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m1kzuua8 28-Jan-2011 12:33 AM

Antenna advice for South SJ, CA

I am in this following location:

I plan to chimney-mount the antenna on the rooftop (single-story, assuming 25 feet).

I am mainly trying to get to these stations:

- ABC (high VHF Ch 10): 71 miles @19.
- NBC (high VHF Ch 12): 40 miles @315
- KTLN (UHF Ch 47) : 71 miles @329.

I wonder what antenna is the best choice. These are what I have in mind:

Winegard HD8200U/HD7084P.
AntennaCraft HD1850/HBU55.

For UHF, HD7084P is rated 45 miles while HD8200U is rated 60+ miles. I wonder if HD7084P is good enough?

I wonder if I need an amplifier, though some stations are only 10-15miles from my location.

Also, I wonder if I do need a rotor to get both the UHF stations 71 miles @329 and UHF stations 51 miles @ 51 (KACA-LP in Modesto/Manteca areas, not shown in the report) as they are about 90 apart.


John Candle 28-Jan-2011 11:00 PM

Tv Antennas and Reception
If the building is not wrapped with metal such as but not limited to metal siding or stucko with stucko WIRE. If the building does not have a metal roof. If the walls are not made of poured concrete. If the building does not have foil backed insulation. If the Tv is not in the basement. Then a SIMPLE NON Amplified indoor Tv antenna will get you most of the channels in green. In any event try a simple indoor Tv antenna FIRST before installing a outdoor roof top Tv antenna . . . If you go to a roof top Tv antenna then ANT751 or similar small roof antenna will power 1 or 2 Tv's. . Read and understand this about Real Digital Tv Channels and Virtual Digital Tv Channels and Analog Tv Channels. . Here is how to aim Tv antennas . . Indoor or roof top Tv antenna point at about 330 degree magnetic compass.

GroundUrMast 28-Jan-2011 11:15 PM

Channel 12 and 47 do not require a large antenna. KXTV CH-10 is going to require some effort though. Is there a reason KGO CH-7 won't be an acceptable alternative?

If you absolutely must have KXTV CH-10, I would recommend a two antenna system. The ANT-751 John has suggested is an excellent choice, another would be an Antennacraft HBU-22. (One of those would be your primary antenna system)

A dedicated high band VHF antenna such as the Y10713 would be my suggestion if you are going to explicitly attempt to receive KXTV. Click on the call sign in your TVF report and you will see the cross section of terrain you will be trying to overcome. I can't offer a guaranty of success even if you gang two Y10713 antennas. Amplifiers will be prone to overload from the other strong signals. A commercial quality single channel filter would likely be needed ahead of any amplifier.

John Candle 29-Jan-2011 12:15 AM

Tv Antennas and Reception
I agree with GUM , the odd one out is channel 10. Really not advisable to use a amplifier because it will overload from the strong channels that are real close and yes I agree with the rest of what GUM has to say. If you just have to have 10 it will be some bucks with no guarnaty of success.

m1kzuua8 29-Jan-2011 2:59 AM

This is a 55 years old single-story house with stucco exterior wall all around. The stucco does have metal wires inside.

The cable will be going to a 3/4-way splitter to 3/4 TV outlets.

I've tried a few others and I am using an RCA-ANT121 non-amplified indoor antenna right now placed above and connected directly to the TV in the living room (no splitter right now). This seems to be a good low-cost indoor antenna I've tried so far compared to other low-cost indoor antennas.

The output goes to a Channel Master CM-7000.

I am able to pick up KRON (4), KPIX(5), KQED(9.1), and KTEH (9.2), KNTV(11) for VHF channels.

Does not pick up KTVU (Fox) or KGO (ABC) in the scan.

Being able to pick up the channels in the scan doesn't imply I can view the channels. At most I can see KRON/KPIX (I need to keep switching the knob). I cannot see any VHF channels at all at night. Maybe KRON--with frozen image--sometimes. I need to turn the knob to find the spot where it works.

For UHF, I can pick up KTSF (26.1) KMTP (32), KICU (36) KCNS(38) KSTS (48) and the PBS channels (54.x), ION (65), KFSF (66.1), KDTV (66.2).

