At 1420 MHz (the hydrogen line), the lowest system noise temperature an amateur can realistically achieve depends on the quality of the antenna, feed, low-noise amplifier (LNA), and how much…
For a 1.2 m prime-focus parabolic dish, the beamwidth depends mainly on the operating frequency (or wavelength), not strongly on the F/D ratio. A typical prime-focus dish has an F/D…
With a 1 m dish, observing astronomical masers is challenging but not impossible if you use a low-noise receiver and target the strongest sources. The most practical maser lines are:…
Radio astronomers use temperature because the random electrical noise generated by a resistor is directly proportional to its physical temperature. This creates a natural link between thermal physics and radio…
In radio astronomy, several different “temperatures” are used to describe sources of noise. They are all expressed in Kelvin (K) because radio noise power is conveniently represented as an equivalent…
Tsys = Trx + Tant Where: Tsys = total system noise temperatureTrx = receiver noise temperatureTant = antenna temperature (everything seen by the antenna) Expanded form: Tsys = Trx +…
Calibration of radio telescopes usually uses cold sky and hot ground, rather than hot sky. However, for completeness here is hot sky. (Cold sky is best achieved by pointing at…
If you want a receiver with 20 MHz instantaneous bandwidth, there are only a few realistic options — and one stands out as the simplest choice. — Best simple answer…
At the hydrogen line (21 cm wavelength, 1420 MHz), many common structural materials are essentially transparent provided they are non-conductive and not loaded with carbon or metal. For bracing a…
CHATGPT OPINION: For tracking astronomical masers (or any fixed celestial radio source that drifts slowly across the sky), I would actually lean toward the TV1 miniCASTER positioner rather than a…
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