Sacramento, CA - OTA - Page 301

KVOR? Another new station I wasn't aware of

Btw, KTFK has also increased power or will soon be increasing power. I know the new transmitter was being constructed a few weeks ago.

Given all the discussion about beam width, maybe this would be a good place to pose this question. The discussion here has made me consider adding a field to the RabbitEars database, "beam width" or similar.

But how would I define "beam width" exactly? I don't think I've seen a clear definition of what beamwidth is officially. I was thinking about making it the space between the points at which the signal is dropped 10 dB from its peak. So for KOVR, the beam width would be about 5 degrees, while for KQCA it would be about 2.1 degrees. But is this a fair number? Is this the official definition, if there is one? And what about stations like KQCA which drop off at that point, but then recover to -6 dB before falling off again?

In a bit of quick research, I found the "half power beam width" which I assume is a 3 dB drop but I'm not sure how helpful that information would be or if that's what I'm looking for. Is that the official definition? For that, KQCA would be about 1.2 to 1.4 degrees while KOVR would be about 3 degrees.

Thoughts are appreciated.

- Trip

trip: The angle across the main lobe of an antenna pattern between the two directions at which the antenna's sensitivity is half its maximum value at the center of the lobe

From http://www.answers.com/topic/half-po...#ixzz1YeL0nHNk

To the best of my knowledge, unless otherwise specified, beam width means "half power beam width" or 3 dB beam width.

I pulled out my data sheet on my M2 2M beams and the horizontal beam width is specified as 40 degrees. It's clear from the accompanying graphs that they refer to +/- 3 dB.

Ignore any "recovery" in the pattern. Those are side lobes. Sometimes the first null and the first lobe positions are mentioned for antennas but most of the time they are not.

If you add that to your database, you should mention it is vertical beam width.

Chuck

I made my arguments outlining why low gain broadcasting antennas need to be implemented in areas serving hilly and foothill regions in a detailed 4-30-11 posting which you may have missed:

Why Broadcasters Need to Choose Better Suited DTV Transmitting Antennas
04-30-11, 03:45 AM
http://www.avsforum.com/avs-vb/showt...2#post20376102

There is no benefit to a broadcaster using a high gain antenna to save a few bucks on power when the narrow beam of the high gain antenna misses much of its target viewing audience during inversions and inclement atmospheric conditions. My Pollock Pines location is capable of receiving the signals of all Walnut Grove stations plus some Bay Area stations so long as the center of the beam is not bent by refraction beyond an effective elevation angle which provides a signal with sufficient ERP to be viewed. The low gain antennas used by KOVR and KSPX consistantly provide the most reliable UHF reception here. The KCRA/KQCA/KMAX antenna is the highest gain UHF broadcast antenna in the entire state of California, providing the most unreliable signal to foothill regions locally. This is a very large and expensive panel antenna which yields very poor results.

From Trip's website, it seems like KOVR has the highest (or at least equal) gain antenna of the bunch.

KOVR = 15.35 dB

KCRA = 15.04 dB

KQCA = 15.145 dB

KMAX = 15.35 or 14.9 dB

Ron

dr1394:

You're looking at the aux antenna. The main antenna currently doesn't have a gain listed (because construction permits don't contain a TPO value) but for the 760 kW value I have this in my database:

58.6 kW TPO - 1.66 dB line loss + 12.79 dB antenna gain = 760 kW ERP

- Trip

I've left the TV set tuned to KOVR this morning with an eye on the signal strength. Overall I'd say the signal is about 1 to 2 dB stronger now than it used to be here in San Francisco. The other stations are at about their normal levels today, so I think this is a fair judgement, but we'll have to see how things go over the long run.

Larry
SF

12.79 dB is correct.

Interesting thing is that we have a viewer in the city who has been watching KOVR with an indoor antenna for years now. She calls me every time we switch to the backup. I told her she lives in a sweet spot and never to move.

Bob

That's what I'm seeing on 10.2. Although, there is some 16:9 programming on 10.2, and that programming's aspect ratio looks correct.

10-2 Looks like shitt. Upconverting 4x3 to fit 16x9 ?
It is blurry and does not fit in the standard 4x3 tube here.

Looks like a upconverted feature in those cheap DVD players.
That makes a standard movie look HD size ... but a little blurry.
7-2 looks better (If you can get that station) use it.

It's all about location. KOVR tv says "No Signal"
Only 9 and 10 from Walnut Grove come in ... actually quite strong too.

