San Francisco, CA - OTA - Page 256

I've never thought about checking the loss in RG-6. If it worked I figured that it was okay. But after hearing that a 3 foot piece had a 1.3 dB loss, I'm going to be checking all of my cables from here on out. I have no way to measure except to compare one cable to another cable, but at least I'll be able to see any drastic losses.

I guess my 4228 pointed at Walnut Grove works so well because I have just one 65 foot piece of quad shielded RG-6 between the antenna and the antenna switch selector box. The other antenna set up, the 4228/Y7-13 combo, has short coax pieces connecting the antennas to the coupler then a 100 foot run of RG-6 to a distribution amp then four runs of various lengths to the TV sets. I get nowhere near as good results with that set up. I suspected that it was antenna location, but it could be bad coax, connectors, etc. causing loss. One bad cable could mess up the whole shibang.

Larry
SF

Since KTVU, KRON and KPIX are all transmitting from the same antenna with the same 1000 kW of power, I find it interesting that so many people have experienced trouble receiving KPIX, but make no mention of having any trouble with KTVU or KRON. Reports of bad KPIX reception have come from several directions, too... from north in San Rosa to south in Sunnyvale.

I can't imagine what would be causing the problems. If it was multipath it wouldn't be so wide spread. Anyone have any ideas on this? I'm really fascinated by this irregularity.

Larry
SF

I'm not sure multipath can be ruled out for KPIX. I'm receiving KPIX indoors here. It never goes into the less than 10% range, and it shouldn't. It's a very strong signal for uhf from Sutro. It's not DX-ing that I'm receiving it. I've not been experiencing the bad signal problems here. It's been quite strong.

It's interesting that I've had the most success with KGO (prior), KPIX, and KQED. All three are on the top of their respective antennas at Sutro. 66.1 also appears to be at the bottom of one of the Sutro antennas.

Outdoor reception may share something with indoor reception. It's like playing a pachinko machine. That's how signal is actually arriving.

I scanned in KCSM last night.

I will guess "29" is not fully clear. (In some areas) Or something along those lines.
Maybe some type of home device use that UHF frequency.
It seems every channel has "something" I can't find a totally clear one.
There are business band UHF two-way radios with multiple frequency settings.
I bet the problems disappear if they switched (Changed Channels)
Too bad we lost spectrum, then they would be UHF 55 or something.
29 = bad luck ... LOL

For those looking for sporadic E openings for TV DX, there is a pretty cool website that maps current openings in the 50 MHz amateur radio band. Here's the map of North America from the last half hour.



http://www.vhfdx.info/spots/map.php?...=NA&DXC=N&HF=N

Ron

There's a big difference in signal strength between the Sutro Stations here, bigger than what would be expected based on power alone. KQED, KBCW, and KOFY are the strongest stations here. KBCW suffers from analog K45HC and KOFY suffer from adjacent KUVS. KPIX is the strongest of the 3 stations on that antenna. KGO, being on VHF, is in a league by itself, with no correlation to the UHF stations at all. I cannot explain the big differences.

KCNS is not receivable here because of (believe it or not) KMMD-LD.

Chuck

looking at fcc contour map for kmmd, being south of sf you being mt ranch east of sutro towers, you're not seeing kcns is mostly that kmmd being at higher elevation blankets the signal totally. I have the same occurence happening in my dma in the same rf 39 a low power station being much closer to full power station that is 50 miles away. btw whats distance from sutro towers to mt ranch ?

Hi,

~ 110 miles.

But there is a huge mountain in the way, named "The Devil Mountain", "Mt Diablo". About 2,000 feet of rock higher than the LOS.

SHF

As SHF said Sutro is 111 miles from me and Mt. Diablo is in between but KMMD is 132 miles from me and an LP station but yet it is stronger. This has more to do with my location than Mt. Diablo though. I have a very good path to the Salinas direction and a low ridge close in to Mt Sutro. About a year ago I took a UHF antenna and a portable TV over to the close in ridge and the Sutro stations were easily received there even at 111 miles.

Chuck

gee whiz thats getting into 7 ft parabolic dish territory.

Hi,

I just checked my station at 97 miles (KFTY) and it is coming in strong as is KRCB at 75 miles.

It's location, location, location and the weather.

Both are high up and LOS over water.

I do have a CM4228HD with two amps in line and as that does not change as well as the stations, their coming and going are due to the weather.

I just checked the Sounding Analysis and I still cannot understand where the inversion layer is, the main culprit.

http://www.spc.noaa.gov/exper/soundings/11061512_OBS/

SHF

I scanned 32.1 and subs last night. I used the aim of the night prior, and turned the television to a different direction on the turntable. The amped combo is definitely being influenced by nearby objects. Standing near the antenna makes a difference in Sutro uhf reception. Objects other than the television are also difference makers. The rabbit ears are now fully extended, but KGO and KNTV are not scanned in. In a different room away from the television, I would guess both would scan in.

KFTY is my most distant station at 65 miles and is always in here with a solid signal. I have pretty much a clear shot up the bay and across the Napa Valley to Mt. St. Helena. The station doesn't seem to be affected by the various weather conditions, fog and inversions like the stations from Sacramento, 62 miles distant, but behind the 1000 foot East Bay Hills. KRCB, at 42 miles distance, on the other hand, varies a lot... from solid signal to below the cliff-edge, but the hills of Marin and Sonoma county are between us.

