San Francisco, CA - OTA - Page 307

Would this be a good antenna for me to use in Concord... LAVA HD2605 Ultra G3 or would this be better, Winegard HD8200U Heavy Duty Platinum VHF/UHF/FM HDTV Antenna? I was planning on installing it on a mast above our 2 story house ( the driveway is 120 feet above sea level in Concord).

I really want to cut the cord to cable and retain my local HDTV.
tia,
Ron
Edited by ellisr63 - 3/5/13 at 6:34pm

You probably need the Winegard HD7698P in Concord. The HD8200U has low VHF elements which are not required.

But..... Can you post your TVFool results? Concord can be a tough place for OTA and it could be that no antenna is going to do it depending on where you are. I have a friend on a hill in Walnut Creek that receives Sacramento easily but SF is impossible.

Chuck

Here are the results...
http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d1ddabf6ca55a4b

Your tvfool reception report shows you are around 35 miles to the Sacramento tv towers, and 30 miles to the San Francisco tv tower.
But miles are not the deciding factor..... You have one blocked path to sacramento, and two blocked path(s) to San Francisco
On paper, the Sacramento stations would have less tv reception issues, then the San francisco ones.
You have several options......
With one antenna, .... lock it down pointed to the Sacramento tv towers (Hwy 5, at Walnut Grove) with NO UHF-tv San Francisco stations.
With one antenna, .... purchase an antenna rotor to select "Spin" the antenna between the two tv market stations.
With two antennas, ... two cables,... and a high isolation A/B switch,.... click between the two tv markets. Pointed 180 degrees of each other.
A large antenna like the 7698 is needed. You need the largest most directional model that each antenna manufacturer makes.

You may notice some weird reception like 6-KVIE, 7-KGO, and 10-KXTV come in on one antenna without rotation.
But the UHF stations are more directional and will not work like that. And LOS is more important with UHF tv stations.
You will get tv reception, but nobody knows what stations will be "easy" and what stations will be "hard" to get.
So that location is a mixed bag.
No guarantee of all stations in both tv markets.

Which one of these 2 would be best?
http://www.winegard.com/kbase/upload/HD7698P.pdf

http://www.winegard.com/kbase/upload/HD8200U.pdf

You have no use for an all-channel antenna such as the 8200. That extra aluminum used in the low-V elements would best be used for something useful, like beer cans .

If you pick the 7698 and you'd like to access both potentially available markets, you'll need several additional things: A very sturdy mount, a heavy duty rotor (the under $100 ones won't cut it), and a medium gain pre-amp that can tolerate high inputs without overloading. The CPA19 is the best choice if you can still find it, the HDP269 is a fair second choice.

Here's my 2 cents to add to the good advice you've already received.

Go with the HD7698P. It's hard to say from your TVFool report which stations you will receive and which ones you won't. Hopefully your antenna won't be looking through trees or buildings. That would reduce your chances of reception and would require a higher antenna mounting.

I think you'd be okay with a medium gain preamp like the Winegard AP-8700 since you have only two strong stations (KTNC and KRCB) and those will be off the sides of the antenna when pointed at SF or Walnut Grove. They should not overload the preamp.

Since SF and Walnut Grove are essentially opposite in directions, you need to be able to point the antenna in each direction if you want to receive those stations. Maybe you'd be happy with just the Sacramento stations? I'd suggest getting the antenna, put it up and manually rotate it to see what you can receive. If you have good results in both directions then you need two antennas and an A/B switch or one antenna and a rotor.

I do not recommend the inexpensive TV antenna rotors. I recommend one of the least expensive ham rotors for problem free operation and long life. If you get that far come back and we'll discuss that issue separately.

Chuck

I just ordered the preamp and antenna... Any suggestions as to a rotor? If I end up running 2 antennaes do I need 2 masts or can they be stacked?

You can stack two on one mast. I would suggest about 6' apart which should be enough VHF and plenty for UHF.

