Help adjusting antenna

[canman94]

I have been battling a while with different antenna setups and here is what I finally went with (I realize that not everyone will agree with my choice of antenna):

My antennaweb.org stats:
red - uhf WVBT 43 FOX VIRGINIA BEACH VA 257° 4.3 43
red - uhf WVBT-DT 43.1 FOX VIRGINIA BEACH VA 257° 4.3 29
red - vhf WVEC 13 ABC HAMPTON VA 229° 2.5 13
red - uhf WVEC-DT 13.1 ABC HAMPTON VA 229° 2.5 41
red - uhf WPXV 49 PAX NORFOLK VA 245° 4.3 49
red - uhf WPXV-DT 49.1 PAX NORFOLK VA 245° 4.3 46
red - uhf WTVZ 33 WB NORFOLK VA 245° 4.3 33
red - uhf WTVZ-DT 33.1 WB NORFOLK VA 245° 4.3 38
red - uhf WHRO 15 PBS HAMPTON-NORFOLK VA 245° 4.3 15
red - uhf WHRO-DT 15.1 PBS HAMPTON-NORFOLK VA 245° 4.3 16
red - uhf WGNT 27 UPN PORTSMOUTH VA 220° 2.7 27
red - uhf WGNT-DT 27.1 UPN PORTSMOUTH VA 220° 2.7 50
red - vhf WAVY 10 NBC PORTSMOUTH VA 257° 4.3 10
red - uhf WAVY-DT 10.1 NBC PORTSMOUTH VA 257° 4.3 31
red - vhf WTKR 3 CBS NORFOLK VA 226° 2.5 3
red - uhf WTKR-DT 3.1 CBS NORFOLK VA 245° 4.3 40

There are other channels but these are the ones I am most concerned with. I have a SquareShooter 2000. I connected the antenna directly to my reciever - it is not diplexed. I am using the SS2000 amp inside. The antenna is mounted with my DTV dish (using the adapter mounter). The antenna is outside on my roof (2 story house). I do have a tree line about 50 yds away that is a little higher than my house in the direction of the signals. I have finished my antenna setup and right now have just eyeballed everything. I am relatively sure that the antenna is 230 deg (probably +- 20 deg) using visual references. I have adjusted the tilt and angle to about the same as my DTV dish (yes, I realize they are different, but it was a starting point).

My problem is I do not get nearly the signal strength I expected and I have trouble with CBS digital (uhf WTKR-DT 3.1 CBS NORFOLK VA 245° 4.3 40) even though it is very close to FOX digital which comes in fine. CBS will not stay in and runs about 10-30% signal strength. Even my best stations like FOX run at about 45% with some spikes up to 70%. I really expected to get these stations stronger.

I have not done a lot of adjusting to see if signal strength will improve, but are there any fundamental concepts I should look at other than trying to focus more on the exact direction to point to? Any help would be appreciated. I really thought that I would be able to lock up all the major stations easily since they are all close (<5 miles) and all within about 30 deg. Thanks.

[LeeS]

I checked www.winegard.com for the specs. UHF range (ch 14-69) for the digitals is up to 50 miles. That fits into the area of a good medium range antenna, most likely with a preamp.

If you looked at the polar patterns you saw that the antenna is directional, you need to be able to rotate the antenna.

One thing that is confusing is the ranges reported by AntennaWeb, those transmitters are very close. What is strange about your location?

That is a good antenna, but like you figured, not my first choice.

Lee

[Ratman]

Lose the amp... you're probably overdriving the receiver.

You don't need to tilt. Point the antenna at approx. 235 degrees.

[LeeS]

Lose the amp... you're probably overdriving the receiver.
I agree, still wondering why AntennaWeb is recommending a RED (medium range) antenna. Strange.....

Lee

[canman94]

Thanks for the help. Here are some answers:

Not sure what is weird about my area. I also thought it was unusual that some many stations were so close (essentially the same spot.) I am not close to any TV stations, but there is a spot that is close by that has a lot of large satellite dishes and other antennas (possibly transmitters?). I do not know what it is. Is it some sort of relay station? Just by eyeballing it is pretty close to the directions given by antennaweb - it is approximately 4 miles away direction about 200 deg. Anyone know of any relay stations like this? How else could all of the major networks be so close together?

As for why antennaweb says red, I have not been able to figure this out either. On antennaweb.org, I do say "yes" that there are trees in my path. Answering "no" here instead changes the recommendation from red to yellow. Not sure if my tree line really affects reception, but I thought I would answer conservatively since the trees do kind of meet what antennaweb asks about.

