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Quote:
Originally Posted by youseeme  /t/369015/san-francisco-ca-ota/9930#post_24200689


I need help getting 26.1 KTSF in the Richmond district. I'm a block or two away from the guy in the thread below:
http://www.avsforum.com/t/1150610/2-edge-reception-in-san-francisco-ktsf-need-help


I bought a ANT751R and have it installed on my roof (2 stories). I tried 3 different antennas already. DIY outdoor, indoor leaf, and ANT751. The ant751 brings in addition 68.1 sub channels (when aim correctly) while others didn't. I tried repositioning all sort of degrees and I can't pull in 26.1 KTSF. Any advice would be appreciated.
Hi,

 

Please go to:

 

http://www.tvfool.com/?option=com_wrapper&Itemid=29

 

and enter your exact address.

 

Post the generated link here.

 

Then click on KTSF to produce a graph like this one:

 



I got the location from the post you linked.

 

What I see is that a mountain is blocking the signal, Sutro likely. Edit: NO, I do not know the names.

 

Not a good place.

 

SHF
 

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About the only thing left is to try a high gain antenna, either a CM4228 or a 91XG. You probably have a major multipath issue.


BTW, the TVFool link in the link you gave us is no longer valid.


Chuck
 

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Hi,

 

I used the Lat. and Lon. in the first line of the linked thread to enter into:

 

TV Fool Google map:

 

http://www.tvfool.com/?option=com_wrapper&Itemid=90

 

You should again enter your exact address.

 

Click on "Show lines pointing to each transmitter"

 

and then scroll down to "KTSF" and select it.

 

And wait, and wait, and wait until the colors come up on the map.

 

There is NO link you can post, sorry.

 

If you are only two blocks from the given location then there might be hope as I see some green.

 

But for the given location there appears to be a string of hills directly in the path.

 

See image.

 



You are doing the right thing by "I tried repositioning all sort of degrees", have you tried different locations on your roof?

 

If you are playing the game of "DTV Antenna Battleship" then a better method is needed.

 

DTV Antenna Battleship is when you position your antenna and rotate it and ask your DTV if it sees the desired station.

 

If not then you move the antenna to a different position or rotation and again ask your DTV if it sees the desired station.

 

If not repeat until you get success or give up.

 

Not a good game to play and one I would quit quickly.

 



A better method is some way to see in real time if the station is being received.

 

I have a HDHomeRun tuner on my wireless network and a laptop that I could take to the roof and watch the signal strength and quality as the antenna was rotated or moved.

 

Something like that is needed to see if there is any antenna location and rotation that can receive KTSF or any station of interest.

 



But I must say that there are some locations drilling multiple test holes produces no gas, no oil or water. Just dirt and rocks.

 

SHF

 

 

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Quote:
Originally Posted by veedon  /t/369015/san-francisco-ca-ota/9930#post_24196973

 

KGO (ABC) is RF 7.

How easy is that to get if you don't have an antenna that is specifically designed for VHF?
Hi,

 

That is discussed in:

 

http://www.hdtvprimer.com/ANTENNAS/comparing.html

 

"Using a UHF antenna for VHF".

 

The CM4228HD is unique in that document.

 

That document has lots of useful information, I need to find the time to read it all.

 

SHF
 

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There are many hills/ mountains blocking the path.. But 11.1 and 65.1 both come from there and i'm able to pull those in no problem (even after using many different splitters, maybe 5 TVs in home.) Even when I directly hooked up the antenna to 1 source only there's no luck with 26.1. I see -47.6db for my exact address http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d5b949179714a75

Strange thing is no matter where I rotate the antenna 11.1 and 65.1 is always found but 68.1 come and goes.
 

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Hi,

 

Chuck's suggestion that you get an 91XG is a big step and perhaps out of line for the neighborhood. The CM4428HD also is huge and IMHO not as good a choice for solving a multipath problem.

 

If you have a laptop check into USB tuners, mine has a real time display of signal strength only, signal quality which is the important number is not shown.

 

Then a silver sensor like tabletop antenna could be used to move around your house to see if there is any possibility of getting KTSF.

 

Dismounting your ANT751R and moving it around the room would be the same but more unwieldy.

 

With a real time display I found that one station to the North East comes in best with the antenna pointed to the South East.

 

The wave length for RF 27 is quite small, just moving the antenna up, down, back, forth, left, right might produce a better result with less than 12 inches of movement.

 

But if you are playing "DTV Antenna Battleship", it may be a battle lost. At least with the real Battleship game you have a chance.

 

> 68.1 comes and goes.

 

Normal multipath symptoms.