Let me tell you why I don't recommend the TV antenna rotors in the <$150 range. They have only 3 wires which are used to run the motor only. There is no positional indicator in the rotor so the rotor and the control box get out of sync if the rotor doesn't turn at exactly the expected speed. This happens all the time and you're constantly re-syncing the two. They also don't have any real bearings so any corrosion can cause the rotor to slow or stop altogether. It's common for them to become stuck if you don't turn them frequently. They can be fixed by taking them down and cleaning them up but do you want to do that?

I recommend the Yaesu G-450A. This about the least expensive ham rotor. You'll see why I recommended trying the antenna before buying a rotor.

http://www.aesham.com/rotors/rotor-cable/yaesu-g-450a/

You need to add a bottom bracket to mount the rotor on a mast:

http://www.aesham.com/rotors/rotor-cable/yaesu-gc-038/

You also need rotor cable:

http://www.aesham.com/rotors/rotor-cable/davis-rf-rch/

You cannot use a 1 1/4" mast on this rotor. It takes a 1.5" - 2.5" mast. You can get aluminum tubing here if you can't find anything local.

http://www.dxengineering.com/search/department/rigid-tubing/part-type/aluminum-tubing/product-line/dx-engineering-aluminum-tubing?autoview=SKU

Chuck

Yikes... I see what you mean about the rotor. I could buy both antennas for the price of the rotor and still have cash left. If I was to do a chimney mount for the antenna... I was thinking 10' above the chimney but if I have to run 2 antennas then would it be ok to run one 5' above the chimney and the other 6' above that?

There are stations in other directions too that you might be interested in.



Yes, especially if you don't use the fireplace.

Chuck

Everyone is talking about the perfect dream antenna system. So before you go on a shopping spree, start with one antenna, so you can see for yourself what type of system works for you.
And BTW, I would not do any scanning first. Just manual entrys. In the antenna mode of your tuner.
So for San Francisco tune 44 & 45 (Its best to use the weakest and upper UHF stations for tuning)
Sacramento use 48 & 26

As far as placement goes, It goes where it works. So forget 10 feet here, and 6 feet there. You are blocked from direct LOS reception, so general antenna install does not apply. You have very low signal margins, especially for KTVU & KBCW
I think 100 feet of forward clear , works better with UHF Yagi antennas (Nothing in front of the UHF antenna for about 100 feet) I've seen signal drop off just walking in front of it.
Tune one channel, and with a sharpie marking pen write the best elevation and aim on the pole. (If you do not have a tv outdoors, you will need 2 people)
And allow 5 seconds for buffering with every antenna adjustment. Then scan for ALL channels on the same tower.

Erase the scan by pulling the coax plug out and scan with no cable attached. To zero out memory.
Turn antenna to sacramento, and start the process over.
Some people will find antenna tuning & scanning stressful. But it is, what it is.

After your done, hopefully your tv has an update scan feature (Because you will need to use it.)
Scan Sacramento, then switch to San Francisco, now do an update scan for those channels, and so on.
good luck...

6 foot spacing between antennas is a bit more than 1 wavelength on channel 7 so that should minimize interaction between two antennas if he should end up with that configuration. You don't want them too close together as the patterns can get messed up, especially when the elements are parallel to each other as they would be with one pointed to Walnut Grove and one to SF. Otherwise they can go anywhere.

Chuck
Edited by Calaveras - 3/7/13 at 1:37pm

True, .... all things considered ... i don't think his VHF reception is going to be the issue. It's his strongest signals.
I haven't found a location here in the East Bay where Channel 7 doesn't come in. It's very strong.
UHF from San Francisco is going to be real tough. Multipath will determine where the antenna goes.

