Thanks to that website,
http://www.mediumwaveradio.com, good tip -thank you, I looked a frequency or two up.
TalkSport 1053kHz on top of bin 244 would appear to be on the Black Isle peninsula,
An t-Eilean Dubh, (it is not an island despite the name), which is on The East Coast, a wee bit further north than me, north of Inverness in fact. So even though they are all the way over on the east coast we have a couple of Broadcast radio stations making trouble for people even a good 70 miles away and there are hills on Skye in the way and then the towering
Cinn t-Saile mountains especially
Beinn Fhada on the mainland in the way too.
A noise bump of height approx 6dB over bins 204-205 879.75 - 884.0625 kHz went away in the second sync compared with the first.
I dug up the following from
http://www.g8dhe.net/ADSL-DSL%20paper%20INTFR-I1.pdf :
8 815-8 965 kHz AERONAUTICAL MOBILE (R) - Civil and non civil aeronautical communication services, including data link services. BT on 8.960 MHz from Rugby. NATS joint use of 8 831 kHz, 8 864 kHz, 8 879 kHz, 8 891 kHz, 8 906 kHz and 8 957 kHz using transmitters located in the Republic of Ireland.At 882 kHz there is a 100 kW
Radio Wales transmitter looking Northwards out over the sea from the Somerset Coast, but even at that power that
has to be way way too far away surely at 429 miles [!], and there are the Welsh mountain ranges in the way, if that makes any difference at all.
More realistically we have a source on 883 kHz, weather broadcasts for shipping coming from
Tiriodh (anglicised as ‘Tiree’) an island which is 60 miles away to the southwest and a clear line from the house over the atlantic but just over the horizon. I can even just about
see Colla which is closer and is next door to Tiriodh. So that is what I will put my money on.
Given that two bins are knocked out, it could be that we have something just on the wrong frequency, straddling two bins or even two disturbers.
Seems that the authorities should over time require new stations or perhaps even existing ones to stick to certain quantised frequencies in future to avoid the two bin zapping / straddling problem. But what frequency grid? What if designers ever want to change the spec of new replacement DSL systems in the distant future? I wonder how enormous the cost would be if designers wanted to have unequal width bins and a territory-dependant map of their frequency allocation. This could perhaps one day optimise performance for some unknown reason or do better at living with the pattern of high power narrow-ish broadcaster disturbers’ centre frequencies and widths.