Can someone explain why on a 1955 Zenith

[Olorin67]

Minneapolis/ St. Paul used channels 2, 4, 5, 9, and 11. So that system would have been convenient there.

[wa2ise]

Some places, like Princeton, NJ, were halfway between NYC and Philly, there you'd have TV stations on all the VHF channels except channel 8, IIRC. So you'd need a complete VHF dial.

[Electronic M]

Originally Posted by wa2ise

Some places, like Princeton, NJ, were halfway between NYC and Philly, there you'd have TV stations on all the VHF channels except channel 8, IIRC. So you'd need a complete VHF dial.

The old zenith knob would still be useful since stations from either city would separated from eachother...You could search one city, turn your antenna rotor then sweep the other city.

[Jeffhs]

I bet those Zeniths didn't sell well in northeastern Ohio or other areas with mixed high- and low-band TV stations; here's why. The city of Cleveland has channels 3, 5 and 8. To go from channel 3 to channel 5, for example, would mean turning the tuner knob at least one revolution, and from channel 5 to 8 would require another complete switch through most of the channels. Depending on how much the set was used and how often channels were changed, the tuner could wear out within a year.

These sets were obviously made for markets like New York, Los Angeles, Philadelphia, Seattle, Portland, Oregon and others with channel lineups that matched (or were very close to) the channel arrangement of the tuner.

New York and Los Angeles are the only two TV markets with seven VHF channels that exactly match the Zenith's channel knob. As VK member wa2ise mentioned, this tuner would work perfectly in areas between New York and Philadelphia stations, since the former would be in the 2-4-5-7-9-11-13 range and the latter in the lower 3-6-8-10-12 range. The only blank channel in the latter range would probably be channel 8, unless the set owner were in an area that could receive all New York stations; channel 8 would be in New Haven, Connecticut, near NYC if I remember correctly. Channel 12 would likely be blank in Philadelphia in 1955, depending on when the educational TV station in Wilmington, Delaware on that channel went on the air.

I've only seen one Zenith TV with a tuner arranged like this. Was this TV very popular in markets outside the ones I mentioned above? I would think not, due to the way the channels are arranged. This set may have had a great picture and all, but I would think most set owners in cities with more than three channels in a straight line, i. e. 3, 5, 8 or 2, 4, 7 (Cleveland, Detroit, Buffalo), would quickly get tired of having to flip through unused channels just to get to the local channel they wanted to watch.

[dieseljeep]

Originally Posted by Jeffhs

I bet those Zeniths didn't sell well in northeastern Ohio or other areas with mixed high- and low-band TV stations; here's why. The city of Cleveland has channels 3, 5 and 8. To go from channel 3 to channel 5, for example, would mean turning the tuner knob at least one revolution, and from channel 5 to 8 would require another complete switch through most of the channels. Depending on how much the set was used and how often channels were changed, the tuner could wear out within a year.

These sets were obviously made for markets like New York, Los Angeles, Philadelphia, Seattle, Portland, Oregon and others with channel lineups that matched (or were very close to) the channel arrangement of the tuner.

New York and Los Angeles are the only two TV markets with seven VHF channels that exactly match the Zenith's channel knob. As VK member wa2ise mentioned, this tuner would work perfectly in areas between New York and Philadelphia stations, since the former would be in the 2-4-5-7-9-11-13 range and the latter in the lower 3-6-8-10-12 range. The only blank channel in the latter range would probably be channel 8, unless the set owner were in an area that could receive all New York stations; channel 8 would be in New Haven, Connecticut, near NYC if I remember correctly. Channel 12 would likely be blank in Philadelphia in 1955, depending on when the educational TV station in Wilmington, Delaware on that channel went on the air.

I've only seen one Zenith TV with a tuner arranged like this. Was this TV very popular in markets outside the ones I mentioned above? I would think not, due to the way the channels are arranged. This set may have had a great picture and all, but I would think most set owners in cities with more than three channels in a straight line, i. e. 3, 5, 8 or 2, 4, 7 (Cleveland, Detroit, Buffalo), would quickly get tired of having to flip through unused channels just to get to the local channel they wanted to watch.

You weren't going to wear out that tuner that easy. They were overbuilt and seldom, if ever needed cleaning.
In the 1956 model year, Zenith switched to an Oak or Standard Coil tuner.
The bandswitch tuner was used in the UHF equipped sets and the Standard Coil was used in the UHF strip equipped sets. There was a lot of those in Milwaukee.

[Eric H]

The earlier Zeniths had this arraignment also, the 1949 models like the Mayflower Porthole used it, but on those the numbers are on a rotating plate inside the cabinet, not on the knob.

You can re arrange the strips inside the tuner any way you want, I wonder if they sold different knobs or indicators for different areas?

[Electronic M]

Originally Posted by Eric H

The earlier Zeniths had this arraignment also, the 1949 models like the Mayflower Porthole used it, but on those the numbers are on a rotating plate inside the cabinet, not on the knob.

You can re arrange the strips inside the tuner any way you want, I wonder if they sold different knobs or indicators for different areas?

Models with the 'projection knob' (numbered transparencies that would appear lit in the knob center when in front of the dial light) allowed you to replace sections of the transparency with UHF numbers when using UHF strips, so you could probably re-order the transparency and channel strips any way you wanted on those sets....Even make them not match for April Fool's Day.

[wkand]

Here is a YouTube video of a Zenith Film that deals with UHF reception issues, but also explains Zenith philosophy regarding tuner design.

https://youtu.be/7lu5jqXaHRE

I don't understand the argument being presented here. Are some of you saying that the 1955 Zenith sets would not be able to succesfully receive directly adjacent vhf channels, unless the strips were arranged such that adjacent channels had to be separated such as the sequence 2,4,6,8,3,5,7,9 ?

[old_tv_nut]

Making a single-conversion tuner that could get more than say 20 dB rejection of adjacent channels was an expensive proposition. Interference 20 dB down (10% amplitude) is enough to ruin an analog picture. Overall best economy for the public was to not use adjacent channels in a given market. On UHF, the restrictions were worse. The so called "taboos" due to image frequencies required UHF stations in the same market to be spaced 6 channels apart. With digital, reception is fine if the total interference is below -15 dB, plus the digital broadcasts required lower power and could be slipped into empty channels while analog was still on the air, and then eventually packed more tightly, including even adjacent channels in the same market. Plus, tuners for digital receivers were gradually improved to provide more rejection of out-of-band signals.

[wkand]

Excellent, thanks for the additional detail! 😀

[Josef]

Originally Posted by Electronic M

Models with the 'projection knob' (numbered transparencies that would appear lit in the knob center when in front of the dial light) allowed you to replace sections of the transparency with UHF numbers when using UHF strips, so you could probably re-order the transparency and channel strips any way you wanted on those sets....Even make them not match for April Fool's Day.

This is also possible within minutes in my vintage Austrian sets even though there was only one TV station back in the 50s
Maybe this was caused by the manufacturing process and mixing up the channels was just a side effect...

Greetings
Josef

[jr_tech]

Here is the Table of Allotments; 73.606 that the FCC used to assign television channels. This was developed to minimize interference from out of town stations, by staggering channels, and also minimize local interference by NOT assigning adjacent channels in a given city.
Note: channel 4 and 5 are not considered to be adjacent channels due to a 4 mHz wide aircraft locater band between the two channels.

http://www.ecfr.gov/cgi-bin/text-idx..._1606&rgn=div8

The funny skip channel tuning layout of the mid 50s Zenith sets makes perfect sense considering FCC channel assignments made in that era, although in hindsight, it seems weird, and likely met with some customer resistance.

jr