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post #12001 of 12010 Old Yesterday, 06:40 PM
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Originally Posted by SFischer1 View Post
Now Sutro may be different, perhaps there are agreements between stations as there are so many there that other engineers can do minor fixing. Larry likely can shed some light if he wishes.

Enter "1 La Avanzada St. San Francisco, CA 94131" into Google Earth if you have not done it before. You can zoom in and look right down the center of the tower. What is the flat structure to the North East?

KNTV is different as they do not have the huge number of other stations in the same or next building.

SHF
First, an overall statement that no station has an engineer on duty at their transmitter site. The transmitters are all controlled and monitored remotely from the station's master control center at the studio. Engineers visit the transmitter sites as needed to make adjustments and repairs, but no one works at the sites full time any more. Transmitters have become so reliable and stable, they need very little work.

Each station at Sutro has their own locked room. I can only speak for KGO, but only KGO engineering staff and the Sutro site general manager have keys to the KGO transmitter room. If something went wrong with the transmitter on the air and it went out of tolerance or went off the air, the system would automatically switch to the other transmitter. The few times I saw this happen, the station was off the air for just 8 seconds. That's all the time it took to switch the antenna coax from one transmitter to the other and have it turn on. Someone would then have to drive up to Sutro to make the adjustment or repair on the transmitter that went down. Only once did I see where both transmitters were down. The station was off the air for 55 minutes while an engineer drove up to the site and got the station back on the air. (Comcast and DirecTV viewers kept seeing programming as those services get a direct feed from the studio.)

On Mt. San Bruno, the only difference is that the transmitters are in separate buildings, not separate rooms.

Some stations contract their transmitter engineering to an outside engineer. I know several engineers who are responsible for more than one station.

That huge flat structure to the North East of Sutro Tower, as seen on Google Earth and Google and Bing maps, is one of the city of San Francisco's reservoirs. The city has several at high locations around the city, so in case of emergency and loss of power for the pumps, gravity will continue to supply water to the system. A little side story... all of the reservoirs were covered over with cement back in the late '60's when someone indicated how easy it would be to get the entire city high with LSD by just dropping some into the various water supplies.

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post #12002 of 12010 Old Yesterday, 06:48 PM
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Originally Posted by PeninsulaMark View Post
Thank you, Larry. Will do. The issues with the rotor, other than adding $150, are:

1. They don't seem to last long nearly as long as the antenna
2. Installers give a three month warranty on them
3. It can get stuck in a sub-optimal position

It's fun to be able to rotate an antenna. Anyone have a suggestion for an excellent lon-lasting reliable rotor ?
Strangely, the signal has been fine for the past 24 hours. Typing in this forum has been therapeutic in several ways!
My first rotor lasted 20+ years. I would re-sync it every year or so (if I remembered) just to make sure it worked. The control was an analog switch. When we installed a metal roof, we bought a new rotor, a Channel Master (RT-CM-9521A) with the 9537 remote control, and had the Antenna Doctor reinstall the antenna with the new rotor (I wanted the remote control). That was 4/26/06. We rarely move the rotor because we don't have to but I did re-sync it over the weekend and it worked just fine.

I too have the fear that it may get stuck in a sub-optimal position if I move it, but I never have to move it. And based on my experience, moving it every year or so has not been a problem. Right now it's really windy down here, and there is no problem with reception, even on 11-1!
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post #12003 of 12010 Old Yesterday, 07:03 PM
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Originally Posted by Otto Pylot View Post
... we bought a new rotor, a Channel Master (RT-CM-9521A) with the 9537 remote control, and had the Antenna Doctor reinstall the antenna with the new rotor (I wanted the remote control). That was 4/26/06.
That was the exact same rotor as the ones that failed for me. I used to turn mine a lot though, so maybe they wore out from too much use, not from the wind. LOL

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post #12004 of 12010 Old Yesterday, 09:47 PM
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Interesting. I wonder at times why I even bought a rotor because we get everything we want with one orientation. I guess the thinking was that over time the wind and environment would move the antenna but that just hasn't been the case.
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post #12005 of 12010 Old Today, 07:10 AM
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Quote:
Originally Posted by Otto Pylot View Post
My first rotor lasted 20+ years. I would re-sync it every year or so (if I remembered) just to make sure it worked.

How long those rotors last has a lot to do with how corrosive the environment is. San Jose (especially south) is less bad than Menlo Park which is better than SF. Any location on the coast is awful. I've had antennas up here for 10 years and the aluminum elements are still shiny. I know a guy east of here in Arnold at 4000' and he had one of those TV rotors for his antenna. He had trouble with it after 20+ years, took it down, re-lubed it and it worked fine again. There were no corrosion issues.

