HD box interferes with DTT

glineli

Hi

I have an issue where when my Sky HD box is turned on it causes the DTT picture to start to break up. I have a sky+ box and HD box into an F140 combo. This goes into a 4 way distribution box. So the sky+ is rf out on 51 and HD on 60. I have DTT in all the other rooms, no problem. But when i turn the box on it splits up.

Before i got messing, has anyone come across this? Could it be the shielding on the HD cable to the tv or the rf out channel of 60 is causing interference?

slegs

Sounds like channel interference from your chosen RF Out channel on one of the Sky boxes. Try changing the RF out channel to something else. It doenst need to be the same channel to interfere. There was a link posted here before describing something called the 9 channel rule which explains it.

I have a similar setup to yours with no interference.

Antenna

OP, What RF channel or frequency are you receiving DTT on?
(depends where you are in the country)

glineli

Antenna wrote: »

OP, What RF channel or frequency are you receiving DTT on?
(depends where you are in the country)

Thanks lads, so there is hope!!

I am in Meaghara, channel 48. I will double check the rf outs later, i think 51 for the hd and 60 for the sky+, or else other way around.

So how close can channels be or what do you guys think? i will double check later to confirm

Antenna

Wouldn't expect problems to Ch48 with that channel choice, but try say Ch 22 instead of 51?


If you are using a set-top aerial, it may be picking up other interference from the HD box or cables unrelated to the RF out.

glineli

Antenna wrote: »

Wouldn't expect problems to Ch48 with that channel choice, but try say Ch 22 instead of 51?


If you are using a set-top aerial, it may be picking up other interference from the HD box or cables unrelated to the RF out.

Will try that setup later, thanks.

Thats what i was thinking, maybe the HD cable isnt shielded well enough, it was an ebay one.

So let me try those things later and will report back

glineli

Ok so got home and tried a few things. Firstly the sky+ box is rf out on 25 and HD box is 50. I changed hd cable, turned off rf out but what i have narrowed it down to is that when the 2 boxes are on the interference occurs.

So any ideas?

Slegs what channels do you rf out on?

So its the following:

Sky+: 25
DTT: 48
HD: 50

slegs

glineli wrote: »

Ok so got home and tried a few things. Firstly the sky+ box is rf out on 25 and HD box is 50. I changed hd cable, turned off rf out but what i have narrowed it down to is that when the 2 boxes are on the interference occurs.

So any ideas?

Slegs what channels do you rf out on?

So its the following:

Sky+: 25
DTT: 48
HD: 50

I would chage the HD on 50 to something like 32 if I were you..

glineli

I will try that once i get home. I think i had that but i found it interfered with the picture from the sky+ box, but i will try again later

thanks

glineli

I tried that but still made no difference. I tried a few different channels, went to 60, back to 25, 20, 15 but no difference. If anything the sky+ and HD receptions in the other rooms got worse.

Any last ideas?

slegs

glineli wrote: »

I tried that but still made no difference. I tried a few different channels, went to 60, back to 25, 20, 15 but no difference. If anything the sky+ and HD receptions in the other rooms got worse.

Any last ideas?

It shows at least that there is some channel interference going on. But tehre may be something else at play also.

Antenna

glineli wrote: »

I tried that but still made no difference. I tried a few different channels, went to 60, back to 25, 20, 15 but no difference. If anything the sky+ and HD receptions in the other rooms got worse.

Any last ideas?

Are you just using an indoor/set-top aerial?

If yes it might be just barely adequate, but a small bit of interference radiated by nearby equipment/cables, might be putting the DTT over the 'cliff'

glineli

Antenna wrote: »

Are you just using an indoor/set-top aerial?

If yes it might be just barely adequate, but a small bit of interference radiated by nearby equipment/cables, might be putting the DTT over the 'cliff'

Its an indoor aerial alright, in the attic.

I thought of that alright. Thats why i am hoping that come October the signal will be boosted, fingers crossed.

thanks

Booms

Have you tried removing the distribution box and running the combined signal directly to one tv? Maybe there's too much signal causing cross modulation?

glineli

Booms wrote: »

Have you tried removing the distribution box and running the combined signal directly to one tv? Maybe there's too much signal causing cross modulation?

Thats a good point, i will try that, thanks

glineli

I tried a few things at the weekend, cables etc but nothing worked.

I did notice however that when the 2 sky boxes are on, it causes the bit rate to go up to 7 or 8 and thats when the picture breaks up. What is the bit rate?

Picture quality is around 50%