All posts by Jim F
Below are all of Jim F's postings, with the most recent are at the bottom of the page.
Panasonic equipment tend to be a bit keen to come up with a "new signal found" message and ask for a retune (unless you turn the message off).
I've seen Panasonic kit also baulk at a signal that it regard as "too strong" and then decide to choose the signals from a distant relay Tx.
I'd suggest a signal attenuator for your aerial lead - just for retuning purposed (so the box or TV can't see the weak signal and the strong signal isn't too "bright" for it. Probably need as much as 18dB, maybe more.
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Jonathan: I'd hesitate before recommending permanent attenuation. I have a box of attenuators so I can choose the value that I need (but I also have a meter which means I'm not having guess the signal power). I know a chap that lives almost directly underneath the Clennon Valley relay Tx - his aerial points to Beacon Hill (main Tx) and his Panasonic kit (TV & DVD recorder) needs 42dB of attenuation for tuning, but works fine when that's removed and it gets the full whack. Without the attenuator, both will tune themselves to the Occombe Valley relay (next nearest), which gives pixellation 'cos the power is low & quality poor.
I'd suggest trying the aerial without any boosters - it may have helped for analogue, but digital may not need them.
24dB is the highest attenuator I use - doesn't cost any more than the 3, 6, 9 (or 10), 12 or 18dB attenuators (have a look at CPC), or you could get one of those little variable ones (don't think they go up beyond 20dB though).
Traffic interference - is your coax in good condition (i.e. hasn't got a break in the jacket & screen)?
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Jonathan: Interesting reading about your setup and performance. I think you're saying you have a masthead amp and a further amp (distribution?) in the loft.
You're 10.7km from Mendip, with the edge of a hill (Folly Hill / Clapton) slightly in the way of the signal.
Pre-switchover, I'd expect the adjacent analogue channels would've made things tricky except for MUX C and D (UHF 56 and 67) which weren't adjacent.
Post-switchover, those PSBs are up at 100kW whilst two COMs are at 10kW and your elusive Arq B is at 26kW (on UHF 67).
When you removed the loft amp, did you put in something to provide power up to the masthead amp? Without any power it wouldn't give you any signal. I'm hoping that your loft amp "is" providing power up to the masthead (and isn't full of mains ripple on top of the 12VDC).
Looking at the map, I'm still concerned that you're needing any amplification - there should be loads of signal, and no interference from traffic at all.
When you get the traffic causing trouble, does this show on the Panasonic power / quality indicators?
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Jonathan: I'm thinking that the retune event for Mendip on 11th January has changed both the Arq B MUX frequency and the programme content.
Prior to 11th Jan, the MUX was operating in 2k mode on UHF59 with the "pre-switchover" channel lineup (i.e. no HD programmes, and with things like BBC Four and the BBC radio programmes).
After 11th Jan, the MUX is now operating in 8k mode on UHF67, and may also have the "post-switchover" channel lineup (i.e. HD programmes only, no radio at all).
Manually tuning your Panasonic to UHF67 should show a full (green) power bar, but nothing for the quality bar (unless your recorder has an HD tuner?). There will still be a number 10 at the end, but there wouldn't be any (green) bar at all.
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Oops - that's cobblers what I've just typed Jonathan.
I've sent a mixed MUX message - sorry; please ignore above!
The change to the MUX (2k to 8k) is right, but the programmes (Film4 etc.) are similar to what they were before.
The full retune for the Panasonic may well be the next thing to try - it could well be holding on to the old tuning information for these channels. You'd have to make sure the box had completely "forgotten" any of the old tuning info and then start from scratch.
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Graham - have you checked that your ITV signal (as received by the BT Vision box) is actually coming from SC (should be using UHF channel 44 for digital)?
I'm wondering whether the box has tuned itself to a different Tx (e.g. The Wrekin) at a lower UHF channel which might explain the duff reception.
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Vicky,
Just a thought - some coax plugs use a tiny screw to secure hold the coax centre core. Over time, this can unscrew itself and cause a short circuit to the outer shell of the coax plug (which can in turn knock out all, or some, of your channels).
Check any coax plugs you have - also, if you have a flylead from a wall socket to the TV, try a different (preferably known good) lead.
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Keith,
I've seen the "green screen" effect before with dodgy HDMI connections. You don't say if you're using an HDMI lead (but with an HDR box I guess you are). Could be a dodgy HDMI lead (or possibly something amiss with the HDMI sockets either end).
It would be worth removing the HDMI lead and seeing if works via a SCART lead - after that you'll need to experiment with different HDMI leads, and have a close look at the sockets on the Humax and the TV.
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Steve,
Could you have a close look at the aerial input socket on your Panasonic HDD? Remove the aerial lead, and see whether the coax socket's centre connector (female) seems to be at all loose. I've just been looking at a Humax PVR behaving similarly - the slightest waggle of the aerial input lead made the picture freeze momentarily - that's with a brand new lead that I'd just made up.
On the Humax, it felt very wobbly - didn't get a chance to investigate further as it's only a month old, so is going back to the shop.
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Saturday 5 March 2011 1:11PM
Julian,
The ITV, C4 & C5 MUX from Oxford is on UHF channel 68 (until September).
The occasional atmospheric signal loss probably comes from Midhurst (analogue C4, nearly in the same direction as Oxford, but a bit further on).
UHF channel 68 happens to be the default RF channel for a Sky box. As the problem occurred just after Christmas, I'm wondering if a neighbour has connected their RF1 / RF2 output into their aerial, which might interfere with your signal.
You could try your TV aerial straight into an analogue TV tuned to UHF 68 and see if there's an analogue picture visible. If there is, you just have to find out which neighbour got Sky for Christmas.