Question about TV channel spacing

[kevtronics]

UHF tuners added click stops for each channel in the early 1970s due to an FCC mandate that required them to be as easy to tune as VHF tuners. The exception was small portable TVs with continuous tuning on VHF (no click stops) could still use continuous tuning on UHF as well.

This was because the earlier mandate in the 1960s for UHF tuners to simply exist at all didn't actually require them to be any good, and many of them were afterthoughts that had poor sensitivity, were difficult to tune, and prone to drifting.

Also, the "all-channel receiver act" never actually required TVs to tune in all channels simultaneously. Many older VCRs had varactor tuners with presets for channels 2 to 13. If you wanted to add a UHF channel, you had to sacrifice one of the unused VHF channels in your area and reprogram it to UHF.

 

[Mike in Destin]

Our b&w Zenith tv in the 60s didn't even have a UHF tuner, at least I don't remember it (was a kid) having it. No big loss, in those days don't think there was much on UHF anyway. Unfortunately I can't remember the model number. Anyone remember Larry Ferrari playing the organ on Philadelphia WFIL-TV? 6
Sunday mornings.

 

[vchimpanzee]

Our b&w Zenith tv in the 60s didn't even have a UHF tuner, at least I don't remember it (was a kid) having it. No big loss, in those days don't think there was much on UHF anyway. Unfortunately I can't remember the model number. Anyone remember Larry Ferrari playing the organ on Philadelphia WFIL-TV? 6
Sunday mornings.

I don't know what brand our TV was but it didn't have UHF. Fortunately we lived between two markets. There was no PBS (NET back then) but we had one CBS, one ABC and two NBCs.

 

[Mike in Destin]

We had reception from both NY and Philly, being in Central NJ. Two channels from each of big three, plus some independents. 5 was WNEW NY, Meteomedia TV. 12 was in Delaware, and 13 in Newark,NJ (across from NYC.) Those were the days. Now NJ has their own network. We could see channel 52 tower from where we lived. That also had 101.5 on it. That network didn't exist in the 60s.

 

[Gregg.]

Plenty of TV sets didn't have UHF until the late 1960s. I'm sure someone here knows the year that all televisions were required to have UHF tuners.

I can still remember my dad buying a portable B/W television for my parents' bedroom around 1970. I was so amazed that it had a UHF tuner. In the NYC area, I think we only had Channel 31 WNYC-TV, 41 WXTV and 47 WNJU. WNYC-TV was owned by the City of New York and it ran only public TV shows, some done in-house, such as a weekly half hour for police officers, another for firefighters, etc. And some free films, such as travelogues.

41 was, and is, Spanish-language. 47 was a mix of bad classic TV shows, cartoons and movies in the daytime with a few Spanish-language shows in the evening. I don't think we had Univision or Telemundo then.

 

[tvnut]

The all-channel act was passed by Congress in 1962 and required sets sold beginning Jan. 1, 1965 to have VHF and UHF tuners.

 

[IM42A]

incorrect. The digital switch had nothing to do with it. In 2014 Sinclair bought out Albritton who owned WCIV. This would have given Sinclair 2 big station which was frowned upon (yes I know about the Sinclair run companies that they usually use to get around this). So they moved ABC to a subchannel and sold WCIV to Howard Stirk Holdings which carries subchannels (they are the ATSC 3.0 station right now). Thats how stations get around it now in other markets. They move the programming from the station they cant buy outright to a subchannel of the station they own. Its not that big of a deal about "oh no its not on channel 29 anymore its on 9-2". Thats what Minneapolis did to the 3 different dual stations owned. They merged the digital channel together. So our old 17, 29 and 45 are now part of co-owned 2, 9 and 5 and have been for years.