Does not pick up KTLN (Ch 47) or KACA-LP in the scan.

Among these UHF channels, I can only view KICU(36)/KSTS(48)/PBS channels (54.x). No signal/picture for all other UHF channels.

I don't know if other indoor antennas would be any better... .

Perhaps the stucco/stucco wires are blocking the signals from going inside the house? If so, then I'd need an outdoor antenna.

GroundUrMast 29-Jan-2011 3:28 AM

May I suggest you look more closely at your TVF report... The column labeled "Real" lists the actual channel that each station broadcasts on. It's easy to get confused by the "Virtual Channel" numbers.

The stucco will likely have wire mesh embedded in it, making it an effective shield, blocking and reflecting the signals you are trying to receive. Your plan to mount an antenna outdoors is well founded. You can expect to receive higher quality signals when you eliminate the reflective and absorbing characteristics of the building it self.

The ANT-751 and the HBU-22 are both designed to receive the real channels available to you.

FWIW: KTVU is on UHF 44, KRON is on UHF 38, KPIX is on UHF 29...

KNTV, KGO and KSBW are the only stations still on real VHF channels that are readily available to you. All the rest have moved to UHF.

m1kzuua8 29-Jan-2011 4:03 AM

Thx so much. I was looking @ the Virtual channel numbers from the Channel Master 7000. Looks like I am not picking up KSBW (NBC) either.

Pretty much all the houses on this street have stucco exterior walls. This explains the confusion I had--as I looked @ the TVFool report and the really poor signal I saw inside.

I wonder if any antenna similar to ANT-751/HBU22 you can recommend that can also pick up FM signals (or should all VHF antennas pick up FM signals?).


OK, I now see FM is 87.5–108 MHz: Band II Radio, so it is in the low-VHF... (correct me if I'm wrong).

GroundUrMast 29-Jan-2011 4:31 AM

The antennas we have been suggesting will offer some FM reception, though they are not optimized for that band. The high VHF band is from 174 to 216 MHz and the FM band is about 88 to 108 MHz. Expect some improvement over an indoor antenna though.

m1kzuua8 29-Jan-2011 4:46 AM

Thx. I am using a 300 ohm indoor antenna for the FM tuner. So looks like the outdoor antenna would definitely be better in some way... .

GroundUrMast 29-Jan-2011 4:57 AM

No harm comparing the two signal sources...

Given that KNTV is also an NBC affiliate, I would think it not worth the effort to go after KSBW, it's much weaker and off in the wrong direction.

m1kzuua8 4-Feb-2011 6:02 PM

1 Attachment(s)
I realized there was an old outdoor antenna mounted on the chimney. The longest leg @ the right end of the antenna was lost (see attached pic).

I realigned the antenna's angle so to point to around 319 (true north).

I got almost every channel I needed,

except KGO (ABC Ch 7, 44.3 miles @ 319, power -46.9dBm) where I got nothing. On the Channel Master CM-7000 it showed 0-20% signal during the day. No pic. Occasionally a picture came in, and soon it disappeared.

KGO is the only VHF channel I want right now (all other channels are on UHF as far as I am concerned).

** There were a few tall trees about a block away from the antenna along the line where the antenna pointed toward (319). They were taller than the antenna. Not sure if they posed any obstruction.

Other channels:
KRON - 44.3 miles @319 signal @ 60-78% (@ night 28-40%, occasional pic freeze).

KTLN - 71 miles @ 329 signal @ 55-78% (@ night 40%). It dropped to 0% from time to time (day or night), causing pic freeze every minute or two.

This was with a direct connection (no splitter).


Going thru' a 3-way splitter (7dB signal drop),

KRON signal dropped from 60-78% to 20-33% (occasional freeze) during day time after the 3-way splitter.
Some (not all) of the channels that got 100% dropped to 50-68% signal during day time after the splitter.
Channels that got about 50-60% (5-6 channels) dropped to 28-30% signal during day time after the splitter.

I will eventually need a 4-way splitter (7 to 7.5dB drop).

I think I'd need a better outdoor antenna than the one I have now to capture the VHF channel KGO (ABC Ch 7) and to compensate for the signal drop for some of the semi-weak signals for some channels.

