why did they reserve channel 3 for vcrs?
also, why is there no channel 1 or 0 (at least on my tv)
Chief’s Domain - http://www.seas.ucla.edu/~ravi
I don’t know the exact answer, but when you purchase a CD player that uses an FM frequency (FM modulator,) the signal must be set on a specific frequency that is rarely used. I can’t remember but it was 89.9 or something like that.
Using this as an example, channels 3 and 4 are rarely used in analog transmission. Video games use the same channels, at least my Super Nintendo does…haven’t gotten around to buying anything other than that, 'sides I like my Donkey Kong Country.
It may not be right, but it makes sense to me 
Because. Probably exactly that reason, or the reason techchick stated. Except I seem to recall that the networks use those channels.
It’s probably just a randomly chosen industry standard. Sometimes channel 3 is ABC, but it can also be your VCR.
I sold my soul to Satan for a dollar. I got it in the mail.
I’m not sure why accessories use channel 3, but The Big Buy covered the lack of channel 1. Check http://www.straightdope.com/classics/a1_372.html
Actually, channel 4 is very common. Major markets such as New York (WNBC) and Washington DC (WRC) use channel 4. (And I am almost sure KNBC in Los Angeles, too…)
But channel 3 is very uncommon. And wether by design or chance, no market seems to have both channel 3 and 4 at the same time. So most VCRs are set by default to “broadcast” to the TV on channel 3, but most also have a little switch that allows you to use channel 4 if your area happens to have a TV station using 3.
Cecil covered the Channel 1 situation in the first SD book, and the link’s above.
- Rick
Big Buy? Did you mean Big Boy?
You can’t have both a channel 3 and a channel 4 broadcast in the same area. The FCC assigned them frequencies that would interfere with each other.
The maximium number of VHF channels that can be broadcast into one city is 7, and I believe they have to be channels 2, 4, 5, 7, 9, 11, and 13.
I don’t know if this will change once all the frequencies get changed around because of HDTV.
Bob is correct. You shouldn’t find a channel 3 and 4 next to each other. That’s why your VCR has a choice. Pick the one that ain’t on the air.
Your VHF TV frequencies are divided between Channels 2 and 6 (55.25 Mhz to 87.76 Mhz) and Channels 7 to 13 (175.25 Mhz to 215.75 Mhz).
Whoops! And Bob is not correct about what channels show up in one market.
The channels were assigned by the FCC.
They vary by market.
Now, wait a minute. Say I live in Fairfield, CA.US. This town has no TV stations itself but KRON, San Francisco (about 50 mi SW), is on Channel 4 and KCRA-TV, Sacramento (about 40 mi NE) is on Channel 3. True they’re both NBC, but if you live halfway in between, you may want to watch local programs on both channels. Of course, you may not wish to here about all the crimes in both of these cities and choose to watch neither.
Only techies know how to reach Channel 0. You have to hack to get there, but zero’s always a good place to start. 
Ray (0 ventured, 0 gained.)
It’s my understanding that the FCC assigns channels in a regional manner designed to minimize interference. That’s why Philadelphia uses channel 3, 6, and 10 and New York uses channel 4, etc. - if both cities broadcasted on channel 4, lots of folks halfway between the two cities wouldn’t be able to receive either version.
I seem to remember that my VCRs are all programmable to use either channel 3 or channel 4 (your choice). It’s been a long time since I’ve had to set up one, but they’re both currently using channel 4 (I’m in the Philadelphia area, and channel 3 on my VCR would potentially suffer from interference by the local broadcasters).
Cuz no one was using chan 3 or 4 for much when vcrs came out. Same with the old video game systems.
Does anyone remember the old color tv ads? You would have a black & white tv, they would show ads for color tvs & tell you just how nice the color was & you couldn’t see it cause you have b/w.
Kinda like that today with HDTV. You can’t see how nice it really looks.
No, I meant Big Guy. Sorry, Cece.
Facts.
Not all channels that seem to be adjacent actually are. Some have non-television uses in between.
When VHF channels were assigned in the 1930’s, truly adjacent channels were never assigned to the same city, to prevent interference. Because of that, 3 and 4, in particular, are never in the same city, and, therefore, most VCR’s, videogames, etc., use them (with a switch to decide which of the two).
Modern televisions don’t have a problem with adjacent channels, anyway, so cable uses them all.
4 is quite common; historically, it was the channel for NBC in major cities.
3 is less common, because it was assigned to second-rank cities.
A Channel 1 was assigned in the original 30’s scheme, but in the 40’s it was withdrawn for use by the military.
ABC heard a rumor that the military was going to take Channels 1-6, and ran around buying the rights to 7 and 8 wherever possible. 7-13 are in a different region of VHF that isn’t as good as 1-6, but they figured that they’d end up first on the dial. When only Channel 1 was taken, ABC was left holding the bag, which is why, from the 50’s to the 70’s, ABC was the network that took the most chances – they had to catch up.
A Channel 1 and a Channel 0 are to be found on some cable systems, but they are usually scrambled and unadvertised. I suspect they may be hotel services, or something of the sort. I don’t know whether this Channel 1 is the same as the old Channel 1.
All the other VHF channels (14 and up) are in regions of the spectrum that are used for non-television applications in broadcast, but are perfectly free in cable. They are not the same as the UHF channels 14 and up. (A cable that’s good for carrying VHF has different characteristics from a cable that’s good for carrying UHF.) That’s why they used to call them Channels A, B, C…, but after they got to Z, they decided to junk that idea and simply number them, despite the confusion with UHF.
John W. Kennedy
“Compact is becoming contract; man only earns and pays.”
– Charles Williams
No one else has mentioned it, so I’ll take an educated guess and add that the reason they chose 3 or 4 was that the lower channel numbers use lower frequencies and that made the RF modulators in VCRs & games a little cheaper to mass produce.
A related question, why do TV manufacturers advertise cable ready TVs with ‘X’ number of channels (recently I heard about a 256 digital channel cable ready set)? Since most cable companies with more than about 50 or 60 channels in their service require a converter box that outputs on channel 3 or 4. Seems to me that a better definition of a cable ready set would be one that has only channels 3 and 4! Even better, drop the tuner altogether to cut the costs of the set and let the cable boxes output composite video and audio (some of them do already).
But has the FCC ever assigned 7 VHF channels to one market that were not in the 2,4,5,7,9,11,13 combo?
There are other things to consider than the strict midway point between to stations. First, of course, is going to be the power of the station. Probably the Sacremento station is going to be the more powerful. This may seem counter-intuitive, however the more of a station’s viewership is located in a relatively compacted area (like a city) the less power it needs to broadcast to their audience.
Also, many (maybe all?) radio antennas send out a shaped signal, so that it can reach farther in some directions than others. I assume TV antennas do this as well. This is so you can use your signal more efficiently, by targetting areas with more population or businesses. I don’t know if this applies in this case, but it’s a possibility.
Checking KRON’s and KCRA’s website seems to support this. KCRA markets themselves as servicing all of northern Califonia. KRON, OTOH, markets strictly to San Francisco. So, if you live halfway between, more or less, KCRA is probably going to be your NBC affiliate.
Have seven VHF channels ever been assigned to one market at all ?
Los Angeles has those seven channels and I am pretty sure New York does as well.
Los Angeles didn’t give any of its VHF channels to PBS however.
2-CBS
4-NBC
5-WB
7-ABC
9-Independent
11-FOX
13-UPN
The Channel 3 in Southern California is KEYT, which is an ABC affiliate in Santa Barbara.
I would assume that New York and Chicago would have 7 VHF stations in their market.