"Channel 37 is an intentionally unused ultra-high frequency (UHF) television broadcasting channel in the United States, Canada and Mexico and some of Eurasian region. The frequency range allocated to this channel is important for radio astronomy, so broadcasting is not licensed. "
Why the need to bring aliens into it? I like how this isn't in the topic here, because it's really clickbait. I didn't find one mention of any talk about aliens in the whole thing. But it is a great article about radio astronomy.
> Somehow the news got around that here was this new way of listening to little green men on Mars. This is what radio astronomy seemed to the ordinary public. And the FCC was preventing it from being developed in the United States. We got rumors, George particularly from friends he knew, that gradually a huge accumulation of letters arrived at the FCC, protesting against this nonsupport of this new science, whatever it was. And that this finally persuaded the FCC that they’d better give in. Nobody knows. [emphasis added]
That's the part about aliens. McVittie's perception that the popular understanding of radio astronomy (listening to Martians) influenced the FCC decision (which, at least officially as described in the next quote, was not the case).
Well, there is this thing that some humans do called "humor" where one party will perform some action that serves as a benign violation, usually of another party's expectations. When this benign violation is revealed to be in jest, both parties receive a rush of endorphins; which many find pleasurable.
If the cynic in me wants to assume the copy-editor who was tasked with coming up with the title skimmed the article, saw the phrase "and found it had an extraterrestrial source", and interpreted the wrong definition for "extraterrestrial".
Thinking an editor made an honest mistake isn't a very cynical outlook. Average cynicism would assume the editor knew the difference and played up the angle as clickbait, hardcore cynics would assume the editor changed something like the radio waves "originated off planet" to "were extraterrestrial" to force click bait in.
I assume that you are wholly unfamiliar with Vice to be able to say this.
Ok, since I constantly get downvotes for no reason. Vice, runs tons of stuff about aliens. They're a meme news outfit that runs shows such as "Fuck, that's delicious" and shows with Action Bronson and friends who get really high and do commentary on episodes of "Ancient Aliens." So again, you have to be totally unfamiliar with Vice, to say "Why aliens?"
A more recent similar case would be Starlink. Fast forward a few years and the night sky will be filled with satellites disturbing astronomers. It would be interesting to see how that one ends up. My bet, more outer-space telescopes to compensate for all the new disturbance.
LEO satellites in earths shadow are effectively invisible to ground based telescopes. Which is why StarLink and other LEO satellites have zero effect on ~98% of current observations, but do impact a few very specific types of observations.
IIRC, StarShip will result in something like 1 Million tons of annual launch capacity -- 3 orders of magnitude greater than today. Commercial applications are required, and satellites such as StarLink are a natural start.
Meanwhile, some of that launch capacity can be used to build space-based instruments for much cheaper.
More importantly, take away something, and provide no alternative in any way while taking in lots of money while causing considerable external cost to others. Then offer cheap platitudes and maybe hint at throwing more money their way.
You never identify who is taking the different sides of this bargain. It is almost as if it is a fate accompli that some people want to pretend is some sort of trade undertaken with some other people, because trade implies consent.
In fact, it is what it always is, a rich person taking something in order to sell you a poor replacement while calling it progress.
Except you won't get comparable telescopes with what Spacex Starship offers, or any other launch vehicle currently in development. And we have mostly solved atmospheric interference.
7-8 meter diameter mirror in outer space would be too small? Should be possible to put into orbit in one starship launch. And a system of big mirrors could be probably assembled and aligned together, without gravity and outside vibrations.
I assume you're talking about the ELT. It's composed of something like 800 individual segments with their own position-adjusting actuators. I'm not intimately familiar with its construction (and the tolerances!), but I presume it would be possible to launch individual segments for space-based or moon-based construction...
The big, monolithic secondary mirror is entirely within Starship's payload volume (4.2m diameter) and mass (3.5 tonnes).
Bonus: Space-based radio astronomy will achieve much higher SNR!
Edit (since reply is slow): You probably benefit on your mass-related support structure costs due to the lower-gravity (or zero gravity) environments.
ELT pretty much would require space manufacturing base - for the mass involved, you could probably furnish a small moon town.
The problem is that the ones making the mess aren't going to pay for that, and I shudder at the costs involved in just space assembly of something the size of ELT...
Edit to the slow reply ;) - the 400 tons is just the estimate zerodur mirror segments for the main mirror, nothing of the support structures... and didn't include ~65 tons of spare segments (ELT plans to replace two daily or something like that).
Starship will be an incredible game changer for space economics. Look at this progression:
- $50,000/kilogram for 27,500kg of payload (Space Shuttle, 1981-2011)
- $2,500/kg for 22,800kg of payload (SpaceX Falcon 9, 2010-present)
- $20/kg* for 100,000kg of payload (SpaceX Starship, 2022??)
