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Old 24-Mar-2012, 11:03 PM   #1
guido_groundplane
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Any chance I can get KCRA 35 or KSBW 8 in San Jose?

Here's my location (?):

http://www.tvfool.com/?option=com_wr...0b86b079b55caf

Roughly where 85 and 17 intersect.

Have separate VHF and UHF antennas. I get everything on UHF that's close by. Want to pull in stations from Sacramento and Monterey areas. KCRA 35 and KSBW 8 for examples.

With either the VHF or UHF antenna about 30 feet AGL, I can't get anything from the Sacto or Monterey directions.

Thinking about extending the mast another 10 feet, adding amplifiers, but if someone knows from experience this CAN or CANNOT work at my location, that would be helpful. Don't want to extend the mast / add amplifiers if this is a lost cause to begin with.

Also, is KGO 7 also broadcast on 35 ? If yes I think there's no hope to also get KCRA on 35 (?)

Thanks,

"GG"
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Old 24-Mar-2012, 11:48 PM   #2
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Tv antennas and Tv reception

The radar report was only resolved to the to the street level , [please] make your own post with the exact address.

Last edited by GroundUrMast; 25-Mar-2012 at 12:04 AM. Reason: Edited to reflect that this thread has been seperated from an existing thread.
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Old 25-Mar-2012, 1:06 AM   #3
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First, I can't offer local knowledge for the Bay area.

You may want to use the Interactive TV Maps tool to generate a more precise TVFR.

That said, the first TVFR provided clearly says that you have little hope of reliable reception of KCRA. You have interference from KGO-real 35, KICU-real 36 and KFSF-real 34. Even if that was not the case, a noise margin of -13.9 and a 2-edge path make the situation very difficult.

A 10 element high-VHF antenna (or stacked set of two or four) may be able to see KSBW-real 8. You'd be gambling a bit.
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Last edited by GroundUrMast; 25-Mar-2012 at 1:09 AM. Reason: Suggesting use of Interactive TV Maps
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Old 25-Mar-2012, 1:24 AM   #4
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If you click on the call sign of a station listed in your TVFR you'll see a profile of the terrain that lies between the station and your location.

Here's KCRA for example: http://www.tvfool.com/?option=com_wr...ALLTV%26n%3d42

It show that the mountains NE of your location are quite formidable obstructions.
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Old 25-Mar-2012, 5:27 AM   #5
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Tv antennas and Tv reception

A tvfool radar report with exact address is more accurate for reception evaluation. The exact address does not show in the radar report it just makes a accurate report that we can use to recommend a antenna and etc. .
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Old 9-Apr-2012, 8:55 AM   #6
guido_groundplane
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Well, I put the VHF antenna on the mast, it's a Channel Master 3610, tried to get KSBW 8 from Salinas, no luck at ~10 and ~20 feet above the roof. Haven't pushed the mast up the last ~10 feet, too windy. But don't think it's going to help. Don't have an amplifier yet, wonder if it's even worth trying that last ~10 feet of mast without one. FWIW, there's a balun at the antenna with coax all the way to the channel box.
I did run the report with my exact address, looks the same to me:
http://www.tvfool.com/?option=com_wr...267e3ee6f67e5c
Thanks,
"GG"
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Old 9-Apr-2012, 9:22 AM   #7
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Most TV's with built-in DTV tuners force you to scan for new channels. A few TV's and converters will let you manually add channels... If you are able to manually add the channel and the tuner has some sort of signal metering, you would be able to tell if you're seeing some signal even if you can't get a lock.

If you know you're seeing some signal, then it may be worth trying an Antennacraft Y10713 or even a stacked pair. http://forum.tvfool.com/showthread.php?t=1024
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Old 18-Apr-2012, 11:02 PM   #8
guido_groundplane
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Since last time I did push the mast up another 9-10 feet, so it's about 40 ft AGL by my estimate. Still no channel 8, zero. Strong signal from 7 if I point it at 7, so the antenna, balun, coax are at least functional.
Am now considering buying a Spartan amplifier, 300 ohms in, 75 out ... that will take the place of the balun?
Some interest also in building a single channel coax balun, but how to connect that to an amplifier - 75ohms in and 75ohms out?
I've called KSBW 8 twice and asked for an engineer but they haven't called back.
Had record-setting lightning last week, am thinking about grounding the mast. Radio Shack has very small gauge copper-coated steel wire sold as "grounding wire", is it up to the task?
Thanks,
"GG"
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Old 18-Apr-2012, 11:42 PM   #9
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If you build a coax balun, the output will be 75Ω. Therefor a preamp would need to be specified with a 75Ω input.

