Some people (almost certainly those who are unfortunate to be suffering with problems) seem to have a pathological hate for Humax. Now I don't say that their equipment is entirely faultless, but neither do I think it warrants the bile that appears to be thrown in their direction every time that something (usually beyond their control) hiccups.
I have owned Humax equipment for many years now including a PVR8000T, PVR9200T, F2FOXT, Foxsat and 32" LCD Tv/PVR and have been delighted. True the EPG on the 32" LCD could be better, and it doesn't do Accurate Record, but then I have the 9200 for that anyway.
Recently my (very early production) PVR9200T developed the 'no clock in standby' problem that seems to afflict this model and I wondered if it was time to try something else. I couldn't find any other model that appeared to offer the same level of features and build quality as the Humax. The closest I could find was the Topfield (5810?) which I considered buying until I found that it had no modulator. The PVR9300T too has no modulator so I was reluctant to get that, the Vestel (And the Alba Wharfedale, Digifusion clones) based machines don't look that great, nor do they have any better reputation than Humax either.
What did I do? I ordered a clock panel for the 9200. I got a machine that does what I want, and does it well too.
Perhaps once HDFreeView arrives, something 'better' will come along, be totally reliable and last 100 years. Then again...
.....
but neither do I think it warrants the bile that appears to be thrown in their direction every time that something (usually beyond their control) hiccups.
.....
I’m afraid sometimes frustration sets in.
Not many people require a modulator these days so you can understand why manufacturers are dropping them, TVs are losing the analogue tuner as well. The modulator in my 9200 has actually caused a bit of a problem with some new kit I've got, it would be nice if I could switch it off.
I used the modulator on my 9200 to send recordings from the PVR to my DVD Recorder as the USB backup function was so temperinental but it's no hardship cos now I'll just use one of the AV sockets instead. To be honest it's probably better quality than using the RF out anyway. With the switch off of analogue you don't really need it unless your TV doesn't have any spare scart sockets but there are ways round that like fitting an RF modulator.
I feel that on all the TV's i've owned, there's never been enough AV sockets on the back. I've only got 2 on my TV. One for my Humax and the other for my DVD. So in order to get my Ninteno wii and my camcorder plugged in I have to connect them to the spare AV sockets on my DVD recorder and run it through that. I hope that now that analogue is switched off we'll see loads more input/outputs on new TV's. I think there should be at least 7 inputs on the rear of every TV. 2 scarts, 2 HDMI, 1 Svideo, 1 RS232c, 1 RGA plus one on the front for DV input.
These days people don't just connect a video to a TV. People connect games consoles, camcorders, Laptops, DVD players, digiboxes etc. and some TV's (mainly smaller TV's) just haven't got enough inputs and it's just not convenient to keep unplugging stuff.
I should have said, I use the modulator for watching recordings in the kitchen whilst my wife is cooking the tea, and I am eating the (wifey prepared) tea.
Also very handy for watching whilst putting the kettle on ready to brew a tea, for drinking as opposed to eating.
Not essential I know, but to not have this facility would be a retrograde step.
Not many people require a modulator these days so you can understand why manufacturers are dropping them, TVs are losing the analogue tuner as well. The modulator in my 9200 has actually caused a bit of a problem with some new kit I've got, it would be nice if I could switch it off.
FWIW - the gain of a linear RF amp (which is what is used in an "active" antenna, or in a masthead amp), is related to the power supply voltage. Typically, the higher the voltage, the higher the gain (i.e. more amplification, stronger signal) - until you supply too much voltage and fry the amp! If turning on the Humax aerial PSU makes a difference to the signal amplitude, then it strongly suggests that the Humax voltage is higher than the separate PSU that you have for the aerial amp OR that the Humax has a better DC pathway to the amp than the separate PSU.
This may or may not be a good thing. If the amp is designed to run at 3.5V (say) and you give it 5V, then you are effectively over-running it and may, in time, cause an accelerated failure.
