distribution amplifiers

borotom

i currently have an SLX4B aerial amplifier 4 way splitter box sending my sky signal through my house, this is being fed fron my rf2 signal from my sky but recently i'm getting a lot of interference on my tvs is there a better box available or am i doing something wrong. it worked fine for a few years but signal got bad lately

Liameter

borotom wrote: »

is there a better box available or am i doing something wrong.

If you haven't changed anything, what do you think you might be doing wrong?

If it worked OK for years, what sort of "better" box do you think you need? If it's faulty, simply replace it. If you want better reliability, try one made by "Global". If the box isn't faulty, think what else might have changed.

borotom wrote: »

but recently i'm getting a lot of interference on my tvs is

Which TVs? Which channels? What does the interference look like? (Lines? Horizontal/vertical? Colour, number, spacing, movement...)

MACHEAD

Did the interference start just recently?, Is it in the form of 'wavy' lines across the screen?, or is it more like a grainy/snowy picture? If it's the former, then it's likely you may be getting co-channel interference from a nearby transmitter. If this is the case, then you will have to adjust the RF output frequency of the sky box. If it's the latter, it may be the amp done faulty, though these usualy last a long long time. I'm using a second hand one from a TV shop that closed down about 18 years ago and its still going strong!

Firstly try to bypass the amp by feeding the RF 2 output to just one of the additional TVs (just join the coax with an inline joint) and check the picture, if the interference is still there, then it's co-channel! Finding a free channel to reset the box to will be a trial and error job unless you know what channels are used for both analogue and digital in your area. If you do, or can find this out it will make the process a lot quicker.

Antenna

MACHEAD wrote: »

Did the interference start just recently?, Is it in the form of 'wavy' lines across the screen?, or is it more like a grainy/snowy picture? If it's the former, then it's likely you may be getting co-channel interference from a nearby transmitter. If this is the case, then you will have to adjust the RF output frequency of the sky box. If it's the latter, it may be the amp done faulty

The latter could also be due to co-channel interference from a DTT/Saorview transmission

Where in the country and what UHF channel is the box outputting at?

borotom

thr interference is in thr form of horizontal lines moving down the screen and is on all my tv's execpt my main one which is not fed through the amplifier

MACHEAD

Antenna wrote: »

The latter could also be due to co-channel interference from a DTT/Saorview transmission

Yes admitidly so, these kind of issues are normally sorted by a process of elimination.

Work your way thorugh the most likely/obvious causes first, then get to the less likely. As a faulty amp a much less comon cause, look at the UHF channel allocation in your area, a different output frequency on the sky box is all that it may take.

Is the clear picture on the main TV via scart or is it from the RF1 output? It's down to a bit of detective work here, you've got a number of scraps of 'evidence'. You have to invstigate all of them, to catch your 'culprit'.

borotom

Sorry for the delay in answering but i've been away. i tried changing the rf output which is set on ch 68. this didn't make much difference . my main tv is fed through a scart connection and the rf1 output which doesn't have any interference. i tried to bypass the amp feeding the rest of the house and the interference disappeared which leads me to think that it's the amp thats faulty. so if anyone knows a good reliable make please let me . thanks for the replies

Tony

wolsey/triax are pretty good as are labgear. I wonder is the RF out from the sky box overloading the amp by any chance ? Is there anything connacted to the RF/aerial in of the sky box ?

borotom

yes i have a chorus connection going into the rf input which is also rebroadcast around the house . this has been connected since day 1 so there has been no change with this connection

Tony

Ok try disconnecting the cable into the RF input and see does the sky picture become clear on the other tv's

borotom wrote: »

yes i have a chorus connection going into the rf input which is also rebroadcast around the house . this has been connected since day 1 so there has been no change with this connection

borotom

ok i'll try that when i get home if it is that is there another way to combine my chorus and sky before i distribute it to my other tv's

Tony

borotom wrote: »

ok i'll try that when i get home if it is that is there another way to combine my chorus and sky before i distribute it to my other tv's

There are options but lets first identify if over load is the problem.

borotom

I removed the chorus signal going into my sky box and the interference disappeared so it looks like this siganal was causing the interference. I have a mate working in chorus and he said he has a combiner and he'll drop it up to me with a few connections. He said that if i put the rf2 signal and my chorus signal into this combiner and then feed the output into my amplifier it should get rid of the interference. Is he right .


thanks for the help

Tony

Usually the problem is the level of signal is too high going into the sky box and it causes over modulation. Your mate is right and this should work but it may well mess up the return remote path back to the sky box . The correct cure would be to lower the chorus signal level going into the sky box, inserting a splitter or two may well acomplish this , normally you would use a variable or fixed attenuator.

borotom wrote: »

I removed the chorus signal going into my sky box and the interference disappeared so it looks like this siganal was causing the interference. I have a mate working in chorus and he said he has a combiner and he'll drop it up to me with a few connections. He said that if i put the rf2 signal and my chorus signal into this combiner and then feed the output into my amplifier it should get rid of the interference. Is he right .


thanks for the help

borotom

ok i'll try the the combiner when he drops it to me if it doesn't work i'll get my hands on a fixed or variable attenuator and try that cheers. once i found the problem hopefully it will be just trial and error to fix it

nikon1000

borotom wrote: »

thr interference is in thr form of horizontal lines moving down the screen and is on all my tv's execpt my main one which is not fed through the amplifier

Nobody mentioned it yet, but it's possible that your amplifier is being overloaded by a nearby TETRA transmitter.
Does the interference look like that in the example in this link: http://www.blake-uk.com/tetra.aspx

borotom

the interference doesn't seem as bad as that picture in the link. my mate droped me in a variable attenuator and a combiner today so i used the attenuator as there was no work in attaching it and it seems to work, but i had to go to work after i installed it so i'll have to wait til i get home and see if the signal is still ok tonight. hopefully this will have cured the problem. cheers for the info. when the interference started i went to my local maplin store as this is where i got my amp and they didn't seem to have any idea how to fix it they just wanted me to buy a new distribution amp so i said i'd try here first , thank god i did or i'd have a new amp with the same interference. it's great that people pass on their thought on how to fix problems without any hastle.

thanks for the replies