Home TV/FM distribution issue..

[wipeoutdude]

Hi,

Hopefully someone can shed some light on this..

I have Triax TV/SAT/FM wall plates in three rooms of the house.. In the loft I have a TV antenna and an FM antenna.. These are connected to an Antiference (http://www.antiference.co.uk/distribution-amplifiers-0) amplifier to the UHF and VHF ports..

From the amplifier I feed the TV signal into a Triax TV/SAT combiner along with an LNB connection from the sat dish.. Then down to the wall plates..

The issue is that if the FM antenna is connected I loose a number of TV channels.. Specifically channels like BBC1.. In fact the first channel I can get is channel 11 "Pick"..

If I disconnect the FM antenna all TV channels work fine..

I have tried removing the combiner and the wall plates but still loose the channels when the FM antenna is connected..

Anyone have any ideas?

Thanks..

 

[Sam Gangee]

Hi,

Hopefully someone can shed some light on this..

I have Triax TV/SAT/FM wall plates in three rooms of the house.. In the loft I have a TV antenna and an FM antenna.. These are connected to an Antiference (http://www.antiference.co.uk/distribution-amplifiers-0) amplifier to the UHF and VHF ports..

The DA240LTE amplifier?

So that's combining the UHF TV and VHF Radio signals?

From the amplifier I feed the TV signal into a Triax TV/SAT combiner along with an LNB connection from the sat dish..

By "TV signal" do you mean the combined amplified UHF + VHF aerial signals?

Then down to the wall plates..

The issue is that if the FM antenna is connected I loose (lose) a number of TV channels.. Specifically channels like BBC1.. In fact the first channel I can get is channel 11 "Pick"..

If I disconnect the FM antenna all TV channels work fine..

I have tried removing the combiner and the wall plates but still loose (lose) the channels when the FM antenna is connected..

Anyone have any ideas?

I'd need to see your wiring diagram. Your signal levels may be too high so I'd measure them.

 

[winston1]

Could be a strong FM signal overloading the amplifier. Maybe try an attenuator on the VHF input to the amplifier.

 

[wipeoutdude]

The DA240LTE amplifier?

Yes.

So that's combining the UHF TV and VHF Radio signals?

That's right..

By "TV signal" do you mean the combined amplified UHF + VHF aerial signals?

Yes..

I'd need to see your wiring diagram. Your signal levels may be too high so I'd measure them.

Diagram attached.. View media item 87927

 

[wipeoutdude]

Could be a strong FM signal overloading the amplifier. Maybe try an attenuator on the VHF input to the amplifier.

I thought they were on totally different frequencies so didn't affect each other?

 

[Sam Gangee]

If, as Winston suggests, the FM signal is overloading the amplifier, the frequency is irrelevant.

As I stated, "Your signal levels may be too high so I'd measure them".

 

[wipeoutdude]

How do I measure the FM and TV signal levels? Is there a cheap meter that can measure the VHF and UHF signal strength?

What is the ideal level for them to be?

 

[Sam Gangee]

That depends on your definition of "cheap". You can get a very decent one that includes spectrum analysis for around £1500. Obviously you'll have to learn how to use it.

Or simply pay a professional to come and do the investigation.

Or take a gamble and try Winston's suggestion of an attenuator.

Unfortunately, without measurements, it's all guesswork.

 

[Sam Gangee]

BTW I believe the DA240LTE amplifier has adjustable gain? If so, what happens when you adjust it? If not, try replacing it with a simple Y splitter to act as a combiner.

 

[wipeoutdude]

BTW I believe the DA240LTE amplifier has adjustable gain? If so, what happens when you adjust it?[/quote]

I don't think mine has an adjustable gain.. It was there already so maybe an older model or something..

If not, try replacing it with a simple Y splitter to act as a combiner.

So you are saying a simple Y splitter can be used to combine the VHF and UHF signals and I could potentially bypass the amplifier completely?

If I have a good signal could the two antenna's be connected to a Y splitter which would then be connected to a 1-4 splitter and fed into the TV/SAT combiner? Effectively replacing the amplifier with a Y splitter and a 1-4 splitter?

 

[winston1]

No don't use a Y splitter, they have no frequency discrimination. Use a VHF/UHF diplexer.

 

[Sam Gangee]

So you are saying a simple Y splitter can be used to combine the VHF and UHF signals and I could potentially bypass the amplifier completely

Yes, temporarily as a test to see if it makes a difference. For minimal outlay, it may give useful information about your fault. If so, you could then spend more on a proper VHF/UHF diplexer, as Winston suggests.