View Full Version : channel at 400MHz
Living in ex C&W cable area. Bought a new Philips tele, set to autoscan.
Picked up :
BBC1
BBC2
ITV
C4
Sky 1
Eurosport
and a computer image at 400Mhz, weird - can anyone enlighten me ?
Oops should have noted that this is the normal signal from the cable NO stb in place.
Originally posted by Nemesis
normal signal from the cable NO stb in place.
You lost me. How can you pick up a TV signal from cable without a STB ?
So you plugged your cable directly into the aerial port on your TV? IIRC this is a big no-no as your TV will send interference back down the cable which will affect other users' service.
poolking
26-06-2003, 12:36
Stop assuming folks.
People too quick to jump on other's backs, let Nemesis reply to clarify.
Hang on,
Cable comes into house, goes to NTL splitter, one cable goes to NTL stb, other cable plugs into Aeriel(?) distribution box.
Analogue signal is supplied down cable anyway, has been like this for years.
Plug in tele, autoscan and that's what I can tune into.
poolking
26-06-2003, 12:38
Originally posted by Nemesis
Hang on,
Cable comes into house, goes to NTL splitter, one cable goes to NTL stb, other cable plugs into Aeriel(?) distribution box.
Analogue signal is supplied down cable anyway, has been like this for years.
Plug in tele, autoscan and that's what I can tune into.
Can you take a pic of the screen and post it?
At work at the mo, but ....
The screen is slightly fuzzy, shows a windows based machine with a realtime graph on it, ( seen it crash a couple of time too - hehehehehe).
I have assumed that it's showing signal strength, but where ??
Can't be to house, I wouldn't have thought anyway.
Can anyone else get this ??
The signal you are recieving is the anologue one, the graph is a logistic one, that's what an NTL engineer told me when i enquired.
Originally posted by Mimizuku no Lew
So you plugged your cable directly into the aerial port on your TV? IIRC this is a big no-no as your TV will send interference back down the cable which will affect other users' service.
Hi..
There is no problem with connecting your TV in that way, as long as there is a isolator in line between the customer equipment (your TV) and the cable companyââ‚à ‚¬Ã¢â€žÂ¢s equipment. The reason for this is to isolate you ariel which could back feed a DC voltage back to the tonertap.. (I think thatââ‚ ¬Ã¢â€žÂ¢s how it spelt), and affect the other TVâ₠¬ÃƒÂ¢Ã¢â‚¬Å¾Ã‚¢s feed from the same roadside cabinet. Also you are then protected if the amp in the roadside cabinet develops a fault and feeds a 60 volt square wave in to your equipment..
As for the frequencies of the TV channels most cable companyââ‚à ‚¬Ã¢â€žÂ¢s start forward transmissions at 120 Mhz up to 600Mhz and above. Apart from a couple of frequencies which are for the civil aviation and emergency channels. Here is another however, NTL and CTI transmit BBC and Independent Analogue TV in the UHF band between 471.25 to 847.25 Mhz.. The cable company can not transmit in that band with out screening the cables, otherwise their TV Presentation will have ghosting/interference..
The reveres path is usually in the area of 0 up to 50 Mhz .. The frequencies may change depending on which cable company you are connected to.
I hope that helps a little :)
So how come I'm also getting Sky 1 and Eurosport through the analogue connection ??
I'm sure there's another one, but I can't remeber offhand.
Also what's also intersting is that other older analogue tele's using UHF tuning can't pick these up.
Nemesis
It goes out on VHF i believe.
hi
With the new TV the tuners are capable of tuning in to lower frequencies, TVâ₠¬ÃƒÂ¢Ã¢â‚¬Å¾Ã‚¢s say over ten years ago cannot tune any lower that ch 21 / 22 which is around 400 and a bit Mhz.. Aslo as the tv gets old the components in the tuner start to go out of tolerance sky 1 and Eurosport most be transmitting fairly close to 400 Mhz mark..
TV broadcast are transmitted on UHF, well analogue is .. Not too sure what frequencies digital TV is transmitted on i will have to ask the guys upstaires who transmit the suff
Proppinupthebar
27-06-2003, 00:58
DTT is UHF as well. It fits in around the analogue channels.
Are you based on Jagger Lane by any chance? I also used to work there.
Originally posted by Proppinupthebar
DTT is UHF as well. It fits in around the analogue channels.
Are you based on Jagger Lane by any chance? I also used to work there.
ha ha ha yes i am..:wavey:
Nemesis, what franchise are you on?. What you are seeing is a Return Path diagnostics tool.
Originally posted by Nemesis
At work at the mo, but ....
The screen is slightly fuzzy, shows a windows based machine with a realtime graph on it, ( seen it crash a couple of time too - hehehehehe).
Does that mean you actually watch that channel?????????
Originally posted by Womble
Does that mean you actually watch that channel?????????
No, just tuned it in and left it, I check it every couple of days to see how stable it is. It was crashed again yesterday. :D
I live in Addlestone Surrey and are on an Ex-CWC franchise now, though have been with NTL for about 5/6 years.