I did know that he SS2000 is directional, and my inital setup is relatively close to the right direction, but I will verify it with a compass. So I will point it in the best direction (about 235 deg) and see what happens. What about angle and tilt? I know Ratman says no tilt which I can easily fix (currently about 20 deg tilt), but what about angle (currently about 30 deg angle).

As for the pre-amp, I have thought about removing it and will try that. If it is overdriven will that give the low signal strength? Someone previously did mention perhaps having to intentionally offset the antenna to lower the signal, but I am not sure this would be right.

[Ratman]

The front of the antenna should be pointing at the horizon in the same direction of the towers (~235 degrees).

Fix this first.

If there is still a reception problem. Try removing the amplifier.

The meters in the receivers are in reality showing 'signal to noise ratio' not actual 'signal strength'.

Over amplifying increases noise as well as signal.
Over amplified 'good' signals produces the same effect. Think of it as someone that screams in your ear!

[hd4me2]

The front of the antenna should be pointing at the horizon in the same direction of the towers (~235 degrees).

Fix this first.

If there is still a reception problem. Try removing the amplifier.

The meters in the receivers are in reality showing 'signal to noise ratio' not actual 'signal strength'.

Over amplifying increases noise as well as signal.
Over amplified 'good' signals produces the same effect. Think of it as someone that screams in your ear!

Meters in receivers do not show signal to noise ratios. That would mean when you add a pre-amp and the value increases that the s/n got better? We all know that s/n gets worse when you amplify by the NF amount.

[Ratman]

Believe what you like. We all know... some 'think' they know.

[hd4me2]

Believe what you like. We all know... some 'think' they know.

It's not s/n that the receiver displays as signal strength. You can't increase signal to noise buy adding an amplifier, you increase signal and noise and take a hit for it by the noise figure, plain and simple (hopefully simple enough).

[Ratman]

Yep... thanks. You just cleared up exactly what I said.

In an analog world it would/could be referred to SNR.

Excerpt from another forum:

Chris Thomas (cthomas([at]mminternet.com) wrote in alt.tv.tech.hdtv:
| Digital tuners do not display signal strength. They display "singal
| quality", which is the inverse of the bit error rate on the decoded
| signal. Generally a stronger signal means a lower bit error rate,
| which casues a higher signal quality reading. But the display does
| *NOT* indicate strength directly, and does not enable one to evaluate
| conditions such as overload directly.


The signal meter on your STB (at least every one I've ever seen) does NOT measure signal strength, it measures signal quality, which is
approximately the inverse of the bit error rate (BER) of the decoded
digital bit stream. A very slight difference in multipath can cause
the BER to vary all over the map.

The reason tuners don't display signal strength is that it isn't
relevant - the quality of the displayed picture depends directly on
the BER, and only very indirectly on the strnegth. Most displays are
labeled "signal" and not "signal strength" for this reason.

[hd4me2]

Quote:
Chris Thomas (cthomas([at]mminternet.com) wrote in alt.tv.tech.hdtv:
| Digital tuners do not display signal strength. They display "singal
| quality", which is the inverse of the bit error rate on the decoded
| signal. Generally a stronger signal means a lower bit error rate,
| which casues a higher signal quality reading. But the display does
| *NOT* indicate strength directly, and does not enable one to evaluate
| conditions such as overload directly.

Quote:
The signal meter on your STB (at least every one I've ever seen) does NOT measure signal strength, it measures signal quality, which is
approximately the inverse of the bit error rate (BER) of the decoded
digital bit stream. A very slight difference in multipath can cause
the BER to vary all over the map.

The reason tuners don't display signal strength is that it isn't
relevant - the quality of the displayed picture depends directly on
the BER, and only very indirectly on the strnegth. Most displays are
labeled "signal" and not "signal strength" for this reason.

Now that makes sense, that the signal meter indicates signal quality (proportional to 1/BER) and *NOT* S/N as stated in post #6.

[Ratman]

Also from another forum:

I'm not sure how far you are from your towers. And I'm not sure how your receiver defines "signal strength". But usually that actually means signal to noise ratio. With a digital signal, you either have it or you don't. My Sammy 151 never shows a "signal strength" above about 60%,

Keep in mind that the meter is not a signal meter, but a Signal to Noise Ratio meter. That is telling you that your signal to noise ratio is in the good area.

If you're reading the "signal strength" from the built in meter on your receiver/decoder, it's giving you false information. It's NOT signal level or amount of gain, like the preamplifier specifications, but Signal to Noise ratio.

[hd4me2]

It's amazing how many people think the meter is showing signal to noise. They are probably the same people that think if you use a splitter in reverse you get 3 dB of loss.

