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reception problems

I'm in Greenhill and can receive from Emley Moor or Sheffield - they are roughly in the same direction. I manually tune to Emley Moor and the signal strengths are as they have been recently: 65% to 75%.

My set-top antenna is in the loft and feeds a distribution amplifer (came with the house). So I don't suffer from wind/rain etc.

Is your antenna vertical or horizontal? Has it been skewed by the wind?

Martin
 
bixieupnorth said:
just done another rescan this time selecting south yorkshire, i now have four very good muxes, 21, 44, 47 and 48. the quality is 100% on all except 48 which flickers between 80-90%.
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No that isn't correct as 21 is from Sheffield and 44,47 and 48 are from Emley Moor. Try doing a manual tune using the instructions at http://hummy.tv/forum/threads/hdr-fox-t2-tuning-advice.472/page-2#post-5824 first tuning to Sheffield which is 21 (HD), 24, 27, 39, 42, 45 and the Emley Moor which is 32(HD), 41 (HD), 44, 47, 48, 51, 52 and see which is better.
 
From my observations of the orientation of the aerials in Woodseats I would say that the majority are tuned to Sheffield - Vertical orientation - particularly as Woodseats' "centre" is halfway down a valley. The Sheffield transmitter provides the fill-in.

Martin
 
ours points towards the hallamshire from woodseats.

odd that the youview box isnt affected tho?

the fins on the aerial are horizontal, and no, it doesnt seem to have been altered by the wind, again backed up by the youview box

shame you cant choose region before you tune
 
That's the right direction for both Emley Moor and the Sheffield Transmitter (at Crosspool). Approximately 337 degrees - 20 miles and 331 degrees - 3 miles respectively, using S8 in http://www.wolfbane.com/cgi-bin/tvd.exe?.

Wolfbane indicates the best transmitter for Woodseats is Sheffield and that will need vertical elements for best reception. If you are in one of the higher up roads and your aerial is not blocked by other houses then you have a better chance of good reception from Emley Moor.

Different boxes have different tuners and designs so some are more/less sensitive. Does the aerial cable go first into the YouView box and then into the HD Fox-T2 or are they on separate ouputs from your distribution amplifier? Have you a TV with a digital tuner?

Although your aerial has horizontal elements it will pick up the vertically polarised signal from the Sheffield Transmitter, because the polarisation is not perfect, certainly by the time it gets to the aerial. And your aerial will pick up vertically-polarised signals but with a lower signal output. As MartinLiddle has said RF CH21 is from Sheffield, whereas the other channels are from Emley Moor.

Do you know what MUXs the YouView box is tuned to?

At the moment, probably the best thing to do is to follow MartinLiddle's advice, remembering to delete all the channels prior to the manual tunings.

Martin
 
I would personally not attempt to use a transmitter that is vertically polarised if your aerial is fixed horizontally, to quote something I found on the net " On line-of-sight (LOS) paths, it is most important that the polarization of the antennas at both ends of the path use the same polarization. In a linearly polarized system, a misalignment of polarization of 45 degrees will degrade the signal up to 3 dB and if misaligned 90 degrees the attenuation can be 20 dB or more"
 
Agreed. But you need to convince someone to spend time, and maybe money, to re-orient their aerial and that means carrying out trials to collect data.

The loss from the orthogonal signal, as you are probably aware, can be dependent on a number of factors, including purity of the signal polarisation, distance from the transmitter, the design of the receiving aerial and its siting.

Wolfbane, on its default setting, gives a signal strength difference of 25dB between the Sheffield Transmitter and Emley Moor. [We may be talking different ratios here, of course.]

I believe bixieupnorth should look to the Sheffield transmitter for the signals. But, as she says, "odd that the youview box isnt affected tho?"

Martin
 
thanks for advice

we are very high up, so will try to manually tune into the emley moor ones. but looking thru the signal strenght of those muxes they still appear to hover around 30% with quality of 10% so hardly worth bothering with

i'll look on the huawei box to see if i can work out which muxes it uses
 
bixieupnorth said:
i'm in woodseats mike
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I know, I was just saying that the transmitter was fine. Anyway, just noticed you use the Emley Moor transmitter direct. That is horizontal, but you also mention using the Sheffield transmitter which is vertical. How come you receive both? I would suggest your aerial needs to be turned vertical and pointed at Sheffield, or horizontal and pointed at Emley Moor.

Do you get a signal from a portable aerial behind a glass window? That might help you decide where to point and which polarization to use. I find those perspex embedded ones hopeless, but there is a wire one that used to be on eBay that is excellent. This sort:

http://www.ebay.co.uk/itm/Indoor-TV...t=UK_ConElec_TVAerials_RL&hash=item2333b57ebd

The signal is far superior to what I can get from this sort:

http://www.ebay.co.uk/itm/Telecam-T...t=UK_ConElec_TVAerials_RL&hash=item461783de5e

PS To all those who think they can "look up" what might be the best transmitter for a region, they should try living in Sheffield! Does anyone market a motorized aerial? :p
 
MartinLiddle said:
You mean like this
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Coo! Does it draw its power from the tuner box?

We got a satellite dish when Sheffield was so slow to roll out digital (Channel 5, even!) and mostly use that. We get no signal from Emley Moor. There may be several miles of rock in the way. Sheffield is line-of-sight, and our last resort in heavy rain or sticky snow, when, despite my following recommendations to put a larger dish up, we still lose our satellite signal!

