by Steve Anderson » Sun Apr 11, 2021 1:00 pm
...reminds me of the days when I worked in radar at Decca in New Malden and Chessington in/near London in the 70s. By chance I have a couple of exactly the same CRTs, 5ADP7s, and a couple of 5ADP1s.
All kudos to the guy in getting this far...not sure what use he may have for it, but certainly educational!
As he mentions, his biggest hurdle is going to be the receiver. The Klystron he's using as a transmitter was usually used as a local oscillator for the receiver, they were eventually displaced by Gunn diodes as the power required is only 20mW or so. The 10GHz [1] antenna input was mixed with the Gunn diode's output to produce an I.F. of around 70MHz.
The receiver had to be logarithmic as the reflected power goes down with the square of the distance to the target. In other words the receiver needs to have a large dynamic range. A target 100km away, in marine terms - over the horizon, returns a very weak signal, but when the vessel is berthing the crew want to have a resolution better than 15m or so and hence a very strong return signal.
Typically a radar uses a Magnetron as the transmitter, the frequency and power output is set by its design and can only be varied over a very small range. A microwave oven Magnetron is a somewhat different device, its power can be varied, but it's frequency stability is rubbish!..no good for radar. But your meat pie doesn't really care...
Steve A.
[1] 10GHz (X-band, 3cm wavelength) is the most often used marine radar frequency, the other other common frequency is 3GHz (C-band, 10cm wavelength), the advantage is it's less reflected by rainfall where an X-band radar would be effectively blind. Large vessels will typically have both, often duplicated too.
The same problem as Ku-band satellite TV (12-18GHz), during heavy rain - no TV.