Antenna Question

General Discussion
1

Hello all, I haven’t cut the cord yet but I’m getting ready to. I currently have a directional antenna in my attic that is wired throughout the house. I thought we were getting all the local channels but when I used the channel finder here I discovered another station that has a station my wife would like to get. It does not come in with our current antenna and is about 45 degrees away from the majority of stations.
The channel list here shows all the stations with 5 dots (strong signal). When I go to AntennaWeb it says with the majority of stations (that I get now, 20 miles) to use a small multi-directional but with the new station I’d like to get (30 miles), to use a large directional with preamp.
TV Fool says for the main channels to use a set top antenna and for the new station to use a attic mounted antenna.

I’m confused on what to use. Should I add a new multi-directional antenna for the main channels and move my directional or just get a new multi-directional that says it can get stations up to 50 miles away. I’ve read there can be problems when you combine two antenna signals.

Any help would be appreciated. Thanks!

2

You could go with a single attic or roof mounted antenna … and you don’t need to split the signal since the TABLO can stream live tv to all the other tv’s in your house (assuming you use a ROKU or some other method to view content) … I use a chimney mounted omni directional antenna (though I neglected to to check VHF channels in my area and got a UHF only antenna)… The antenna question is one of the hardest aspects of cutting the cord (I live 40+ miles away from our big antenna location) and if I had to do things over … I would prob pay a professional for that … but since you are closer you could prob get away with attic mount or get a good 50+mile MOHU leaf and try that (its easier than futzing in an attic and if it doesnt work out you can always put it on another TV that you dont watch too often or dont care bout the stations it cant tune)

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I live 58 miles from the towers and pickup all the stations from 2 tower locations that are 30 degrees apart with the Mohu Sky 60 mounted in the attic. I have a pre amp and distribution amp. One thing a lot of people do not anticipate is that the Tablo is basically a splitter, hence the distribution amp.

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I should mention I also use a preamp… but I dont use a distrubution amp since the antenna only connects to the TABLO.

5

for about $25 you can build an attic mount antenna that I use and pick up all channels in my area plus some from the north.  It works better than any antenna I have purchase.

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I should mention I also use a preamp.. but I dont use a distrubution amp since the antenna only connects to the TABLO.

A good point to consider is that you only need a preamp and/or distribution amp IF YOU NEED IT.  Best practice would be to test signal strength without either, and work from there - first adding a pre-amp, and retesting, then a distribution amp if needed.  It is possible to have too much gain/signal strength adding amps that you don’t need.

It is all very situation/installation dependent, and with antennas/reception it is really best to add one variable at a time to see the results.  
A large attic or outdoor antenna and a single run to a Tablo (depending on cable run length) will possibly require nothing to be added.
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Thanks for the replies. With my current antenna I don’t have any amps and it is distributed to 3 TVs but this is from the more powerful stations. I’m trying to figure out the best way to add this new station that is 45 degrees from the current stations and another 10 miles away. I may try repositioning my current (directional) antenna to see if I can pick up this new station. If it can, then add a smaller antenna to pick up the closer, more powerful stations and combine them together.

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Thanks for the replies. With my current antenna I don't have any amps and it is distributed to 3 TVs but this is from the more powerful stations. I'm trying to figure out the best way to add this new station that is 45 degrees from the current stations and another 10 miles away. I may try repositioning my current (directional) antenna to see if I can pick up this new station. If it can, then add a smaller antenna to pick up the closer, more powerful stations and combine them together.

Combining antennas can work, or can result in all sorts of problems.  I have a large UHF only antenna combined to a VHF directional antenna to receive the only VHF station in my area (channel 11) using a specialty UHF/VHF combiner.  That works perfectly for me. 

http://www.solidsignal.com/pview.asp?p=UVSJ&utm_campaign=base&utm_medium=organic&utm_source=google_base&gclid=CjwKEAiAsJanBRCgnpfa0orvyz4SJAAbxEq-yZ51LB8R8vuIVVagpkj67VEvB9IUpVbpz15zn5RkKxoCI1Dw_wcB

In addition, like you, I have one UHF station roughly 45 degrees from all the others - which I combined an additional directional antenna  using a simple coax splitter (basically use it in reverse - two feeds in, one feed out).  
This can sometimes cause reception problems, but there are a ton of variables that will determine if it works for your specific application.  I’d say give it a try using a highly directional antenna for the one off-center channel.
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if they are on different bands eg VHF / UHF a splitter wont be an issue but I am guessing this is probably not the case here.