Freesat has a better range of channels, and a few extra HD channels.
 
Mike0001 said:
I know, I was just saying that the transmitter was fine. Anyway, just noticed you use the Emley Moor transmitter direct. That is horizontal, but you also mention using the Sheffield transmitter which is vertical. How come you receive both? I would suggest your aerial needs to be turned vertical and pointed at Sheffield, or horizontal and pointed at Emley Moor.
Click to expand...

i'm not an expert but the aerial has fins that appear to be horizontal and the whole thing points towards crosspools, is that what horizontal means, does a vertical aerial point skywards, or is it the fins that point upwards??
no idea how i receive both??
Mike0001 said:
Do you get a signal from a portable aerial behind a glass window? That might help you decide where to point and which polarization to use. I find those perspex embedded ones hopeless, but there is a wire one that used to be on eBay that is excellent. This sort:

http://www.ebay.co.uk/itm/Indoor-TV...t=UK_ConElec_TVAerials_RL&hash=item2333b57ebd
Click to expand...
http://www.ebay.co.uk/itm/Indoor-TV...t=UK_ConElec_TVAerials_RL&hash=item2333b57ebd

we've got hummy tv in bedroom which works off indoor aerial, but its just an single upward pointing one, seems to have a fanastic signal, but then again its right in the eaves at same level as the rooftop one
 
bixieupnorth said:
i'm not an expert but the aerial has fins that appear to be horizontal and the whole thing points towards crosspools, is that what horizontal means, does a vertical aerial point skywards, or is it the fins that point upwards??
no idea how i receive both??
Click to expand...
Yes, for Crosspool the fins must be vertical, that is possibly what is wrong.

wpa168c865_01_1a.jpg


bixieupnorth said:
we've got hummy tv in bedroom which works off indoor aerial, but its just an single upward pointing one, seems to have a fanastic signal, but then again its right in the eaves at same level as the rooftop one
Click to expand...

One vertical fin, not directional, signal fantastic, so which signal does it pick up? Almost certainly Sheffield, as it is vertical. I suggested the other aerial as it is directional and would allow you to see where your best signal came from, but you seem to have answered the question.

The rooftop aerials generally have a square hole and you can stick them on either horizontal or vertical, by turning through a right angle. You need vertical, and to point at the transmitter at Crosspool. You will get a signal with it horizontal, but very much reduced.

So, question is, can you get at it safely?
 
cor no chance!! its right on the chimney stack of what looks like an ordinary terraced house, but its actually a four storey drop onto stone steps!! no way am i going up there!!

the indoor aerial just looks like a wire with a bobble of the end of it, like a car aerial but black.

hard to believe that the fins being vertical or horizontal can make any difference??
 
Absolutely it does. Try looking at polarised light through Polaroid sunglasses, and rotate the glasses. You get polarised light from the sky, or more particularly from reflections off non-metallic surfaces - so Polaroid sunglasses are orientated to suppress the polarised light reflected from a horizontal surface.

The polarisation of radio waves is used to reduce cross-talk between different transmitters, and typically main transmitters are horizontal while repeater stations are vertical.

If you have a TV aerial which doesn't care which orientation it is at, it's a crap aerial.

(For information: there is another type of polarisation called "circular", such that the EM vector rotates 360° over one wavelength. Antennas designed to receive circularly polarised radio waves have helical elements instead of the straight rod directors on a linear polarisation antenna, and the helix can be either left-handed or right-handed to suit the left or right handed circular polarisation.)
 
Mike0001 said:
There may be several miles of rock in the way.
Click to expand...


Don't worry. I'm sure the government has plans to sell off all the rest of the electromagnetic spectrum to phone companies. They'll then put a few £k into making transmission of TV by neutrino stream work properly - and put the transmitters in Australia, where there's plenty of land with no nimby's.
 
bixieupnorth said:
cor no change!! its right on the chimney stack of what looks like an ordinary terraced house, but its actually a four storey drop onto stone steps!! no way am i goping up there!!

the indoor aerial just looks like a wire with a bobble of the end of it, like a car aerial but black.

hard to believe that the fins being vertical or horizontal can make any difference??
Click to expand...


Looks like you may have to pay someone! Do you have a clear view from lower down the building? You might be able to fit an aerial lower down and adapt the wiring. Alternatively, being as the aerial is clearly intended for Emley Moor and not Sheffield, it could be that it isn't wideband. How old is it?

The relays (eg Sheffield) are polarized differently to the main transmitters (eg Emley Moor) so as not to interfere with one another. As for how it works, think of those aerial rods as hollow and containing a tiny ball bearing each. Think of the transmission as a magnet moving near the rods. If the magnet moves in the direction of the rods, the ball bearings will move. If the magnet moves at right angles to the rods, the ball bearings will not move at all. That is what is happening with you.

Try turning the indoor aerial so it is horizontal but at right angles to the line from you to Crosspool and you should see your signal fall off. However, with it horizontal, you should see the Emley Moor signal strength increase.

Finally, has this just recently started to happen? Loose wires? Aerial socket behind TV shorting out? Have you tried a different cable from TV to aerial socket to eliminate that? Swap cables between Youview box and T2? I know the aerial is wrong for Crosspool but there could be something else causing problems with Emley Moor, eg, some loss of signal locally or a brand new 4G mast being tested between you and Emley Moor?
 
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