Of all the shows I watch on ABC, Castle is the only one that continues to have audio problems season after season. The problem-

Center channel dialog missing or very low or coming through the rear channels and/or bad echo effect. Worse at the very beginning of the show, sometimes clears up, sometimes gets bad again after commercial break.

Happens on OTA antenna and Comcast. Posted in National master "Castle" thread, no other markets affected. Can KXTV please fix???

Amen to your request. It was particularly bad in a couple of scenes last night. It is not a new problem. I've noticed it during the last three years on many 10:00 PM ABC dramas.. I wonder if someone prematurely flips a switch in preparation for the 11:00 PM news.

Besides Castle I only watch two other ABC shows in that time slot, Revenge and Pan AM. Revenge seemed OK.

I've noticed some more weird conditions here in San Francisco over the past couple of days. Some stations have got stronger while others have gotten weaker than their average signal levels.

KCRA 3, KMAX 31 and KQCA 58 have all been lower than normal by as much as 6 dB. KQCA dropped below the cliff edge yesterday and disappeared. KVIE and KOVR from Walnut Grove and KFTY from Mt. St. Helena were all 5 to 6 dB stronger than normal. In fact, KFTY was putting in a 30 dB signal here from 65 miles away. Not bad for their 20 kW ERP signal! KXTV never seems to change.

That was until this afternoon. Today KCRA, KMAX and KQCA were all higher than normal. KQCA, that was gone yesterday, was putting in a 21 dB signal today, and I was getting a 27 dB SNR signal from KMAX, while both KVIE and KOVR were back pretty much to normal. KFTY was about 4 dB lower than normal and was only coming in at 20 dB today. KXTV didn't change.

I find these radical changes to be quite amusing. It's interesting how some go up while others go down, and, as I've pointed out before, it doesn't seem to be frequency related either.

One other thing... I think KQEH 54 (RF50) has raised their power. They used to always be near the cliff edge here, often dropping out completely. For the past few weeks their signal has been solid and coming in around 20 to 21 dB. Anyone else notice the difference in the KQEH signal?

Larry
SF

Yes, Saturday had unusually bad inversion conditions affecting all Walnut Grove UHF stations at some time. At one point, KOVR barely hung on to a viewable signal here in Pollock Pines even with the power increase. By Sunday morning, conditions had totally reversed. KQED was even viewable for a while. Of course, KCRA/KQCA/KMAX was most affected, as I have previously emphasized, due to its overly high gain, narrow beam broadcast antenna.

Most of the Bay Area stations are using high gain antennas, such as the Dielectric TUM-C5SP-14/60H-2-R-T, a 14 layer panel antenna, only slightly lower gain than the 16 layer KCRA/KQCA/KMAX panel antenna. If Bay Area stations were using lower gain antennas like KOVR's, I would be regularly receiving UHF Bay Area stations here in Pollock Pines instead of just the KGO and KNTV VHF stations. Before the DTV transition, many Bay Area DTV stations were using lower gain antennas and I received Bay Area UHF stations far more frequently even though the antennas were at lower height and power. That all changed when the Sutro Tower antennas were "upgraded" after the transition.

Compared to what I see here, I'm amazed at the relative stability of distant signals at your location.

Over the long term, I've discovered that inversions affect different transmitter sites in different but consistent ways. Walnut Grove signals almost always go down, rarely up. Mt. Sutro seems to go up and down about the same amount, maybe +/- 10 dB. VHF and UHF usually don't track each other. Fremont can have large increases in signals. Decreases are usually brief. KAXT which is normally not receivable, can achieve SNRs in the upper 20's. Salinas stations rarely drop below their nominal levels but 10 dB increases occur almost everyday and last for hours. Good conditions can bring signals up 30 dB. KMUV analog 23 which is typically quite snowy, can become full quieting. These conditions affect VHF and UHF equally.

Chuck

My sister lives in Banta and for some reason I could get stations ranging from San Jose/San Francisco, Fresno, Chico, Salinas and Redding. She lives off Chrisman Rd in Banta.

I had to check Google maps to see where Banta was located. I see that it's east of Tracy, south of I-205, and west of I-5.

What is your sister using for an antenna? She's getting a lot more channels than I would expect from that location.

