Antenna advice needed

[Martyn]

Hi guys,

What antenna would you recommend for my location. I'm in the San Francisco market, but it seems some of the Sacramento stations will be a stronger signal. Seems crazy that KTVU, the local Fox news station, will be weaker than Sacramento. I'm probably thinking of putting up a rotator to help because stuff will be coming from everywhere and will have the antenna up to 15/20 feet.

Thanks in advance.

 

[FaT Air]

Think I'd use something like a Channel Master (CM-5016) MCM Part #30-2655 on the rotor .
You've got UHF, VHF Hi & Low so need an 'all channel' antenna.
Or if the VHF Lo channels are not in your 'must have' list a VHF Hi/UHF antenna would suffice.
(although at this time I can't find a link for one)

 

[Jason S]

The Winegard 7694 (aka HD7694P) covers VHF-Hi and UHF - I have one of these and it did very well when we lived near a 'saturated' market. When we moved, I found it actually performed pretty well in a fringe location with 2-edge and 65+ miles to transmitters.

Others:
The Winegard 7698 also covers VHF-Hi and UHF, larger than the 7694 and suitable for fringe locations.
For VHF Lo/Hi and UHF there is the Winegard 8200, like the 7698, it's big.

http://www.winegard.com/hdtv-outdoor-antennas?q=offair

 

[Mr Tony]

Those 3 VHF low stations are the same actual station....a bunch of religious stations (and K02QX isnt the station anymore...it has an actual call sign)
http://rabbitears.info/market.php?request=station_search&callsign=ktvj

Larry Kenney is in the San Fran area. Hopefully he comes along and can comment on a good setup for that area

 

[Martyn]

Those 3 VHF low stations are the same actual station....a bunch of religious stations

Thanks for all the advice. I get enough religion on Galaxy 19 that I think I can forget the VHF-Low channels and just go for the VHF High and UHF antenna.

This is great advice.

 

[larrykenney]

Hi guys,

What antenna would you recommend for my location. I'm in the San Francisco market, but it seems some of the Sacramento stations will be a stronger signal. Seems crazy that KTVU, the local Fox news station, will be weaker than Sacramento. I'm probably thinking of putting up a rotator to help because stuff will be coming from everywhere and will have the antenna up to 15/20 feet.

Thanks in advance.

Hi Martyn,

Looking at your TVFool report, it appears that you're on the east side of the East Bay hills, maybe Walnut Creek, Concord, Pleasanton, Livermore, etc. Those 2,000 foot "hills" block most of the San Francisco/Oakland/San Jose signals coming from Sutro Tower and Mt. San Bruno for those of you on the other side, so the Sacramento/Stockton stations that transmit from towers near Walnut Grove in the Delta give you stronger signals. The hilly and mountainous terrain around herein be terrible for over-the-air reception. Besides signals being blocked, multipath reflections cause havoc to the main signals, so antennas that have good directivity are needed here.

Besides the Sutro Tower and Mt. San Bruno sites, there are transmitters down in the South Bay in the hills above Fremont at Monument Peak and Mt. Allison, from the top of Mt. Diablo, from Mt. Tamalpais and Novato in Marin County, from Sonoma Mountain near Santa Rosa and Mt. St. Helena north of Napa. You can check the list of stations that I publish for the 100 mile radius from San Francisco to see where the stations are located, along with call signs, programming, and other data: http://www.choisser.com/sfonair.html

The antennas recommended by the others above will work well for you here, but since the stations come from several different directions, you will need a rotor if you want to get all of them. As you'll see from my list, there are stations on just about every channel in this area. Four channels, 15-18, are set aside for mobile radio operation and cannot be used for TV in the Bay Area. Channel 37 is set aside for Astronomical use everywhere.

If you have any questions, feel free to ask me. I'll do my best to answer them.

Larry

 

[Martyn]

Hi Martyn,

Looking at your TVFool report, it appears that you're on the east side of the East Bay hills, maybe Walnut Creek, Concord, Pleasanton, Livermore, etc.

Larry,

Bingo! I'll be living close to downtown Concord.

I realized after posting that I should have looked at what all those channels are rather than just asked about an antenna for them. The VHF-Lo and many of the smaller stations hold little interest for me.

