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All posts by jb38

Below are all of jb38's postings, with the most recent are at the bottom of the page.

J
Freeview reception - all about aerials | Installing
Sunday 2 January 2011 5:29PM
Stamford

On any installation where the aerial is liable to have very slight drift analogue is undeniably always the best, however freeview would be the second choice with freesat the last as dishes are the most critical of all to any movement no matter how slight.

Advice cannot really be given as a very important aspect has not been mentioned, that being your location in relation to the nearest multiplex transmitters, as depending on where located an easy to mount simple log aerial may well be suffice, these type of aerials being ideal for narrow boat / caravan etc use, and indeed even home use as I use two of them (built in amplifier types) for long distance reception where direct line of site isnt possible.

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J
Freeview reception - all about aerials | Installing
Monday 3 January 2011 10:47AM
Stamford

Rusty - The reason for your restriced number of channels is because you are only picking up one multiplex with the others most likely being underneath the receivability threshold
level, this usually being referred to as the digital cliff.

Assumming your aerial is pointing to the West for Emley Moor(approx 27miles) you should carry out a manual tune on 40-43-46 and 50 as you will already be receiving 52, and of course on each channel entered (whether or not anything recived) select a "signal condition" (Panasonics description) check on strength / quality, the latter being the most important.

It should be said though that you "might" not get reception on all channels mentioned until after high power switchover, but the signal strength / quality scale would allow you to trim the aerial alignment should this prove to be necessary.

(PS: Belmont (39mls to West) is also a possible for DN7)

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J
Freeview reception - all about aerials | Installing
Monday 3 January 2011 3:30PM
Stamford

Richard (Smart) - You dont mention what station you are receiving as both Belmont and Waltham are possible, Belmont being (or should anyway!) be by far the most powerful as in your area Waltham can be a bit iffy in many places and so really requires a roof mounted outdoor aerial for satisfactory reception, whereas with Belmont a reasonable loft aerial or one mounted at gutter level on a single storey property should suffice.

Of course aerials and predictions are not exact sciences and so satisfactory results very much depends on local surroundings, like for example being screened by trees etc, something which can be a real killer to a less than perfect signal if wet.

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Michael - I would temporarily install the set that's giving problems on the downstairs aerial and then carry out a re-tune, once done give it test to see if its picking up roughly the same number of channels as the set originally installed there.

If all is OK then reinstall upstairs again and carry out another reception check, should it have gone downhill again then it has to be an aerial feed problem to the set.

You haven't mentioned the method you are using to feed the sets, but they should really be fed from a powered booster / splitter, this preferably located as near to the aerial as possible although if you are in a good signal area then its not just so important.

A final point to note is that different brands of TV sets do not necessarily have the same reception sensitivity, this making it whereby if the signal strength received is a good bit less than perfect the less sensitive sets may not respond properly due to the signal being underneath their reception threshold level.

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Unni - Purely for test purposes I would move the TV into the old ones position and try giving it a retune, as with a roof aerial at only 8 miles away from the transmitter you shouldn't really have any problems, that is unless an intermittent technical problem occurred at your local transmitter, something which does not necessarily always get officially reported and especially if it concerns the power supply to the station. (Eitshal)

Also without wishing to cast aspersions on the socket fitted by the electrician, but do not automatically take it for granted this is OK as electricians can, depending on experience or the lack of, show scant regard when dealing with anything of an RF nature as its not really their line.

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Susan - Are you sure nothing has changed since you first carried out the scan on your separate freeview box? as your problem suggests the possibility that your aerial has moved and the few channels you are getting is just the slightly higher powered ones.

You are in an area that depending on location within the post code mentioned there is a chance of picking up three different stations, that said though only one (Angus) will give all the channels as it operates with six multiplexes, whereas the other stations (Tay Bridge & Camperdown) only operates with three thereby limiting the availability of channels.

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Rich Martindale - Apologies for intruding on Briantists replies to you, but being fairly knowledgeable of the Newark area I can say that certain areas in and around Newark have always experienced reception problems, that also applying to analogue right from when it first started transmission.

Even in a couple of villages slightly South of the town where friends of mine reside, tests I carried out last year proved the DTT signals received from Belmont were far in a way better than Waltham, this to the extent that when the former switches to high power I may possibly have to by-pass the internal amplifiers located within the log periodic aerials I had fitted up for them when they went digital.