Larry
SF

Hi,

Here is a post with a link to the FCC document.

I only read a little bit and saw where it was going.

http://www.avsforum.com/avs-vb/showt...9#post20594419

SHF

When scanning yesterday I found a new channel 14.3 showing a Latino game show, with KDTV 14.1 and KFSF 14.2, but later it disappeared. Maybe they're just experimenting with the additional channel, but keep an eye out for it.

Larry
SF

Anybody else in West San Jose (95129) having problems with KNTV 11? I am getting
signal loss, image breakup etc for the last few days. I never had any problems
with KNTV before.

Thanks

I'm in the city, 3 miles from mt. sutro. I just put a radio shack antenna on my roof.

I tried using tvfool to see what channels we'd pick up... it looked like a lot of channels.

but i'm getting really weird results. i'm picking up KCRA 3.1 and 3.2 from sacramento, but not kntv. and, it appears i'm not picking up anything coming off of mt. sutro., except for kgo 7.1 that kinda makes sense because i can't see the tower from my roof. is there a way to remedy this, or am i out of luck?

It sounds like you may have your antenna aimed incorrectly. Tell us what RS antenna you have....

The omnidirectional 5MS921 Amplified HDTV Antenna.

TV antennas have all - metal elements for the tv UHF - VHF bands.
Small elements for UHF, Medium size elements for the upper VHF band.

Due to the fact your antenna may have some electronics in a plastic disk, It lacks elements for quality reception.

That antenna may be designed for "Boats" due to the compact waterproof circular plastic. Where weird & erratic reception may be tolerated, and changed with boat movement.

The fix is a traditional designed Metal tv antenna. (Indoors or Outdoors)
Without the amplifier.
Tv antennas don't wear out. They just get corroded from the outside.
So a circa 1950 tv antenna ... will still work.

That model # has popped up on a .. "safety alert" from the FCC
.... causing problems to GPS equipment in a 2000 foot radius.

Hey, thanks for the help. I'm going to try a new antenna today if I can find one. anyone know a place in the city where i can get a winegard or the cm 4228?

I'm in West San Jose and haven't noticed any problems.

here's my results from tvfool... not much line of sight, as you can see. will i be able to use an indoor antenna, or do i need to go back up to my roof?

http://www.tvfool.com/?option=com_wr...03d9db1d157acb

You must be blocked by a high hill because the predicted signal strengths are far weaker than I would expect only 3.6 miles from Mt. Sutro. It would be worth trying an outdoor antenna but nobody can say for sure what the results will be. It may turn out that reflections are far stronger than the main signal. Sometimes you can get a useable signal from a reflection and sometimes there's too much multipath.

My guess would be that with an outdoor antenna you will receive some stations but not all of them and the direction may not be at Mt. Sutro.

Chuck

I would first check out what people are using in your neighborhood.
(So you can be sure what size, & model that may work.)
The roofs of houses, bars, restaurants, Etc. > Look at a lower elevation than you, and more blocked spots can also be helpful.
4228 is a good model, for UHF sensitivity but VHF passive.
Winegard is a good model with high directivity.

Low-Tech antenna test.
If you still have those famous tube "Analog" tv. Plug a antenna directly into the UHF jack or CATV VHF UHF Jack.
Set the tv channel to "Air" channel 40 Adjust antenna for a clear (Less ghosts) signal
Make a mental note of the general antenna position location.
That is the antenna position you will want to try a scan-in of your HDTV digital stations.

There are several areas of the city that have terrible over the air reception since they are blocked from direct line of sight to Sutro Tower... places like the Marina, along the waterfront, behind Mt. Davidson and Diamond Heights, etc. KGO-TV cannot get decent OTA reception at their studios on Front Street near the Embarcadero and have to use a remote receiver for it. From your TVFool results it looks like you might be in that same general area.

Reflected signals off of surrounding hills are often stronger than the direct signal, causing terrible multipath problems. Unless you can find a very good reflection that's stable, you chances of getting good reception are pretty hopeless, no matter what antenna you use.

This can also be a problem for receiving the stations that transmit from Mt. San Bruno. A friend is located north of Diamond Heights and cannot receive KNTV, KTSF or KKPX no matter what he uses for an antenna. However, a CM4228 on his roof picks up several of the stations from Sacramento, so they watch NBC programming from KCRA 3, which transmits on channel 35. He says his reception is good 99% of the time.

Good luck!

Larry
SF

How long has KTNC been off the air? I just noticed today. KAZV comes in nicely when KTNC is off.

Chuck

Hi,

It's off now.

I got a good movie capture Thursday and watched it.

I just click on schedule movie and my scheduling program does the rest.

If it is a bad capture, it is just deleted and marked as not seen so it will be captured the next time around.

It takes me a day or so to discover that something is wrong with a station.

No movies scheduled soon for me now.

Live TV, what is that.

SHF

KTNC was on the air last night around midnight when I was tuning around. I just checked, and as of 12:15 am it's still off the air.

KCNS has a signal on 38.3, so that proves they get the KTNC signal from some source other than OTA.

I'm not familiar with KAZV analog. If it's on 14 it must have a heck of an interference problem from KTNC. I have KAZV listed as a proposed digital station for channel 36 from Modesto. Is that correct?

Larry
SF