TV signal strength issues.
In a river valley midway between CP and Sandy!
Signal 100%, Quality 100% except for UHF channel 35 (586000kHz) which has 92% and quality anything from 10 to 100%.
Conventional pole mounted aerial with mast head booster.
Is this really an aerial issue or a duff channel?
Sounds like CCI to me... you have a Ch 35 breaking through from another Tx.
Quite probable in the hot weather we have been having and you ahev whats called atmospheric lifts....
Hmm. Any d-i-y cure?
Certainly going on for a couple of months.
See if you can pickup the same mux from a different off axis transmitter
- then just use manual tune to ignore the Ch 35 version.
Hmm. Something comes up from Sandy but the aerial points to CP roughly the opposite direction! No way of filtering with some sort of diverter?
>Sounds like a reflectionissue, this is where it was so much easier in analogue as you could see the ghosting. Brian
If that were the case it would tend to be time of day dependent in my experience Do you have any tower cranes nearby? Sometimes just moving the aerial a bit can fix it, butlog periodic tend to reject off beam signals better than ordinary yagis do. I remember one occasion where on a particular set of channels the best place for the aerial was down low, but all the others needed it high. If you get a very strong signal of course, you can get cross mod onto another channel lowering the quality by the interference. Brian
I think short of having a second aerial and filtering there is not much left to try. Sometimes with a suitable audio scanner you can tune to the various frequencies and see what they sound like. If the one with the issue does sound less like a hiss with a tickin on it, is phasey sounding or weak you might get an idea of the problem. Its best done switched to AM and as wide a band as possible to see if it is odd, often if its co channel then as you tune through it you will hear louder and quieter bits as well as that sound down a drainpipe effect.
Brian
Might be other things like reflection or over-the-horizon interference. Lossa high pressure at the moment.
Slight misalingment of the aerial, or a narrower beam aerial *might* help Bets test is a cheap TV dongle in a laptop attached by a short length of coax and then go up there and physically move it
If it is CP interference, shoving a wall of foil backed celotex behind the aerial might do something. What sort of aerial is it? Maybe it has a massive love at 180 degrees
CP has com8 on CH35. I'd look up the polar pattern of your antenna, and if its not got massive rejection at 180 degrees switch it with something that has
My friend had a lot of problems with channel 40 (DVB-T2) but the other channels were okay. Could this also be due to atmospheric effects? I thought DVB-T2 was more robust. Meantime I (closer to the transmitter with a much bigger aerial) had no difficulties.
Huh! After you. This is a chimney mounted pole. Relatively young so likely to be chosen for post digital performance.
Umm. The post digital transmitter map has CP putting out 6 multiplexes. I'm only getting 5 so it is not actually CP although the aerial points that way.
Hmm. Beyond my skill set and *Great romance* on channel 52 not a huge loss.
At a glance my aerial points directly away from Sandy. Also Anglia is offered during a re-tune. So what is a log periodic filter?
AFAICS Channel 35 is not used by Sandy Heath. It's used by Crystal Palace* but at lower power than the other muxes. If your power and quality readings are from a TV I wonder if that might explain it.
*for TinyPop, RealityXtra etcIn message snipped-for-privacy@4ax.com, Scott snipped-for-privacy@gefion.myzen.co.uk> writes
Seemed OK through the Winter so the consensus points that way. DIY cure? Log periodic filter has been mentioned. I have easy access to the aerial distribution point.
No fancy test gear here! My LG tv has a provision to check signal strength and quality on an individual tuned channel.
Low power plus interference seems the likely issue.
Log periodic is a type of aerial that is slightly more expensive, but has a different radiation polar diagram to a cheap Yagi.
It seems possible you are actually picking up Crystal Palace multiplexes. Not Sandy. CH35 is not broadcast by Sandy
Is your aerial pointing the 'same way' as everyone elses...where I am as you go over the Great Ouse/Orwell watershed all the aerials stop pointing at Sudbury and start pointing at Sandy Heath...in analogue days my aerial could receive both. although Sandy was pretty crap. The new aerial means I really cannot get Sandy at all now.
You need a log periodic *aerial* not a filter. More gain and less interference broadly. e.g.
Plus ch35 is being broadcast from CP at 20KW whereas all the other MUXs are at 200kW
On your receiving device - has it got DVB-T2 tuners (tuners capable of HD decoding)?
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