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RF channels 2-3 vs 3-4


Andromeda Stardust
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My 4-switch Atari has a channel 2-3 selector. My NES, and nearly everything 3rd generation and up, uses 3-4. Nearly every RF modulator or VCR or consumer electronics I have ever seen used channels 3-4. Very rarely used 2-3-4.

 

I understand the early "heavy 6er" models did not use a selector switch and had channel 3 programmed by default. This could cause problems in areas with strong channel 3 broadcast.

 

So when did channels 3-4 become standardized? Was it FCC mandate? It seems back in the early days, it was left up to the device manufacturer?

 

Kind of novel that my 4-switch Atari uses channel 2 as an option, which I keep it on. What other pre-crash consoles used something other than channels 3-4 in their design? When did they all switch to 3-4?

 

BTW, my 7800 has a best AV mod installed and the RF switch was removed so I don't know which channels it used by default.

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:idea: Wikipedia helps

I went and researched some before my last posting. Wikipedia was one of the places I sniffed around. Didn't find anything helpful on answering the OP's question, but did learn about the long lost channel 1. I'm going to dig into the link you provided now. Somehow I missed that.

Edited by fujidude
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The 7800 uses channels 2 and 3 just like the 2600 and 5200. The only one that comes to mind that started using channel 3 and 4 for the RF switch was the NES.

So all the Ataris used channels 2 & 3. Cool.

 

A lot of VCRs had the 3-4 option.

Yeah pretty much all VCRs and RF modulators did.

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I don't recall any FCC mandate saying a mfg. had to use ch 2-3 or ch 3-4. And modulators we had for the Apple II were tunable over a larger range like 2-6 or in the case of the UHF variant, 28-36.

 

Just the usual Part 15 consumer spiel applied about creating and accepting interference.

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So all the Ataris used channels 2 & 3. Cool.

 

Yeah pretty much all VCRs and RF modulators did.

 

Didn't know Jaguar had channel 2/3 option?

 

 

 

:D j/k

 

Intellivision and Colecovision also had 2/3 and SMS which came out about the same time as NES has 3/4

 

When I moved from near Ann Arbor to near Lansing, I had interference on all channels. I was still able to pick up channel 2 and 4 from Detroit and 3 from Grand Rapids. It was the start of AV mod back then, and ugly hack. Right now it's moot point, no one's doing any VHF channels broadcast anymore since FCC mandated digital signal a few years ago, and digital signal has completely different behavior than old analog signal so interference with older equipments are a lot less noticeable.

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Right now it's moot point, no one's doing any VHF channels broadcast anymore since FCC mandated digital signal a few years ago

VHF is still part of the FCC's band plan for ATSC (digital) TV. It's not utilized as often as UHF but is still used. The stations in my local area are still in the same bands they were before the switch to pure digital. One of them was, and still is, in VHF.
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VHF is still part of the FCC's band plan for ATSC (digital) TV. It's not utilized as often as UHF but is still used. The stations in my local area are still in the same bands they were before the switch to pure digital. One of them was, and still is, in VHF.

 

We had three VHF channels in my area, 3, 6, and 12. All of them moved to unused UHF channels during the digital transition. Most of our UHF stations also moved up or down one frequency slot during the period when they simulcast in analog and digital.

Edited by stardust4ever
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I always thought as a kid there was some FCC rule where, among channels 2,3,4, you couldn't have two consecutive stations(no 2+3 or 3+4). Why? Video game consoles & VCRs.

 

You could, but it was very uncommon. That according to info I read recently somewhere on this topic. I suppose it was an "avoid doing it unless it is necessary" type allocation.

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I always thought as a kid there was some FCC rule where, among channels 2,3,4, you couldn't have two consecutive stations(no 2+3 or 3+4). Why? Video game consoles & VCRs.

 

Because back in the old analog day, even with 1MHz spacing between each channels, interference will happen. Stations were still to avoid a channel that is right next to another existing channel. For example if there were a TV station that has channel 2 and another nearby with channel 3, people near those 2 would have had a hard time picking just channel 2 or 3 without interference. So all stations left a 1 channel gap minimum.

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Ah you're right. I must have brain farted somehow.

 

Did you know? FM radio is between old TV channel 6 and 7, there's a wide gap there.

 

The FM band is 88 MHz to 108 MHz so it's not between any TV stations

 

In Japan, the FM radio dial occupied a lower frequency range. NTSC-J channels 1, 2, and 3 occupy the US FM broadcast band. Famicom channel 1 & 2 can be tuned on NTSC-CATV channels 95 and 96. Audio can also be received on an FM radio tuned to 95.75 or 101.75.

 

The other major segment is air traffic control, running from 108 megahertz up to right below NTSC channel 7.

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In Japan, the FM radio dial occupied a lower frequency range. NTSC-J channels 1, 2, and 3 occupy the US FM broadcast band. Famicom channel 1 & 2 can be tuned on NTSC-CATV channels 95 and 96. Audio can also be received on an FM radio tuned to 95.75 or 101.75.

 

The other major segment is air traffic control, running from 108 megahertz up to right below NTSC channel 7.

 

I knew that a long time ago

 

On a Radio Forum I go to, Had talked about expanding the Japaneses FM Band up to 108 MHz when Japan shut down there Analog Stations in 2011

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