Larry
SF

has anyone in sf area ever receive the la stations btw of tropo ducting? is not possible, i can get boston 175 miles away when tropo is strong. i even gotten virginia beach 350 miles

I haven't, but keep in mind, in LA and SF, the tv dial is full in both markets.
Seems like every UHF-VHF dial spot is used, in every city.
Example
40 San Francisco, 40 Sacramento, 40 Los Angeles, Etc.

i think most areas also have a channel 7 too. And 9, and so on.

Not sure what dial spot is used the most. 25 ? 40 ?
There are 3 stations flying the (ABC-7) circle 7 banner. I don't think California uses channel 2 and 6 much for digital. Everything else is kinda full.
Chico/Redding, San Francisco, Los Angeles

From Oakland I have received KSBY 6 San Luis Obispo, KCOY 12 Santa Maria, and possibly KEYT 3 Santa Barbara, but I didn't get an ID on that one. This was before the digital transition.

As was pointed out, co-channel issues would make it difficult to pick up LA from the Bay Area. Also the path down the coast range isn't conducive for good tropo openings.

The ducting situation is much different here in the west than it is in most of the east. We have lots of high mountain ranges and those break up ducts. Those multi hundred mile ducts are mostly impossible here.

Even though many of the LA stations are on Mt. Wilson and are in the 6000' foot elevation range, there are higher mountains directly north which shield the signals from getting into a duct that might extend up the San Joaquin valley. If they were on the mountains south of Bakersfield instead of the mountains north of LA, then that would be a different story.

An exception is one lost_mesa pointed out. There's a narrow channel down the Santa Clara valley and then down the Salinas valley to the KSBY transmitter site is that lines up with the East Bay the best. Occasionally there was a duct that permitted reception of KSBY. KCOY was farther south and more difficult to receive.

Although I never heard of anyone receiving KEYT on 3 in the Bay Area, I have experienced several ducts down that same path when I lived there and was able to work into a Santa Barbara 2M repeater on 147 MHz that was atop the mountains north of Santa Barbara.

The reason I get such tremendous signals from the Salinas TV stations at my current location is I think there is only one ridge to cross between here and Fremont Peak or Mt. Toro. It's almost line of sight but not quite. Any duct that forms works quite effectively on this path.

I'm only 82 miles from the main Reno transmitter site but I can't receive any of those stations because the path crosses the Sierra Nevada. Ducts can't form across those mountains.

Chuck

In the analog days, at my parents' house in Davis where they have a roof antenna with a rotor, sometimes stations from all over the place would come in on channels 2 and 4. I saw stations from Kansas, Colorado and some from Canada and Mexico. Usually they would all come in at the same time- if you kept it on one channel, one station would come in, fade out and then a different one would start coming in. Channel 3 would have obvious interference on it too, but KCRA's signal was too strong to be completely overtaken.

On UHF, stations from Fresno and Bakersfield sometimes came in. Never got anything from Los Angeles.

Yep, mountains can be a curse, they break up ducts and as you point out, can completely block reception on some paths. I never saw a hint of any of the UHF stations from the San Joaquin valley with my 7 ft. UHF dish antenna.

But mountains can also be a blessing. From near the top of the Oakland hills I did have a gap toward the Sacramento valley. KOLO 8 Reno from Mt Rose was always there, no tropo needed. At 160 miles it was pretty weak, but by carefully nulling out KSBW 8 Salinas, it was sort of watchable.

KHSL 12 Chico was also usually there. On very rare occasions, when 7 or 9 in SF where off the air, I could pick up a very weak signal from the Redding stations. This was in the 60s and 70s, I no longer live there.

I had 10 element single channel yagis for channels 2, 6, 8 and 12, along with the 7 ft dish and assorted home brew preamps. The TV I.F. was narrowed down to about 2 MHz to increase the SNR, but made for some pretty low res pictures.

Until yesterday, I was getting KFTY's programming per their published schedule. Now all I get on 50.1 is soccer! Any suggestions?

KEMO (formerly KFTY) is now the Azteca America afffiliate for San Francisco.

- Trip

Wow- KEMO was channel 20's original call letters in the 60s and early 70s. It was a real bargain-basement UHF station then from what most remember about it- and after that it became a Spanish station before being bought by Jim Gabbert and going back to independent!

What happened? Bad time to be off the air with the 49ers game on in 1.5 hours if you depend on OTA.

Chuck

Edit: Back on the for the game but at 1/4 power or maybe less.

Edit 2: Now they're have all kinds of bit errors even though the signal is SNR 25 dB. I switched to KCBA. No problems there.