Advice on 2nd D500C Installation

[q2uantum]

Hi guys,

I have recently ran some cable (original cable that TW left years ago when they did the original install - it was on drum and they forgot to take it with them ;-) ) up stairs (under floorboards etc) to our bedroom so I could put a second D500C in there. But I am having issues with high BNR and channel not found etc on the one upstairs.

My current setup is this:

• White TW installed box on wall downstairs
• 2m Cable running to Yellow Brick Booster
• 1m Cable running to Variable Attenuator
• 2m Cable running to 3 Way Splitter
• 5m Cable running to D500c In Front room
• Approx 15 - 20m cable running Upstairs

The situation I currently have is the yellow brick booster is turned up full for both dials (S.C and G.C), the attenuator is turned fully clockwise.

This makes my TV downstairs 100% perfect (well from what I can see), BUT the TV upstairs struggles to fix on a channel for very long and most of the channels dont work.

I have even tried putting a SLX1 booster upstairs as well to boost the signal (If i dont have it the SNR is only about 64 and with it its about 91). I can normally pick up BRAVO Upstairs first - i.e. I cant get BBC1 to get a picture unless I go to BRAVO first (Dont know why this is!) , but once the picture has been ok for about 5 mins the SNR drops to 64 and the BER goes absolutely mad!

Can anyone suggest anything that may help get the TV OK upstairs?

Cheers

q2

 

[mrdude]

Probably you have not fitted the ends of the cable properly, and have the outside screening touching the centre copper core - this will produce interferance (noise) which will give you a high bit error rate (BER)

 

[Devilfish]

It's always best to put the booster as early in the line as possible, as you have. The more cable you have in your house, the more noise and interferance is generated by the distance. If you add a booster after 20mtrs of cable, you're going to amplify the noise as well as the signal.

Maybe put the variable attenuator after the splitter but before your box downstairs. Then there will be a stronger signal going through your splitter and up to your box in the bedroom. The splitter will still act as an attenuator to some degree and you'll still have the variable attenuator, just in a different position.

 

[q2uantum]

It's always best to put the booster as early in the line as possible, as you have. The more cable you have in your house, the more noise and interferance is generated by the distance. If you add a booster after 20mtrs of cable, you're going to amplify the noise as well as the signal.

Maybe put the variable attenuator after the splitter but before your box downstairs. Then there will be a stronger signal going through your splitter and up to your box in the bedroom. The splitter will still act as an attenuator to some degree and you'll still have the variable attenuator, just in a different position.

I have moved the attenuator after the splitter and the downstairs tv is still fine BUT the upstairs tv is still the same.

What i was thinking of doing is splitting the signal BEFORE the booster (so that the downstairs is ok still) and then possibly boosting/attenuating the signal for upstairs seperatly.

My problem could also be the ends as pointed out earlier in the thread so might replace all those as well

 

[mgb]

Maybe you need an second variable attenuator for the line which leads upstairs.
At your first try with the fully enabled variable attenuator before the splitter you decreased the signal at around 20db and the signal was too weak for upstairs.
At your second try the signal was 20db higher for upstairs and that is maybe too much.
You could also try to decrease the gain at the yellow brick until the picture is good upstairs and after that lower the attenuation for downstairs.

 

[q2uantum]

Yeh maybe I should concentrate on getting the upstairs correct first before i adjust the one downstairs....

BTW on the Variable Attenuator which is the input and output? I just want to make sure i have it correct?

 

[mgb]

For instance go to manual scan at the box upstairs and you see the numbers for BER. Let the screen open and decrease the gain at the yellow brick until you get a BER around zero.
After that do the same for the box downstairs and adjust the attenuator until you get a ber around zero.
Do you got an attenuator with f-connectors or coax connectors?

 

[q2uantum]

For instance go to manual scan at the box upstairs and you see the numbers for BER. Let the screen open and decrease the gain at the yellow brick until you get a BER around zero.
After that do the same for the box downstairs and adjust the attenuator until you get a ber around zero.
Do you got an attenuator with f-connectors or coax connectors?

The attenuator has COAX connectors so i have a made up cable with f-coax adaptors on them

 

[mgb]

The female socket is the input.
Btw slope control at the yellow brick is for the balance between low and high frequencies. You should turn it down for the first try.

 

[mgb]

@q2uantum
Have you solved your problem?

 

[q2uantum]

No m8 i havent had time to look at it yet - g/f has been working so ive been running around after my 2 year old son most of weekend

Ive ordered some decent cable ends (original TW type ones) so when they come im going to re-end the cables and that should remove the ends from the equation...

Once Ive done the ends Im going to disconnect the one downstairs all together and concentrate getting the one upstairs working first. I may buy another attenuator just incase i need it.

Regards

q2

 

[mgb]

I don't think is a problem with cabeling.
Its just a problem with signal strength. You overrun the tuner at the box upstairs with the full blast from the yellow brick.
Downstairs only the attenuator can prevend the overrun.

 

[q2uantum]

Ive tried the box upstairs just now with no booster at all and i get SNR about 50 and BER about 1680000.... i have also tried with booster turned down and cant get above 71 SNR and the BER is still about 1690000 (cant seem to get it any lower)

I know the box is ok as I have had it on downstairs no problems

 

[mgb]

You have to turn up the gain control in smaller steps.
The gain control has a range between 12 db and 30db gain.
Btw did you try it with installed splitter. Adjusting without splitter makes no sense.

 

[q2uantum]

LOL sorry m8 having a slow day today - i only tested the box with no booster or it turned vey low - i will do some more testing tonight when the little un is in bed nd the g/f is home (she can sit and watch the numbers on the box upstairs while i turn the controls downstairs )

 

[q2uantum]

Right - i have some news on this problem

I have changed all the screw F-type ends for the snap and seal ends I purchased from the US (see https://www.digitalworldz.co.uk/index.php?threads/148495/ for details)

and low and behold I can now get majority of the channels upstairs

On the Freeview channels i got 0 - 10 BNR (94 SNR) which is good

On Sport, Living etc i get 800 - 3000 BNR (91 SNR) (picture looks ok but havent watched it long enuff to see if it locks up)

On BBC3 - I get 63 SNR and 284000 BNR! and probably get the same on some other channels but havent tried them all yet!

BTW all these are without using the 2nd Booster upstairs!

So the moral of the story is put decent ends on your cable

Think its another Variable attenuator for me to fix the problems upstairs... BUT i have yet to play with the yellow brock booster downstairs which is still set at FULL for GC and SC

Thanks for all the info so far guys...

q2