Reception in Northwest Georgia
 

I am a complete newbie to the OTA tv. I live in NorthWest Georgia where the maps on this site show most of the local channels to be 40-55 miles away. I don't have any trees in front of my house for about 300ish ft. My house faces the same direction as the signal. My Internet source is 4glte to router then wifi so I didn't know if they would interfere. I would like some advice on what hardware to try. I would like to try to install attic if possible. I definitely do not have room for a 12 ft antenna up there but 5-6 ' is possible. I have R6 cable and a SWM splitter I'd like tie in to if possible coming from my Directv satellite. I will try link the map information. Thanks in advance.

http://tvfool.com/?option=com_wrapper&Itemid=90

http://www.tvfool.com/?option=com_wr...e6a4877a9ab45c

Greetings!

I would suggest you keep things simple, especially at first. Most of
your stations come out of the Atlanta market. I would aim for those
stations using a Winegard 7694p antenna using RG6. That antenna
is available at either Walmart or Home Depot .com for less than
$50.00 including shipping. Run that cable to ONE tuner and see what
you get. Be sure to keep your cable run as short as possible. Runs
over 50 feet cause problems you'll want to avoid. Later, you can
add other tuners or perhaps another antenna pointed toward the
multiple transmitters to your Northnorthwest.

I forgot to mention that an attic installation with your
location and weak signals is not advised. You would
likely only receive a very few channels. The Winegard
7694p is sturdy, compact and may be helpful with the
repack coming.

Thank you. So would you suggest rooftop being only real option. I really only need ABC, fox and CBS. With rooftop and your suggested antenna do you think getting those channels are possible given the weak signal?

I believe that in your case, a rooftop antenna is the ONLY way
to go. I understand that your main interest is ABC, CBS and fox.
What if your provider has a contract issue with, say WXIA, in
Atlanta?? With the Winegard, you still should receive WXIA ota on
RF 11. You could go with a UHF only antenna. There are many
to choose from. Some like the Clearstream models have VHF
kits that help with VHF reception. MCM Electronics sells 4 and
8 bay UHF antennas that are inexpensive, work well and are
compact. You do have the possibility of receiving stations that
serve the Chattanooga area. They too have high band VHF channels.
I again repeat to keep things simple, especially at first. Aim
your antenna, whatever you purchase at Atlanta, do some scans,
see what you receive. Then aim at Chattanooga, NNW, of you.
Do some scans, see what you get. Get back to us so we can
give you some additional insights. Hope this helps.......

Awesome, thanks.

Well I tried a CleaStream 2max with a 20 dollar amplifier from Walmart. Just have it sitting in living room facing out window, 2 ft off the ground and am getting 30+ channels. Getting everything I want except abc. Maybe if I actually install it I can get abc to come in.

That is very good news.....
Not sure the amplifier is needed. You should try the antenna
without the amplifier and see what, if any, changes occur.
I suggest you make a temporary mount for the eaves or
roof and do scans moving the antenna from point to point.
You may find some antenna locations work far better than
others! Good Work!

Well I have upgraded to the front porch. Getting abc clear now. How are the channels listed? Like why do u 5-1, 5-2 etc.

Fantastic!
In the old days of analog TV, a station that identified itself as WSB,
channel 2 was actually on that Rf frequency. In the digital age,
WSB channel 2 is a virtual identification. They actually transmit
on Rf 39 these days. Rf 38 is their physical identification.
In the old days, one Rf channel carried one program. Now, one
Rf channel can carry several programs, simultaneously. Channel
2.1 is the main channel. 2.2 is the Escape Network, 2.3 is Laff
Network. So instead of getting one program, you now get three.
Hope this helps.

I am interested in running a splitter for 2 tvs. How do I incorporate an in line amplifier when two tvs are used. The amplifier I have now plugs into wall at tv. Does splitter go after the amplifier that plugs into wall?

Yes. Generally, it's a best practice to install the amp as close to the antenna as possible. Split the signal downstream from the amp.

Channels may be identified by their displayed channel (virtual) number, real (RF) channel number, or by the station's call letters. Identifying by network affiliation is usually the least useful as they then require additional look-up in order to identify the underlying real channel which determines the antenna requirement.

