All posts by Chris.SE
Below are all of Chris.SE's postings, with the most recent are at the bottom of the page.
Mike Parkins:
In addition to StevensOnln1 comments, the fact that you are using vertical polarisation does not make you more vulnerable to breakup in certain weather conditions (ie. when there's tropospheric ducting). In fact it is more likely with horizontal polarisation as most of the likely interfering signals are also horizontally polarised.
Having said that, things can sometimes be a bit hit and miss as polarisation can change when there are multiple reflections if the "tropo" path is quite long!
The advantage you have with vertical polarisation for Rowridge is that the COM muxes are also 200kW, the same as the PSBs, but only 50kW in horizonal (although the site owner hasn't correctly updated the Rowridge transmitter page with those details).
Also, with regards the Local mux, the transmission mode means that lower power can be used and still have quite good coverage (but the available bandwidth is less - ie. less TV channels on it).
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Peter Hayward:
Hi Peter. Having done a check on the postcode, the predictor suggests good reception from Malvern BUT better reception from Sutton Coldfield! It's variable to poor from Lark Stoke.
One thing neither of us mentioned which perhaps we should have is that aerial polarisation for Malvern and Lark Stoke is vertical (ie. the rods or squashed Xs should be vertical).
For Sutton Coldfield (and other main transmitters) it should be horizontal.
Just FYI for your location, Malvern is at compass bearing 274 degrees (virtually due W), Lark Stoke is at 95 degrees, 5 degrees S of due E. As already mentioned Sutton Coldfield at 19 degrees.
As with all predictions, it can be a case of trying for which is best at a specific site.
Although you haven't supposedly been sent a postcard from Restore TV, see
https://restoretv.uk/post…ure/
IF you get any constant or frequent disruption to reception (picture breakup etc) then it may be worth getting in touch with them for a Free 5G filter. There are at least two EE masts within 1.5km of you.
Any filter should be fitted BEFORE any Booster/Amp.
In multiplex order BBCA/PSB1, D3&4/PSB2, BBCB HD/PSB3, SDN/COM4, ArqA/COM5, ArqB/COM6
UHF channels for Sutton Coldfield are C43, C46, C40, C42, C45, C39
UHF channels for Malvern are C41, C44, C47, C29, C31, & C37
UHF channels for Lark Stoke are C26, C23, C30, C33, C36, C48
If you are getting any others, post back with more detail.
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Simon T:
In addition to Matthew Bell's comments, what aerial is it and is it a group K?
When you say 39, 42 & 48 are affected at some time of day, when this happens are all 3 affected at the same time or is it more often just one of them on one occasion and another on some other occasion?
If it's all three at the same time, is it always at exactly the same time(s) of day when it happens?
Typically how long does it last, is it different on different occasions?
If the three are affected independently on different occasions, then it could have been recent weather conditions, the high pressure can sometimes cause "tropospheric ducting" where interfering signals from distant transmitters using those channels can travel further and cause reception problems for periods of time. In the SE these can often be from Europe.
The BBC did issue several warnings of this in recent weeks.
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Matthew Bell:
He's on the Oxford transmitter, 34km away, unless he's moved.
I'm not sure you are correct with your explanation. When signals are very strong the receiver agc will turn the gain down but when they are too strong you can get front end overload and that's when problems can occur. In addition the signal strength figure given by the receiver can appear to drop - it hasn't actually done so. When it becomes excessive, the quality figures can also deteriorate.
Because of the transmission mode for HD vs SD, HD is a bit more vulnerable to noise and corruption, so in an overload situation this could occur.
Also, even when all multiplexes are transmitted with the same power, the received signal strength is often pretty much the same for them all, but not always. Even where the path is perfect line-of-sight, there can still be multipath reflections along the way which are also received. Within limits it's virtually negligible BUT all these factors are often frequency dependant. Eg. one example, nearby trees on or very close to the line-of-sight can sometimes severely disrupt one multiplex but not others.
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Sunday 27 July 2025 11:19PM
Mark Agius:
That's not correct I'm afraid. You've either mis-read something or looked at some old information.
Until recently 4seven was on ArqA/COM5 until the 18th June 2025 when it moved to D3&4/PSB2
I'm afraid the blurb at the top of this page hasn't been updated by the site owner since that move.
5Select LCN45 is on the BBCB HD/PSB3 mux but as an SD channel, did you get confused with that?
4seven HD was on the COM7 multiplex until that HD version closed on 22nd June 2020.