Here KVIE & KXTV come in with the antenna 2 feet above the roof (On a steel plumbing ventpipe) Elevation does not make a big impact here. It does get 2% better every 4 feet on the mast (up or down.) So I locked it on the down peak.
And also I'm in a blocked location (Dublin Hills, and Mt. Diablo) from Walnut Grove.
It is a direct signal with no dropouts.
UHF from Walnut Grove is a big zero. I've never seen it. It never comes in. (NM on tvfool for Sacramento UHF starts at -7db) and drops from there.
KVIE 45% signal, KXTV 25% signal
In the analog days, all VHF from Sacramento came in. But it was very fluttery. The moving ghosts.
Not bad for being walking distance to Mission Boulevard in Hayward
That antenna also piggybacks sideways KGO & KNTV so only one antenna is needed. Those channels only dropout if an aircraft flys by. And only for a second.

His issues will most likely be the UHF channels.

Will I be able to use the same antenna for HD radio or does that require another antenna?

One never knows how things will play out. Here KVIE is the strongest VHF station followed closely by KXTV tied with KSBW. But KXTV suffers the worst from multipath of all the Walnut Grove stations and KSBW has no detectable multipath. I'm less concerned about his VHF signal strength and more concerned about F/B ratio being degraded if the antennas are too close together. Could be no issue at all but better safe than sorry.

Chuck

The HD7698P does not have elements for FM. It might work if the stations you want are very strong but the preamp has a FM trap which you'd be better off to leave switched in and use a different antenna for FM. I have an FM antenna combined on the transmission line down to the house and my TV doesn't like being blasted by all those FM stations. I use a diplexer to divert those to the FM receiver and keep them away from the TV.

Chuck

Any tv antenna that covers Low-VHF will also work on FM
FM Radio is next to tv channel 6 (No full power network tv stations in this area are using the low-vhf band) so as suggested, .... the 8200 antenna is overkill for tv.

# 7698 No, but Antennas such as Winegard 8200 and other Large element models that cover FM do.

For AM HD Radio, No tv antenna will work

Most FM radio from San Francisco have boosters / repeaters on or near Mt. Diablo for Inland East Bay FM service.
I am not sure if the repeaters carry a full stereo / HD / and data service signal. Or are just some type of mono signal for blocked areas.
Call the station ...

101.7 is repeated here in Hayward at 100 watts from cal state east bay hayward. The main tower is over the hill and blocked here.
But I don't have a HD radio.

HD Radio & HDTV are not the same thing. Tv is totally digital now. Radio is not.
Edited by 888CALLFCC - 3/7/13 at 7:54pm

I know HD radio is not the same... I have HD radio in my car and my av receiver has it also so I thought it would be nice if I could pull in a stronger signal for the HD radio too. I know with my car it uses the stock antenna, but I have no idea if a rooftop antenna will pull in HD radio. If I recall properly the old rooftop antennas used to pull in FM.

You are correct. And keep in mind OTA tv then used channels 2 through 83. Now it's 2 through 51 (Thank you, cell phone companies) enjoy the spectrum that used to be free.
In the bay area, it's 7 through 51 .... for full power network tv

In basic terms. The lower the channel = The bigger the metal antenna element.
So channel 2 has big (over 5 foot) metal elements.
and channel 51 has teeny elements (a few inches)

If you see antennas that have elements in the 4.78 feet range (57.3) inches, It covers FM (Next to channel 6)

The winegard model # HD 7698 has antenna elements around 2 feet. Metal elements cut for channel(s) 7 and above.
They are made exactly for tv markets like the bay area.

The 7698 antenna dropped channels 2 through 6 including FM, so it could be made a smaller size. (And less metal cost)
And even smaller antennas are made for just channels 14 through 51
Home stereos used to include a 5 foot roll of twin-lead dipole wire to connect to the fm jack.
Some cars embed 5 feet of copper wire next to the rear window defrost wires.

A lot of posts in this forum complain about channel 7 reception.
Well guess what ? .... They are using the wrong size antenna.

Interesting conversation regarding antenna, amps and rotors. Here are my comments and suggestions for Ellisr63.

Rotor: I initially used a cheap Channel Master rotor here in San Francisco. Worked great until blustery winds came up in mid-July and snapped something inside the rotor. It just couldn't handle the stress of the antenna being buffeted by the gusts. So if you do go with a rotor, be sure to follow Chuck's suggestion and spend the money for a good one.

