Kitz Forum
Broadband Related => ADSL Issues => Topic started by: Loading on March 30, 2014, 11:12:53 AM
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Anyone else noticed that this morning no large spike on the QLN? Tone 46, Plus where has Radio 4 gone?
Transmitter Channel Effect When
Droitwich Radio 4 LF Off Air from 10:12 today
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The main transmitter is down for maintenance "soon", and to be replaced by a (presumably) lower powered device.
BTW a RF3 sees Droitwich off for me, but I'm 100 miles away.
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100 miles away, in Wales? Where did you get your RF3 from?
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3 years ago ! from run-IT-direct
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Just Noticed 198Khz is back broadcasting, lowering snr on tone 46 to 7.25db from 34db, and affecting the others next to it by them decreasing by 2-3db
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Quite a noticeable difference at The Cattery. :o
First you see it, then you don't . . .
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I personally find that it's pointless, as it is available through tv,fm,dab radio, the sooner am stops broadcasting the better >:D
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But it keeps my Casio radio watch accurate and I didn't have to put it right for BST either.
Tony
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That would be MSF Anthorn (http://www.npl.co.uk/science-technology/time-frequency/products-and-services/time/msf-radio-time-signal) surely?
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You are quite right, 4candles. I take it Anthorn is the new location for Rugby which has closed? I'm just so out of date!
Tony
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Aye, Rugby shut down in 2007.
I believe the timing on some Economy 7 electricity tariffs is still controlled by coding on 198 kHz.
Plenty more opportunities until June/July for those experimenting with QLN graphs when Radio 4 LW is off air -
http://www.bbc.co.uk/reception/news/news_item30.html
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I get all my RFI from radio China international 7310 kHz and 198 kHz does not effect me at all on fttc.
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After installing Iplate it seems tone 46 is not being used as the QLN spike is larger? :lol: Opposed to the second QLN before, Second pic
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Although everyday they are turning 198khz on and off it kills my adsl connection, with errors galore it will come back on at about 5:00pm, even though the tone affected isn't in use the connection still stops working! 250khz-254khz also when this is enabled the surrounding tones also loose around 6db per tone. This is now really frustrating >:(
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Loading; in another forum someone removed breakthrough from the 3 Moorside Edge transmitters which were all of 1 mile from him !
Suggest :=
1) mainly for overhead lines use RF3 ( included in I Plate)
2) for pickup on 'phone extensions, use filtered faceplate ( NOT I plate) to stop 'phone extensions acting as aerial.
3) If these are not a 100% cure, consider filtering/spacing from 50Hz wiring.
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All of these have been done exactly the same in the test socket even with the iplate i'm about 70 miles from droitwich. AC balance is 61 which was fine?. Every night the QLN has alot of spikes which only appear after dark? No 50hz wiring by line
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I have the issue with the Moorside Edge Transmitter and confirm the RF3 does little at those frequencies here is a before and after of the QLN.
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Sorry which colour is before and after? :). It's the fact it's worse at night AC balance is fine, but the signal cause the line to be all over the place, when the transmitter switches off the adsl is perfectly stable with very little errors. Surely there Must be something wrong?
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??? Hard to spot from the performance isnt it?
To be fair there is a marginal improvement over some of the tones but it is not enough to make a credible difference.
I bet you can spot my "three peaks" (Moorside Edge tansmissions) between tones 200-300?
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Yeah and i also noticed you are about the same distance if not shorter from the Droitwich transmitter, but aren't affected as much as i am? http://forum.kitz.co.uk/index.php?topic=13555.0
This is what happens during the night, it's a mystery. Your also a mile away and the peak is at -84dbm, i'm about 70 miles from droitwich and still it about -95dbm even with the iplate, faceplate, test socket everything :o :(
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Has anyone noticed that they keep turning on and off he 198khz frequency it messes with my connection constantly!
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I have the issue with the Moorside Edge Transmitter and confirm the RF3 does little at those frequencies
Semmy, I would interpret the results as some rf going round the RF3. There are several other points of entry, even if the modem was in a properly screened box, which isn't usually the case. You have a power connection and probably, Ethernet connections which parallel the modem input.
