All posts by Mike Dimmick
Below are all of Mike Dimmick's postings, with the most recent are at the bottom of the page.
steve: If signals are bad on C55, C59 and C65 but good on the others, the most likely explanation is that you have a Group B aerial, covering only channels 35-53, rather than a wideband. A Group E semi-wideband, covering channels 35-68 is recommended before switchover.
The HD service will be worse affected than Mux C and D because it's half the power, and requires more than twice as much power as those multiplexes do. (This page shows this for Mux 2 and A, which also use a mode requiring more power than Mux 1, B, C and D, but not for the HD mux.)
However, at switchover, all services move into Group B, so I wouldn't bother for just two more months (plus two weeks - only BBC SD services move on the first day, HD services don't move until 22 June).
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Sutton Coldfield (Birmingham, England) Full Freeview transmitteThursday 7 April 2011 5:43PM
Reading
Patrick: Mux B is converted into the HD mux at switchover. Therefore it isn't shown on any transmitter that has switched, and it's not shown after Switchover Step 2.
(The services that were on Mux B go on BBC A, for BBC services, on ArqB for Sky Sports 1 and 2, on ArqA for the new slot if anything actually starts up on it.)
Otherwise, the predictor shows the channel number but no prediction where it thinks the results will be unusably poor - not reaching 70% coverage 50% of the time. The DUK predictor is a bit hard to get your head around because it's based on probabilities of probabilities. Usually this problem occurs where two transmitters in range are allocated the same frequencies.
Looking at the trade view I can't see why it would think Bromsgrove would be best. It won't get to final channels and powers on the commercial muxes until a week after Sutton Coldfield switches over, because SC is currently using the frequencies it's been allocated. SC has no post-switchover retune events and no power restrictions, and the probabilities are higher than Bromsgrove and Lark Stoke.
The Wrekin is about equal with SC in its final configuration: the PSBs are 99% in the first column rather than 100%, but ArqB is 100% compared to 99% for SC.
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London dates are out: 4 April and 18 April 2012. Guildford does not change in advance.
I think you assumed Guildford had to change before Hannington, because of the channel clashes. The dependency is the other way round - if Guildford goes high power before Hannington does it will break Mux 1, 2, A and B, so Hannington has to go first.
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Ridge Hill (County of Herefordshire, England) Full Freeview traThursday 7 April 2011 5:55PM
Reading
Walter Johnson: It starts when the ITV Central high-power digital service starts, on the 20th.
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Susan: The problem may simply be that he's out of coverage. Could you provide a full postcode, so we can see the predicted coverage?
Eastbourne has two relay transmitters, one on top of South Cliff Tower (called Eastbourne) and one on top of a newer development (called Eastbourne Old Town), which appears to have been added when that development was constructed. These relays were added because Heathfield doesn't cover the whole town.
Both relays currently only broadcast analogue signals: BBC One, BBC Two, ITV1 and C4.
At switchover both relays will be 'Freeview Lite' transmitters, transmitting only the three PSB multiplexes. They will both transmit at higher power levels than their current analogue levels - normally digital power is one-fifth of analogue, but Eastbourne will be slightly higher and Eastbourne Old Town double the power.
Heathfield's current digital signals are much, much quieter than the analogue transmissions. It's possible they just don't extend out to Eastbourne at present. The power boosts for the Eastbourne transmitters suggest that they won't be great after switchover either.
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Bernadette Pruden: The commercial multiplexes are on reduced power, but this is not for engineering work. It is to stop them harming the transmissions from another transmitter. From the channel allocations and the power-up date, it looks like it's the low-power PSB transmissions at Crystal Palace, and also Mux B at Rowridge.
The power will be increased on 18 April 2012. However, on the same date, Rowridge and Crystal Palace will start transmitting the commercial multiplexes at full power on those frequencies, so your reception is expected to get worse, not better.
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BBC B on the VP aerials should be 4.4W, the same as BBC A and D3&4.
I guess you can't show the HP and VP analogue power levels separately? HP should be 45W and VP 22W according to UK Television Reception Advice . An old IBA booklet had 55/14. (RG47SH)
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iR: Did you retune your box or TV's digital tuner? The BBC services have moved from C34 to C26, so you won't get BBC One, BBC Two, BBC Three, CBBC, or BBC News until you retune. Also, Mux C has moved from C26 to C34 to allow this.
You ideally need to do a full reset - delete all channels and rescan - to ensure that there's no stale information pointing to the old location. Try 'Factory Reset', 'First Time Installation', 'Default Setting', or similar. See TV Re-tune for instructions for your box.
If you've definitely retuned, check that the box is not on the list of 2K-only or Split NIT equipment: http://www.digitaluk.co.uk/2kequipment http://www.digitaluk.co.uk/splitnit
If you previously fitted a high-gain aerial, you may have too much signal. Predictions are for really good results with a small aerial. It looks like a lot of people in that area have loft aerials (no external aerial).
I know that at The Wrekin, BBC One analogue moved to BBC Two's old frequency, but I'm not sure what happened at Bromsgrove because the new frequency for BBC A wasn't previously an analogue channel. (It was Mux C.) (RG47SH)
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Steve: Yes, that's correct.
On the 20th, D3&4 goes up to 20k and moves to C23. Mux B closes (services have already transferred to BBC A, except Sky Sports which go to ArqB on the 20th). The HD services, which replace it but on C30, start at 20k.
Mux A takes over Mux 2's frequencies of C31 and C49, staying at 2kW. Mux D becomes ArqB, takes over Mux C's channel and doubles to 2 kW, while Mux C becomes ArqA on Mux D's channel but stays on 1 kW. Some people may lose channels on Mux C because of this.
On 28 September, the commercial multiplexes go to the channels and power levels listed above, once Sutton Coldfield has finished with them.
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Thursday 7 April 2011 8:05AM
Andy Newark: It looks like ITV have bought the minimum possible equipment to provide the slots they have available on satellite. 6 slots, 6 Freeview services. The Meridian South-East ITV1 +1 regional service is actually broadcast throughout the Meridian and Anglia areas.
The ITV1 +1 Wales service is broadcast throughout Wales, the West and the south-west, so we're not alone.
The other services are London, Central West (so no East Midlands news), Yorkshire West and Granada. I'm not sure how Border and Tyne Tees are served.
As for Sky, they probably have you down as Meridian Sussex. ITV care more about their advertising regions than about the correct news service: see http://www.itvmedia.co.uk/assets/itvmedia/content/downloadables/itv%20meridian%20micro%202009.pdf for the advertising splits in the Meridian region. ITV's map at
ITV Local | Local Regional News & Weather - ITV
seems to put Midhurst in the 'Meridian West' news service and Heathfield in 'Meridian East'.
You can add other regional variants to the EPG using Add Channels. Follow the procedure at Add ITV 1 Regions, ITV1 Channels to Sky TV Digibox, Freesat . Some of the information is out-of-date but Meridian South is still on 10891 H according to Eurobird 1 & Astra 2A/2B/2D at 28.2°E - LyngSat . (RG47SH)