THE TRANSMISSION GALLERY
|Photos by John Martin
|Page last updated: 2023-08-26
|23 April 2022 Today I had a message from my mobile network provider (Three) that there was going to be some disruption to the service ...
|... so I looked out of my study window and saw a cherrypicker near the Blair Atholl tower. It was there for about four hours and indeed I had no mobile signal ...
|... the TV multiplexes on Chs 40, 43 and 46 remained on all the time but the interference I get at home on BBC-A (650MHz) disappeared...
| Three use 700MHz for 4G up here and it's a strong signal. Strangely PSB-2 on 674MHz is not affected, despite being closer to 700MHz. I do use a 700MHz filter, have checked on three different TVs and two separate aerial systems and have a perfectly moderate 40dBuV signal level.
Guessing from the collinears on the cherrypicker, I would think that the network provider is checking RF output from the GSM panels. But why this method rather than sniffing the RF sampling port? Could it be that a panel is suspected of generating IMD products which wouldn't necessarily be evident at the sniffing ports? Might that be the reason for interference on BBC-A? Maybe the GSM signals are affecting the incoming channels from Pitlochry (22, 25, 28) and it's not my equipment at fault.
Update: John added these remarks in July 2022:
Looking at the local spectrum, it seems that this exercise was one of moving mobile phone traffic from the 700MHz band to the 800MHz band. I think the operators were using the 700MHz band as a temporary way of extending 4G coverage but have now moved up to 800MHz, leaving the 700MHz band clear for possible 5G rollout.
None of this affected the interference problems I reported earlier. Those problems seem to have disappeared very shortly after I posted about them (almost as if someone from Arqiva was reading them!) which was well before this latest activity took place.
August 2023 Another dish from the microwave backbone has now been downed. Also some graffiti has appeared on the brick-built equipment hut. The graffiti is identical to that which I saw at the Kenmore TX site last year - even the name tags are identical - so I assume both were done by the same artist. Since both sites are on the way to nowhere and in the middle of nowhere, this is obviously premeditated. I assume the artist is someone who works for one of the one of the mobile operators or even Arqiva. Has anyone spotted anything similar?
|All that goes up must come down
|Graffiti at Blair Atholl
|Kenmore with identical name tags
Blair Atholl index
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