Any antenna used in an attic is handicapped by virtue of
the wood, pipes, HVAC, electrical, shingles, etc, etc.
Even very strong signals can be severely reduced to the
point of reception issues.

I have ALWAYS understood that an amplifier, preamplifier,
or similar does nothing to increase the ability of the antenna
to receive signals. An amplifier or similar only need be
used in cases where the cable run is over 50 feet or more
from antenna to tuner. The amplifier helps overcome those
signal loses associated with long cable runs. I do not
understand the need for any amplification with short cable
runs except for possibly a distribution amp, where you have
multiple tuners connected to one antenna. Is this information
correct or am I misunderstanding???

A well-selected amplifier located close to the antenna can improve the system noise margin by the (difference in noise figure of the amp vs the tuner) plus (all downstream insertion losses). That means that very weak signals otherwise just below the noise floor at the tuner's input can be raised enough to make them receivable.

As an example: Assume a tuner NF of 6 dB (probably fairly typical) and a preamp NF of 2 dB. Before the coax, one would already enjoy a 4 dB improvement in the system NF. Add in 50' of RG6 (3 dB) or 100' of RG6 (6 dB) or a 4-port splitter (8 dB) and it's illustrative as to how a weak signal which would otherwise lost in the system, can be preserved enough to be receivable.

I see that ADTech posted while I was eating dinner, but I'll also give my answer to your question, since I already did the draft.

Your general rules are correct, but every reception location is unique.

Yes, attic loss is difficult to predict; it can be very high or minimal.

Yes, a preamp, if needed, should be as close to the antenna as possible, because it primarily determines the System Noise Figure which is expressed in dB (lower is better). And, as you have said, try the antenna first without a preamp.

Yes, a preamp will make the signals stronger to offset distribution losses.

Yes, if you are using a preamp and want to split, try a passive splitter first before adding a distribution amp. Both are rarely needed.

But, there are cases where a preamp can make it possible to receive weaker signals with a more negative NM, because the Noise Figure of the tuner is buried in the amplified noise floor, making it irrelevant.

The Noise Margin calculation of the tvfool report assumes that a preamp will be used, which means that a signal must be at least -91 dBm signal power for a NM of 0 dB. If you look at a tvfool report you will will see that there is a constant difference of 91 dB between the NM and dBm signal power.

This is where the -91 dBm comes from:

The Thermal Noise Floor for a DTV signal is -106 dBm (-15 dB NM). Any signal that is weaker can not be received; an antenna with more gain can not "pull it out of the noise." If you are able to receive a signal with a NM less than -15 dB, either the tvfool report is wrong or the signal has been enhanced by Tropospheric Propagation.

To that you must add the minimum required SNR of 15 dB:

-106 dBm + 15 dB = -91 dBm, before allowing for the preamp Noise Figure

If you do not use a preamp, then you have to add the tuner Noise Figure which is 6 dB average:

-106 dBm + 15 dB + 6 dB = -85 dBm; which is where most tuners will drop out

What is going on is that the antenna gain must make the signal strong enough to allow for the minimum required SNR of 15 dB and the Noise Figure of the preamp. Once the signal is strong enough for the preamp input, it will compensate for the distribution losses and bury the tuner Noise Figure in the much stronger amplified Thermal Noise Floor.

In the case where no preamp is being used, the antenna gain must make the signal strong enough to allow for the distribution losses and the tuner Noise Figure.

Maybe a few diagrams will help.

Indoor or attic, with and without a preamp:

http://forum.tvfool.com/attachment.p...1&d=1499692287
Outdoor, with and without a preamp:

http://forum.tvfool.com/attachment.p...1&d=1499692621

You can see how damaging attic/indoor loss is, You can also see how a preamp makes it possible to receive weaker signals, by about 5 dB.

This is what a System Noise Figure calculation looks like with and without a preamp.

http://forum.tvfool.com/attachment.p...1&d=1499692847

http://forum.tvfool.com/attachment.p...1&d=1499693062

reducing coax loss between antenna and preamp:

http://forum.tvfool.com/attachment.p...1&d=1499693334

The main limiting factor when using a preamp to receive weak signals, is the strength of the local strong signals that might overload the preamp or tuner. Even a partial overload can create IMD (Intermodulation Distortion) that can damage the weak signals.

