byte wrote: » You'll need to find where the potential short is. That could be a joint or break in the cable allowing water ingress. Or the masthead amp itself could be faulty (the power supply can't be ruled out as being faulty either). Do you find the issue more likely in rainy weather?
Cerco wrote: » Is the power supply connected to a resistive splitter? If so then you need to isolate it using a diplexer. Feed the mast head amp directly and split the signal using a diplexer. After the diplexer you can use resistive splitters if you wish.
realdanbreen wrote: » I also have an aerial to receive the RTE,s TV3'S etc and that is where my problem is arising with the psu. I would have thought it should be pretty much a plug & play situation in this day and age, in other words I just want to receive RTE etc. How do I do this without having to go through a big rigmarole with a TV installer?
realdanbreen wrote: » I also have an aerial to receive the RTE,s TV3'S etc and that is where my problem is arising with the psu.
Mooshroom wrote: » Not sure what your point is here. If the PSU is in the attic, it's most likely directly connected to the amplifier, with the splitter 'downstream'. Actually, this is how it's described in the OP. Does the resistive element in RF signal splitters affect DC power passing anyway?
Mooshroom wrote: » As I mentioned already, I wouldn't be surprised if there's no amplifier at all. With no way of assessing the OP's competence in this area, I don't think it does any harm to ask questions that might even seem a bit insulting.
realdanbreen wrote: » I also have the proper aeriel on the chimney.
realdanbreen wrote: » If I were to start from scratch-how do I receive RTE,TV3 etc? I live out from the city,no cable TV, and have the saorview box etc. I also have the proper aeriel on the chimney.
Mooshroom wrote: » Who installed your current TV reception setup? Do you know is the terrestrial side completely separate from the satellite side, no shared cables? You know that the thing you refer to as a "masthead power supply", is just that: a device for injecting power (usually 12 volts, maybe 100 milliamps max. current) into the coaxial cable? The power supply doesn't provide any amplification, the amplifier is a separate device that is typically mounted as close to the aerial as possible (hence the "masthead" name), so you need the remote power supply if you want to put the amplifier outside. If there is indeed no actual amplifier in your system, you could just replace the PSU (& splitter) with a distribution amplifier, as mentioned in the previous post, & see how it goes.
realdanbreen wrote: » OK, a recognised installer set it up ... The device which is causing me problems is a ' 12v DC Mashead power supply' thats what is written on it. it works sometimes and other times doesn't-the power on indicator goes off.
The Cush wrote: » ... Do you still require the masthead amp, I removed my one last year and just use a distribution amp in the attic fed direct from the aerial.
Mooshroom wrote: » That's just replacing one kind of amplifier with another, & a distribution amp. will usually have a worse noise figure than a masthead type, not to mention that the masthead gets the amplification in as soon as possible, before any cable losses between aerial & distribution point, though the latter wouldn't be a big problem in most domestic installations. Some people seem to regard mastheads as a separate species to other amplifiers, that the problems they can cause are somehow different to those that can be caused by any amplifier. The old problem was interference picked up (& radiated) by the amplifier itself, made worse by being outside & high up, but modern mastheads should be well screened against this.
Mooshroom wrote: » That's just replacing one kind of amplifier with another, & a distribution amp. will usually have a worse noise figure than a masthead type, not to mention that the masthead gets the amplification in as soon as possible, before any cable losses between aerial & distribution point, though the latter wouldn't be a big problem in most domestic installations.
Cerco wrote: » I think you are confusing the remedy suggested. Cush was asking if the masthead amp was required now presumably because of the increased power of the transmitters on Saorview. The distribution amp would not replace the mast head amp, it would just amplify the split signal.
realdanbreen wrote: » I probably should also mention that sometimes everything works fine! I could go home this evening, plug in the power supply and bobs your uncle. Alternatively I could plug it in and zilch! nothing happening. What I am trying to achieve is just a constant reception of RTE etc.
Mooshroom wrote: » The OP's masthead amp is feeding a passive splitter. It's performing the same function as a distribution amp. As I said, mastheads are not some special device, apart from all other amplifiers.
realdanbreen wrote: » The device which is causing me problems is a ' 12v DC Mashead power supply' thats what is written on it. it works sometimes and other times doesn't-the power on indicator goes off.
Mooshroom wrote: » What's the make of the PSU? Ones I can think of, the power light will change from green to red if there's a short, like could be caused intermittenly by moisture, it doesn't just go out. I don't know if this PTC fuse can trip with excessive ambient temperature but 0 - 40C is typically given as the operating temparature range for these PSUs. The masthead amplifiers typically work away just fine. Most modern ones are in a sealed metal box inside a weatherproof cover that should protect the cable connections too.
The Cush wrote: » If the Saorview signal is good enough from aerial to attic why not replace the existing setup with a distribution amp in the attic so he won't have to go thru all this at some point in the future. If the distribution amp was to fail in future it would be a simple DIY job without having to call in an installer again.
realdanbreen wrote: » Sorted at long las folks. I opened the psu,even though its a sealed unit. The brown live wire was badly pinched (it could have happened when the back was being screwed down in the factory)
