Crystal Palace Vertical MUXes ?

[Channel Hopper]

I've noticed quite a few new vertical polarised yagis installed round here in the past few weeks (and some not so new), all pointing towards Crystal Palace. Is there something due to appear on the transmitter thet I do not know about, or could these be existing Reigate/Guidford installs that the 'engineer' has simply turned round ?

 

[Fisty McB]

I've seen a few similar aerial set ups in Belfast, at first I thought they were to look at the Black Mountain relay site (the two are quite close, especially since BMs relay service area is to cover a spot that's in the shadow of Divis), but apparently it was a cheap, dirty but rather effective way of attenuating strong signals from Divis that was overloading the tuners. Maybe this is what's happening here?

 

[Channel Hopper]

Thanks. There's not much else in the region once the aerial is pointed to the tower. Plus this is all DVB-T stuff and everything is on completely different parts of the UHF spectrum

 

[Fisty McB]

With DVB-T2 mispolarising the aerial has an advantage over analogue that the anti-ghosting properties that the aerial would have if it was correctly polarised being otherwise reduced is not a major concern with digital terrestrial. Those aerials I seen in Belfast seem to have been up for some time, I guess attenuators cost a lot more back in the 70's.

I could certainly imagine that there are some parts of London where the signal strength from Crystal Palace would easily overload tuners. I remember hearing a story that BBC Engineers were doing a Ceefax demonstration in the basement of a multi-story building - because of issues with ghosting at their location they had to use one of those "high-gain" X-beam aerials to ensure Ceefax would be error free, the problem was that even after using an entire 100 metre reel of coax cable down to the basement, the signal still overloaded the tuner for the set up!