[Ratman]

Can you tell us "exactly" what the signal meters are referencing then?

You provide the disagreements, but have not provided a definitive answer.

Also (since you decided to add another slam), provide us with proof that using a 'hybrid' splitter as a combiner doesn't attenuate the signal(s).

And not just your opinion... please provide some references on both subjects. That will help clear up my misconception(s).

[hd4me2]

Can you tell us "exactly" what the signal meters are referencing then?

You provide the disagreements, but have not provided a definitive answer.

Also (since you decided to add another slam), provide us with proof that using a 'hybrid' splitter as a combiner doesn't attenuate the signal(s).

And not just your opinion... please provide some references on both subjects. That will help clear up my misconception(s).

No one is slamming anyone here, there are just misconceptions out there that don't hold up. Your sources that you quoted a few posts back that believe the signal meter, we are talking digital now, is related to BER and not S/N seems to make sense. Once the signal is received by the antenna the S/N can never be improved on, it can only become worse. You can increase the signal strength by adding an amplifier but you also amplify the noise so there is no improvement in S/N, if fact it gets a bit worse because the amp is not a perfect noiseless source, this is the noise figure (NF). By adding the amplifier the reading on the signal meter increases but S/N hasn't improved so saying the meter is a measure of S/N doesn't hold up.

As for the splitter question it's quite easy to understand. If you use a splitter in the forward direction, input into port 1 lets call it, is split equally out to ports 2 and 3 with some extra loss, insertion loss, since the splitter has its own inherent loss ~0.3 to 0.5 dB. Now if I use it in reverse input two signals into ports 2 and 3 that are in phase like you do if you want to use two antennas to improve gain, they will add and give you the 3 dB improvement in gain, minus again a few tenths for insertion loss, that you expected. This type of device and many others are called reciprocal devices, they work the same forwards as they do backwards.

I will try to find some sources that I can provide that backs these things up so no one needs to take my word on this.

[Ratman]

Further reading on my part shows that you are correct in regard to the combiner debate. My confusion was created by the fact that the -3.5 dB loss occurs when the antennas are not aimed in the same direction and combined.
In phase/same direction and combined... +3dB gain.

I am humble...

[mjones73]

You can't remove the amp on a SS-2000, the unit in the house is the power supply, it just injects voltage into the line for the amp in the antenna. Removing power from a pre-amp usually causes more loss then not having one at all... At those ranges I'd suggest returning it for a SS-1000 or just go with something like the $25 Yagi from Radio Shack, the antenna and pre-amp set up you have now is overkill.

I'd suggest pointing the antenna straight or angled back slightly aimed at the top of your towers, the side to side rotation on the SS is for VHF reception, just leave it straight up at 0. Also, get a compass, I'm gonna guess your eyeballing is a little off and those towers you are seeing are closer to 235 degrees then you think...

Just so you know, the locations of the transmitters for Virginia Beach are down towards the bottom of this page.. looks like they are all located in the same area

http://www.vartv.com/easternshore.htm

That area is shown below, is that the towers you are seeing by your house?

http://www.mapquest.com/maps/map.adp?ovi=1&zoom=7&mapdata=5u7zQrYT8FCrFcoAS3Aoyfyd0T69sfhhagMsGvowctmlsNoyT7pSuw4ljuwg0QJhl5GTdVfBn0Xuk5P%2bE4unEh9szWwh1ZLbK%2fBIMX5xZWJI8YYJzC%2buda92Vacj37B5egSAY%2fREtvWFQLnfsImbq55WKblZovbW08GI5XfXp5VDDvsGFrX3dcPFmy62p%2bRhR9%2bJHuOGSTSHtjqhNwH5TLqWrnkg%2fPWWWuksjgPYIpBG23eO5t25XYiccDrkX4IvU5OxeTi%2bV80zZZhYZsk%2bJgVJA4%2b%2fl2KusiCp2loRYlo5QX9jidsYwRwM8fObwDCFiV%2fDQvxXRduExGItx7RYHGt8SFltEynAmpLfDjsqS5h7TgCjPAOwhZKBdcqwvex5DkoBJI4Gz9lVHW9rfXG6NiLnOeg5laO1CLPGf2Ixt2A7lqzo3JzLfVrQSe%2beRRyQqVKknBfSQaeJyhFfaSFFeXCQs8Bxo8tfAwTbfeEKSatFC9J5Rb%2bHDaEP4o7w6BSlqt1QAlQTNt1V098BgEX76DSA40k2v%2bPUc7eDIvleDJPV0LQYDdG95YvQ9gKsn43joBCFV5AUvNT3kd8WX3JddA%3d%3d