I'm looking for the major networks, so pretty much a system for Sutro Tower and Walnut Grove. I presume from Concord, an antenna aimed at Sutro Tower will also be close enough to pull in any signal from Mt. San Bruno too. I also want KRCB from Sonoma, but that's a strong signal I think.

So, is an antenna on a rotator the best option? Or would it be better to mount a couple of antennae in opposite directions, and a small one for Sonoma?

There would be no moving parts, so less to go wrong, but would the vertical spacing mean one was losing signal because it would be too low? Or would two large antennae plus a small one be an eyesore or just require more weight and engineering on the roof?

If you have any input, I'd love to hear it.

Martyn

 

[larrykenney]

Larry,

Bingo! I'll be living close to downtown Concord.

So, is an antenna on a rotator the best option? Or would it be better to mount a couple of antennae in opposite directions, and a small one for Sonoma?

There would be no moving parts, so less to go wrong, but would the vertical spacing mean one was losing signal because it would be too low? Or would two large antennae plus a small one be an eyesore or just require more weight and engineering on the roof?

If you have any input, I'd love to hear it.

Martyn

With a rotor you can pinpoint the exact direction for each station, picking the point where you get the best signal. You'll find that signals originating from a specific point, like Sutro Tower for example, might not all come in best from the same direction. Due the different frequencies of the stations, reflections differ and you might find a better signal on a station that's a few degrees one way or the other from where you get the best signal from another station coming from the same tower. Generally, though, you usually can find one direction where all the signals are acceptable, but not always. There have been lots of posts from people missing a station or two that they think they should get. With the rotor you have one coax line running to your TV but you have to remember to turn the antenna when you change channels from one area to another.

If you put up fixed antennas, you will have to find the best direction for each direction and lock them in. You might think you can connect all of them together with a combiner, but in most cases you end up with worse reception doing that. The signals from one antenna will cause problems for the others and you end up with problems. You'll need to run three separate coax cables, one from each antenna, to an A-B-C RF switch so that you an select the antenna you want to use.

Three antennas will mean no moving parts, but they will require a strong support system, guyed well, to keep them from being blown around in the wind. One antenna with a rotor will be less of a wind catcher. You mentioned two large antennas plus a small one might be an eyesore. That might be true for some, but for people like me it's more of an art project than an eyesore. (You can take a look at what's on my roof at: http://www.larrykenney.com/tvantennas.html)

As you can see, there are pluses and minuses for each system. You'll have to make a decision as to which system will work best for you. Seeing your TVFool report, I wouldn't guarantee good reception from some of the San Francisco stations. You'll get better signals from the Sacramento/Stockton stations. Looking at the list you'll see a mix of SF/Sac stations, but there are more Sac stations near the top than SF stations. Many of the ones you want from SF are way down the list, below the Marin/Sonoma stations and the South Bay stations, so you'll want the antenna with the best gain if you use a rotor, or if using separate antennas, the best one will have to point toward SF.

Let us know what you decide, and how it all works out for you.

Larry

 

[Martyn]

Let us know what you decide, and how it all works out for you.
Larry

Hi Larry,

It's been a while since we chatted on this. I've moved and finally got the OTA antenna up. The TV situation here is enough to put up with but it's not perfect.

I'm running a Channel Master CM5018 and a Channel Master Titan 2 masthead amplifier. The antenna is about six feet above the roof top of a single-story house. It's on a rotator. I tried it with and without the amp and the amplifier did bring signals up a bit.

My biggest problem is that I can't get reliable reception on San Francisco channels. Some, including KTVU, are missing altogether and others, including KPIX, KQED and KGO are spotty at best. I get KNTV OK, but I believe that's because it's repeated on a local Telemundo station. I'm getting better signals from Sacramento, although I also can't pull in Fox from there.

My experience is also quite different from the TV Fool report (attached), which makes me wonder if I'm dealing with some localized interference, reflections from a building or something else.

Looking at it, KPIX should be the strongest of all the SF stations, but I only managed to get the TV (Sony XBR-X850D) to scan it in yesterday after weeks of trying. To get it, I'm pointing away from SF, which furthers my suspicions after multipath or reflections.

KGO comes in OK usually, but the antenna doesn't have much margin for aiming error. KVIE and KXTV are much easier to receive. The San Jose stations come in very well.

