I have a simple question. We have no cable where we live so I purchased a large VHF/UHF antenna and mounted it inside the actic. I figured it was much more secure and I didn't have to worry about lightning and wind. Luckily the antenna farm for all of the local TV stations are in the same part of town. Point it southwest and I'm in business!!! I also purchased an RF amplifier to put in line. With my digital encoder box I get wonderful pictures on most stations. There are a couple where the signal strength is too low and I get "digital freeze" from time to time. My question is, would I get the signal strength up enough if I went and purchased another RF amplifier and put both of them in line? It seems to me that I would be doubling the signal strength if I ran the output of the first amp into the input of the second and get twice the output. Thoughts?
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RF Amplifier Question
- Thread starter pobryan
- Start date
Don't do it. You're only amplifying noise at that point.
Seems contarary,but have you tried without the amp? It could do better without.
You may find improvement at one end of the attic over the other.
Try re-aiming the antenna as well. Very slight changes can help eliminate/change multipath, which
is more likely your problem than low signal strength.
Which channels are funny?
Seems contarary,but have you tried without the amp? It could do better without.
You may find improvement at one end of the attic over the other.
Try re-aiming the antenna as well. Very slight changes can help eliminate/change multipath, which
is more likely your problem than low signal strength.
Which channels are funny?
The larger, (longer) and more elements a yagi antenna has, not only does the gain increase but so does the directionality.
Some antenna designs used to sweep the elements back about 20-30 degrees, thus widening the pickup angle at some cost to gain.
It was common at one time to see multiple bow-tie UHF antennas and vhf yagis diplexed on masts in all rural areas.
Sounds like you need something like this. Is the amp up at the antenna?
It really should be. If not, try this first.
Some antenna designs used to sweep the elements back about 20-30 degrees, thus widening the pickup angle at some cost to gain.
It was common at one time to see multiple bow-tie UHF antennas and vhf yagis diplexed on masts in all rural areas.
Sounds like you need something like this. Is the amp up at the antenna?
It really should be. If not, try this first.
If there is space in your attic, try tilting the business end of the antenna upward. The UHF end of those all channel arrays tends to be more tightly focused. If you are more than 25 miles from the towers there may be nothing to do but put up a multi-bay UHF array with a short mast on your roof. Grounding the mast well should minimize lightning danger. You can diplex them all with a VHF/UHF combiner into the same downlead.
As some of the other posters have said, don't look at an RF amp as the solution. Maximize the antenna you have by good RG6 coax, an a decent antenna. Look at something like an Winegard HD1080, which can be mounting in an attic.
The problem with amplifiers is that they are wideband, and they amplify noise. The noise will affect any DTV signals, and due to being wideband you get varying results depending on how many FM stations are in your area, plus ham radio, 2-way, etc. Also, a close digital station can cause intermod in the amp, again causing loss of performance. As a rule of thumb I would not use an amp unless you're in a rural condition.
The NBC 8 Lima web site has information on antennas and tests they have done.
The problem with amplifiers is that they are wideband, and they amplify noise. The noise will affect any DTV signals, and due to being wideband you get varying results depending on how many FM stations are in your area, plus ham radio, 2-way, etc. Also, a close digital station can cause intermod in the amp, again causing loss of performance. As a rule of thumb I would not use an amp unless you're in a rural condition.
The NBC 8 Lima web site has information on antennas and tests they have done.
A friend in Evansville is receiving UHF signals with an HD tuner from Newburgh.
WFIE 14 Great.
CH 25 - Not there (at same site as WFIE or nearby)
CH 9 now on CH 12 (2 miles out) Not there.
In Indy I have all my stations fed to my HD tv on cable in analog. TV doesn't support both formts at once.
17 miles to the tower farm. 2nd floor 20 feet up rabbit ears.
Ch 6 - awful. Pixelized on 6.1 most of the time.
CH 40 - 6 great channels and only the last at low resolution (JCTV) has pixels.
I have experimented with antennas and such only to see that what is great on analog stinks with a similar correct frequency wavelength antenna on HD.
Not all of the Indy stations in the farm at 79th and township line road have identical signals.
Why are signals so BAD on a great new technology that makes the former great analog signals outmoded? I have heard (self promoting HD plugs in commercial form) how good the picture is til I want to puke.
Are the TV stations just hoping that we will all have cable?
WFIE 14 Great.
CH 25 - Not there (at same site as WFIE or nearby)
CH 9 now on CH 12 (2 miles out) Not there.
In Indy I have all my stations fed to my HD tv on cable in analog. TV doesn't support both formts at once.
17 miles to the tower farm. 2nd floor 20 feet up rabbit ears.
Ch 6 - awful. Pixelized on 6.1 most of the time.
CH 40 - 6 great channels and only the last at low resolution (JCTV) has pixels.
I have experimented with antennas and such only to see that what is great on analog stinks with a similar correct frequency wavelength antenna on HD.
Not all of the Indy stations in the farm at 79th and township line road have identical signals.
Why are signals so BAD on a great new technology that makes the former great analog signals outmoded? I have heard (self promoting HD plugs in commercial form) how good the picture is til I want to puke.
Are the TV stations just hoping that we will all have cable?
ChiefEngineer said:Why are signals so BAD on a great new technology that makes the former great analog signals outmoded? I have heard (self promoting HD plugs in commercial form) how good the picture is til I want to puke.
Just another example of the fact that digital is not the answer. Look at nature - everything exists in nature as an analog form. Sound is an analog concept. Don't see any ones and zeros floating around in space!
Why are signals so BAD on a great new technology that makes the former great analog signals outmoded? I have heard (self promoting HD plugs in commercial form) how good the picture is til I want to puke.
IMHO, the home consumer would put up with a minor amount of noise pulses in analog pictures when the signal is weak, but the fact that digital has a cliff effect puts the perceived perception into a whole new arena. People are more sensitive to something that goes away rather than looking a little noisy.
In these cases it's mostly due to an amplified antenna, low signal, or multipath issues. But the receivers are not as good as they were years ago. Tests I did on two sets, (one a Toshiba and the other a Pioneer), indicated they had only about 60% of the sensitivity of legacy TV tuners. One has to ask why. But the worse tuners by far are saved for the converters, some of which have a very hard time getting signals in the grade B.
It's true that when a digital signal is decoded properly, it's a beautiful picture. The issue is the cliff effect, when someone gets a marginal signal that decodes 100%, only to have it lock up for a second when someone in the house turns on an appliance. I've always thought that there should be an on screen meter that the home viewer could pop up on the screen, just like you do with a DishTV or DirectTv box to aim the dish. Or at the least give the viewer the option of a SNR or BER meter so they know when the signal is on the weak side.
Digital is only another modulation method that has its own unique quirks to it. Don't think you're the only one. I've been fighting with viewers and cable companies over these issues for a while, and besides the reception issues we also have to deal with the failure of PSIP and lip-sync issues which raise their ugly head weekly due to a variety of reasons.
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