Rotor vs two antennas: I have a rotor... a new, much better one, thank you... but it's quite time consuming to have to keep swinging the antenna around when going from one direction to another. If the antenna is pointed toward Walnut Grove, I don't get the Mt. San Bruno or South and North Bay stations. If pointed toward the South Bay I don't get Walnut Grove, Mt. Diablo or the North Bay, and so on. Since stations come from several different directions, a rotor is necessary here. But maybe two antennas would work for you, and you'd avoid the problems with a rotor. I'd try your new antenna, first pointed toward SF to see what you get, then pointed toward Walnut Grove, using 888callfcc's suggested method. See if you get the South Bay stations, see if you need to move the antenna to get the Mt. San Bruno stations vs Sutro Tower stations. Play around with the antenna to see if two antennas would work. If not, then invest in the rotor.

I find that just a few degrees one way or the other can make the difference between a good signal or no signal from the more distant stations, so if you don't get some of the stations you think you should, try turning the antenna a little one way or the other.

Good luck... I hope you have a lot of success. Let us know how things work out.

Larry
SF
Edited by Larry Kenney - 3/8/13 at 12:43am

I find your reception of Walnut Grove stations to be quite interesting where you get the VHF stations, but not the UHFs. Here I get KMAX 31 (RF 21) and KQCA 58 (RF 46) very consistently, usually 21 to 25 dB SNR, but all of the other stations vary a lot. KXTV 10 is the next best, then KVIE 6 (RF9), followed by KOVR 13 (RF25), but all of them will often drop below the cliff edge. Signals on these stations can vary as much as 10 dB here, but KXTV is normally around 19 dB, KVIE at 18 dB and KOVR about 16 dB. I used to get KCRA 3 (RF 35) all the time, like KMAX and KQCA, but when the KGO translator came on the air, KCRA disappeared. I only get it now when conditions are super good. I've never received KGO on 35, but I do get KAXT 1 (RF 42) most of the time. Shows how conditions are so different from one location to another.

For the three North Bay stations, KTLN 68 (RF 47) is usually about 30 db and KEMO 50 (RF 32) varies from 23 to 28 dB. KRCB, on the other hand, is very unpredictable. Sometimes I get it fine, other times it's gone. It can vary in strength from below the cliff edge at 13 dB to as high as 26 dB.

RF is such an interesting subject!

Larry
SF
Edited by Larry Kenney - 3/9/13 at 12:42am

I've had many months now to evaluate and get a feeling for reception with my optimized antennas. The VHF/UHF antennas have nearly lossless baluns and combiners and the preamps are as good as I can get with adequate gain for low system noise noise figure. The UHF antennas are at 71' and the VHF antennas are at 66'.

It's quite clear that VHF is far better for distance than UHF with outdoor antennas.

VHF Results

KGO on 7 - 90% reception, nominal SNR 18-21 dB. Sometimes gets up to 28 dB. Signal becomes unstable and subject to airplane multipath below 18 dB with intermittent dropouts.
KSBW on 8 - 100% reception, a VHF rock.
KVIE on 9 - 100% reception, only Walnut Grove station that never drops out.
KXTV on 10 - 99% reception, SNR only about 20 dB due to multipath but is pretty stable for such a low SNR.
KNSO on 11 - 90% reception, only Fresno station I can receive. SNR 18 - 20 dB but can get higher or drop out at times.
KNTV on 12 - 50% reception. Very unstable signal except when the ducting is in. It can be perfect for a few minutes and then disappear. Very ugly spectrum analyzer display.
KCBA on 13 - Essentially 100% reception which is remarkable considering it is 26 dB weaker than KSBW with only 55 watts ERP in my direction and 115 miles away.