*: This is the estimated operational cost, not the price of a launch
For a ballpark launch cost estimate, assuming that the mirror segments would be mass constrained rather than volume, it would cost $8M (plus however far off the cost estimates are, plus profit) just to get the mass into space. Maybe say $20M just to pad it a bit? There would almost certainly need to be more money spent on designing the whole thing to work in space, of course. But these projects have long planning horizons, there's no way anyone would have considered building something large in space before Starship was announced (other than nation-state level prestige projects).
I suspect we'll see a flood of small to medium sized projects announced once Starship completes its first commercial LEO launch, then larger projects tentatively announced in the following couple of years.
Let's admit, this telescope is also one of a kind, and it (ELT) is not online yet, too.
If we care about telescopes which are built by hundreds, their mirrors are an order of magnitude smaller.
OTOH with the massive launch capacity SpaceX is building, we could put a dozen 5m telescopes in various high orbits around Earth. With orbital assembly, very large diameter mirrors can be formed; even if these mirrors had a relatively small area (many holes between mirror elements), the angular resolution could be higher than anything reasonably achievable on the planet surface.
Starlink's effect on astrophotography is overstated. Starlink is in a fairly low orbit, so past twilight, the satellites are in Earth's shadow and aren't visible. The Iridium constellation orbits at 780km, for instance, while Starlink is 550km. During the darkest parts of the night, peak time for observation, the satellites aren't visible.
My guess is that there won't be an appreciable difference in the number of space telescopes. Hubble cost $4.7 before it was launched, and it was just a derivative of keyhole, so even though launch prices are cheap these days (compared to the $550 million it cost per Space Shuttle launch) the cost of a space telescope is still pretty steep.
And the funding for comparable spaceborne telescopes will come from where? You can't even take a ride on black budget, because there is nothing to spy on in direction opposite from earth, and and space telescopes with parameters comparable to ground based ones are bigger than what's possible to launch with any of the perspective super-heavy launchers - and critically, would be too big for spy agencies to use against earth targets.
Vice has always been hit and miss for me. On one hand you have some really well produced documentaries, such as Hamilton's Pharmacopeia, the great reports on Ukrainian Protests or Xinjiang camps.
I remember that the home computers of the 80s (Commodore, Sinclair, etc) were sending their display signal to channel 36 in Europe. That was an unallocated frequency.
I quote the "ZX81 BASIC Programming" manual from Sinclair, page 8:
> The ZX81 operates on channel 36 UTF
I wonder if they had a different version of the display adapter for the USA or it didn't matter. After all we disconnected the antenna cable and connected the computer to that input. We could use any channel, not necessarily an empty one.
In the US you usually had a choice between channel 3 or 4. Both channels were in use across the country but no market had both in use so you could always switch to the other if there was a broadcast on one.
>The tale of channel 37 reflects one thing: Without resistance, a commercial use case will usurp a noncommercial use case for a given resource.
Capitalism needs a check in the form of a strong government because without one, it will consume every available resource in service of privatizing and charging for resources that used to be available to all, like an economic plague. The joke can of "Perri-Air" from Spaceballs will be our actual future if we don't stop it.
Is a "strong government enough"? To quote the article:
> The FCC’s attempt to balance science and commerce was not well-accepted by said scientists, who took their story to the media.
This suggests to me that the government had enough strength to make an enforceable ruling, but very nearly made a ruling that would have not prioritized science in the way that the radio astronomers would have wanted.
It took something else (public attention, persistent outreach by scientists, etc) for the FCC to come to the ruling that it ultimately came to.
>it will consume every available resource in service of privatizing and charging for resources that used to be available to all
Minor nit-pick: I don't think the story is a good example of your concept here. The radio telescope, regardless of what it did for scientists, served fewer people than what commercial use of channel 37 would have.
You could think of it that way. You could also think of it as denying hundreds of thousands of Spanish-speaking New Jersey residents programming in their native language in exchange for the discovery of one new type of Active Galactic Nucleus and two supernova remnants, from a telescope that only operated for ten years and which the scientific community cared so little about they didn't even bother fixing it when it eroded away in 1970.
Because of FCC rules and limitations elsewhere, the city of Paterson had no other options to bring a TV station on air other than channel 37.
The fun part about this is that McVittie, who helped to set the wheels in motion for the blanket ban of channel 37 in the U.S., never learned exactly why the FCC made the decision to flip its mindset on this issue.
Racism? Against Latinos in 1963? Nah, couldn't be.
The ban was precipitated by a case that happened to be a Spanish language channel, but not all channel 37s would have been in Spanish. The result was that a channel was barred across the entire country. It's a big leap to say that the official rationale is bogus and go to "FCC is racist against Latinos and decided to bar the channel for everyone".
$8 million will go nowhere towards rebuilding it, at best that’d suffice for part of a clean-up.
And from Universe Today:
> If Channel 37 were ever lost to TV, the gap would mean a loss of information about the distribution of cosmic rays in the Milky Way galaxy and rapidly rotating stars called pulsars created in the wake of supernovae. Closer to home, observations in the 608-614 MHz band allow astronomers track bursts of radio energy produced by particles blasted out by solar flares traveling through the sun’s outer atmosphere. Some of these can have powerful effects on Earth. No wonder astronomers want to keep this slice of the electromagnetic spectrum quiet. For more details on how useful this sliver is to radio astronomy, click HERE.
