All posts by Dave Lindsay
Below are all of Dave Lindsay's postings, with the most recent are at the bottom of the page.
jb38: Dover uses C59 and Nick says that it comes in strong. Do you think that the difficulty with Sudbury's C60- could be that it is offset towards Dover's C59 ?
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Helen: Run the automatic tuning scan and unplug the aerial when it gets to 30% and then plug it in again when it gets to 53%.
This will avoid scanning of Sutton Coldfield's channels/frequencies.
The problem you are experiencing is usually caused by the memory being full. Because it has stored Sutton Coldfield's channels, it would appear that there isn't enough room for all of Waltham's. BBC on C61 is obviously the last to be scanned, so that probably explains why it is it which gets "forgotten".
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Helen: I am suggesting that because it stored Sutton Coldfield's channels that the memory is full. Thus, if you prevent it from storing them, then this should alleviate the problem.
Presumably it stores the channels in the order it finds them, i.e. low frequency to high frequency (as that is how the scan works). BBC on C61 is the highest one.
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John McConnell: The terrestrial Freeview service could be being affected by co-channel interference. See the inversion effect. This does not affect satellite services.
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Nick: I wonder if the problem is Dover's C59 which is drowning out Sudbury's C60-. I wonder if there is any experimentation you could do, e.g. by measuring Dover's C59 from your shed aerial at different times and I wonder if when Sudbury reception is worse, Dover's may appear better.
Perhaps a phased array will help:
http://www.wrightsaerials….pdf
Wright's Aerials
A higher gain aerial has a narrower acceptance angle; i.e. one is traded for the other.
Obviously you will need two identical model aerials, but I don't know what sort of gain you will need on each. An array of two aerials will give a narrower acceptance angle than a single aerial (of the same model).
jb38, can you suggest? Perhaps the fact that the 14kW signals came in quite well might be a clue. Two Log 40s maybe?
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Nick: Further to the above suggestion, I have calculated that you need to set the two aerials 744mm apart from their centres. This gives a spacing of half a wavelength at 345 degrees (clockwise) at 778.0MHz which is C59.
That is, the distance from the point on one aerial to the same point on the other aerial, measured perpendicular to the the direction they face, should be 744mm. It is NOT the distance between the two aerials (which will obviously be less than this).
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B.Denham: Firstly, if you haven't already done so, confirm that you are tuned to Kimmeragh and not one of the other transmitters:
PSB1 | BBC One | Kimmeragh=C44 | Jurby=C46
PSB2 | ITV1 | Kimmeragh=C41 | Jurby=C43
PSB3 | BBC One HD | Kimmeragh=C47 | Jurby=C50
The UHF channel number that is tuned is usually given on the signal strength screen.
I have made a number of other observations that might be of help:
The Digital UK Installer Newsletter published at switchover is here:
http://www.digitaluk.co.u….pdf
It says that the channels used by Kimmeragh are outside of the old analogue Group. Prior to switchover it used Group C/D channels (top third of the band) and after it uses Group B channels (middle third). A C/D aerial may be OK where the signal is stronger, but the more of a marginal area it is, the more likely that this could be an issue.
For an explanation of aerial groups, see:
Freeview reception - all about aerials | ukfree.tv - 10 years of independent, free digital TV advice
Aerials, TV Aerial and Digital Aerial
The DUK Newsletter also says that at DSO Jurby (and Ramsey) became full PSB transmitters. Prior to switchover they carried BBC One and BBC Two only so as to give NW programming to those receiving ITV1 and Channel 4 directly from Caldbeck.
If you can receive signals from Jurby, but discounted it in the days of analogue simply because it only carried BBC channels, then you may be able to realign your aerial on it as it carries all PSB services now. Like Kimmeragh, it is Group B, but your C/D aerial "may" work.
Jurby (40W) operates as a Single Frequency Network (SFN) with Beary Peark (200W) and Port St Mary (2kW). This means that they all broadcast on the same channels (frequencies), as allowed by the digital system. Hence in areas where they overlap, the sum of the two is received.
Finally, come the Northern Ireland switchover on 24th October, you "may" be able to receive the full complement of Freeview services from Divis. The channels used for Divis and Kimmeragh/Jurby are such that two aerials could be combined (diplexed) into one downlead if you would prefer to watch North West programming instead of that of Ulster.
If you are looking for more information and/or products such as aerials, then see www.aerialsandtv.com
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fiona: Whilst tuned to BBC One, bring up the signal strength and ensure it says that you are tuned to UHF channel 25 for the Leek transmitter. If it says C24, then it is tuned to Fenton and that is the problem.
If the set has manual tuning, then try and wipe what's stored, probably by running it through the scan with the aerial unplugged, and then manually tune to C25 for BBC, C22 for ITV1, Channel 4 etc and C28 if it is a HD receiver.
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Chris Verrinder: The services you identify are carried on the Commercial multiplexes which have a lower transmission power horizontally, so your aerial should be vertical.
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Wednesday 25 July 2012 9:19PM
Nick: What is the make and model of your receiver?
Am I right that you have said a few weeks back that others in your locality also cannot receive C60, but can pick-up C58 and C56 ?