You said :=
"I like to learn how things work, why they work etc...
Conversation, The desire to exchange views and information.
The desire to make the most of a given situation."
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Has anyone noticed that they keep turning on and off he 198khz frequency it messes with my connection constantly!
Yes. ;) I explained (http://forum.kitz.co.uk/index.php?topic=13986.msg262872#msg262872) in your other thread (http://forum.kitz.co.uk/index.php?topic=13986.msg262799), where you asked (http://forum.kitz.co.uk/index.php?topic=13986.msg262862#msg262862), essentially, the same question!
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Semmy, I would interpret the results as some rf going round the RF3. There are several other points of entry, even if the modem was in a properly screened box, which isn't usually the case. You have a power connection and probably, Ethernet connections which parallel the modem input.
Hmm, I have tried to eliminate those avenues as much as possible.
I use a short (0.5m) twisted pair cable from the SSFPO to the modem.
The ethernet cables are of the screened/shielded variety (only 1m to the router).
I have a good sized ferrite fitted on the DC adaptor lead.
I hadn't considered direct propogation of the RF into the modem, might be time to consider a faraday cage for that ;D
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Semmy, I would interpret the results as some rf going round the RF3. There are several other points of entry, even if the modem was in a properly screened box, which isn't usually the case. You have a power connection and probably, Ethernet connections which parallel the modem input.
Hmm, I have tried to eliminate those avenues as much as possible.
I use a short (0.5m) twisted pair cable from the SSFPO to the modem.
The ethernet cables are of the screened/shielded variety (only 1m to the router).
I have a good sized ferrite fitted on the DC adaptor lead.
I hadn't considered direct propogation of the RF into the modem, might be time to consider a faraday cage for that ;D
Ferrite - I remember one organisation having a very embarrassing failure with those things !
Mostly a good luck charm ! OK at this frequency you can uses a high permeability core, and possibly tune it
Ethernet cables How long in total from computer via router to modem ? With a field strength of (from memory) 1 v/meter you don't need much, and screening can be a very good aerial ! Ferrite may help here too.
Faraday cage - you need Electromagnetic Wave screening not just capacitive. Don't waste your time with non-conductive "metallic" paint - a biscuit tin with holes for cables & ventilation is a quick option. Oven foil is probably too thin at 1 MHz to give much effect, OK at much higher frequencies.
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To be honest I suspect the overhead line into the house really is the primary source.
Having mapped the locations I get the following (see attached piccy).
12 miles almost line of sight (I am on a hill crest facing the transmitter), a 16.3 m overhead wire that crosses the line of sight at nearly 90 degrees makes for good reception!
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Ouch! :ouch:
It looks as if things are set for optimal reception from the transmitter into the drop cable. :(
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So as my next "experiment" I decided to pursue JGOs suggestion concerning a faraday cage for the modem to see what happened.
Hmm.. What to use though? A quick trip to Wickes and I am the owner of some 6mm x 6mm galvanised mesh (a steal at £2.49 for 1m x 1m).
When I get home I fabricate a 7" x 7" x 2" box using 1mm copper wire to "stitch" the sides together.
This is then connected with a 1MOhm resistor (to isolate any potential ground issues) in series to a convenient central heating pipe.
The results are as on the following graphs.... Amazingly there are some changes! ???
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Amazingly there are some changes! ???
Nothing was immediately obvious to me. ???
However, after careful study, I notice a difference at approximately tone 330. What are the other changes of which you are aware?
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I ran a comparison of the bare numbers in excel comparing means for the differing bands etc.
There is approximately a 0.63% improvement over all :lol:
This tends to indicate it is not a problem I need to fix, though I will let it stand for a couple of days to monitor error rates.
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Semmy,
Has your mesh box got a bottom ? people sometimes forget it and it is needed to complete current flow.
With the sort of level you are dealing with several paths may inject noticeable interference so don't expect anything to "fix it" alone.