:eeek:
Well, Surrey's my patch!. Don't know what you mean by "crash" though, it's probably us changing the area we are monitoring. Look at it friday when you get home from work!!!
Originally posted by Nemesis
So how come I'm also getting Sky 1 and Eurosport through the analogue connection ??
I'm sure there's another one, but I can't remeber offhand.
Also what's also intersting is that other older analogue tele's using UHF tuning can't pick these up.
Nemesis
Before we got digital we used to just use the cable to pick up the free-to-air analogue channels. For some reason, one day e4 also appeared. It was available for about 6 weeks then vanished.
When the engineer came to install our digital we asked about it and he said it was just 'one of those things'. He didn't explain why it happens, but he did reveal that he had heard of unscrambled p0rn being piped into unsuspecting customers homes on more than one occasion...
I will check it out when I get home, am I looking for anything special ??:shrug:
You are looking at a Return Path Analyser. It shows you the Noise level (The lower the better!), CPD (Common Path Distortion) and the cable modems "talking back". Its the channel to put on to get rid of unwanted guests!!!!
Originally posted by Womble
Well, Surrey's my patch!. Don't know what you mean by "crash" though, it's probably us changing the area we are monitoring. Look at it friday when you get home from work!!!
Well I looked at it on Friday night, It apperared to have communication error ??:p
What would i need to hook my tv up to view the analogue channels over cable? A spltter and isolator was mentioned, can someone give me a maplin product code or similar for them? Is that all id need? Also, would i actually be able to get this in my area? Im ex-c&w, in stoke-on-trent, staffordshire. I read on the old nthw forum that some older stbs have this built into their passthrough, which models supported this?
Paul
I'd be interested in knowing this as well (especially as I may be calling an engineer out to look into an STB problem soon) as the signal from my TV aerial is absolute pants and it would be nice to at least be able to get channels 1 to 5 (Langley network)
stephenn
21-08-2003, 17:25
I have read a lot of things about this and many posts saying it is not a good thing to do. Might be best to talk to the engineer about it, he may be able to sort something out.
Bill Payer
21-08-2003, 19:18
Prior to going Digital,I ran a cable from the STB to the TV upstairs.I was able to receive,admittedly poor quality,channels that Sky broadcast but NTL didn't & still don't,including some Foreign language Art films.;)
stephenn
21-08-2003, 21:03
Yup coming out of the STB is fine apparently (analogue or digital) but not splitting the cable going into the STB.
When I first got NTL (C&W) the original STB's allowed passthru.
This meant that you could pick up the analogue channels on the nearside of the STB.
When I moved to a real NTL area the STB's had changed and no longer allowed passthru, but was told that the analogue channels were still available. I was advised to get a splitter and put it on the far side of the STB. I did and the analogue channels were fine.
The place I am now, the idea of a splitter was never mentioned, but tried it anyway. Works perfectly. The older portable TV's can pick up BBC1,BBC2,ITV,C4 no probs. The newer TV's that search using MHZ can pick up the same plus Sky 1, eurosport (noe deceased) and a couple of others.
Splitting the signal using a good quality splitter should give a good picture to the STB and to the analogue TV's.
stephenn
22-08-2003, 16:10
Won't splitting the signal lower the signal strength? Doesn't that have an affect on say the digital tv via stb and cable modem?
Also surely the second tele is sending noise up the return path? The term ingress has been used in some posts I was reading on nthellworld.com about this. It seems like on that site the ntl people are dead against splitting.
Well, I've had no probs at all, I'm running Fullpackage tele and BB via STB.
I seem to have missed the plot here are you all saying that before te cablegoes into the Settopbox you can split it and recieve anolog channels if this is the case what type of splitter do you need as the cable going into the box is not a normal coax connection
stephenn
23-08-2003, 11:25
An F-splitter would work. Have a cable coming out of the splitter with a F-male socket on the splitter end and a standard coax plu on the other. *I'm sure someone who has done this will be able add to /correct this*
Btw where are those screenshots?!
can anybody post a pic of the screen shoots
if you use a normal f splitter to "t" into the cable before the stb you alter the impedance of the load the ntl cable "sees", this will cause power levels to alter possibly by quite a large margin, making all that magic ntl did with signal meters when you were installed quite useless, also RF front ends on TV sets don't normally have that much filtering on them to stop TV generated RF leaking back up the coax(therfore turning your TV into a transmitter), if you must tap into the NTL cable in this manner get a proper tool for the job,(din't know if he's registered here bit "altis" on .com has some good advice on this matter).
Jon
I have tried what was suggested by using a satalite to coax plug on the cable from the wall box to a splitter .. one into the STB and one to my TV in Kitchen all seems to work fine and you also get the channels mention before plus 1,2,3,4,5 my Broadband also still works fine
Can somebody please confirm this is ok to do this as it resolves my earlier problem of interferrance from my outside areal and my set top box
What you have done is basically the same set up as I have, but I pumped the analogue into the roofspace and split it again 4 times.
I see no prob with wht you've done at all :D
The anolog is great you can split it as many times as yoiu want but when you split the Cable Signal it dosent work as good on the second TV any ideas
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