Comments by "H. de Jong" (@h.dejong2531) on "How Is NASA Still in Contact With The Voyagers?" video.

It's not necessary for the Voyagers (if they didn't run out of power, we'd still be able to reach them in 2050). For new missions at much larger distances, a relay might be useful, but it'd be expensive: you'd need to launch a giant antenna with a large power source. The DSN uses 70 m antennas and up to 20 kW of transmitter power (that's 50 x more power than the Voyagers had at launch). The relay would have to be in deep space itself, so you're launching a multi-ton spacecraft on a Voyager-like trajectory (compared to the Voyagers which weighed ~800 kg at launch). You'd also need a relay for each mission. It's easier and cheaper to just build better antennas on Earth.
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TV shows often show space with all kinds of rocks floating around to add drama, but we know from measurements that even in the asteroid belt, asteroids are millions of km apart. Space is empty: it's a huge expanse of nothing, with the very occasional rock. The average density of space is emptier than the best vacuum we can create on Earth.
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they're still providing useful information on the interstellar medium from the 4/5 working instruments.
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RTGs are still used when necessary: the Mars rovers Curiosity and Perseverance use them, for instance. Juno is the first Jupiter mission to use solar panels instead of an RTG, because solar panel technology has improved to the point where that's feasible. RTGs are also very expensive ($100 million), so you want to use them only when no alternatives are available.
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The Voyagers do use nuclear power. It's not a reactor: they use the decay heat from Plutonium-238.
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You can receive a signal from so far away with careful design of the transmitter and receiver. Dish antennas concentrate the signal into a narrow cone, providing an enormous amount of gain over omnidirectional antennas. You can also build very sensitive receivers by cooling them to cryogenic temperatures (which reduces noise). NASA uses a 70 m dish to receive Voyager's signals, and builds the best receiver electronics money can buy. The Voyagers don't use GPS. Instead, they use star trackers to determine their attitude. Pointing the antenna is easy: the beam Voyager transmits is focused, but it's still 100 million km wide when it arrives at Earth, so the pointing accuracy required is not that high. Space is empty: it's a huge expanse of nothing, with the very occasional rock. The average density of space is emptier than the best vacuum we can create on Earth. There are no temperature fluctuations. Just a very gradual decline as the spacecraft travel farther away from the Sun. Heaters keep all of the sensitive components at a constant temperature. Temperature fluctuations don't interfere with radio. The amount of dust between us and Voyager is on the order of nanograms - the 12 billion miles of vacuum is less of a problem than our atmosphere. The cell system is built deliberately to have short range, because the shorter the range, the more cell towers you can install without them interfering with each other, and the more users you can serve. Radio waves don't travel well through solid obstacles, so each wall between you and the cell tower reduces your signal. Radio amateurs with a few hundred $ worth of equipment can reach each other on the other side of Earth if the conditions are right. The radio horizon is something that applies on Earth: high-frequency radio is limited to line-of-sight: these signals travel in a straight line. Voyager has an unobstructed line of sight to Earth.
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it's very unlikely. Voyager sends its signals in a narrow cone aimed at Earth. Anyone receiving them would be between us and Voyager, or on the other side of Earth on that same line, and pretty near us (or the signal would get too weak to receive). There's no sign of alien life inside our solar system.
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no. the Voyagers are too small to be visible at that distance.
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Yes, occasionally, mostly during the planetary encounters. The environment around Earth is worse than outer space because we've generated a lot of space debris in Earth orbit (satellites exploding or colliding).
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You can receive a signal from so far away with careful design of the transmitter and receiver. Dish antennas concentrate the signal into a narrow cone, providing an enormous amount of gain over omnidirectional antennas. You can also build very sensitive receivers by cooling them to cryogenic temperatures (which reduces noise). NASA uses a 70 m dish to receive Voyager's signals, and builds the best receiver electronics money can buy. This is simple physics.
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Wifi is designed to be short range, because the shorter the range, the more wifi hotspots you can install without them interfering with each other, and the more users you can serve. Radio waves don't travel well through solid obstacles, so each wall between you and the hotspot reduces your signal. The same goes for cell phones. That doesn't mean all radio is short range. In 1901, Marconi was able to send a radio message across the Atlantic. These days, radio amateurs can contact people on the other side of the world with inexpensive equipment and the right conditions. NASA uses a giant dish to receive Voyager's signals, builds the best receiver electronics money can buy, and they have a clear line of sight without obstacles between transmitter and receiver.
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