Would ANT751/HBU22 work better than my existing outdoor antenna and be strong enough to pick up KGO (with 7 - 7.5dB drop going thru' a 4-way splitter)?

GroundUrMast 4-Feb-2011 10:19 PM

Nice antenna... when it had all it's elements. Let's presume it has served well but needs to be retired along with the coax that has been with it in the weather for quite a few years.

You mentioned trees in your path... Let's be conservative and budget 10 dB of loss as a worst case. KTLN CH-47 was on your original priority list. I see a predicted NM of 24 dB. Subtract the path loss due to trees and you're down to 14 dB NM. Add the antenna gain of 7 dB (UHF section of an HBU-22 or HBU-33) and you are up to a 21 dB NM, (more than enough for a line of site path but adequate for an edge path). Now let's say you have a total of 60' of RG-6 between the antenna and the farthest receiver, (conservatively 5 dB of loss) and 8 dB of splitter loss. 21 - 13 = 8 That's not much wiggle room. Still, at the antenna you have a comfortable NM. If you install an HBU-22 aimed at KTLN (315 per your compass) you should easily get a reliable KTLN with no amplifier and no splitter.

If after adding a splitter, KTLN becomes unreliable, you can add a high input preamp such as a Winegard HDP-269. I've looked at the TV signals and see between 60,000 and 65,000 micro-volts of signal in the air (that does not include antenna gain), that will overload most preamplifiers but the HDP-269 is rated for 350,000 micro-volts input. There is still a chance you would need to add an FM trap ahead of the preamp given the strong local FM stations. (Read this to mean, "An amplifier is likely to have problems with overloading." and "Add an amplifier only if you have proven you need it.")

KGO is predicted to be 20 dB better to start with. Still, as insurance you could go with an HBU-33 for it's better VHF gain. Both the HBU-22 and 33 have fairly broad beam widths so they should easily see the stations to the NW all the way down into the yellow section of your report, also expect to see the stronger stations to the north.

After having said all that, I think a new antenna and coax will do you wonders.

John Candle 4-Feb-2011 10:23 PM

Tv Antennas and Reception
Directional Tv antennas have a what known as forward beam width , the bigger and longer the directional is , the higher the gain (signal gethering ability) of the antenna and narrower the forward beam width of the antenna. The compass width of the Tv stations of north , north west is 56 degrees. Large Tv antennas have what is measured as -- half power beam width. Typical half power for Large antennas is 20 , 35 degrees. So what happens is the loss of stations that are out side of the beam width. It's a balancing act , the wider beam width of a smaller antenna with beam widths of 60 , 70 , 80 beam widths and lower gain ----or---- a bigger longer Tv antenna with a beam width of 20 , 35 and higher gain. If compromise can not be found with stations you will like to keep and stations you will give up. Then to receive All the stations that are receivable from Tv stations that have widely spaced directions , you will have to go to a rotor or more the one antenna pointed in different directions , and in this situtaion because of the mix of UHF and VHF Tv in the directions that you will like to receive , more then one antenna can not be combined on to one coax. I am very tired now , I will be back with more info.

m1kzuua8 5-Feb-2011 6:58 AM

Thank you much for the responses--the calculations really helped me get to look at the situation quantitatively.

While the few tall trees caused some signal loss, the most surprise I have is that I am not seeing KGO (my most frustration...) with the current older antenna, while reception from KRON is still decent @ 60-78% signal as reported by CM-7000 (w/o a splitter). KTVU (2.1), KQED (9.1), and KMTP (32.1) all @ same angle/distance, and all had excellent signals (100%). They all had slightly better NM's than KGO, but don't seem to explain the relatively weak signal from KGO.

I am seeing that other people in the neighborhood are experiencing the same weak incoming signal from KGO station:

As you can see from the other reports (locations in other zip codes), KGO's signal is always marginal.

If I can get a large VHF boost to mainly get KGO,

and a medium boost on UHF channels enough to get a stable view of KTLN and a few other semi-weaker stations, for example (with splitter in place)--while not losing the signals from other UHF channels, then I am really happy.

