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121 posts

Master Geek
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Topic # 206147 11-Dec-2016 21:11
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Hi,

 

Just after some advice, I live in a very fringe area for Freeview (big hill blocking between the transmitter and my house) although I've found a spot which works reasonably well for Freeview and have an older amplifier (VHF/UHF combining) beefing up the signal.

 

I’m looking to replace this and move the amplifier right beside the aerial, but assuming it would be best to find a amplifier which only amplifies the Freeview UHF signal and not the old non-existent VHF signals (may cause interference with 4G now?) 

 

Also is it possible to add in an FM aerial and incorporate that signal on the same Coax as the TV signal?

 

Cheers

 

 

 

 

 

 

 

 


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536 posts

Ultimate Geek
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  Reply # 1686980 13-Dec-2016 11:40
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OK, first to clear up a misconception. 4G is NOT on the old VHF frequencies (30-300MHz) It operates at 700-800MHz, in what was the top end of the UHF TV frequencies. 

 

As to your other questions, yes, you can mix the FM signal onto the same coax as the UHF digital signal, but be aware that FM is in the middle of the VHF range (87-108MHz)

 

Your best bet in a fringe area is either a good phased array or long yagi antenna, then a short cable hooked to a good masthead amp with inbuilt UHF/VHF diplexer (the FM antenna can go on the VHF connector in most cases)




121 posts

Master Geek
+1 received by user: 35


  Reply # 1687128 13-Dec-2016 15:17
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tangerz:

 

OK, first to clear up a misconception. 4G is NOT on the old VHF frequencies (30-300MHz) It operates at 700-800MHz, in what was the top end of the UHF TV frequencies. 

 

As to your other questions, yes, you can mix the FM signal onto the same coax as the UHF digital signal, but be aware that FM is in the middle of the VHF range (87-108MHz)

 

Your best bet in a fringe area is either a good phased array or long yagi antenna, then a short cable hooked to a good masthead amp with inbuilt UHF/VHF diplexer (the FM antenna can go on the VHF connector in most cases)

 

 

Thanks Tangerz,

 

For the FM aerial, any recommendations? assuming this should be vertical (I'm off CHCH sugarloaf so the UHF is horizontal) and do you have a recommendation on a good quality master head amp?

 

Cheers

 

 

 

 


 
 
 
 


536 posts

Ultimate Geek
+1 received by user: 154


  Reply # 1687270 13-Dec-2016 19:03
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pchs:

 

Thanks Tangerz,

 

For the FM aerial, any recommendations? assuming this should be vertical (I'm off CHCH sugarloaf so the UHF is horizontal) and do you have a recommendation on a good quality master head amp?

 

Cheers

 

 

 

 

For the FM antenna, anywhere from something like this:

 

http://www.supremeantennas.co.nz/view/aerials-antennas/supreme-aerial-1-element-fm.php

 

to something like this:

 

http://www.supremeantennas.co.nz/view/aerials-antennas/supreme-aerial-5-element-fm.php

 

depending on how much "help" the FM signal needs.

 

In fact an old VHF antenna is sometimes enough to get reasonable FM reception. (I used to do this when we lived in a distant rural area with pretty good results!)  If you don't mind a bit of DIY and have a suitable old VHF antenna around you could try this:

 

http://www.axino-tech.co.nz/documents/Repurpose%20the%20old%20VHF%20TV%20antenna.html

 

As for polarisation, I don't know if you'd be vertical or horizontal. I've often seen FM antennas at a 45 degree angle as a compromise between the two. Best bet is to just try both (or even H, V, and 45 degree) to see which gets you the best result in your area.

 

 

 

As for the masthead amp, something like this:

 

http://www.supremeantennas.co.nz/view/kingray-products/wideband-vhf-uhf/kingray-mhw24fs-masthead-amp-incl-psk06.php

 

or this:

 

http://www.supremeantennas.co.nz/view/kingray-products/wideband-vhf-uhf/kingray-mhw34fs-masthead-amp-incl-psk06.php

 

depending on how much amplification you need for the UHF signal. Best to get the shielded versions I linked to rather than the unshielded ones so as to best protect a weak signal.

 

 

 

 

 

 


1738 posts

Uber Geek
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  Reply # 1687313 13-Dec-2016 19:53
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Which part of ChCh are you in?


1943 posts

Uber Geek
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  Reply # 1687382 13-Dec-2016 21:38
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tangerz:

 

As for polarisation, I don't know if you'd be vertical or horizontal. I've often seen FM antennas at a 45 degree angle as a compromise between the two. Best bet is to just try both (or even H, V, and 45 degree) to see which gets you the best result in your area.

 

 

FM Polarisation in NZ is slant polarised.

 

See http://www.radionz.co.nz/listen/fmhelp

 

"The rule for slant polarisation is that the aerial, when viewed from behind, that is, looking toward the transmitter, should be tilted ‘right-hand-down’ 45 degrees."


536 posts

Ultimate Geek
+1 received by user: 154


  Reply # 1687511 14-Dec-2016 08:50
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B1GGLZ:

 

tangerz:

 

As for polarisation, I don't know if you'd be vertical or horizontal. I've often seen FM antennas at a 45 degree angle as a compromise between the two. Best bet is to just try both (or even H, V, and 45 degree) to see which gets you the best result in your area.

 

 

FM Polarisation in NZ is slant polarised.

 

See http://www.radionz.co.nz/listen/fmhelp

 

"The rule for slant polarisation is that the aerial, when viewed from behind, that is, looking toward the transmitter, should be tilted ‘right-hand-down’ 45 degrees."

 

 

Yeah but if you read the sentence before that one...

 

"The polarisation, or sideways tilt, of the aerial may be vertical or horizontal as for television or it may be slant for FM radio. The rule for slant polarisation is that the aerial, when viewed from behind, that is, looking toward the transmitter, should be tilted ‘right-hand-down’ 45 degrees."

 

The second part was just to describe how slant works.


1943 posts

Uber Geek
+1 received by user: 130


  Reply # 1688979 14-Dec-2016 22:14
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tangerz:

 

 

 

Yeah but if you read the sentence before that one...

 

"The polarisation, or sideways tilt, of the aerial may be vertical or horizontal as for television or it may be slant for FM radio. The rule for slant polarisation is that the aerial, when viewed from behind, that is, looking toward the transmitter, should be tilted ‘right-hand-down’ 45 degrees."

 

The second part was just to describe how slant works.

 

 

Yeah, I know that but you need a dedicated slant polarised FM antenna for optimum reception as all FM Transmitters in NZ are slant polarised. Vertical or Horizontal is just a compromise (for FM) for those using TV/FM combination antennae where the antenna is mounted (polarised) to suit the local TV transmissions. Trying to receive vertical transmissions with a horizontal antenna results in a 22db loss of signal so I guess using H or V for FM would give 11db loss. Not good if you are on the fringe. I've found here in Auckland that a very short piece of wire stuck in the FM antenna socket on my amp is normally sufficient for good reception and in many places the Rx will work with nothing at all plugged in the antenna socket.


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