.

Lines 7 and 8 give the same S/N estimates referred at a 2500 Hz bandwidth, the scale used in JT65.


Parameter KP4AO Sat-Stn QRP


1.  Ant gain (dBi)  60  16  10
2.  Tx Poweer (W)  400 100 10
3.  Tsys (K)  330  300  300
4.  Echo S/N, 100 Hz BW (dB)  +68  -30  -52
5.  S/N at KP4AO, 100 Hz BW (dB)  +13/ -3
6. S/N of KP4AOm 100 Hz BW (dB)  +19/ +13
7.  S/N at KP4AO, 2500 Hz BW (dB)  -1/ -17
8.  S/N of KP4AO, 2500 Hz BW (dB)  +5/ -1





My estimate for Tsys at Arecibo includes 120 K from the receiver and 210 K from the Moon. To be very conservative, the other ground stations are assumed to have something like 2 dB NF and 1 dB of feedline loss. It's clear that satellite-class stations should be able to work KP4AO on CW. Even 10-Watt stations with hand-held yagis should be able to hear KP4AO, but their CW signals will be marginal at Arecibo. They should be able to easily make the QSO easily if JT65B is used. (It's not 100% certain that JT65 will be available at KP4AO in April... but if there is sufficient demand, it may be.) 


Good luck in April... and let's all return our thanks again to the great operators at KP4AO, for putting Arecibo on 70 cm EME !


-- 73, Joe, K1JT


Audio file MP3 SSB QSO OK1DFC - KP4AO



Audio file MP3 CW QSO DL9KR - KP4AO


Here is a picture with CW CQ of KP4AO

CQ signal of KP4AO peaking -95dB what is 45dB over noise

Pile up over CQ

Other CW pile up

KP4AO calling CQ SSB

Finally worked KP4AO SSB 59/59++ as a #105 432 MHz and #57 DXCC 432 MHz EME. Used on my side 10m dish and 1kW RF.

Thanks for great effort guys!!!!

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