Here's my recent response to a similar grounding question:

Quote:
I do live in a very active area of lightning, though, and have lost televisions (cable, no antenna), phones, and even computers to lightning in the past. Are there good ways to protect my television from lightning when using an outdoor antenna?
Grounding the mast and coax shield are prudent and relatively inexpensive steps that limit the buildup of static-electricity which can damage the tuner. When done correctly, grounding can also reduce the risk caused by a nearby lighting strike.

http://forum.tvfool.com/showthread.php?t=901

Grounding in a basic system is a two step process:

1) Connect a #10 gauge copper wire to the antenna mast. A bronze ground clamp such as the Halex #36020 is well suited for this application. Run the wire directly to the electrical service ground. Avoid sharp bends in the wire. (Often you can use a 'split-bolt' electrical connector to clamp the #10 wire to the existing ground wire close to the ground rod outside the building. If possible, avoid running the new ground wire inside the building, energy from static or electrical storms is best directed to ground before it has any path into the building. The wire can be bare or insulated, your choice.)

2) Run the coax from the antenna to a location close to the electrical service ground. Install a ground block and with another peice of #10 wire, connect it to the electrical service ground at the same point you connected the mast ground.

I don't recommend short-cuts such as driving a new ground rod that is not connected to the existing electrical service ground. An isolated ground rod often has a high resistance that provides very limited ground connection. The goal is to connect to the same ground system that protects the rest of the home.

Surge protectors located inside outlet strips at the TV, computer or similar devises are worth consideration. A surge protector with a high joule rating is able to absorb more fault energy than a unit with a lower joule rating. Some surge protection units include phone jacks and F-connectors to enable protection of a phone line, coax cable and the power cable(s). However, in the case of an outdoor mounted antenna, this type of protection should not be considered a 'first-line of defense'.
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Old 2-May-2012, 8:16 PM   #10
guido_groundplane
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Well, I bought that Spartan 3 VHF only amplifier off eBay, might be able to try that out this weekend. Anyone willing to predict if its even possible I will go from zero reception to clear reception with that addition alone? That will likely be the end of this experiment, even if it fails.

OTOH, I've spotted another Channel Master 3610 on an apartment building nearby, doesn't look like it's being used anymore. If I can get permission, pay someone to take it down, then I could try dual 3610's on the same mast, just for kicks.

While I'm in the neighborhood, thought I saw a reproduction of the 3610 and 3617 a while back, but don't see them now. Saw an antenna on a business trip like a 3617, but had even more V-shapes, like twelve pairs at the front. Should have stopped and asked about it, but was in a hurry. Any idea what it was?

Thanks,

"GG"
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Old 2-May-2012, 9:12 PM   #11
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I'm rooting for you... but the KSBW path profile looks like you need a lot of luck, something that I never studied in physics or electronics.

Compound that with the adjacent channel interference from KGO on real channel 7 and I can't say I expect a miracle.

Do you have room for a rhombic? Cut for CH-8, a five wavelength per leg rhombic would be roughly 60' long.

http://forum.tvfool.com/showthread.php?t=291
http://forum.tvfool.com/showthread.php?t=2865
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Last edited by GroundUrMast; 4-May-2012 at 1:08 AM. Reason: Rhombic suggestion
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Old 10-Oct-2012, 6:05 AM   #12
guido_groundplane
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Which way to point 8 bay and "arrow" antennas?

Sorry I went off the air for a few months. Only pushed the last 9' of mast up recently, no joy with Channel 8 despite the extra height and addition of an amplifier. So the VHF antenna is just a roof decoration for now.

For UHF I've got an 8 bay "flat screen", and one that looks like an arrow pointing away with the transmitter, a "Diamond Quantun 4248, both from ChannelMaster. Each connected to its own channel converter. I need now to move those two to my main mast.

Wondering if there'd be any point in aiming one at 36/35/50/48 and one at 27/19/38 ? If yes, which to point in which direction, of the two I already have ?

Thanks,

"GG"
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Old 10-Oct-2012, 6:55 AM   #13
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Just to catch back up....

Are you able to manually tune to a real channel and view some sort of signal meter function?
Quote:
Originally Posted by guido_groundplane View Post
Sorry I went off the air for a few months. Only pushed the last 9' of mast up recently, no joy with Channel 8 despite the extra height and addition of an amplifier. So the VHF antenna is just a roof decoration for now.

For UHF I've got an 8 bay "flat screen", and one that looks like an arrow pointing away with the transmitter, a "Diamond Quantun 4248, both from ChannelMaster. Each connected to its own channel converter. I need now to move those two to my main mast.

Wondering if there'd be any point in aiming one at 36/35/50/48 and one at 27/19/38 ? If yes, which to point in which direction, of the two I already have ?

Thanks,

"GG"
Are you thinking of combining the two UHF antennas into a single down-lead? If so, you'll almost certainly need a rather complex and expensive tuned combiner network custom built. I would try a single UHF antenna to see if all of the signals you've listed can be received with far less complexity.
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Old 10-Oct-2012, 5:56 PM   #14
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The following is a , if it works it works , if not well then it's not.

For reception of KSBW VHF channel 8 install a Winegard YA1713 VHF high band antenna , channels 7 thru 13 , aimed at about 130 degree magnetic compass direction.

Install a http://www.kitztech.com , KT-200 amplifier.

