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All posts by F Farrar

Below are all of F Farrar's postings, with the most recent are at the bottom of the page.

Rick: You are lucky to have had ANY HD so far. HD is presently transmitted with only 10kW - the power of 3 fan heaters, so reception is severely affected by all adverse weather/atmospheric conditions, interference, engineering works & bad luck.

Basically, your reception is on the edge and will stay that way through the retune 4th April until 22nd April, when transmitter power goes up to 200kW (including the HD MUX). This should solve all your problems without any subscription fee......

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Briantist: I am sure what you say is true - but wonder if work in advance of reconfiguration of antenna arrays in ahead of swithover could be having some effect on signal levels for some marginal locations - although ERP is maintained. Whether this happens or not; it should all sort itself out after the final switchover when Freeview gains from a massive increase in transmission power.

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David: Pre-switchover, signal levels here from the Hannington were up & down like a fiddlers elbow for months - and now even the unnaffected Muxes are stable. Pre-switchover it was always denied that engineering work was having any effect on digital signals. I suspect ANY site work slightly affected signals in marginal reception areas, taking them below threshold. I suspect much the same for Crystal Palace.
Whether this is true or not; I would hold off enquiries until after the switchover process is completed - because even if you get any relevant answers; they can only refer to a situation which is about to change - or by the time you get them, will have already changed!
I am fairly sure most of the problems people have now will disappear with substantially increased transmitter power.

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Graham: Whatever the reasons for your now poor Freeview reception; you are almost bound to be OK after the main switchover which will take signals well above threshold. Unless you live at the topographically High end of Camberley; your Freeview signal right now is at best likely to be barely large enough & will be susceptible to every conceivable cause of drop-out or channel loss.

David: I agree that reporting absolutely definite, confirmed transmitter faults or questioning their possibilty continue as always to be like talking to the dead. It is virtually impossible to connect with anybody who has the slightest idea what they are talking about - which is infuriating. Nevertheless I still think it is premature to pursue your issue unless the technical problems persist after the Switchover process is completed & may even divert attention away from matters much worse than official obfuscation.

Tim: I do hope when you say the installer removed your Aunt's PVR, this didn't mean he took it away (ie stole it). Such schemes sadly have plenty of potential for rip-offs.

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Interference: DTV is inherently less susceptible than Analog. However DTV receivers & PVRs have much greater flat-out sensitivities than Analog TVs & CAN work well with signals only a fraction of a microvolt. However, we are surrounded with a whole world of things splurging out RF, and in lowish signal situations, these (such harmonics from a nearby pub's tills & fruit machines etc) can very easily produce in-band signals much larger than the TV signal. This has the effect of swamping DTV receivers by turning down their sensitivity by AGC action. So an interfering signal which in itself would not affect DTV reception simply "deafens" the receiver to the wanted DTV signals. Even the existing massive analog signals can "deafen" DTV receivers in this way.
Because DTV is "all or nothing" & atmospheric conditions also vary the received TV signal a bit; reception already affected by interference can be variably lost with weakest MUXes/channels most to be lost.
When transmitter powers substantially increase after switchover & the analog signals disappear; DTV receivers find the wanted signals are much larger compared with all interfering signals - the interference is then submerged under the TV signal. Everything in the garden is then lovely......
UNLESS the new big signal just too much for sensitive DTV receivers - simply cured with attenuators but will surely trap the unwary.

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Hannington (Hampshire, England) transmitter
Saturday 3 March 2012 1:19PM

jb38: There is another "Trading Standards" situation with some TVs with Brand names most have never heard of. These are sneakily marketed as HD TV's by containing the relevant decoders (cheap); but not displays with the capability (expensive) to match. In other words: Yes, they can show HD pictures - but only in Standard Resolution and sometimes worse than that.
Not so very important with small-screen TVs, but not exactly a big-screen bargain!

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David: Best of luck. I fear your quest is fighting against the tide of an endemic cost-cutting Call-Centre Approach to everything:

Decent but deliberately totally untutored staff are cheaply employed to give human voice to FAQ & the blindingly obvious - confined by rigidly controlled scripts which sadly often force them to appear to be high-functioning cretins. They are also very forcefully discouraged from escalating anything to "waste the time" of a minimised number of expensive technicians & experts who - perhaps I am being cynical in suggesting this - could blurt out unpalatable or actionable truths whilst addressing genuine enquiries. Websites erect barriers/obscure useful contact information for similar reasons.

This has to be almost impossible to rectify. It has spread because it successfully & cheaply copes with a numeric majority of issues, which organisations can then loudly boast about - leaving only the detailed or major problems of a minority whose effect on the balance sheet is diddly-squat.

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BBC broadcast test Card "X" during CH54 Preview to help HDTV set-up which is mostly as always. 5 "Bandwidth" boxes to the right of the little girl are for HDTV - corresponding from the top to resolutions: 1080 X 370, 740, 1057, 1482, 1852 & 2225 lines. 1080p/i HDTVs should reproduce equally "clean" vertical lines for boxes 1 to 4 (25MHz) but CANNOT reproduce the 5th (30 MHz) which is beyond the system spec. To demonstrate the absolute limit of the system, the last box should perhaps have been nearer 1920 lines (26.92 MHz) - but it isn't & legends alongside would have been helpful.

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Sorry, should read:
"6 bandwidth boxes"
"vertical lines for boxes 1 to 5" and "CANNOT reproduce the 6th".

I wish it was possible to edit your own posts when you spot mistakes like this!

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LesG: What you describe is also typical of the effects of the RF reflective sky-layers, which tend to move up & down around dusk & dawn, affecting "skip-distances". If you are already in an area with lowish signals, you will either get drop-out periods twice in 24hrs - or just as likely only have good periods only twice a day. Again, when power is increased (and it is going to increase signal levels a lot!) at final switchover, most such effects will disappear. Be patient.

Incidentally, why Crystal Palace when Reading is smack in the middle of Hannington's coverage?

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