The TV rotors don't have much in the way of any bearings in them so they freeze up more easily. The ham rotors have two tracks of ball bearings in them. Even if they become ugly on the outside they are still good on the inside. Ham rotors also have dedicated indicator circuitry so it's impossible to get out of synch. But that comes at a price. All the rotors use pots for the indicator and those wear out. The more rotating you do the faster they wear out. I had to replace the pots in both the rotor and the control box in the rotor with the TV antennas after close to 10 years. I did a huge amount of rotating for TV antenna tests. The rotor in the other tower has been up for 10 years with no problems.

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post #12006 of 12010 Old Today, 08:35 AM
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Is there a channel signal strength indicator on the Samsung?

Speaking of TV signals, the Sharp 3D Aquos has a signal strength indicator for each channel. Cannot find this feature on the Samsung 60" 8550. Anyone know if that feature is available on this Samsung ?
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post #12007 of 12010 Old Today, 02:31 PM
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Cool

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Originally Posted by PeninsulaMark View Post
Wow! Didn't know that TVfool existed.

MY LINK: http://www.tvfool.com/?option=com_wr...f1f0927ffe9f43

I don't mind replacing the 40 year old antenna with another one, but since labor is $250 to $350, I'd like an excellent antenna. I have four HD TVs which are hungry for RF. What's wrong with getting a better antenna, like db of 20 or more ?

Until recently, the reception was excellent and continuous. The antenna is on the roof and perhaps 25 feet higher than the roof.


Okay. On the home stretch and on information overload. A nearby TV place recommended a ChannelMaster 4228 HD, but another TV place said it is too unidirectional, and I should instead get a ChannelMaster Advantage 60, new RG6 coax, and probably a CM7778 Titan Two preamp at the antenna. For a rotor, she said the ChannelMaster CM9521.

She also said that likely there is a $20 box part which needs replacing, and thinks I don't need a new antenna. Replace that part and put in new coax.

So antenna choices are: Keep the old one, or new Advantage 60, ChannelMaster 4228 HD, Wineguard 7694, or Wineguard HD8200.

Pre-amp at antenna (optional): CM7778

Rotor (optional): CM9521

My TV Fool link again: http://www.tvfool.com/?option=com_wr...f1f0927ffe9f43

Any comments ? I have a picture of the old antenna, but don't know how to post it here.

Last edited by PeninsulaMark; Today at 02:35 PM.
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post #12008 of 12010 Old Today, 02:46 PM
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It looks like TV Fool gets fooled by stations that have construction permits to move to new sites. If a station is moving location, TV Fool reports the station for its location outlined in its construction permit and not what the station is currently licensed at.
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post #12009 of 12010 Old Today, 03:05 PM
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Quote:
Originally Posted by PeninsulaMark View Post
Okay. On the home stretch and on information overload. A nearby TV place recommended a ChannelMaster 4228 HD, but another TV place said it is too unidirectional, and I should instead get a ChannelMaster Advantage 60, new RG6 coax, and probably a CM7778 Titan Two preamp at the antenna. For a rotor, she said the ChannelMaster CM9521.

She also said that likely there is a $20 box part which needs replacing, and thinks I don't need a new antenna. Replace that part and put in new coax.

So antenna choices are: Keep the old one, or new Advantage 60, ChannelMaster 4228 HD, Wineguard 7694, or Wineguard HD8200.

Pre-amp at antenna (optional): CM7778

Rotor (optional): CM9521

My TV Fool link again: http://www.tvfool.com/?option=com_wr...f1f0927ffe9f43

Any comments ? I have a picture of the old antenna, but don't know how to post it here.
Yes the CM4228HD is unidirectional to a point. Not good here in the land of multi-path.

Enter your address into this TVFool page : http://www.tvfool.com/?option=com_wrapper&Itemid=90

Then select "Show lines pointing to each transmitter" and zoom out. That might help with the rotor needs.

As far as the picture, see this sticky http://www.avsforum.com/forum/43-forum-operations-center/1565041-how-put-image-post.html#post24936137

If you are going to replace the antenna I would go with Chuck's suggestion.

Where is the lady? We discovered a place in Cupertino that Mark uses, but if the owners wife is behind the counter, just leave.

You may have found another place that if you see a lady, just leave. Brick and mortar stores sell what they have on hand perhaps not what you need. Her advice just does not compute for me.

SHF
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post #12010 of 12010 Unread Today, 03:55 PM
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At 25 miles you simply do not need the CM 7778 unless your coax is very, very long. I use one here at 50 miles or so and it works well. My coax is also 100 feet. Please try not to get oversold. Listen to what some of the experts here are telling you....

Bobby 

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