Reducing Aerials to UHF, need diplexer?

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scuwp

3230 posts

Uber Geek

# 107439 11-Aug-2012 20:20

Removing old analogue aerial, and also helping a mate sort out TV at his new place.

Past installs have always included a diplexer. If the only aerial installed is a UHF (Freeview terrestrial) which then goes straight into the distribution box, or straight to the TV, do you still need a diplexer or perhaps something else now?

Not actually sure what the diplexer did, only that one was necessary. Is that still the case?

Thanks

Always be yourself, unless you can be Batman, then always be the Batman

grant_k

3539 posts

Uber Geek

Trusted

# 671174 11-Aug-2012 20:51

The diplexer would have been to combine VHF and UHF aerials, and perhaps split off a feed for FM to a receiver of some sort. With the demise of VHF aerials, all of that is redundant. If your mate still wants an FM aerial, it is better to run a separate aerial with its own coax for that.

oxnsox

1923 posts

Uber Geek

# 671175 11-Aug-2012 20:55

Diplexer is a way of getting 2 aerials (signals) into one cable without them being aware of each other. Stops the signal from one effectively going up the other instead of down to the tele.
You should be able to safely remove it without affecting you signal

scuwp

3230 posts

Uber Geek

# 671176 11-Aug-2012 20:59

Great stuff, that makes things a bit easier. Thanks

Would the signal actually improve without the diplexer?

Always be yourself, unless you can be Batman, then always be the Batman

Jaxson

6988 posts

Uber Geek

Trusted

# 671178 11-Aug-2012 21:00

There are potential signal level losses by keeping it in the system too, so remove if you can.

scuwp

3230 posts

Uber Geek

# 671181 11-Aug-2012 21:06

Great, thanks for the clarification.

Always be yourself, unless you can be Batman, then always be the Batman

PimpMyMagic

267 posts

Ultimate Geek

# 671242 11-Aug-2012 23:32

UHF, being much higher frequencies, tend to suffer greater signal loss in cables so it was common to use a diplexer which included a mast head amplifier. Removing this could reduce your UHF signal strength on the output of the aerial cable.
This setup will normally be indicated by the presence of a small power injector box, usually fed with volts from a plug pack.

As long as this is not present then all the foregoing advice will apply.