 

SHF

 

P.S. I am going to change the name to "DTV Antenna Battleship" game, it just sounds better.
 

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Quote:
Originally Posted by youseeme  /t/369015/san-francisco-ca-ota/9960#post_24201486




There are many hills/ mountains blocking the path.. But 11.1 and 65.1 both come from there and i'm able to pull those in no problem http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d5b949179714a75 .

Absolutely not true ..... The red rays are signal overload...... that picture shows no areas that lack signal.

The fact that you mention 11 & 65 come in means you are in range.


The industry standard for UHF antennas for decades has been the "Yagi" type model of antenna. That would most likely solve the problem.


You see how these models like the leaf, .... just don't cut it for performance.
 

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Hi,

 

He has a ANT751R which looks like a "Yagi" to me, about as much as my Terk HDTVa does.

 

His is for outdoor, mine is for indoor.

 

Neither look like anything like the UHF CM4228HD bow-tie and other bow-tie antennas I have seen.

 

Yes, the leaf is a non-starter.

 

SHF
 

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Quote:
Originally Posted by youseeme  /t/369015/san-francisco-ca-ota/9960#post_24201486



There are many hills/ mountains blocking the path.. But 11.1 and 65.1 both come from there and i'm able to pull those in no problem (even after using many different splitters, maybe 5 TVs in home.)

That's telling you there is plenty of signal.

Quote:
Even when I directly hooked up the antenna to 1 source only there's no luck with 26.1.

That's because it's not a signal strength issue, it's a multipath issue. Multipath can vary widely from station to station at the same transmitter site. How's channel 40 from San Bruno?


It's entirely possible that the multipath issue cannot be solved with any antenna at your location. The ANT751R isn't much of an antenna. You just have to try something better. You pays your money and takes your chances and you hope for the best.

Quote:
Strange thing is no matter where I rotate the antenna 11.1 and 65.1 is always found but 68.1 come and goes.

KTLN 68 is located in the north bay and predicted to be more than 30 dB weaker than KTSF. You can't compare that to 11 or 65. It's going to be weak and sensitive to antenna position just because of that.


Chuck
 

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Quote:
Originally Posted by Calaveras  /t/369015/san-francisco-ca-ota/9960#post_24202048


That's because it's not a signal strength issue, it's a multipath issue. Multipath can vary widely from station to station at the same transmitter site. How's channel 40 from San Bruno?


Chuck

I do not get channel 40. TVfool says its 63 miles away. Is something this big: http://www.amazon.com/Antennas-Direct-DB8e-Extreme-Multi-Directional/dp/B00C4XVOOC/ref=sr_1_1?ie=UTF8&qid=1389603088&sr=8-1&keywords=db8e my last resort? My DIY antenna was 6 bow ties.
 

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Quote:
Originally Posted by youseeme  /t/369015/san-francisco-ca-ota/9960#post_24202300


I do not get channel 40. TVfool says its 63 miles away.

That's KTXL and is the station I get on 40. For you channel 40 is KMMC on Mt. San Bruno. It's one of the yellow stations on your list at 20 dB noise margin.


Did you build the Hollands 6 Whisker bow tie shown here?

http://imageevent.com/holl_ands/dipoles/uhfbowties


That's not much gain and no reflector. The DB8 would be much better.


Or did you build something completely different? I still favor the 91XG. I don't think you can beat it for gain and best pattern.


Chuck
 

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Back-up Antenna


I've been threatening to drop Dish Network for quite awhile and I may finally do it now that they're raising the price again. How do they justify a 25% rate increase in the last 2 years when inflation has been about 4%? I probably watch 90% on OTA and 10% on Dish. I can live without the 10% but I want the OTA to be reliable.


Most of you probably know I have my TV antennas way up on a tower at 70'. It's the only way I can receive anything from my otherwise poor OTA location. Up high means they're subject to a beating in bad weather and I've had my fair share of problems keeping them operating. I have made changes that have improved the reliability. Still though, if I'm going to drop Dish as a back-up I wanted something else as a back-up. I decided to put antennas up on my taller tower.


I did a test on UHF some years ago and even though the antennas were 10' higher than what I use now, the location didn't seem to be as good for Walnut Grove. The location is 95' north of the other tower. I didn't have a spectrum analyzer to make detailed comparisons at that time.


To keep this short, I added a 7' fiberglass mast to the top of the steel mast and I ended up with a very light weight high VHF antenna of a custom design at the top (89' above ground) and I used my extra pair of 91XGs below that at 86'. The base of that tower is 6' lower than the main TV antenna tower so the back-up antennas net out about 10' higher.