The WCIV saga is one of the more complicated stories in the history of local broadcasting. It breaks down something like this: Sinclair sold WCIV to Howard Stirk (Armstrong Williams's company), which changed it to WGWG. Long story short, the WCIV intellectual unit was transferred to Sinclair-owned WMMP (channel 36), the ABC affiliation and WCIV's branding went over to 36.2 (leaving My Network TV on 36.1), but they still continued to call it "ABC4", WMMP's call letters changed to WCIV. Fast-forward to present, WGWG is PSIP channel 4 and uses this for their various subchannels, AFAIK they don't actively market themselves as "channel 4" (not sure if they have any local programming at all, it's all diginets, MeTV et al), and you're left with the quirky situation of WCIV calling itself "ABC4" on PSIP channel 36.2 (but no quirkier than WBTS in Boston calling itself "NBC10 Boston" while being on a Class A station that shares a full-power transmitter with WGBX --- confused yet? --- and, on top of all of that, is on PSIP channel 15.1).

I don't know how Charleston viewers, who were used to WCIV being on channel 4 forever and a day, deal with two stations being "channel 4", and as to WGWG, I don't know what they call that:

 

[valvashon]

Almost the same situation in Fargo, ND with KVLY and KXJB. KXJB (4!) was the long time CBS affiliate eventually ending up under an LMA run by KVLY. The CBS affiliation was moved to KVLY with NBC (1080i) being on 11.1 and CBS (720p) being on 11.2. The KXJB license, tower and transmitter (I think) was sold off to Parker Broadcasting and now has 12 subchannels on it.
KVLY now has an in-city LP station with CBS on 30.1 in 1080i and NBC on 30.4 in 720p. I'm sure there is still a whole bunch of people in Fargo that have no idea what happened to channel 4 and why isn't CBS on it anymore?
Fargo is a great place to be from.

Val

 

[IM42A]

The all-channel act was passed by Congress in 1962 and required sets sold beginning Jan. 1, 1965 to have VHF and UHF tuners.

We had a floor-model B&W TV set that only got twelve channels with a plastic cover over a hole labeled "UHF", got it probably sometime in the early 1960s. Our TV Guide (West Virginia edition) listed WTAP-15 Parkersburg WV and my five-year-old mind couldn't comprehend how there could be a "channel 15" when there wasn't a place for it on the dial. We were too far away from Parkersburg to get that station.

 

[alok]

see chart link below . . .

Television channel frequencies - Wikipedia

Scroll down to VHF chart . . . if you look at the VHF band Channel 2-13 you'll note all channels, except 4 & 5, their lower edge is 6 mhz from the previous channel . . . but it is different for channel 5, it is 10Mhz from the previous channel, 4.

The reason this is, these two channels (4 & 5) , between them . . . 4 Mhz worth is used for aircraft / airport navigation signals.
Again, look at the chart in the above link, note the difference on Channel 5 where the lower edge is 10 Mhz from Channel 4, but all the others VHF channels are 6Mhz.

. . . from Internet

The 72–76 MHz band is used for aeronautical navigation and is located between TV channels 4 and 5.

This is why Channel 4 & 5 can be next to each other.

 

[kevtronics]

. . . from Internet

The 72–76 MHz band is used for aeronautical navigation

Don't believe everything you read online. The actual allocation is:

72.000 - 73.000 MHz: Intersystem, Paging, RC

73.000 - 75.460 MHz: Astronomy

75.460 - 76.000 MHz: Intersystem, Paging, RC

It mostly is used for remote control systems (especially model aircraft and boats), telemetry, and wireless microphones. Also by radio call boxes on the side of highways in the era before widespread use of cellphones.

 

[Mike in Destin]

Plenty of TV sets didn't have UHF until the late 1960s. I'm sure someone here knows the year that all televisions were required to have UHF tuners.

I can still remember my dad buying a portable B/W television for my parents' bedroom around 1970. I was so amazed that it had a UHF tuner. In the NYC area, I think we only had Channel 31 WNYC-TV, 41 WXTV and 47 WNJU. WNYC-TV was owned by the City of New York and it ran only public TV shows, some done in-house, such as a weekly half hour for police officers, another for firefighters, etc. And some free films, such as travelogues.

41 was, and is, Spanish-language. 47 was a mix of bad classic TV shows, cartoons and movies in the daytime with a few Spanish-language shows in the evening. I don't think we had Univision or Telemundo then.

Philadelphia had 17, 29, and 48. I too remember cartoons being on some UHF channels. Like "Astro Boy." I think 48 has been off the air for many years. Don't know the status of the other stations.

