All posts by KMJ, Derby
Below are all of KMJ, Derby's postings, with the most recent are at the bottom of the page.
Dave Lindsay: Mux D3+4 at Midhurst changes from C61 to C56 in October 2012. This will be the reasont for the prediction of possible interference to reception from Whitehawk Hill.
| link to this comment |
Dave Lindsay: This is true, despite a reduction in the prediction for reliable reception it is quite likely that the viewer might see no change whatsoever if the aerial position coincides with the percentage shown as being able to receive the service, although I am not sure how tropospheric ducting is accounted for in the predictions. In my own postcode area the prediction for Waltham reduces on C29 when Bilsdale switches, and likewise the prediction for C56 and C58 goes down when Sudbury adopts these frequencies in June. I can say that from past experience Sudbury is usually the first out of area signal that appears when high pressure is present, aided no doubt by the fact that Sudbury is in a similar direction to Waltham from here. If the aerial is positioned in a null for the interfering signal, the reception of the desired signal could well be trouble free, finding the correct position can be very time consuming, especially if the unwanted signal is intermittent or fluctuating! As you say, different aerial types give differing results, an experienced installer would normally select the aerial with the best characteristics for the reception conditions.
| link to this comment |
Greg: There are no problems shown on the BBC status report with regard to any of the transmitters serving your area. Check that your aerial is still mounted correctly (rods vertical) and pointing North, I say this because C29 which carries the HD services from Chesterfield is also used at Waltham for the SDN mux. The Chesterfield signal is normally strong enough to drown out the Waltham signal, but in the event of the aerial being out of alignment the signals could simply cancel each other out. What is the signal strength like on the standard definition muxes? If you have any amplification on the aerial it is possible for too much signal to be the problem, as the HD mux is transmitted at double the power used on the other muxes to give Chesterfield a helping hand when competing with a signal from Waltham. Try a manual tune on C29, selecting DVB-T2 if asked to make a choice.
| link to this comment |
Nick: There was a requirement by Ofcom for the local muxes to be planned in such a way that the signal did not stray out of the intended coverage area! As radio waves do not respect county boundaries this was rather impractical, resulting in under-powered signals in some instances, whilst in others listeners are (fortunately) able to enjoy reception miles outside the target area. The D1 national mux has tended to target the areas of largest population and major roads, whilst the BBC is now trying to give good general coverage in preparation for the suggested FM switch-off. The latest Ofcom plans for local services allow for more comprehensive coverage in unserved areas to match the current FM service areas. I will be interested to see if the coverage of existing local muxes is extended to match the FM service areas of all the BBC local radio stations.
| link to this comment |
Andrew: The COM muxes are now all transmitting at 10kW from Midhurst, which is full power for the current post DSO network.
| link to this comment |
Richard: As it is only ITV1 that is showing the poor signal strength it suggests that this particular signal is not from Hannington, but from an alternative transmitter- Crystal Palace or Oxford being likely candidates depending on whether the tuner places the first variant found or the last found in position three in the channel list. Check in the 800's for an ITV1 that works correctly. If possible check which frequency/channel you are receiving for your ITV1, often shown by pressing the info button. For Hannington it should read C42. Crystal Palace is C23 and Oxford C60-. To restore the correct version if there is no channel swap facility, you will need to clear the channel list, then do a manual tune on each of the Hannington frequencies.
| link to this comment |
Michael Hedderly: Note that there is engineering work posted, with Hannington digital TV liable to interuption this week. Strong winds do not affect TV signals directly, although they can cause delay to engineering work, as well as possibly damaging power cables or viewers aerials.
| link to this comment |
Marie Turner: Could you give more information with regard to your location, such as a postcode, so a check can be made on predicted reception. The number of channels you are able to receive depends on which transmitter the aerial is pointing to and may be affected by the type of aerial and in the case of communal aerials (and some domestic installations when two aerials are coupled together) the presence of filters.
| link to this comment |
Gary: This is most unlikely, as when the owners of the COM muxes were asked if they wished to extend coverage to any of the relay transmitters they declined on the basis that the extra cost would not be justified for the small number of viewers that would be added to the service. Your best option for receiving the COM muxes is to see if a signal is available from Crystal Palace or Hannington. Satellite reception would give you ITV3, ITV4, Film4, 5*, 5USA, Sky News and loads of shopping channels, but most of the entertainment channels on the COM muxes are Sky subscription channels on satellite.
| link to this comment |
Saturday 28 April 2012 10:45PM
Pat Brock: It is just possible that ITV from Sandy Heath has been tuned in when scanning, in which case the ITV channel from Crystal Palace could be present in the 800's of the channel list.