Reply With QuoteHmm... What is the quality like when it is good? What kind of cable are you using? Although, I have seen a box that will do that.
Digital reception spikes
Are there any techies that can explain why my digital will suddenly drop off reception quality for 1 or 2 stations and then return to the previous quality when I switch on any light in that room ?
Whenever, say , channel 7 drops out I get up walk over to a light switch turn it either off, on or off and on and the signal resumes, immediately.
This isn't once-off, it is every time.
Is this due to the box, the antenna signal, the power supply or what ?
If it's something in the box I'd probably take it back and swap it for another one.
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Hmm... What is the quality like when it is good? What kind of cable are you using? Although, I have seen a box that will do that.
Simple...plug the receiver into the light switch !
Sorry...couldn't resist it....
Quality is about 60-65% then may drop to about 10%, which loses signal, then goes immediately back to 60-65% when I hit a switch.
It may be 60-65% for a few hours or a day then suddenly drop, but as soon as I hit a switch is returns to a good signal - no delay.
It's a HD stb that I bought recently to replace a SD stb that just died. The signal is actually much better than the old box was, but it's odd how a another electrical connection can influence the digital signal.
I'll leave the more detailed to the more knowledgable folk.Originally Posted by Lofty2
But what you're seeing is low frequency noise being picked up by the antenna. More specifically the low band, i.e. what Channel 2 Analog sits on. Its more apparent with the wachine machine doing its thing,.. or the fridge kicking in, or the Mrs with her hair dryer.
I'm told there's 2 options,.. a digital only antena, which is what I did - and still get the noise.
Or call the techy to reposition the antena to get a better quality signal - this is what I'll be doing as I've tried 2 locations with similar results and I'm not gona go trecking all over the roof. I believe I have to go up, (previous owners did), hence the delay in getting it sorted.
Root problem is poor signal reception.
When watching analog in your scenario, you'll notice the same effect as a slight line, or snow, or similar,... but on the digital side, the feed gets interrupted, hence pixelation, plips, plops, squeaks, etc,..
Hope that helps.
Jim.....
What kind of cable has been used?
Do you have a booster?
I think you'll find it's some gumpy air-core Tandy brandy shit from the 1970's, with 3 strands of copper braided around the air core.
Check the whole length of the cable as well, some bodgy pricks will join 2 cables by twisting the core wires together, leave the shielding off or twist that together too. I've seen every combination done here.
Also those shitty plastic joiners with 2 small screws inside, etc.. I have really seen some AWFUL stuff done to tv antenna cables.
If you find anything crappy like this in the cabling then I'd start by ripping all the cable out and start again with RG6 Quad shield.
If you see improvement but not perfection, then replace the connectors, wall plates and the booster if applicable.
Don't buy it from the hardware store, go to the local electrical wholesaler to buy your stuff. You can rip the whole lot out and replace it for $120-180 max.
I saw the exact same problem on a system with a bit of salt corrosion and 'twisted braid' for splitters. Completely shit install so to say, with plenty of potential for poor joints and unbalancing.
I suspect the 'light switch effect' creates a 'hi earth current hit' or 'touch current', which 'clears' any poor joints and lowers the rf resistance for a period.
I simply replaced the, the antenna balun (antenna was fine), all feed cable and wall points for f-type with appropriate f-type splitters. Perfect reception.
Perhaps remove any rf loop through devices such as satellite set top boxes, video players etc as a further measure/ problem elimination.
Well said biggeorge - it all comes down to what the antenna sees, improve the S/N at the cable input and most problems are solved. Keep this signal inside a run of quality cable - where the clicks and pops, hum and noise can't get in - and you will have a vastly improved system.
You might still get dropouts, glitches or even the occasional 'MPEG SCREECH', but you can't do much about this...except maybe noise suppression capacitor-resistor networks across every switch contact in the house....but then after fixing all of this you will begin to get interference from all your neighbours' switches.......
See it all the time people are happy to spend thousands on thier entertainment system equipment but presist with old crap antenna and cable. A great signal is so very easy to achive in any capital city one just has to realise 20 plus year old cable was only just good enough for analog TV forget about digital.
It's hard to make a come back when I havn't been anywhere
I finally got my head together, now my bodies falling apart.
為什麼不做你被塞滿
The switches don't interfere with my signal and are nowhere near my antenna cable.
The switches only correct the signal if it drops.
95% of the time the signal is great, just now and then the signal will drop, but bizarrely comes back when the light goes on.
Yup your antenna and switches are fine, .... just fix the cabling and any splitters
explain to me what a digital only is? Please!
Digital Only? Ha! What is meant by 'Digital Only' (sales bullcrap) is that it is specific to the band that digital is on, in your area.
Digital ready is a real term. It's simply misunderstood and misrepresented. It depends where you are really.
Whilst 'digital ready' should prescribe an f-type connector on the antenna balun, the more important feature is that the antenna is only tuned for digital channels (as Mick advises).
In capital city reception areas, the primary transmitters use channel 2 (Band 1) or similar for analogue. The remainder of the analogue channels are in the range 6 - 10 plus uhf channels.