In this particular case, WPXA ION is the strongest signal with a signal power of -33.7 dBm, Fortunately, when a directional antenna is aimed 114 degrees, WPXA will be weaker because of the antenna pattern.

Wow, you guys are awesome. I temporarily put the antenna in the attic and it picked everything up fine on one tv with 25' Walmart R6. That was without the amplifier. I also carried to the roof and held it place between the rooms that I would be splitting tvs to. My cheap Panasonic tv said signal strength was 73 percent in the attic and 84 percent on roof. I don't know if there was any actual science involved with the metering but it obviously shows some signal loss. I figure that when I add a splitter that attic signal would go down more I just wonder how low on the TV meter it can go before it loses the channel. Another bonus of putting it on Roof is that I should be able to get to each tv within 50' of antenna. My plan is to run r6 down outside of house in trim to crawl space. Hook first part of amplifier up on roof near antenna then power inserter in crawl space on antenna side of splitter. How does this plan sound?

That sounds promising.
Which amp?
It's RG6.
The signal strength scale is just a relative scale, and it's different on every TV. Your particular TV will tell you how low it can go and still be able to have good reception. You can add a splitter or two as an attenuator to make the signals weaker as a test, as in the megalithia.com link in my signature

If the antenna is outside, the coax shield should be grounded with a grounding block that is connected to the house electrical system ground with 10 gauge copper wire for electrical safety and to reject interference. For further compliance with the electrical code (NEC), the mast should also be grounded in a similar manner to drain any buildup of static charge which will tend to discourage a strike, but the system will not survive a direct strike.

http://forum.tvfool.com/attachment.p...9&d=1441917363

Thanks. I have also decided to buy an indoor antenna and try in both rooms just to see if by chance it worked. If not I will return but it could keep me from having an afternoon of installing and an antenna on my roof. I was looking at several on Amazon and saw where some didn't support VHF chsnnels or HI-VHF chsnnels (review said channels 2-12). I was confused by this is as some reviews said they pick up ABC which is Channel 2.1. Would this be an issue for me?

It might be an issue.

It is the real channel number that determines what antenna is needed.

VHF-Low, real channels 2-6
VHF-High, real channels 7-13
UHF, real channels 14-51

The virtual channel number (like 5.1) is a holdover from the analog TV days to maintain the identity of the station, and is what the TV displays.

In your case WSB ABC is on real channel 39, virtual channel 2.1. Channel 39 is a UHF channel so you need a UHF antenna for it.

WXIA NBC is on real channel 10, virtual channel 11. Channel 10 is a VHF-High channel, so you need a VHF-High antenna for it.

Most indoor antennas are pretty good for UHF, not as good for VHF-High. That is because the elements for VHF-High need to be 3x as big as the elements for UHF.

I'm using a GE 34792 Attic antenna indoors with an RCA TVPRAMP1R preamp but my channels are stronger than your channels. Channel 13 is my weakest and it is VHF-High. The GE antenna only has a folded dipole for VHF-High; not much gain. It requires assembly, so it would be difficult to return it.

The Winegard HD7694P is only $15 more and it has much more gain for VHF-High and UHF. After you unfold it, it would also be hard to return.

My report:

http://forum.tvfool.com/attachment.p...1&d=1496115034

I think it's worth trying an indoor antenna with a preamp if you have an east facing window without a metal screen or low-E glass, but you will probably need to put an antenna outside.

If you had to use the attic, you would need an antenna with more gain and a preamp. If the signal loss in the attic is great, even that might not work.

You must be prepared to experiment if you can't put an antenna outside.

Thanks to all for the good, useful information.
Another point to remember is that VHF almost
always transmits with less power than UHF.
That means that VHF does not penetrate buildings
nearly as well. If the distance from the transmitter
is the same as UHF, VHF will most always be
harder to receive. Add to the fact the most indoor
antennas do not work very well on VHF and you
can see that an outdoor antenna is the better
way to go....