I'd check the spec on the separate PSU - to clarify what voltage the masthead is meant to run at. If it is 5V then this strongly suggests that the separate PSU may be faulty OR that it is not very well connected to mast head amp.....
Finally, having a stronger signal should make no difference to the performance - in fact it generally is a hinderance. If a signal is already within an acceptable tuner input amplitude range then all that matters is the signal to noise ratio (SNR) which is a measure of the amount to good signal to crap. Just coz you boost the signal with an amp doesn't mean the signal is any better - in fact it may be worse as an amp will degrade the SNR (i.e. add to the proportion of crap). Now, in this specific case, if the signal is in fact better (better SNR) when the Humax PSU is enabled, then it may again suggest that the masthead amp was not getting enough voltage and running in a very poor way. It would then provide some gain, but at a high cost to SNR (probably because the amp was running in a non-linear way and distorting the signal). But this doesn't seem to tally with your quality readings, so I guess this part remains a mystery....
FWIW - the gain of a linear RF amp (which is what is used in an "active" antenna, or in a masthead amp), is related to the power supply voltage. Typically, the higher the voltage, the higher the gain (i.e. more amplification, stronger signal) - until you supply too much voltage and fry the amp! If turning on the Humax aerial PSU makes a difference to the signal amplitude, then it strongly suggests that the Humax voltage is higher than the separate PSU that you have for the aerial amp OR that the Humax has a better DC pathway to the amp than the separate PSU.
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The one problem I see in all of this is that if the mast head amplifier has its own power supply then it's unlikely to be capable of being powered by a supply voltage fed into its RF output socket, the amplifier wouldn't be designed for it.
FWIW - the gain of a linear RF amp (which is what is used in an "active" antenna, or in a masthead amp), is related to the power supply voltage. Typically, the higher the voltage, the higher the gain (i.e. more amplification, stronger signal) - until you supply too much voltage and fry the amp!
Are you sure about this? That seems to be a very odd way of controlling the gain of an amplifier. All amplifier circuitry I have been involved in has been designed to work with a fixed range of supply voltage. For the method you describe to be of any use then the PSU would itself have to have a variable output voltage. Do you have any references to a masthead amp which works in the way you describe.
Are you sure about this? That seems to be a very odd way of controlling the gain of an amplifier. All amplifier circuitry I have been involved in has been designed to work with a fixed range of supply voltage. For the method you describe to be of any use then the PSU would itself have to have a variable output voltage. Do you have any references to a masthead amp which works in the way you describe.
Colin
It's a poor design of amplifier for the gain to be related to the supply voltage, but with these cheapo things anything is possible. Personally I wouldn't touch one with a barge pole unless I really lived out in the sticks and didn't have any choice.
I'd never seen or heard of a masthead amp before moving in to the property so didn't know why I couldn't get a signal off my aerial. The plug on the antenna had an F Type plug fitted which I thought was weird but just thought it was probably something to do with the previous owner's setup. Eventually I did some reading up on the internet and realised my aerial needed a power supply. So I went to Maplin and bought THIS one that was suggested to work. I also had to buy a second F Type plug and a length of coax cos the previous owner also took the patch lead which goes from the PSU out to the TV. I don't know what type of amplifier I have on the mast as I can't get up there to check but I do know it's a 2 way amp like THIS one. One lead comming into the lounge and the other upstairs. The one in the lounge is the one that supplies the power which is supplied by the PSU. As it won't work when I turn off the power supply and try to use the Humax Power only, I presume it's not a 5-12v input like on some of the newer masthead amps. It must be a 12v only input as 5v doesn't seem to power it on it's own.
I did think it strange how after the DSO when the transmission power was supposed to be increased, how my signal level remained the same as before on 70%. That was until I was advised to turn on the Humax Ant Power and after that it went up to full strength. However when I turn on both the PSU and the Antenna Power on the Humax it does appear to get a stronger signal.