Regarding Waltham, I also get quite variable performance from there, and even on Mux1&2 with virtually 80 /100% quality indication (Panasonic & Humax devices) this can suffer from an occasional dive to about 20% every now and again, and although I am in no way line of sight I don't feel its just happening due to atmospheric reasons, albeit of course its quite correct that it could.

I do feel though that when Waltham goes over to high power most of the problems presently experienced will likely disappear, that is as much as can be expected with digital reception of a terrestrial nature.

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Rich (Martindale) - Well my personal opinion on your situation is, that if you don't have any great problems whilst viewing the other main channels then its maybe best policy to wait until after the changeover before making any decisions, as judging by what I have read in various places it seems to be that there is quite a number of people forking out money for the type of upgrades that I know is very likely to only result in a fractional difference in reception, when if they were prepared to wait until after switchover occurs their present problems would most likely to a great extent just about vanish.

Regarding the signal strength you reported as getting on Ch33 (570Mhz) which does seem to be a bit on the low side although the quality diving is the real killer, that being said though as far as strength is concerned the level being indicated for a given aerial signal input level can vary by quite a large degree depending on how enthusiastic the scale is designed on the particular brand of reception device being used, as in my own case my Humax PVR indicates 65% strength & 100% quality on MUX1 (Ch49) whereas the same signal input on my Panasonic G20B TV indicates the level as being 100% on both S&Q, however purely out of curiosity I would be interested to know what strength / quality you get on Ch49 (698Mhz) - Ch23 (490Mhz) & Ch26 (514Mhz) as if "some" channels are not considerably higher (excluding 26) then it could possibly indicate a problem.

Two clarifications - (1) re- Briantist mentioning Ch56 after changeover, it simply means that the programme operator Aquiva that Sky sports is on will then be using Ch56 (754Mhz) @ 25Kw output rather than what they are presently on @ 8Kw output, although at changeover everyone will have to retune their equipment as all the MUX transmitters are changing their channel positions.

(2) Regarding your mast head amplifier, to check if its still operating all you require to do is unplug its mains connection whilst you are watching a programme, if you are on DTT (DVB on some sets) the picture will vanish, and likewise if you are viewing analogue the picture will fade to snow, because if the amplifier wasn't working unplugging it would not make any difference and the fact that it does somewhat proves its OK.




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Rich (Martindale) - Thanks for the signal strength / quality check on the various channels I mentioned as this has proved to be very helpful by making it easier to assess the cause of your complaint by somewhat confirming what I expected, being that although obvious deficiencies do exist with your present reception they are of a nature that doesn't suggest they are in any way caused by problems within your installation but originate totally out with your control, as with the variable signal strength / intermittent quality dive problem only really being evident (in severity anyway) on 570Mhz is just one of these inconveniences that will rectify itself at switchover and is a problem commonly experienced with distant reception from a low powered source, as the low powered signal is vulnerable to all forms of possible interference along the route, coupled of course to possible atmospheric condition problems making matters worse.

I find your report on 570Mhz interesting though! as I experienced this channel increasing in strength to 100/100% last year near to about the same time scale you said your own reception of it went downhill, of course on the negative side (for myself) my 514Mhz took a dive at a similar time whereas you seem to be OK with reception of this frequency, my Ch26 reception jumping on and off the so called "digital cliff" effect.

Although I don't profess to knowing reception conditions out with Newark as far as your neck of the woods is concerned, as aforementioned I do know Waltham to be very iffy in many places hence the reason Belmont is used by quite a number of people, albeit of course that the local news doesn't really favour the area, so although I honestly do feel that come switchover the problem that you presently experience will be no longer in evidence Belmont should not be discounted, this being irrespective of the fact that you have noticed that all aerials in your area point towards Waltham, as to frank about it aerial installers in very many cases just "go with the flow" to save time as the DTG post code predictor (unlike Wolfbane.com) gives Belmont as first choice for coverage with Waltham being second, this with a NG22 8EF post code being entered. (Local Co-op)

Just to finalise as I realise I am going on, I wouldn't touch anything until after switchover as to me all seems OK with your system, fine trimming aerials can sometimes give slight improvements but as well as these being fractional its usually at the expense of some other channel.

Hope the info may have been of some assistance. Regards JB38.


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(Rich Martindale) Thanks Rich! and come later on in the year will look forward to hearing an update from you. Regards - John (JB38)

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