Originally the allocation may have been for that site. That doesn’t really matter.
This now makes me want to go and rewatch all TV I have ever watched to see if I missed that a show had a channel 37 news channel or some other subtle reference to this.
During the peak of Solar cycle 22 in 1989-1991, amateur radio operators (including me) on the US west coast used to listen for New Zealand channel 0 audio on 50.75 MHz (also 50.74 and 50.76 MHz). If you could hear the wideband FM audio, it was almost guaranteed you could make SSB or CW contacts with New Zealand hams around 50.11 MHz.
The US, too, had no channel 1. (Source: I'm old enough that my family owned a TV in the 1960s.) And my current cable TV service, from Comcast, also has no channel 1.
Carried on Charter cable systems in NYC, various other systems throughout the country. Sometimes on channel 1, sometimes on other channels on different systems - likely due to technical challenges.
There was a channel 1 briefly in a few places, but it turns out that it wasn't a good spectrum for TV so it looked awful, so no one wanted it. They didn't bother to renumber all the channels though, so channel 1 just didn't get used (although it's available as a virtual channel now).
Overlapping broadcast areas. It's one less channel to use for deconflicting the need for broadcast spectrum and the desire to have a broadcast channel while avoiding interference from neighbors.
They get at this with the New Jersey case, where in order for the station to get a channel it had to be 37. Presumably this was because of there being too many other broadcasters in the area. It's been a long time since I studied radio so I can't recall the specifics, but if there are 70 channels available (total) in a specific area perhaps only half or a quarter of them might be usable without producing interference with others.
EDIT: You also see this play out with conventional AM/FM broadcasting. You typically won't find adjacent stations, like 91.3 and 91.5, in the same area and when it happens (perhaps you're on the edge between the two broadcast areas) you'll hear one station bleeding into the other.
FM has a property known as "capture effect". The result is that the stronger station will usually "capture" the PLL (back when they used PLLs instead of SDRs for FM demod) and you will not hear the adjacent station. It can become a problem in a mobile environment (car stereo) when the signal levels are constantly changing, but "bleeding" is a problem usually associated with other modulation types (typically AM and SSB).
Supposedly this is one of the reasons aircraft radios are AM instead of FM. If two stations transmit at the same time, you want to recipients to hear the interference so they can ask for a retransmission instead of one hearing a clear message and the other having no idea that someone tried to transmit to them.
Plus the fact that AM is actually capable of better sensitivity than FM, especially in the narrow bandwidths necessary for aircraft VHF communications.
Capture effect has nothing to do with the operation of PLL's.
Most FM radios have a Limiter stage which strips of all Amplitude variations. This means that any strong signal in the passband will completely suppress a weaker signal.
You typically won't find adjacent stations, like 91.3 and 91.5, in the same area and when it happens (perhaps you're on the edge between the two broadcast areas) you'll hear one station bleeding into the other.
Back when I used to listen to terrestrial radio, I noticed that "bleeding" was much more common with "Christian" radio stations. I could be trying to listen to NPR broadcast from 30 miles away, and it would be totally drowned out by a Christian station an entire channel away (e.g. 92.3 - 91.3) broadcast from a different state.
A lot of religious radio types tend to play fast and loose with transmit regulations, or even quality of hw to prevent randomly sprouting harmonics few channels away (a certain somewhat "loud" case in Poland was illegal rebroadcast that managed to spill over to airport frequency...)
In Spain there was the infamous case of "Radio Maria" (no explanation needed, UltraCatholic band) on being tunable everywhere even if you were in the remotest farm ever with no traces of civilization 100 kms around that point.
To explain, that's essentially the same name as the one ultra-religious radio in Poland, that was also known for abusing RDS system to force-switch everyone's car radios to their channel :)
same principle applies to WiFi routers. That's why you look at other channels being used in your aread, and then pick a channel that has the least overlap with your neighbors.
The concept of a "channel" on WiFi bands (particularly 2.4GHz) is pretty much done. 802.11ac can use 80MHz of spectrum on the 2.4 band, which is pretty much the entire set of available channels all at once.
Unless you are in a rural area, trying to use an 80 MHz channel in 2.4 GHz almost guarantees your radio is going to spend far more time waiting to transmit because of interference than doing anything useful. Finding the least congested 20 MHz channel is likely to give higher overall throughput.
[0] claims 802.11ac explicitly does not support 2.4 GHz. Further search did not reveal any strong evidence for any VHT support on 2.4 GHz.
What do you base your claim on? Can you share the source?
True, but if you live in a congested area, chances are good that one of your neighbors does. I have a house in a new community of "smart homes" where each home has two AC WAPs. Every single 2.4GHz channel has several users. MIMO helps, but 5GHz (or the new 6e band) are much more preferable.
Both of those are cable channels. Cable channels (normally) use different frequencies than broadcast tv. I don't see a similar frequency reservation for cable TV (would be around channel 89), probably because cable TV signals are not intended to radiate.