Misc UHF Results

Walnut Grove - All stations run 22 to 28 dB SNR and any can drop out under adverse temperature inversions. Overall 99% reception.
Sutro Tower - KQED, KMTP and KBCW are the only regulars but they are not reliable enough to be able to count on. Maybe 80% reception and stable when they're in. UHF at 110 miles is too far when the transmitters are so low.
Monument Peak Fremont - KSTS (28dB) and KDTV (24dB) are close to 100%. KICU (22dB) is 98%. KQEH (20dB) is about 80%. KAXT, a station that should be impossible here, comes in whenever there is ducting. Using KSTS as a reference, KAXT has 36 watts ERP. I see it on a regular but intermittent basis.
KEMO - 100% except when there is strong ducting to co-channel KION and then KEMO is overridden. SNR is usually 25 - 27 dB which is amazing for 125 miles and only about 5 KW ERP. Transmitter height is everything.
Fremont Peak/Mt. Toro - Most stations have directional antennas with a side lobe in my direction so the ERP is low. KSTS on 31 is almost 100%. KMMD-LD and KION are on the same tower with similar ERP and nearly identical signal strengths here. KMMD is nearly 100% while KION is <50% because of co-channel interference from KEMO.

After monitoring the many stations for a long time now there are few surprises. Nominal conditions with signals in a narrow range prevail. Periods with exceptionally good or poor conditions tend to repeat producing similarly enhanced and degraded signals.

Chuck

Interesting conversation! (I'm a newbie, maybe easily impressed....)

In Kensington I'm high enough to see Sutro line of sight, and maybe not anything in South Bay. Just put in an indoor antenna at my new location, after previous house having had a monster Archer in the attic.

Using the Radio Shack 15-246 with the VHS arms and the UHF coil-in-a-triangle mode, with its "tuning" knob at 11 to 5 o'clock, set top. With a lot of shuffling back from the antenna to see what real reception was like, I have ended up getting quite a few channels nicely, and channel 7 not so bad, generally registering >80% and fully watchable. KNTV is fine, I guess they moved up to San Bruno? As the gear here isn't mine to change other than the antenna, we're still using a digital converter (I'm not in front of it, I want to say Channel Master) onto one of the last-gen of Mitsubishi CRT's, so _output_ is 480i but a few channels are sourced at 1080i.

Interestingly I had thought with an indoor unit, 16 miles from Sutro, that the old antennae (big ears plus a UHF bowtie) didn't work / had low digital percentage would be solved by an amplified antenna. The Shack's guy, though, convinced me to try this less expensive one first!
Thanks for any feedback,
pault1

I bought a RS 15-246 15 or 20 years ago because I thought it would be better than rabbit ears for UHF reception here. It wasn't. I'm happy that it is working for you. If you have problems with KGO, you should consider moving the antenna to a different aim/location/height. What's best for UHF signals isn't necessarily what's best for VHF ones. If VHF signals are good, the location will probably be okay for UHF ones.

It's nice to read that indoor reception is real. Thanks.

I have to agree that there are few surprises these days. I can pretty well predict what reception levels will be like on most days and know what stations I'll receive and which ones I will not receive. I long for the days with heightened conditions and stronger signals so that I can possibly find a new station, but those seem to be really rare lately.

Here, VHF for the distant stations, is not really better than UHF. As pointed out in my post above, UHF KMAX and KQCA from Walnut Grove are very reliable and I get 99% reception, while VHF KVIE and KXTV are not as strong and not as reliable. (This is using a 10 element VHF yagi vs a UHF 4228.) I don't have any other VHF stations outside of the local area to use for further comparison, but UHF beats VHF in this case.

I found your signal strengths for the South Bay Monument Peak/Mt. Allison stations to be quite interesting, as they don't agree with what I get. I'm 35-36 miles from those transmitters with a local hill between us. Here KICU is definitely the strongest, followed by KDTV a couple of dB weaker, then KSTS a dB or two down, then KQEH another dB or two down, but all with 100% reception. KQEH used to drop out occasionally, but since they raised their power a while back they've been solid. I get KAXT about 90% of the time. It varies from 13 to 19 dB SNR.