One thing I have noticed is that on certain occasions (even without the Humax Antenna Power turned on) we have been suffering from Tetra interference which nobody else in the street is getting apart from us. We are the only ones with a masthead amp. Maybe it's faulty, maybe it dragging in too much crap, I don't know. All I do know is that I don't think we need it and it would probably be better off if we had it removed and just had a regular aerial. Can you buy something that will do the same job of splitting the aerial but without it having to be a wide band amplifier? I just think that after DSO we no longer need the extra power and all the masthead amp is doing, is dragging in unwanted rubbish like interference and other transmitters.
I'd never seen or heard of a masthead amp before moving in to the property so didn't know why I couldn't get a signal off my aerial. The plug on the antenna had an F Type plug fitted which I thought was weird but just thought it was probably something to do with the previous owner's setup. Eventually I did some reading up on the internet and realised my aerial needed a power supply. So I went to Maplin and bought THIS one that was suggested to work. I also had to buy a second F Type plug and a length of coax cos the previous owner also took the patch lead which goes from the PSU out to the TV. I don't know what type of amplifier I have on the mast as I can't get up there to check but I do know it's a 2 way amp like THIS one. One lead comming into the lounge and the other upstairs. The one in the lounge is the one that supplies the power which is supplied by the PSU. As it won't work when I turn off the power supply and try to use the Humax Power only, I presume it's not a 5-12v input like on some of the newer masthead amps. It must be a 12v only input as 5v doesn't seem to power it on it's own.
I did think it strange how after the DSO when the transmission power was supposed to be increased, how my signal level remained the same as before on 70%. That was until I was advised to turn on the Humax Ant Power and after that it went up to full strength. However when I turn on both the PSU and the Antenna Power on the Humax it does appear to get a stronger signal.
One thing I have noticed is that on certain occasions (even without the Humax Antenna Power turned on) we have been suffering from Tetra interference which nobody else in the street is getting apart from us. We are the only ones with a masthead amp. Maybe it's faulty, maybe it dragging in too much crap, I don't know. All I do know is that I don't think we need it and it would probably be better off if we had it removed and just had a regular aerial. Can you buy something that will do the same job of splitting the aerial but without it having to be a wide band amplifier? I just think that after DSO we no longer need the extra power and all the masthead amp is doing, is dragging in unwanted rubbish like interference and other transmitters.
You could use something like one from the selection here. Or do what I have done and strip back the insulation on the three coax's, twist the three coax cores together and the three screens together. Wrap with insulating tape taking care the screens are isolated from the cores. Job done, zero cost. Not very professional but if it works OK, no problem.
I suspect your choice of power supply for your masthead amp on the original set-up may not have been the correct one.
If your neighbours are all running without any amps then you probably can too. Do you know what sort of signal strengths they are getting?
If you want a purely passive solution then you need a passive splitter like the ones that Colin just suggested. Note that you get a signal reduction every time you passively split a signal. This comes from both the fact that the one signal is now spread several ways, plus the loss in the circuitry that is doing the splitting. A two way will drop about 6dB and a three-way about 9dB which is quite a big drop - probably not a show stopper but you *may* need to make some of that back by putting in a higher gain aerial and better cabling. Most people don't realise how big is the loss from a long cable run of basic old TV aerial cable - just replacing this with some new low loss double screened cable can make a big difference (i.e. 9dB+).
Anyway, yes you probably could go over to a purely passive solution. At a minimum you could swap the head amp for a passive splitter and hope you have enough signal to run everything. At the other extreme it'd probably cost you around £60 in materials to upgrade everything (aerial, splitter & cable), plus the labour to install it. You'd probably pay £150-£200 for an aerial installer to put in a completely new set up (inc materials).