So perhaps I'll lean on looking @ HBU 33 first (I really want to get KGO...). BTW, I suppose, HBU33 is better than Winegard HD 7695P?

John Candle 5-Feb-2011 9:32 AM

Tv Antennas and Reception
KGO real channel 7 / virtual channel 7 it's the same. At 44 NM (dB) is a good strong signal. Of the VHF High Channels 7 thru 13 , channels 7 and 9 have more problems with multipath and other interference , too much multipath makes the digital tuner not read the signal correctly. I have explained multipath over and over. You will find a ton of information about Tv multipath on the internet. If you have not done so , then connect a FM filter to reduce any interfering FM radio multipath and harmonics. Try raising and lowering the antenna , try turning the antenna some to the left and right. KTVJ real channel 4 might not be transmitting now. So you could use a highly directive channel 7 thru 69 antenna , Winegard HD7698P in a effort to get KGO. However you can also use a highly directive HD8200P all channel antenna in case KTVJ 4 goes back on the air. However as I said before you might loose some channels because the antenna is too directive , and this means going to a 2 antenna system to get the lost channels back. If it were me I would cross my fingers and go with the HD8200P. And if it does not work , then will have one antenna of 2 antenna systems I will be connecting. And if it's a 2 antenna system in your situation then the 2 antennas Can Not be connected together on one coax. It must be 2 Separate Antenna systems and splitters and coax with remote control A/B antenna switches at each Tv location.

John Candle 5-Feb-2011 10:00 AM

Tv Antennas and Reception
Many Tv stations have changed from 7 and 9 to a UHF channel or some other channel. However some Tv stations are Obsessed and have gone Crazy they are staying on 7 or 9 no matter what.

GroundUrMast 5-Feb-2011 8:02 PM

1) I'm not confident that either the antenna or coax are serviceable at this point. Consider replacing the coax as the next step. (Standard RG-6 or RG-6/U, no need for quad-shield) That allows you to test with your indoor antenna on the roof if you choose. (you may need a 'barrel' connector.)

2) If you still don't see KGO, I'm with John on the recommendation regarding an FM trap. They are inexpensive and there is a real chance you will see KGO as a result.

There is more than enough signal in the air for a set of non amplified rabbit ears to receive an excellent signal from KGO provided there is minimal interference from FM or multipath.

The old roof top antenna is missing elements that will effect it's VHF performance, it's not a viable standard to use in judging signal conditions.

An HBU-33 is more than enough antenna based on gain, it's directivity may be needed though. By trying the two steps I've suggested, you can hold off spending money on a new antenna until you have more conclusive information to work with.

John Candle 6-Feb-2011 1:17 PM

Tv Antennas and Reception
I agree with GUM , The HBU 33 is a good compromise antenna to try. Many people are having trouble KGO. Some of the Tv stations are Obsessed with staying on 7 and 9 VHF High Tv channels.

m1kzuua8 6-Feb-2011 9:59 PM

Thx much for all the suggestions. I definitely need to pick up the signals from an outdoor antenna due to the stucco walls the house has.

I am going to try moving the antenna a bit off-angle, and also getting an FM trap, to see if I can find enough improvement w/o getting a new outdoor antenna.

If the lost leg is causing the old outdoor antenna not able to pick up KGO and moving the antenna around/adding FM trap don't help, I'll get a replacement antenna as the next step.

The old RG59 coaxial cable goes way up on the existing antenna above the chimney, and replacing that cable requires pulling down the existing antenna -- I might as well get a new outdoor antenna and the coaxial cable at the same time.

Don't know why KGO is still on VHF, or my life would be a lot simpler... .

What'd be some good FM trap(s) to try that don't affect VHF channels much (or any generic FM trap would do)?

Thx... .

GroundUrMast 6-Feb-2011 10:50 PM and

Both are quality 'consumer' grade filters. Both would seriously impact channel 6 if it were a digital station. A Google search indicates that KBKF-LP is an analog station transmitting only audio, you may be able to receive the audio even after some attenuation through the consumer grade FM trap. If KBKF-LP is on your list of 'must have' signals and you can't receive it using the consumer grade FM trap, you may need to shop at Tin Lee for a commercial grade filter.

The cost of the consumer grade choices would make me try them first.

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