 

[Mr Tony]

Philadelphia had 17, 29, and 48. I too remember cartoons being on some UHF channels. Like "Astro Boy." I think 48 has been off the air for many years. Don't know the status of the other stations.

all 3 still on the air
17 is CW
29 is FOX
48 is TBN

 

[alok]

Don't believe everything you read online. The actual allocation is:

I did not get what I thought was correct on-line, I just saw the info and copied it, I knew this from going back years ago to be true.
The FCC tables, on-line look like they are wrong too.
Yes, you are correct, it seems they no longer use it for aeronautical navigation, moving up too much higher frequencies for that use, but they did at one time.

The main point of this discussion was that is why Channel 4 & 5 is next to each other, there are additional services (unrelated to TV broadcasting), between 72-76 Mhz or between Channel 4 & 5.

 

[KeithE4]

Don't believe everything you read online. The actual allocation is:

72.000 - 73.000 MHz: Intersystem, Paging, RC

73.000 - 75.460 MHz: Astronomy

75.460 - 76.000 MHz: Intersystem, Paging, RC

It mostly is used for remote control systems (especially model aircraft and boats), telemetry, and wireless microphones. Also by radio call boxes on the side of highways in the era before widespread use of cellphones.

Close. Per 47 CFR 2.106, the band is allocated as follows (Pertinent FCC rules in parentheses):

72.0-73.0 MHz: Non-government fixed and mobile services (Parts 22, 80, 87, 90, 95)
73.0-74.6 MHz: Radio astronomy
74.6-74.8 MHz: Private land mobile (Part 90)
74.8-75.2 MHz: Air navigation (Part 87)
75.2-75.4 MHz: Govt and Non-govt private land mobile (Part 90)
75.4-76.0 MHz: Non-government fixed and mobile services (Parts 22, 80, 87, 90, 95)

Part 22: Public mobile
Part 80: Maritime services
Part 87: Aviation services
Part 90: Private land mobile
Part 95: Personal radio, including remote control of boats and aircraft

 

[TexasTom]

all 3 still on the air
17 is CW
29 is FOX
48 is TBN

No, the Philadelphia station that is on channel 48 today is not the same station that "Mike in Destin" remembered. That station went off the air in the early 80s (1983, per Wikipedia) when then-owner Field Broadcasting wasn't able to find a buyer who was willing to pay what they wanted for the station and turned the license back to the FCC. Eventually, a construction permit was granted to a new owner to build a new station on the same channel, but that was a completely different station and there was a gap of almost a decade during which channel 48 was vacant in Philadelphia.

 

[Mike in Destin]

This tv discussion reminds of WPVI-TV6 Philadelphia, PA. Years ago they changed their "Action News" opening theme song which was quite beloved. Immediately their fans contacted the station to complain about it. The station listened, and went back to the "Move closer to the world my friend " theme song used since 1970.
When something works well...

 

[alok]

KeithE4 Thanks for that FCC info, I did see that.

I recall that years ago (long before the Internet) it seemed Aviation Services were what was in that 72-76 Mhz area. I never heard mention of those other services back then being in that 72-76 Mhz area.

Again, Thanks for the FCC info, I saw the July 2022 and Sept 2024 allocation tables from the FCC on-line, they did show all those services. Maybe I'll ask around and see if Aviation is still in and being used in that chunk of frequencies. I recall it was only navigation use (signals), no talk in the 72-76 mhz area.
I have an airport near-by with a control tower, they will know.

Again, Thanks for your input.

 

[IM42A]

This tv discussion reminds of WPVI-TV6 Philadelphia, PA. Years ago they changed their "Action News" opening theme song which was quite beloved. Immediately their fans contacted the station to complain about it. The station listened, and went back to the "Move closer to the world my friend " theme song used since 1970.
When something works well...

 

[Mediafrog+]

I never heard mention of those other services back then being in that 72-76 Mhz area.

Assisted Listening devices for the hearing impaired also lurk in the 72-76 MHz range.

Some years ago I saw some DX reports of Central American Muzak type services in the 72-76 MHz range being heard by VHF enthusiasts. These aren’t to be confused with a similar service in Chile that operated between 47 and 49 MHz and were DXed in the U.S. Those Chilean stations were shut down a few years ago.