Before you do that though I would definitely check a few things -
1) your current set-up definitely has a fault. The PSU you bought looks as if it should do the job, but the Humax PSU on/off should not be an issue and suggests that something is wrong with the way the masthead PSU is working or connected. This all needs double checking - are all connections going to the correct places; are all the earths nicely connected; are all the centre cores on those F-connectors the right length and not bent, and are there NO shorts where a small piece of braid is in the wrong place.
2) is your aerial pointing the same way as your neighbour's (is the interference because your aerial's poorly aligned?)
3) Have you tried an external earth on the UHF lead to reduce the interference?
4) does your house (and not your neighbour's) have any obstructions to the transmitter which may explain why you have an active system, when your neighbour's are passive?
5) do you already have good quality cables? The thing you are looking for is a second outer screen - made of foil, and around the outer braid. This will influence how much of an upgrade you need to do if you want to change it all over to a passive system.
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Or do what I have done and strip back the insulation on the three coax's, twist the three coax cores together and the three screens together.
Colin
You can't do that Colin, the aerial system is designed to 'see' 75 ohms at the ends of the cables. The aerial is designed to feed into 75 ohms and each piece of equipment presents a load of 75 ohms to the cable thereby correctly terminating it. A distribution amplifier or passive splitter maintains this 75 ohm match but simply twisting three cables together results in 75/3 ohms presented to each arm of the system causing a mismatch. This will result in signal reflections in the cable system which, if analogue, would produce ghosting. What it's doing to the digital signal I wouldn't like to guess.
You can't do that Colin, the aerial system is designed to 'see' 75 ohms at the ends of the cables. The aerial is designed to feed into 75 ohms and each piece of equipment presents a load of 75 ohms to the cable thereby correctly terminating it. A distribution amplifier or passive splitter maintains this 75 ohm match but simply twisting three cables together results in 75/3 ohms presented to each arm of the system causing a mismatch. This will result in signal reflections in the cable system which, if analogue, would produce ghosting. What it's doing to the digital signal I wouldn't like to guess.
I hear what you say Les, but I have done it and it's been like that for more than 20years and it works OK for me. Maybe I need to read the article linked by questionmark?
I hear what you say Les, but I have done it and it's been like that for more than 20years and it works OK for me. Maybe I need to read the article linked by questionmark?
Colin
If it was as simple as that Colin then a passive splitter would be no more than a box housing three (or more) terminals simply wired together.
PS. I'm still trying to get that data to you, stay with me.
Comments
I have owned Humax equipment for many years now including a PVR8000T, PVR9200T, F2FOXT, Foxsat and 32" LCD Tv/PVR and have been delighted. True the EPG on the 32" LCD could be better, and it doesn't do Accurate Record, but then I have the 9200 for that anyway.
Recently my (very early production) PVR9200T developed the 'no clock in standby' problem that seems to afflict this model and I wondered if it was time to try something else. I couldn't find any other model that appeared to offer the same level of features and build quality as the Humax. The closest I could find was the Topfield (5810?) which I considered buying until I found that it had no modulator. The PVR9300T too has no modulator so I was reluctant to get that, the Vestel (And the Alba Wharfedale, Digifusion clones) based machines don't look that great, nor do they have any better reputation than Humax either.
What did I do? I ordered a clock panel for the 9200. I got a machine that does what I want, and does it well too.
Perhaps once HDFreeView arrives, something 'better' will come along, be totally reliable and last 100 years. Then again...
I’m afraid sometimes frustration sets in.
Not many people require a modulator these days so you can understand why manufacturers are dropping them, TVs are losing the analogue tuner as well. The modulator in my 9200 has actually caused a bit of a problem with some new kit I've got, it would be nice if I could switch it off.
I feel that on all the TV's i've owned, there's never been enough AV sockets on the back. I've only got 2 on my TV. One for my Humax and the other for my DVD. So in order to get my Ninteno wii and my camcorder plugged in I have to connect them to the spare AV sockets on my DVD recorder and run it through that. I hope that now that analogue is switched off we'll see loads more input/outputs on new TV's. I think there should be at least 7 inputs on the rear of every TV. 2 scarts, 2 HDMI, 1 Svideo, 1 RS232c, 1 RGA plus one on the front for DV input.
