Boosting TV signal

[PeterDove]

Hi All,

Electronics newbie here again...well I know a little more now mostly down to audioguru

Can anyone tell me what chip would be best to use to amplify/boost a TV signal as our reception isnt brilliant... I want to make my own

also would the same chip boost a video signal - I have made a video to cat5 balun and wondered about signal boosting.

Cheers

Peter

 

[Nigel Goodwin]

Hi All,

Electronics newbie here again...well I know a little more now mostly down to audioguru

Can anyone tell me what chip would be best to use to amplify/boost a TV signal as our reception isnt brilliant... I want to make my own

Buy one! - they generally don't use chips, and layout is absolutely critical!. They cost very little, and you're going to spend lots more attempting to build one.

 

[PeterDove]

Buy one! - they generally don't use chips, and layout is absolutely critical!. They cost very little, and you're going to spend lots more attempting to build one.

Actually the purpose is two-fold - I want to learn about signal amplification AND solve a few problems I have.

I have made a Cat5 to video convertor but I also want to learn how I can amplify the video signal too. I thought TV signals might be similar so I thought it would be a cool way to learn about it.

I have found some info on monolithic amplifier chips from

**broken link removed**

but was hoping someone had some direct experience of these type of things.

Thanks

Peter

 

[Nigel Goodwin]

Actually the purpose is two-fold - I want to learn about signal amplification AND solve a few problems I have.

I have made a Cat5 to video convertor but I also want to learn how I can amplify the video signal too. I thought TV signals might be similar so I thought it would be a cool way to learn about it.

I have found some info on monolithic amplifier chips from

**broken link removed**

but was hoping someone had some direct experience of these type of things.

At one time such devices were available, but I haven't seen any for years? - as long as you followed the recommended layout EXACTLY they were fairly easy to use.

 

[stevez]

I've seen a lot of amateur radio pre-amps using MMICs. You might borrow from those projects but they won't be designed with TV in mind.

 

[HiTech]

like Nigel said, just go buy one. Places like Radio Shack sell a broadband RF amp for a mere $20 and that will get you 10db or more of gain and perhaps a built-in splitter, providing 2 to 4 outputs to drive extra television sets. Sheesh, for a $20 US bill you can't build it for less... even in your dreams!

 

[audioguru]

You don't know how much gain you need. The circuit doesn't have an adjustable gain control.
So either you will buy an IC witout enough gain or it will have too much gain and be overloaded by the strongest signals.

I bought a cheap TV RF amplifier from RadioShack. It was overloaded by all my weak cable TV signals and I got all 78 channels at the same time. I modified it and it worked much better.

Get a better antenna instead of an amplifier.
Before I got cable TV I had the best and biggest TV antenna that was made. I had it up high on a rotator and could aim it at up to 3 different stations that were on the same channel but were very far away. Many channels had more than a single station. The TV guide in my newspaper didn't list most of the many channels I could receive. I could also aim the antenna at the clearest reflection to avoid ghosting.

 

[Nigel Goodwin]

Get a better antenna instead of an amplifier.

It really annoys me when people, including aerial riggers (who are supposed to know what they are doing), stick amplifiers on small aerials.

Most of my aerial rigging experience has been in poor reception areas - you fit a good big aerial, THEN you add an amplifier as well. You should also use a masthead amplifier, with power fed up the cable - no good trying to amplify at the bottom of the cable when you've already lost most of it.

 

[Comcat]

How do you receive your TV signal? Is it a broadcast signal received via antenna or is it on cable? If the signal to noise ratio of your received signal is poor, merely adding amplification will not help. An amplifier will help in cases where poor signal quality is the result of passive splitters in the line and the amplifier is inserted in the main input line. Cable TV amplifiers can provide 10, 15, or 20 db of gain but do not necessarily have a good noise figure.
If you are receiving via antenna, a low noise amplifier placed at the mast head will improve the signal.

 

[HiTech]

What many common folk also don't realize is that often you need to attenuate or "pad" down the incoming signal (primarily CATV) before entering the amplifier. Otherwise you are asking for signal problems. I know it sounds weird to lessen the signal first only to amplify it afterwards.... but that's typically how it's done.

 

[Sceadwian]

The main amplification usually takes place after an initial tuned pre-amp or unity gain filter stage to issolate the signal of interest before amplification right? It's harder to filter out a strong signal and leave an acceptable signal of interst. It's easier to take a low signal, use a high order filter on it then amplify it to get to good detection levels.

 

[Comcat]

The main amplification usually takes place after an initial tuned pre-amp or unity gain filter stage to issolate the signal of interest before amplification right? It's harder to filter out a strong signal and leave an acceptable signal of interst. It's easier to take a low signal, use a high order filter on it then amplify it to get to good detection levels.

Cable TV amplifiers must be broad in order to pass all available channels. If the user is interested in only one channel, a preselector can be used to isolate a specific frequency, but this is usually not the case.

 

[tvmanjon]

Look for a PA-8275 pre amp.Its a knockoff of a Winegard made years ago.Takes a beating on all types of signal levels and is very low noise If I remember it less than 1Db Getting a clean signal is a art not a crap shoot.Signal strength,antenna gain,cable length,splits,etc etc...

 

[audioguru]

It is very difficult to make a wideband cable TV amplifier that works well. All the channels (I had 78 channels and now there are many more) all intermodulate each other if the amplifier has the slightest non-linearity. Since the TV picture is Amplitude Modulated then the interference is very obvious.

 

[HiTech]

All you gotta do is the next time the cable man rolls into your neighborhood, sneak up to his truck, swipe a line amp from the supply chest and run. Oh better grab some hardline adaptors too so the standard F connectors will mate to the hardline ports! If you get caught just say that you are borrowing it for a long time.