I found a nice 12V 75 ohm JFW coax switch on Ebay that allows me to switch to the back-up antennas from in the house. I had to run an extra 100' of hardline over to the back-up antenna tower. I wasn't going to run a separate 400' length of hardline to the back-up antennas.


I'm waiting for a new VHF preamp and VHF/UHF diplexer to arrive. In the meantime I tested the VHF antenna by itself with a low gain preamp. Walnut Grove VHF (6 and 10) showed identical SNRs. Channels 8 and 35 were good but KGO was about 5 dB down..... worse noise figure and less antenna gain. It's no big deal to lose KGO on the back-up antenna.


Then I manually switched over to the 91XGs. I've had a few days now to evaluate those in the new location. There have been some big surprises.


Walnut Grove was pretty much as I remembered. Signal strengths are all about the same as shown on the analyzer but KMAX and KOVR (RF 21 and 25) are about 2 dB lower SNR. KCRA and KTXL (35 and 40) are about the same and KQCA and KSPX (46 and 48) are about 2 dB better. I was hoping for a better number on KOVR but it's good enough for the back-up.


The real surprise came on all the other stations. I have years of observing reception for years so I have a very good idea of what I can receive and what I can't. Sutro UHF is limited to KQED, KMTP and KBCW with an occasional appearance by KPIX. The other stations appear only briefly under exceptional conditions. On the back-up antennas I'm now seeing all the stations that are possible to receive here for long periods and the regulars are way up in SNR. I saw KQED and KMTP peak at 27 dB SNR and KBCW at 31 dB, numbers I've not seen even once before. KTVU, KRON, KCNS and KCSM have been in more in the last couple days than all the time put together over the last few years. KCSM is still the weakest and KCNS has co-channel interference issues with KMMD on Mt. Toro. KFSF is not possible here due to KACA also on 34. KKPX on San Bruno is not helped at all. Sutro is so far away that there are still periods of no reception.


The surprises didn't end there. The Fremont stations are better too with KSTS often reaching 31 dB SNR. KAXT is now in about 50% of the time compared to before at maybe 10%. Salinas UHF is also better with KION being almost good enough to record.


Fresno is still a complete no go.


The only test I have yet to run is to crank the tower down 10' to see if the improvement is due to the extra height or if the location is just better. If 10' turns out to be the reason then I might be able to get them up another 5'.


Chuck
 

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Quote:
Originally Posted by youseeme  /t/369015/san-francisco-ca-ota/9960#post_24202300

 
Quote:
Originally Posted by Calaveras  /t/369015/san-francisco-ca-ota/9960#post_24202048


That's because it's not a signal strength issue, it's a multipath issue. Multipath can vary widely from station to station at the same transmitter site. How's channel 40 from San Bruno?


Chuck

I do not get channel 40. TVfool says its 63 miles away. Is something this big: http://www.amazon.com/Antennas-Direct-DB8e-Extreme-Multi-Directional/dp/B00C4XVOOC/ref=sr_1_1?ie=UTF8&qid=1389603088&sr=8-1&keywords=db8e my last resort? My DIY antenna was 6 bow ties.
Hi,

 

the CM4228HD may be a better choice if you are willing to put up that large of a 8 bay bow-tie, it will receive KGO RF 7 and KNTV RF 12 better that the other antenna unless that has been changed.

 

But I still say the 91XG is a better choice as it's reception angle is smaller than the CM4228HD, better for rejecting multipath from the side.

 

I have not looked for but I expect that plans for a multi element home built "yagi" for RF 27 is on the internet.

 

It should be very small and have the smallest reception angle. Perhaps your best bet IMHO.

 

http://www.hamuniverse.com/yagibasics.html



 32.3 miles and LOS to  VC 40.1 RF 40.3 KMMC 3ABN-Latino San Francisco Mt. San Bruno 14 1283 L

 

I have great difficulty in getting RF40 KMMC-LD. I got one (1) video frame in two minutes and only a quick splash of audio.

 

It's power is so low.

 

SHF
 

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Hi,

 

I have been pointed to the device "one" station on Sutro switches from the main antenna to the Auxiliary Antenna.

 

Dielectric introduces 60000 series coaxial switches

 

http://broadcastengineering.com/news/dielectric-introduces-60000-series-coaxial-switches

 
Quote:

it is a mechanical coax switch. it has a motor and rotary wipers. it also has small switches so the transmitter turns off and then the switch moves. when the switch is complete the transmitter comes back on. the switch takes about a 1/4 second. my memory thinks the switch was made by Dialectric.
 

Edit: Questions removed that I do not want to be answered.

 

Thanks to the person for pointing me to the device.


