Yet another Zenith roundie

[TUD1]

This is what I MEANT to say...

[jr_tech]

WBMA-LP is located in Red Mt Park, but is much lower power... worse yet they have a construction permit to move to VHF ch 11.

https://transition.fcc.gov/fcc-bin/t...2=&EW=W&size=9

jr

[zeno]

Examples of HDTV problems here. In Cleveland you only want to cover the city but not lake Erie ! So odds are most the power goes to the S & SW.

AM radio has great examples. WBZ Boston & IIRC WWL Nawlins were granted clear channels ( 50 Kw non directional) in the 30's but also were allowed to be directional so as not to waste power over oceans. Thats why WBZ could be heard in most the country winter nights.
Canada stations would build very highly directional systems south
of the cities & slam the city with power while protecting US stations.
Torontos CFTR 680 can not be heard in the Boston area. We get a local
plus Binghamton N.Y., Baltimore, Raleigh, N.C.
Only when the antenna has "problems" can we hear it & it crushes us
with a needle pinning signal.........

Your new Zenith dont look that bad. You should of see the junk people would watch in the olden days. Like I have said turn off the lights & turn everything down. That can make a HUGE difference !

73 Zeno
LFOD !

[Jeffhs]

Originally Posted by zeno

Examples of HDTV problems here. In Cleveland you only want to cover the city but not lake Erie ! So odds are most the power goes to the S & SW.

Zeno, I live very close to the south shore of Lake Erie (within a mile) and can hear most Cleveland AM and FM radio stations very well. However, I have problems receiving two DTV stations from Cleveland, both on VHF DTV channels. One of those is the CBS affiliate on RF channel 19, DTV channel 10. I remember when this station first signed on the air in 1985, long before DTV. It had a station identification that said, "We're 19. Stereo television for Cleveland . . . and . . . Lake Erie." This tells us this station, which had well over 3 megawatts of ERP before DTV, did cover a large part of the east lakeshore area; however, when it converted to digital, that signal weakened to 9.5 kW ERP, causing all sorts of reception problems east of Cleveland, including where I live. These reception problems on channel 19, and also the FOX affiliate on channel 8, were the reasons I eventually gave up on OTA television and installed a Roku box. Now I can get 8, 19 and every other Cleveland TV station as clearly as I used to get them when TV was all NTSC analog.

[old_tv_nut]

Originally Posted by Jeffhs

... One of those is the CBS affiliate on RF channel 19, DTV channel 10...when it converted to digital, that signal weakened to 9.5 kW ERP, causing all sorts of reception problems east of Cleveland, including where I live.

Jeff, you have reversed the description of the situation. WOIO analog was on RF channel 19, with the requisite high power for analog UHF. They are now broadcasting in digital on VHF RF channel 10, with virtual channel number identifier 19. When they went to VHF, they got stuck with the low ERP due to the erroneous VHF planning factors that got baked into the system and did not take into account the level of ambient interference in the VHF band.

A proportionate increase in power of all VHF stations would solve the noise problem without causing added interference between stations, but this is impractical economically due to the number of transmitters that would have to be replaced and commissioned simultaneously. It also involves international treaties regarding interference levels across the Canadian and Mexican borders.

Hopefully this will be taken into better account with ATSC 3.0 broadcasting. It is a tough nut to crack because stations cannot arbitrarily increase power individually without considering interference to other stations that do not change at the same time.

[TUD1]

I only have a string of Christmas lights hung from the ceiling, and two pretty dim LED's for additional background lighting. It's not very bright in here at all.

[jr_tech]

I had a mathematician friend that once claimed that a circle could be thought of as a polygon with an infinite number of sides and therefore an infinite number of corners... but I thought that definition of a circle was pure BS.

jr

[zenith2134]

Interior to this thread, I can speak to one point:

Christmas lights will interfere with ATSC television reception.

Whether incandescent or LED is irrelevant. Stringing up any type of lamp containing 60 cycles AC, will thwart reception of digital TV to some degree.

FM Stereo will get noiser, and lose multiplex on a lesser tuner.

[TUD1]

I've really screwed up now. I tried swapping the working chassis from the metal cabinet set into my remote set that I got a few months ago, and something happened, and now the thing looks like it's on a drug trip. Rolls horizontally, very unstable, no RF, no audio, etc.

[Electronic M]

I'd look at the synch separator/AGC stage (usually one tube sharing a cathode and a grid or two in Zeniths). No RF/sound and sync issues (presumably found by video injection, right?) sounds like a problem associated with that stage.

This is a really wild guess, but if you connected the tuner wires wrong perhaps you shorted the tuner AGC line and the issue fed back to something affecting both functions of the tube.

Horizontal roll (I assume you can get a slow roll in either direction, but it does not hold lock) could also be a bad H AFC diode package.

Did you try to connect the remote hardware when you did the chassis swap? Most non-remote sets lacked important aspects of the remote wiring and trying to adapt them to support that requires care and double checking of connections.

[TUD1]

I set my Sencore VG91 to 45.75 MHz and injected it straight into the chassis, as I sometimes do for TV's that have lackluster tuners.

At first, I thought that I could have gotten the tuner wires mixed up, but I swapped them around and it made no difference.

I had to swap the volume and power controls by de and resoldering them onto the appropriate chassis. It "works", but I think there is a problem within the remote chassis, because it exhibited this same behavior before I swapped.

[Jeffhs]

Originally Posted by TUD1

I set my Sencore VG91 to 45.75 MHz and injected it straight into the chassis, as I sometimes do for TV's that have lackluster tuners.

At first, I thought that I could have gotten the tuner wires mixed up, but I swapped them around and it made no difference.

I had to swap the volume and power controls by de and resoldering them onto the appropriate chassis. It "works", but I think there is a problem within the remote chassis, because it exhibited this same behavior before I swapped.

Until I saw the thumbnails attached to this post, I had never in my life seen such a weird CRT display on a color TV--and I worked on old cast-off TVs as a hobby for years when I lived in a house with a basement. I would not have thought it was possible to distort a color bar pattern that way, and I have no idea what was going on in your set to cause it. If you just swapped a couple of wires on the chassis, that should not have caused such a display. I am at a complete loss to explain why you are getting this, although I have never worked on a Zenith roundie color TV, or even Zenith rectangular sets. At this point I don't even want to guess what was causing this bizarre screen display.