I'm still amazed at the solid strong signals you get from the Salinas/Monterey area!

Larry
SF

I was looking at the new KQEH antenna pattern and it's unusual. In the direction of Sunnyvale/Mountain View they have only 2.7 KW ERP! That's less power than KAXT or the KGO and KTVU repeaters. For some parts of the south bay KQEH is a low power station. But that entire area is LOS so they don't need much power. In your direction they have close to full power: 310 W ERP. In my direction they have 77 KW ERP which is the highest of all the Monument stations but they are the weakest. KSTS & KDTV have only about 5 KW ERP but they are the strongest. I guess they're in a slightly more favorable location for me. My TVFool report says those stations should be impossible predicting noise margins of -28 and -27 dB respectively. OTOH, TVFool predicts KICU at -14 dB which is just about right when taking into account antenna gain and improved noise figure.

Chuck

Don't get confused by KQEH. They're operating an antenna that looks like this:

http://www.rabbitears.info/pattern.php?request=ant_pat&ant_id=85202&rotation=0&erp=310

FCC Citation: https://licensing.fcc.gov/cdbs/CDBS_Attachment/getattachment.jsp?appn=101429731&qnum=5340&copynum=1&exhcnum=1

But it's down-tilted by 1 degree toward 225 degrees true. The FCC doesn't require stations to register the actual antenna pattern, but only a horizontal slice of the 3-dimensional antenna pattern. Since there's a null at 1 degree above the horizon (when the antenna is level, see the FCC citation), then it will appear as a null on the horizontal slice since that 1 degree above the horizon now appears to be aimed directly at the horizon due to the down-tilt.

Also, the antenna has 1 degree of electrical down-tilt. So this means that you're seeing 310 kW ERP at 2 degrees below horizontal in that direction. Let's do some math.

According to FCC records, KQEH operates from 888.2 meters above sea level. According to Wikipedia, Sunnyvale is at 39 meters above sea level. This is a height differential of 849.2 meters, or 0.8492 km. Sunnyvale is approximately 20 km from the KQEH tower. So this means the angle of KQEH's antenna with respect to Sunnyvale is:

arctan(.8492/20) = 2.43 degrees

So that means that to see Sunnyvale from the KQEH tower, you have to be looking 2.43 degrees BELOW horizontal. Given how narrow the peninsula is, you can see it doesn't really make a whole lot of sense to radiate a bunch of power out toward the horizon, or even 1 degree below the horizon:

.8882/tan(1 degree) = 50 km

It's looking at the beach on the far side of the mountains by that point, and any further out and you're giving great signal to the fish.

So in actuality, the people on the ground in Sunnyvale are not seeing 2.7 kW, but, using the vertical pattern in my FCC citation above, it looks like 1.43 below the untilted horizontal plane is a field value of about .94, and in that compass direction, the antenna has a field value of .947, so:

310*.94*.94*.947*.947 = 245.65 kW

Hopefully that made sense.

- Trip
Edited by Trip in VA - 3/9/13 at 8:12am

It's not as good as you might think. There are 11 digital stations I can think of down there with high elevation antennas but I can receive only 4 most of the time. KSBW is the only station running maximum legal power with an omni antenna so of course it is far and away the strongest. KSMS is the only 1 MW station in that market but their antenna is directional with just 35 KW in my direction. KCBA is the only other station running maximum power but with a directional antenna. KQET and KION are "full power" stations but run only 81KW and 46KW with 1.6KW and 18 KW in my direction. It's good KQET doesn't have a lot of power in this direction because they'd interfere with KOVR. Too bad they're on channel 24. All the other stations are LP with various small amounts of power aimed here and some co-channel with Walnut Grove. KMMD-LD is the highest with 15 KW aimed here and it's close to 100% reception.

I wish KION was running 500 KW so I'd have a back-up CBS station.

The only reason I see those LP stations from time to time is the strong ducting that commonly develops across the valley during times with any strong high pressure over head.

Chuck