[mythtv-users] UK Crystal Palace OTA reception issue on CH55

Stuart Auchterlonie stuarta at squashedfrog.net
Mon Mar 15 15:43:19 UTC 2021

On 11/03/2021 22:49, David Watkins wrote:
> I'm a long time UK MythTV user, originally recording analog TV and now 
> DVBT2 dfreeview,  always broadcast from the Crystal Palace transmitter 
> to the same roof mounted aerial that was on the house when I bought it.  
> I'm 5 miles from the transmitter, with a reasonably good line of sight.
> The aerial looks like this one
> https://www.toolstation.com/loft-outdoor-tv-aerial-kit/p79595 
> <https://www.toolstation.com/loft-outdoor-tv-aerial-kit/p79595>?
> but it's showing its 25+ years age and has a couple of bent elements 
> which can't help.
> Nevertheless I've not had reception problems till recently when I've 
> started getting regular MythTV recording failures for BBC 4 HD.
> BBC 4 HD is a relatively recent addition to the lineup and I think I can 
> see the likely issue.  It's on a high-frequency low power multiplex.
> Looking here:
> https://ukfree.tv/transmitters/tv/Crystal_Palace 
> <https://ukfree.tv/transmitters/tv/Crystal_Palace>
> I see that BBC 4HD is on the highest frequency multiplex (CH55 746MHZ) 
> at 43kW, whereas all the other multiplexes I record from are below 
> 700MHz and at 200kW.

The fundamental problem is that Crystal Palace was originally a Group A
transmitter, which is essentially the lower half of the channel space
and therefore people had aerials installed for Group A.

Now with the move up to ch55, this is outside Group A, and therefore a
different group aerial is required to receive it (this is especially
true if you are further away, like me)

Apparently it is supposed to move back down to the group a freq range,
but I can never find out if that is actually still planned to happen,
or if they have just given up.


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