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Antenna and RF broadcast theory is incredibly complex, and it is nearly impossible without very expensive equipment and education to predict what you will actually get with Antenna “X.”  Usually the best one can do is to try it out and see; an iterative series of tests will usually get you the information you need.

As to the specific question of combining antennas what you are really concerned about is something called “multi-path” radiation.  Multi-path means that you have multiple broadcasts of the same information on the same frequency, but are often time shifted.  Think of it like this:  you get the direct line-of-sight broadcast direct from the transmitter antenna to your receiving antenna.  You also have a large metal building near you and the original broadcast is reflected off of that building.  Because the reflected signal travels a longer path, it takes longer to reach your antenna and is therefore time shifted slightly.  If your antenna or equipment cannot discriminate between these two broadcasts then you will get a ghosted image on your screen, or if they are phase shifted just right it can actually reduce the level of signal you receive. 

This multi-path is usually the real problem when combining antennas.  Most antennas are directional to some degree; this means that multi-path broadcasts can often be “tuned out” by carefully pointing your antenna.  When you combine another antenna you are adding the multi-path back in. Again, the only way to know for sure is to try it out.

On the subject of pre-amps and distribution amps one commonly misunderstood calculation is that amplifiers actually represent a loss to the signal from your antenna.  This is because all amplifiers inject some noise into the signal; the good ones will have a noise figure less than 2 or 3 dB.  Amplifiers are best used to overcome losses in your equipment such as cabling, splitters, and the like.  Everything in the signal path increases the overall loss numbers.  RG6 cabling has a loss of 6DB/100 ft, splitters usually incur about 4 DB, the Tablo itself has a splitter inside.

Here is an example from my system:  Antenna has ~ 17dB gain (the “miles” ratings are meaningless marketing jargon).  So I start at +17dB.  I have a balun on the Antenna to convert to coax–this is -1.5 dB.  I have a Winegard LNA-200 preamp which has a noise figure of 1 dB, and a gain of 18dB.  I have 75 foot of RG6–there is -4.5 dB.  The signal then goes to the Tablo which has a splitter, - 4dB.  The equation looks like this:  +17dB -1.5dB -1dB +18 dB -4.5dB -4dB = 24 dB.  So, my system adds 24dB to the original signal strength.  Calculating signal strength is an inexact science, but tvfool.com can give you a pretty close number.  For my system on the ABC broadcaster tvfool says I should have a strength of -38dB coming to my antenna.  For the CBS station I should have -52 dB signal strength.  But, I get the CBS station very strong all the time, and the ABC is spotty.  The likely reason for the lower performance of ABC is a multi-path broadcast.

Good luck!.

11

I went through 3 different antennas … and spent about 3 or 4 months “futzing” around before I found the optimal combination of preamps, antennas and orientation … (this is why when people ask me about cutting the cord I often say the antenna is the most crucial part and probably the hardest if you are not right on top (or close) to the towers you want to get a signal from … and if I did it over again i’d prob hire a professional for the antenna / installation part)

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I forgot to mention if you are really stumped you can check/ask over on the AVS forums … (the people over there live for television/home theater and usually are very helpful)


http://www.avsforum.com/forum/25-hdtv-technical/
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The folks on /r/cordcutters on Reddit are also amazing at antenna recomendations. 

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The folks on /r/cordcutters on Reddit are also amazing at antenna recomendations. 

Yea I forget about them … (I forget what a good resource reddit is in general)

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Yea I forget about them .. (I forget what a good resource reddit is in general)

Indeed. Anytime I’m doing research on something I like to check out message boards for information. 

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Thanks for all the suggestions! Avsforums is my usual “go to” forum for TV information but never thought about it for antenna info. ddd671 - thanks for the detailed explanation. I’m going to try repositioning my antenna when I get a chance and go from there. Unfortunately I don’t know the specifications of my current antenna as it’s probably 20 years old. I’ll check to see if there’s any numbers on it when I crawl up there.

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I repositioned my antenna today aiming it with data from tvfool and a compass. Unfortunately I still can’t get that station.

Looks like more research on antennas. I ordered my Tablo yesterday so I need to get moving!

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Try and amp or is it possible to move antenna higher?

Make it directional perhaps. Not sure what youre using exactly and I didn’t read entire thread

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Any recommendations?

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On what? Antenna? Amps?