Above are my echos with a 6 meter dish, a system temperature of 75 Kelvins and approx. 5 watts at the feed.
The Time scale runs vertically - Z. Frequency is labelled across the top and bottom. The bright trace at 600 Hz is the transmitted signal and the faint echoes are seen just to the right converging in frequency as time progresses. On the very right there are three vertical bars which are audio signal to noise ratio in a 100 Hz bandwidth each second. Each step to the left is 10 dB. Transmit signal is pegging the scale and in between the approximately 2 1/2 second transmissions one can see my echo which runs from sometimes nothing to up to 5 to 7 dB on up fades.
Thrse plots represent a non copyable signal - one can tell it is there and a really good ear listening with a 6 m dish and 50 Kelvin system might be able to make a QSO out of it - the report would be O's.
The second plot is the same format except that the frequency scale is doubled in width. I run a wide IF bandwidth to get everything I can on the audio screen. For copying CW a I use a tunable audio filter. (DSP 59+ a really fine box).
The top signal is N6BQ and the reason it jumps in frequency is that I was tuning the receiver. One minute later you can see W2UHI. The faint trace trailing off the right at the top means that I heard him somwhere up the band and quickly tuned the receiver up to get him.
One can see that both of their signals have 20 dB peaks and there are seldom fades below 10 dB. These are 559 to 569 copy and were recorded when I had a about 75K Tsys.
Now that I am at 50 K, I occasionally see 30 dB peaks on some of the really big guns.
Here is a plot from last evening. At the top is K5JL peaking well above 20 dB SNR in a 100 Hz bandwidth. He is sometimes stronger but must have been backed off in power.
The very weak signal is NU7Z. He was barely audible in a 200 Hz filter but I could not copy him. On the right hand scale you can see that he only occasionally gets above zero. I had worked JL on 23 cm and noticed the weak signal a couple of hundred Hz up the band. The jog in his frequency happened when I tuned him in.
I have it second hand that he was running 40 watts down 125 feet of RG8 to an 8 foot dish!