The biggest problem with sourcing TV from Sacramento is the loss of local news, otherwise I'm happy with watching other shows on those stations.

Any ideas for things to try?

I do have another possible clue. Quite early on when I was running the antenna cable across the living room floor and had the amplifier power plug in a different socket, switching on one set of the living room lights caused me to lose all reception. It literally was coming and going with the light switch. The other set of lights had no effect and they are the same fittings and LED bulbs. Now the antenna cable is coming under the house, I'm not seeing this anymore.

Thanks for any help you can provide.

 

[larrykenney]

The only suggestion I can offer is to raise your antenna higher. The East Bay hills appear to be blocking some signals from Sutro or multipath reflections are cancelling the signals. You apparently have a good shot at the South Bay transmitters above Fremont as well as Walnut Grove for Sacramento-Stockton stations. You're lucky you get what you do. Viewers south of you in San Ramone, Alamo, Dublin, etc. get very little, if anything, from Sutro and Mt. San Bruno, and poor reception from Walnut Grove since Mt Diablo is in the way.

Larry

 

[Martyn]

The only suggestion I can offer is to raise your antenna higher. The East Bay hills appear to be blocking some signals from Sutro or multipath reflections are cancelling the signals. You apparently have a good shot at the South Bay transmitters above Fremont as well as Walnut Grove for Sacramento-Stockton stations. You're lucky you get what you do. Viewers south of you in San Ramone, Alamo, Dublin, etc. get very little, if anything, from Sutro and Mt. San Bruno, and poor reception from Walnut Grove since Mt Diablo is in the way.

Larry

Thanks Larry,

I'll take what I can, I guess. I did try raising it before by an additional few feet and didn't notice much of a difference. At about 12 feet it wasn't guyed, so I took it down with the intention of getting a better mast and guy wires should I decide to go for height.

A couple of questions: how localized can multipath and cancelling be? If I take it to the other side of the roof, maybe 5-10 meters away, could I get drastically different results?

Second, I had assumed that TV Fool used quite detailed topographical maps and the FCC transmitter radiation data to come up with a pretty accurate representation of what I should be able to receive. I guess it's still quite variable though?

Martyn

 

[Martyn]

Oh, and one more question: What is channel 8.3? I was broadcasting Daystar the other day, but I have no 8.1 or 8.2 and I don't see it in your lists. My TV isn't displaying a name, callsign or EPG either.

 

[Trip]

A couple of questions: how localized can multipath and cancelling be? If I take it to the other side of the roof, maybe 5-10 meters away, could I get drastically different results?

Second, I had assumed that TV Fool used quite detailed topographical maps and the FCC transmitter radiation data to come up with a pretty accurate representation of what I should be able to receive. I guess it's still quite variable though?

Martyn

Multipath can vary at inches, let alone meters, and often moving an antenna up or down a few inches on a mast can make all the difference, as can relocating a short distance away.

The model does use topographic data, but the model can't compute multipath. That would require knowledge of where buildings are located, and would have a whole ton of calculations of the various reflections off terrain alone.

- Trip

 

[Martyn]

The model does use topographic data, but the model can't compute multipath. That would require knowledge of where buildings are located, and would have a whole ton of calculations of the various reflections off terrain alone.

Thanks Trip. That's good news then. I guess it means the signal is strong enough to reach me, as long as I can find a position where it isn't getting canceled out. Back up onto the roof I go! I'll have to do it early one morning before the sun gets too hot.

 

[larrykenney]

Hey Martyn,

I've been busy and haven't logged in here for a few days, so sorry for the delayed response.

You really don't know where the multipath is coming from. It could be really close, like a tall building in your area, a drain pipe on a neighbors house, or it could be some distance away, like a cliff or hill. As others have said, moving the antenna up higher or lower, or moving it a few feet in some direction could make a significant change in signal strength and quality. You just have to play around. Using a portable TV on the roof is one way to do it, or have someone at the TV, both of you with cell phones, and do some experimenting. All I can say is I hope you can find a good spot.

8.3 is the transmitter frequency for KDTS virtual channel 52.1 broadcasting Daystar programming. It's a low power station with the transmitter located on the north peak of Mt. Diablo. You should have no problem getting that station or KTNC, 42.1 and 42.2, broadcasting from the south peak of Diablo.

Larry