All posts by Dave Lindsay
Below are all of Dave Lindsay's postings, with the most recent are at the bottom of the page.
Geoff Liman: Speak to your neighbours and see if they have similar issues. Ensure that they are using the terrestrial system and not satellite (Sky/Freesat) or cable TV (Virgin Media). If it does affect them then it is a fault with the aerial system and therefore should be reported to the party responsible for rectification.
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stacey: If the dish is connected to more than one room then it will be apparent because:
- there will be at least one cable from the dish for each room, and;
- the sockets in each room will be threaded f-connectors rather than push-in aerial connectors.
If the sockets are for terrestrial TV then two possibilities spring to mind:
1. The aerial feeds into the main room such as the lounge. There is another aerial socket which is the "out" feed to all other rooms. There may be a booster fitted to split this single "out" feed into multiple feeds, one for each room. This may have been the case in order to allow the Sky box (assuming it was Sky as the dish can work equally with Freesat) to be viewed in other rooms.
2. If it is a relatively new-build then the feeds in the other rooms may eminate from the loft but not be connected.
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Stacey Green: Yes, the cable that was/is being used for satellite is suitable for terrestrial television.
Within the loft use threaded f-connectors if possible. I say "if possible" because some amplifiers (boosters) use plug-in coax plugs - not that you necessarily require one, you may be able to use an unpowered splitter, depending on the strength of the signal. See here for information:
Satellite, Television, FM, DAB, Aerial, Coaxial Cable, Plugs, Sockets, Connectors & Leads
Before you cut any cables, think about how you might leave them in a state where they could be reused should your requirements change. For example, if the cable from the dish comes into the loft it's probably not a good idea to t cut the cable right at the point where it comes in as you won't be able to join onto it again in future and may require a new piece of cable running from the dish.
If the cable from the dish runs into the loft you may find that the cable from it joins to a separate piece of cable to the socket in the room. It may be preferable to disconnect at the joint rather than cutting it.
You may need some more cable to do what you need. Use f-connectors and a female-to-female adapter to join them (there is no need to cover them in tape if they are within the loftspace):
Satellite, Television, FM, DAB, Aerial, Coaxial Cable, Plugs, Sockets, Connectors & Leads
You can't simply connect two or more aerial cables to the terminals on the aerial. Well you can, but it's a bodge.
If you use an unpowered splitter, then something like this will do:
Konig Satellite F-Splitter: Amazon.co.uk: Electronics
Other models and suppliers are available. Try to avoid leaving outputs on an unpowered splitter not connected to a TV/box.
In the bedroom, if it's a threaded f-connector socket, as it should be for satellite, replace this with a push in coax socket. That said, if it is I don't understand how you've tried it with your TV. The other alternative is to use an adapter with f-connector to coax socket.
Use double-screened cable such as Webro WF100.
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Anthony: I think you must be looking at out-of-date information.
The process of digitial switchover cleared channels 31 to 35, and 37. These channels are now//will be used exclusively by the quasi-national HD multiplexes. Winter Hill does broadcast COM7 on C31. In future, Winter Hill could possibly use other Group A channels and so it is advisable, if installing an aerial, to ensure it's suitable for reception of these channels so that it doesn't have to be replaced again.
A yagi aerial's gain drops off on lower channels. A "wideband" yagi aerial is much more of a compromise because it's gain curve is effectively "stretched" across a much broader range of frequencies. Thus, a "high gain" wideband aerial isn't "high gain" on Group A channels. This can be seen in these example gain curves:
Gain (curves), Again
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Geoff Liman: Whilst you're at it, get them to enable reception of the new channels, if it hasn't already been done. I say this because it may help reduce the number of visits required.
Often communal aerial systems are filtered so as to only allow through, from the aerial, UHF channels (frequencies) used by the designated transmitter. There are a number of new channels being used by, or to be used by, Crystal Palace:
The new HD multiplex which carries BBC Four HD, BBC News HD etc is on UHF channel 33 and has been on air since December.
The new local TV multiplex which will carry London Live is on UHF channel 29. I say "is" because it may be broadcasting a test carrier.
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Julian: There's something odd here and which would seem not to have anything to do with your aerial. The reason for this is that digital signals are "multiplexes" which carry multiple services. So all BBC standard definition TV and radio are carried on a single mux (multiplex). Thus if you have one you must have them all.
Check that BBC One is tuned to UHF channel 49 and same goes for BBC Two, by viewing the signal strength screen.
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Julian: Samsungs are perverse as they do not display UHF channel numbers and instead display frequencies in MHz only. As Michael says, C49 is 698MHz.
The main point is that the information as far as Freq. and Network goes is that BBC One is the same as BBC Two, and that ITV is the ame as Channel 4. Is this so? And if not what are the different values for these fields?
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Jane Cooper: Refer to Radio & Television Investigation Service for your postcode:
Radio & Television Service
The Eastbourne transmitter (South Cliff Tower) was off-air from 10:28 to 22:47 yesterday (Friday).
As I explained in our previous correspondence, the Hastings transmitter uses the same frequencies as Eastbourne, but for those channels which you can't get from Eastbourne. My guess is that when Eastbourne went off the air the Hastings signals are good enough to use. You would have been unable to receive BBC and ITV from Hastings probably because your aerial system is fitted with a filter to only allow through (from the aerial) frequencies used by your designated transmitter.
I imagine that at 22:47 when Eastbourne was turned on again that your reception of the Commercial channels from Hastings would be lost.
You will now have to carry out another retune in order to restore reception of the signals from Eastbourne, this not being necessary had you not carried out the retune this morning.
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Wednesday 12 February 2014 6:17PM
Anthony: Installing a C/D aerial for TV is generally ill-advised these days because in coming years all C/D channels may be given over to mobile operators and C/D transmitters like Winter Hill will have to move to lower channels.
What is being received?
If you have the HD channels broadcast on COM7, which is on C31 then maybe the strength of C54 is OTT. My reasoning for making this suggestion is that C31 is on lower power than the other channels, plus the aerial is less sensitive because it is out-of-group. Reception is a black art, so this may not necessarily be the case, particularly in situations where line-of-sight is obstructed.
Taking the postcode you have associated with your posting it would appear that there are a number of obstructions up to about 3.5 miles out:
Terrain between ( m a.g.l.) and (antenna m a.g.l.) - Optimising UK DTT Freeview and Radio aerial location
Try, as a test, connecting only the inner core of the aerial lead. That is, remove the outer screen, for example from the plug, and plug in the centre conductor. This is in an effort to "loose" a bit of signal. Then try a manual tune on C54.
By the way, if you go to the manual tune screen and enter/select the desired UHF channel but do not press the button to scan/add services and instead wait then you should find that the device acts as a signal meter. Do this before doing the test and after and compare results.