All posts by Nick
Below are all of Nick 's postings, with the most recent are at the bottom of the page.
Chris.SE: sorry Chris only just seen your reply. Where do I start in replying. Its a fairly complicated set up here, all home made! I have two aerials one for the stroud relay and a horizontal antiferance high gain for Ridge hill.
These are fed into a home made combiner which filters the two bands of frequencies. Has about half a db loss on the Ridge hill input. Just to complicate things more I have a home made amplifier (14 db)on the Ridge hill input. Then after all that mess it comes out the combiner and goes into a distribution amplifier which feeds two sets in my house and also the neighbours! There's also a tuned notch on the high side of the combiner for 4g . As for signals on the various multiplexes. Ch 22, 25, 28, 29 are all 100 signal 100 quality.
Ch 24 is variable but around 97% signal 60% quality, much the same on ch 27. They do vary considerably though, but fairly reliable. I'm not too bothered really as there's little worth watching on ch 21 multiplex. It just intrigues me! I've connected my spectrum analyzer to the system and all multiplexes are present and correct but you can clearly see the 3 lower power ones. Some one else commented that the Chalford really could be a problem, well its too weak and feeble here and cross polarised.
Tropo can cause problems but still the situation is the same now with normal propagation.
Anyway thanks for your reply and hope the above makes sense. My complicated system has always worked fairly well! Best wishes nick
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Thanks Chris and Steve, Overload I'm sure is not a problem Chris, I can insert various attenuators until COM5 and COM6 start to degrade in strength and quality. Strange yesterday evening COM4 was 100% strength and 0% quality. So I'm coming round to the idea that the signal is being corrupted by possibly Chalford after all. That doesn't explain why its got so bad recently, but there may be many factors involved. 4G is well notched in my little box and not that strong in the first place.
Steve I can't see Chalford on the spectrum analyzer with Ridge Hill present, anyway digital signals just appear as blocks of noise.
But today just for a laugh I connected the group B vertical aerial (Stroud relay) to the spectrum analyzer and could clearly see the 3 multiplexes from Chalford. I know it was Chalford because the PSB channels from Ridge Hill were not present. But when I checked on the TV diagnostic none of these multiplexes were giving any strength or quality, but could still be capable of interfering. BTW COM 6 (27) was 100% 100% signal and quality, don't often see that.
Anyway as I said I'm not too bothered, just like playing around with this stuff. Often find setting up a system like mine is more interesting than actually using it!
Thanks again both, Nick
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It's very hard with digital signals to distinguish one multiplex from one transmitter to another, they just appear as blocks of 'noise' on the spectrum analyzer, was much easier in the days of analogue TV. These days you'd need more sophisticated equipment than I have to do proper diagnostics, so I don't have any answer to your questions Steve. Channel 22 is absolutely rock solid BTW as are all the PSB multiplexes.
Anyway thanks both
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You must have an aerial problem or something interfering.
I'm in stroud so not really in the normal coverage area but I've checked HD channels from Ridge hill.
100% signal strength and 100% quality so moving wrong with the transmitter
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Sunday 15 October 2023 1:46PM
What's happened to channel 21 multiplex. Did manual tune, 0 signal strength 0 signal quality.
All other multiplexes are normal in strength and quality.
Postcode GL52EL