Here is how to aim antennas , http://www.kyes.com/antenna/pointing/pointing.html.

Reverse engineering your location to within a few buildings , the tvfool radar report shows that going higher then 40 feet antenna height for reception of KSBW Channel 8 , has the effect of less signal strength.

Tvfool shows the reception path of KSBW channel 8 as being a 2 edge path , 2 or more hills in the direction of reception.
2 or more edge paths often have the effect of bending the signal a little downward.

Try lowering the antenna height from 40 feet to about 25 feet antenna height or even on down to about 10 feet antenna height. I think signal strength will improve.

However be mindful trees and buildings and other obstructions reducing or blocking reception at the lower antenna heights.

Last edited by teleview; 10-Oct-2012 at 6:54 PM.
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Old 10-Oct-2012, 6:24 PM   #15
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Re. KSBW reception

Considering the size of the CM-3610 that has already been tried at various levels, it's very difficult to suggest that a YA1713 or Y10713 would be capable of overcoming the blocking terrain and adjacent channel interference. The lack of any indication of signal from KSBW thus far is a rather stark reality.

If there's reason to suspect the condition of the CM-3610 and, cost and time are not the issue, I would suggest a stacked array of four Antennacraft Y10713's might have a faint chance of success. The Winegard product is well built, but lacks the 300Ω balanced feed point connection needed for low-loss stacking. http://forum.tvfool.com/showthread.php?t=1024

Page 18 of the following comments on the gain of the CM-3610. http://www.google.com/url?sa=t&rct=j...yeDhJy1Dw1TGzw A single 10 element High-VHF Yagi Uda has less gain than the CM-3610.

Last edited by GroundUrMast; 10-Oct-2012 at 7:18 PM. Reason: Added another link
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Old 10-Oct-2012, 7:07 PM   #16
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The 3610 is a powerful FM antenna as well & you have the possibilty of harmonic distortion interference from 2 nearby FM stations. I suggest trying a Radio Shack FM trap anywhere between the antenna & TV (no amplifier is best for testing) You can return the trap if it doesn't help.
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Old 13-Oct-2012, 4:20 AM   #17
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Further explanation(s)

Right now each antenna has its own converter box. One is a Magnavox which does allow manual selection of channels. The other is an RCA which does not. One or both have a bar graph signal strength feature. Had a ChannelMaster converter but it died. Guess I need to find something new there.

Looking at my "TV Signal Analysis Results", it looks to me like I'm getting, using UHF antennas only, most of my desired channels from the roughly 320 degree direction:

26, 5, 11, 38, 4, 2, 9. ( Kinda curious that I get 11, "real" 12, with my UHF antennas, yes, no? ) So I could point both the 8 bay and the CM 4248 in that direction and be done with it.

Or I could point one in that direction, and the other at about 14 degrees, at "real" 35, 50, 48. Which of the two is better suited to picking up these more distant UHF stations? Suppose here I could run my own experiment with the signal strength meter.

Back to VHF, guess I should try to get "real" 6 as an experiment, or could point it at "real" 12 and 7, so it has something to do. There is a tunable FM trap in the amplifier, with an on - off switch. If I left it off, was that a blunder?

Thanks,

"GG"
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Old 13-Oct-2012, 6:36 AM   #18
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The FM trap is well worth trying.

Just curious, are these antennas 'new old stock' or have you had them for a few decades?

Do the side by side comparison. The real world trumps the specifications.
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Old 16-Oct-2012, 6:07 PM   #19
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Signal Strength Test

Both antennas bought new by me about 15 years ago.

Could not prove any real difference in signal strength between the two while pointed at Channel 48 / 13 degrees. Tried a couple different channels in that direction, swapped cables on a single converter box for an apples-to-apples comparison.

However, did notice the 4248 did not get 9, 11, 20 and 26 ( off-angle over at ~320 degrees ) but the 8 bay did (especially if connected to the Magnavox not the RCA)

So decided to keep the 4248 pointed at 13 degrees and pointed the 8-bay at ~320 degrees, since it's reception seems to be a bit "wider".

The FM trap switch is now 30ft above the roof, where it will hopefully stay for an other 15 years. But I gather I can try a separate FM trap near the converter box?

I also noticed the RCA converter box, though in most respects inferior to the Magnavox, gets several channels that start with 1, such as 1-1, 1-2, and so one. The Magnavox does not. Maybe an on screen setting somewhere I need to change.

Thanks,

"GG"
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Old 16-Oct-2012, 7:23 PM   #20
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It's OK... but

The ideal location for any trap including an FM trap is ahead of the preamp. The active electronics in the preamp can be as susceptible or even more so than those in the tuner to inter-modulation distortion (IMD, mixing of two or more signals which results in new, potentially interfering signals that were not present in the air). By placing a passive filter (AKA 'trap') ahead of all active electronics, you get the best protection against interference generating IMD.

But, yes, you can try a trap at the TV... it won't hurt anything.

Last edited by GroundUrMast; 16-Oct-2012 at 7:27 PM. Reason: Added title
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