Usually, cooling is not for higher gain, but for lower noise. Considering gain, you just want to stabilize the temperature, at whatever reasonable value, like 30C. Cooling will reduce noise, but in an amateur setup, water condensation and frost are a quite unsurmountable problem. Also, if the antenna is at room temperature, the thermal conductivity of the cable between the antenna and the LNA will be a problem - low electrical loss and low thermal conductivity usually don't dance together.
Marko Cebokli
2025-09-30 05:50, je 'b alex pettit jr' via Society of Amateur Radio Astronomers napisal
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How do you set up cooling? Do you just cool the LNA or do you cool the waveguide too? So for example i use a cantenna for my waveguide - if I wanted to Peltier cool my system, would that mean that I need to somehow cover the entire cantenna and LNA and cool the lot or is just enclosing the LNA in a casing a cooling that sufficient? Then what temperature is ideal? When i am doing astrophotography, I use an Atik 16200M camera which cools to 45 degrees below ambient. I live in UK woth temperature usually in range 15-20 C but can vary 0 C to 30 C. So I cool to -10C which means I can get that temperature at almost any time and the stable single temperature allows me to use a single set of dark frames and flat frames. Does radio astronomy work the same way? Can we calibrate with a single calibration standard used all the time as long as we cool our LNA (or LNA plus waveguide depending on answer to my question above) to the same temperature each time?
Sorry for all the questions but this thread fascinates me as I would love to know how similar radio astronomy and astrophotography are in this regard.
Andy
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Well... I have decided to not purchase /try the Peltier Cooler from Ada Fruit. I am using a Discovery Dish with Hydrogen Line feed. Velcro strapping the large chunk of metal to the plastic case... enclosing the dipole would block E&M waves and probably not help much at stabilizing temperature.. not to mention problems with the weather.I still have my old WiFi dish... so maybe I will set it up again and try to rig it with lna temp stabilization..... which is weather protected.....