← INDEX — FIG. 00 — 18 NOVEMBER 2026, ONE LIGHT-DAY
8.4 GHz · 70 m · 21 K
LINK
THE DEEP SPACE NETWORK
Voyager talks to Earth with the power of a light bulb.
BEGIN — CHAPTER 01 →CH.01 / 06 — THREE PLACES, ALWAYS ONE IN VIEW
Goldstone, Madrid, Canberra
Three complexes, one 70 m dish each.
System noise temperature about 21 K.
CH.02 / 06 — ADDING UP DECIBELS
−308 dB of empty space
Voyager 2, 1996: −145.5 dBm received.
160 bit/s with 13.3 dB margin.
LINK BUDGET
Pr = Pt + Gt + Gr − 20 log(4πd/λ) − L · G = η(πD/λ)² · N₀ = kT · Rmax = (Pr/N₀) / (Eb/N₀)req
η = 0.65 reproduces both gains.
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CH.03 / 06 — NARROW BEAMS, PRECISE POINTING
Gain is just focus
Gain ∝ (D/λ)².
Voyager's HGA: 3.66 m, 48 dBi.
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Beamwidth ≈ 70λ/D.
CH.04 / 06 — SLOWER EVERY YEAR
Voyager's data rate, planned to fade
Each doubling of distance costs 6 dB.
Arraying and higher frequencies.
CH.05 / 06 — HALF A CENTURY OF LISTENING
The longest phone call
A promise written in decibels.
CH.06 / 06 — REFERENCES