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GMAN MUX Winter Hill


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Old 11-12-2016, 16:21
anthony david
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Every week when programming my Humax PVR I look at the signal levels from Winter HIll's ten multiplexes which have remained unchanged for at least two years. A week ago I noticed a large increase in signal level and quality for this multiplex only, there are no changes whatsoever to the other nine. Digital UK said they knew of work at the transmitter site but apart from that had no further explanation. The mb21 website shows the GMAN transmitter aerials not far above the transmitter buildings, two log periodics producing a fairly narrow beam in the direction of Stockport which does not cover my location in SW Manchester although the much wider local TV petal carrying That's Manchester, and located about half way up the mast, comes in quite well. My Sony TV shows an improvement of around 10db carrier to noise ratio, again no changes for any other multiplex, a bedroom TV on a different, rather poor, aerial is receiving this multiplex satisfactorily for the first time as well.

I would be interested to know if anyone else has noticed any changes as I can think of no local reason for them.

This CSV spreadsheet seems to show that the GMAN aerials are now at 140m above ground level, just 5m below the local petal ones. It can be read directly, the first few lines are the key, the local petals (ch56) are halfway down and the GMAN (ch57) are almost at the bottom. It should be possible to drag this onto a blank Excel document for easier reading if you have it.

http://static.ofcom.org.uk/static/br...onal-Muxes.csv
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Old 11-12-2016, 17:25
omnidirectional
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The original placement at the bottom of the mast was intended to be a temporary solution so perhaps they have finally moved higher up? The Ofcom document seems to support that.
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Old 11-12-2016, 17:49
Greebo
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The question is whether this CSV represents reality, or just the location where G_MAN is supposed to be broadcasting from. Was there an earlier version of this doc with a lower height?

140m was the height that G_MAN was supposed to be at in the 2008 award document: https://www.ofcom.org.uk/__data/asse...4/15981/im.pdf - see p17 and p20 however instead they used two log periodics just above the building roof level.

Note that even the transitional beam pattern was also for 140m. There was no change to the beam pattern once the Wrekin freed up C57 in 2011 that I'm aware of.

Could your power increase be the result of autumn leaf fall?
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Old 11-12-2016, 18:58
Stigid
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Would this explain why Winter Hill BBC SD TV transmissions (and other Terrestrial channels on the same MUX) are always lower signal strength & quality than other SD channels on a different MUX

Not checked yet to see if they are any better.

HD always come powering through
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Old 11-12-2016, 19:17
anthony david
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Could your power increase be the result of autumn leaf fall?
No, all the other 9 multiplexes are unaffected in any way including That's Manchester on an adjacent channel. mb21 shows images of the original aerial system just above the transmitter building. Hopefully someone in the area will be able to take a look at the mast and send mb21 a few photos.

The large change occurred over a one week period, Winter Hill is line of sight from my location, I can even see the transmitter buildings 18 miles away on a clear day. There are no trees or other obstructions. Signal strengths here are high and unchanging throughout the seasons.
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Old 11-12-2016, 19:49
Greebo
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...Hopefully someone in the area will be able to take a look at the mast and send mb21 a few photos.
If the weather cooperates they probably will

(Having seen it has been added to the hitlist I'm now a bit more convinced it might have finally happened!)
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Old 11-12-2016, 19:54
Greebo
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Would this explain why Winter Hill BBC SD TV transmissions (and other Terrestrial channels on the same MUX) are always lower signal strength & quality than other SD channels on a different MUX
Not checked yet to see if they are any better.
HD always come powering through
Put simply, no. This is specifically about G_MAN which has always been a low budget arrangement. It isn't related to the PSB and COM muxes high up the mast.
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Old 12-12-2016, 08:34
Mark C
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It should be possible to drag this onto a blank Excel document for easier reading if you have it.

http://static.ofcom.org.uk/static/br...onal-Muxes.csv
No dragging required, the full Excel version is here :-

http://www.ofcom.org.uk/static/broad...uency-plan.xls
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Old 12-12-2016, 09:30
anthony david
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No dragging required, the full Excel version is here :-

http://www.ofcom.org.uk/static/broad...uency-plan.xls
Thanks Mark, missed that, saves messing around and learning how to do a CSV conversion which I failed at miserably the first time I tried. For Apple users, Mark's version also opens in "Numbers".
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Old 16-12-2016, 16:55
Greebo
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... Hopefully someone in the area will be able to take a look at the mast and send mb21 a few photos...
So we have a result - there is indeed a new array for G_MAN. mb21 has been updated - http://tx.mb21.co.uk/gallery/gallery...71&pageid=2839 now shows the new array further up the mast - though nowhere near as high as 140m - but high enough to now be very similar in signal strength and quality to L_MAN.
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Old 16-12-2016, 17:39
anthony david
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So we have a result - there is indeed a new array for G_MAN. mb21 has been updated - http://tx.mb21.co.uk/gallery/gallery...71&pageid=2839 now shows the new array further up the mast - though nowhere near as high as 140m - but high enough to now be very similar in signal strength and quality to L_MAN.
Mystery solved, thanks to all concerned for the new pictures on mb21. The fact that the new aerials are stacked vertically instead of horizontally as before may also have widened the beam improving the service area. It is indeed similar in strength to the L-MAN multiplex here in the SW Manchester area.
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