The lower channels (Ch 1-5 band 1, 2) are far more affected by impulse noise (trams trains sparking, motor bikes, motors, switches etc). It's the big baddy for digital. Keep this noise out and your viewing experience will be improved.
As a consequence the digital channel plan (allocations) are all in the Ch 6 -12 (Band 3) plus UHF bands (Band 4, 4+ and 5).
So ... if your current analogue reception only uses Ch6 and up, you're antenna is most likely 'digital ready' (apart from perhaps the f-type connector bit).
However remember that digital channels are assigned to Band 3 Ch11 and Ch12, which again your old analogue antenna may not be tuned for.
If your in a capital city then most likely it isn't; unless you are tuned to a translator (poor reception areas) which I think are all uhf.
The down side is; if you stick up a band3 /band 4 or 4+ antenna in the big smoke, you'll be unable to receive the Band 1, band 2 analogue channels.
As Mick has said,.. the term was rather loose,... as Mick & Farmsky have put it,.. I was referring to working with the bands that the digital signals are transmitted on,... and assumed the 'big smoke'- maybe my bad. So losing the lower band,.. and the accompanying noise for the sake of ensuring you were getting the transmisions from Ch6 up - no loss if you're pure digital.
As has been mentioned regarding the "drop-out" when light switches and so-on occur, just wait until you try to watch digital tv when there is a huge lightening storm. Lots of luck!
That's when analouge has it hand over fist on the digital signal, picture and sound are always there it's just that on analogue you 'see' the lightening effect on the screen but it won't affect the total picture information. Digital is far more suseptable to 'make-break' type impulse noise and your light switch is a 'make-break' device.
Ain't newfangled tecnology great? Only when it works....
Again, poor signal in ..... poor viewing experience out, but what you say is quite correct.
You can comfortably view a marginal analogue signal with storm interference as the FM audio is unaffected by the analogue storm noise, whilst the analogue picture shows a few annoying flashes etc.
The same marginal digital signal is unwatchable.
However digital reception with sufficient ber margin is bomb proof.
It's all about the 'digital cliff', you need to improve the ber .... which is simply not possible for most fringe and low signal areas, even with the best antenna in the best location, with the best installation practice and the lowest noise mast head amp (if required).
The Aurora satellite service is available for viewers in these circumstances.
Next door neighbour has been complaining for weeks that he seems to miss the first few seconds of storyline when on digital. He reckoned it happens when the station came back from ad breaks????
I thought that was weird, and surmised wrongly that it may have been some sort of suppression relay or the like in his cheapo sound system he runs it through. I redid all his cables, but he said it keeps happening.
The other night he rang me to say all signal had gone, stb saying no signal.It was too late to look, and I said I'd toddle over there the next day after work and try help.
When I got there, he said he had fixed it.
Apparantly whoever changed his antenna a year or so ago, snipped the coax at gutter level and tossed the old antenna. The person ( I reckon it was him and he is fibbing) then simlpy put normal coax connectors on each end ( from antenna and line into house) and then joined them together with one of the female/female connectors, no tape or nothing. He then layed the joined area in the gutterline to hide it...but in the bottom of the gutter. He showed me the old connector, and it was crumbled away in pieces everywhere.He says the line was lying in water that was still in the gutter.He says he has done the job properly now ( I dunno because I didn't hop up tp look) and he has no sound drop outs.
So, I guess the moral of the story is what all you guys are saying...check things thoroughly, and do them right the first time.
I hope this helps somewhat.
signal to noise has very little to do with this problem
i see it all the time down here in tassie with electric fences
its to do with bad earthing
when you turn the lights on or off a pulse is emitted that is stronger than the signal you are picking up and therefore overrides other signals for a brief second
faulty ballasts in downlights are a major cause of this
with electric fences the signal can be excellent but faulty or badly maintained electric fences will cause the picture to go on off on off etc in a regular pattern
basically if its all the lights in the house or the fridge or washing machine its usually indicates a bad earth on the house
how do you fix it well sometimes you cant
in an ideal world for an earth stake to function correctly it has to hit bed rock this is virtually impossible in a lot of situations
the wetter the ground is the better an earth stake will function as well thats why with some people the problem seems to get worse during summer
with electric fences they can be a real pain in the arse
normally this tends to fade the further away from the source however i did one last week in a valley and the electric fence was about 2kms away from where i had to put the antenna but was pointing in the same direction
the customer new the person that owned the electric fence and gave the guy a call and he turned it off and straight away it was perfect
with a lot of messing round we were able to shield his antenna behind his roof and used a smaller amplifier so as not to cause as much of a spike on the spectrum analyser and it worked to the point where there was only the slightest breakup on the abc and no breakup in sound
this tends to happen more in places that transmit digital in the vhf band as it does in hobart and less off repeaters which are normally uhf
aaeon.1, you say that "when you turn the lights on or off a pulse is emitted that is stronger than the signal you are picking up and therefore overrides other signals for a brief second", but why does it cause a low-quality signal to improve ?
If I hit the switch and the signal were to drop I would understand it, but when I have a bad signal I can hit a switch and my signal improves in quality.
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