 

SHF

 

P.S. I had an image of an old railroad tower with persons throwing huge levers.

 

 

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Quote:
Originally Posted by SFischer1  /t/369015/san-francisco-ca-ota/9930#post_24192687


We have beautiful pictures of the tower, pictures of rust on the tower, pictures from the tower, plans that would be a big step in building another tower, but ...


Are there any pictures of the buildings and the equipment in them.

I checked with my former fellow employees at KGO and they don't have any photos of their transmitter room. I should have take my camera up there during one of my visits, but I never thought of it. I've only got a couple taken at the studios. I'd like to see it again, too, now that the channel 24 transmitter is gone. I suspect that the two Harris transmitters for channel 7, which are the same ones used when they transmitted analog on 7, are still in the same place. The only change was to replace the old exciter with a new one when they changed from analog to digital.
Quote:
Originally Posted by SFischer1  /t/369015/san-francisco-ca-ota/9930#post_24192687


I am also interested in how they switch from the main antennas to the aux antennas.

When I worked there, KGO had two humungous electrical switches (which can also be switched manually, if necessary, at the transmitter site). One switches between the output of the two transmitters to the output coax, and then there's another one in the output coax that switches between the main antenna and the auxiliary antenna. The switches are controlled by a simple push of a button on the remote control unit in Master Control. If the on-air transmitter fails, the switch to the other transmitter is done automatically.


When the switching is done on either switch, the transmitter output has to be off. When you make a switch from one transmitter to the other it automatically turns off the on-the-air transmitter, makes the switch and then turns on the other transmitter. When it switches from one transmitter to the other it puts a dummy load on the one that's not feeding the antenna.


When switching between the main antenna and the auxiliary antenna, it turns off the transmitter, makes the switch and then turns the transmitter back on.


Now that the power has to change when going from one antenna to the other, there must be another step involved that was not needed when we were analog. I have no idea how that is done, but I suspect it's automatic, too.


In both cases, switching used to take 7 to 8 seconds. I suspect that they're still using the same switches and same controls. Analog or digital, the switching would be the same.
Quote:
Originally Posted by SFischer1  /t/369015/san-francisco-ca-ota/9930#post_24192687


BTW - KGO showed the newsroom clip again which I have saved waiting for someone to agree to put it on utube. Chuck found the right place.


KGO-GetUP.mp4 (27 Mb) 49'ers related.


I looked at KGO's facebook page and could not find it there.

I saw that on the air a few times this past week. The newsroom still looks the same as when I was there, with a few changes in the color scheme, but the new control room seen at the end, is all new since I was there. The control room used to be downstairs next to the studio.


Larry

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Chuck... I know the new back up antenna installation is a lot of work, but I bet you're having a great time checking them out and comparing what you get from them!


Larry
 

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Hi Larry,

 

thanks for the description.

 

I have removed the
 that I thought would be the response of some people to my railroad tower idea.

 

RF 7 and the mid UHF range station the Dielectric is used by may have very different needs.

 

It looks like a big job to find the switch in the Dielectric web site, I wonder what frequencies and power level it is used for.

 
Quote:
 standard coaxial sizes 7/8” through 4-1/16” in 50 ohms, and 6-1/8” and 9-3/16” in 50 or 75 ohm versions.
 

9-3/16" coax, wow.

 

SHF
 

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Stephan, sorry, but I have no idea if KGO switches are from Dielectric or some other company, and I have no idea how large they are. I've never seen them.


Larry
 

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Another big high pressure with strong inversions bringing wild conditions this morning. Huge signals coming from Salinas and Fremont with KAXT at SNR 31 dB. Nothing from Sutro at all and Walnut Grove was having problems. I saw KRCB which I rarely see because there are 3 stations competing on the channel.


I suspect we're going to see more of this over the next week or so.


Chuck
 

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I decided to try an old reflector I made using an about 2 1/2 ft. piece of Reynolds Wrap aluminum foil to help reception. I'd noticed that reception levels seemed to be better when I was physically near a Leaf antenna here. The reflector could maybe be a substitute for me. It seemed to work. Prior, I'd always tried the reflector behind antennas. This time I walked it toward the antenna just as I would. About 3 feet from the antenna, an extra 4th bar appeared on the sets signal meter. It had been 3 dropping to 2. The 4 was pretty constant, and the 2 didn't return. The Leaf was aimed around 45 degrees off of the reflector position, and the reflector did nothing directly behind the Leaf. The reflector was parallel with the room window. It may be that the reflector was blocking signals from the windows in rooms across the hall that face the other way. Note: this is a very ugly solution.
 
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