All posts by Dave Lindsay
Below are all of Dave Lindsay's postings, with the most recent are at the bottom of the page.
Gary Smyth: I would suggest that the likely answer here is that the receiver is picking up and 'deciding' to use the signals broadcast from the Moel-y-Parc transmitter which is in the opposite direction to that of Winter Hill.
Unplugging the aerial can be used to avoid unwanted signals where those signals are in a different part of the band as the wanted ones. Due to the speed of the scan it is rough and ready, so it can be trial and error getting it plugged in or unplugged at the right point.
In answer to the question of missing ITV/C4/C5 etc then it is worth noting that it uses the highest channel (frequency) from Winter Hill and that there aren't any further channels above that. For that reason, do it again but don't unplug the aerial at 76%, leaving it in until the end.
Or, if there is manual tuning then you can add any missing channels. In this case manually tune UHF channel 59.
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Gary Smyth: Following your follow-up posting, that there is no manual tuning, then in answer to your question: it depends on which channels are missing. Knowledge of which channels are missing will allow an assessment to be made of whether they may be missing because the aerial wasn't plugged in soon enough.
As I say, ITV/C4/C5 etc is on the highest frequency from Winter Hill, so just leave the aerial in until the end of the scan.
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Me: The rear reflector does both. Think of the effect a reflector on a light has.
Size of the relector, elements, dipole and distance between them all play a part. The reason is to do with the wavelength. For this reason, antennas designed to pick up lower frequencies are bigger (because wavelengths are longer). So all the bits are tuned.
I'm not an aerial installer; I have the knowledge of the basic principles.
It may be worth noting that Heathfield and Saltdean are inline with one another, albeit that the latter is vertically polarised. However, Saltdean is a relay of Whitehawk.
Prior to switchover, Heathfield used all Group C/D channels, except for C47 which is just below C/D. After switchover, channels are within Group B, albeit that there is overlap. The COM channels are the lowest and therefore is there are any difficulty it follows that it is likely to be those channels.
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Me: My point in the last paragraph is that if you aren't getting the COM channels from Heathfield then a replacement aerial might do the trick.
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Me: The power of the transmitter is the same at all times. You don't have line-of-sight owing to the high ground at the back of Westmeston Avenue.
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Me: Another Heath Robinson solution is to mount the aerial vertically and directed to Whitehawk. Newhaven is in the opposite direction and also vertically polarised. If you can pick up all channels from Whitehawk then Newhaven will give you the same region as Heathfield due to it being one of its relays.
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Rose: Perhaps it is interference from the 800MHz 4G tests:
Freeview and 4G at 800 MHz coexistence test in south east London | at800
I suggest that you give at800 a ring on 0333 31 31 800 and explain that this is with a communal aerial. If this is an issue with interference from 4G then a filter will probably need to be fitted into the system, which is obviously the responsibility of your landlord or whatever party maintains it.
The at800 team may wish to visit you to ascertain whether it is an issue with interference from their 4G test.
The other possibility is to ring the party responsible for the aerial system. However we don't know how much longer the test will run for and if they were to call out their own engineer the test may have finished before he/she arrives.
At the end of the day at800 cannot install a filter without access to the aerial system. However, they may wish to visit your flat to see whether the interference is the cause and take it from there. As I say, tell them it's a communal aerial system from the outset.
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les thompson: Judging by the Digital UK Coverage Checker and the Streetview photos, your aerial is served by the transmitters of Winter Hill and Skipton.
There are a number of houses on your road with an aerial on each transmitter. If yours is one of those and the aerials are combined into one feed (one cable) then you may find that you are now unable to view BBC services from Winter Hill (which carries BBC One North West), but you should be able to receive BBC One Yorkshire from Skipton.
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les thompson: My first sentence should say: "Judging by the Digital UK Coverage Checker and the Streetview photos, your area is served by the transmitters of Winter Hill and Skipton."
The "aerial" should be "area".
If you have two aerials combined then I can explain why.
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Tuesday 23 April 2013 10:22PM
jamie: Can you not receive from Bilsdale, being in Harrogate 'n' all? It is only 30 miles away.
Pontop Pike is 61 miles away and there is high ground near Ripon which prevents it from being seen from your location.
The terrain plotter suggests there may be no obstructions to Bilsdale.