These days people don't just connect a video to a TV. People connect games consoles, camcorders, Laptops, DVD players, digiboxes etc. and some TV's (mainly smaller TV's) just haven't got enough inputs and it's just not convenient to keep unplugging stuff.
Also very handy for watching whilst putting the kettle on ready to brew a tea, for drinking as opposed to eating.
Not essential I know, but to not have this facility would be a retrograde step.
You can switch the mod off in the menu system.
Sorry for that duff gen. Was getting confused with a sky box I was working on the other day.
OAP dementure kicking in again
This may or may not be a good thing. If the amp is designed to run at 3.5V (say) and you give it 5V, then you are effectively over-running it and may, in time, cause an accelerated failure.
I'd check the spec on the separate PSU - to clarify what voltage the masthead is meant to run at. If it is 5V then this strongly suggests that the separate PSU may be faulty OR that it is not very well connected to mast head amp.....
Finally, having a stronger signal should make no difference to the performance - in fact it generally is a hinderance. If a signal is already within an acceptable tuner input amplitude range then all that matters is the signal to noise ratio (SNR) which is a measure of the amount to good signal to crap. Just coz you boost the signal with an amp doesn't mean the signal is any better - in fact it may be worse as an amp will degrade the SNR (i.e. add to the proportion of crap). Now, in this specific case, if the signal is in fact better (better SNR) when the Humax PSU is enabled, then it may again suggest that the masthead amp was not getting enough voltage and running in a very poor way. It would then provide some gain, but at a high cost to SNR (probably because the amp was running in a non-linear way and distorting the signal). But this doesn't seem to tally with your quality readings, so I guess this part remains a mystery....
The OP doesn't have the original masthead PSU. He is using a third party item which may or may not be to the correct spec.
The one problem I see in all of this is that if the mast head amplifier has its own power supply then it's unlikely to be capable of being powered by a supply voltage fed into its RF output socket, the amplifier wouldn't be designed for it.
Colin
It's a poor design of amplifier for the gain to be related to the supply voltage, but with these cheapo things anything is possible. Personally I wouldn't touch one with a barge pole unless I really lived out in the sticks and didn't have any choice.
I did think it strange how after the DSO when the transmission power was supposed to be increased, how my signal level remained the same as before on 70%. That was until I was advised to turn on the Humax Ant Power and after that it went up to full strength. However when I turn on both the PSU and the Antenna Power on the Humax it does appear to get a stronger signal.
One thing I have noticed is that on certain occasions (even without the Humax Antenna Power turned on) we have been suffering from Tetra interference which nobody else in the street is getting apart from us. We are the only ones with a masthead amp. Maybe it's faulty, maybe it dragging in too much crap, I don't know. All I do know is that I don't think we need it and it would probably be better off if we had it removed and just had a regular aerial. Can you buy something that will do the same job of splitting the aerial but without it having to be a wide band amplifier? I just think that after DSO we no longer need the extra power and all the masthead amp is doing, is dragging in unwanted rubbish like interference and other transmitters.
I suspect your choice of power supply for your masthead amp on the original set-up may not have been the correct one.
Colin
If you want a purely passive solution then you need a passive splitter like the ones that Colin just suggested. Note that you get a signal reduction every time you passively split a signal. This comes from both the fact that the one signal is now spread several ways, plus the loss in the circuitry that is doing the splitting. A two way will drop about 6dB and a three-way about 9dB which is quite a big drop - probably not a show stopper but you *may* need to make some of that back by putting in a higher gain aerial and better cabling. Most people don't realise how big is the loss from a long cable run of basic old TV aerial cable - just replacing this with some new low loss double screened cable can make a big difference (i.e. 9dB+).
Anyway, yes you probably could go over to a purely passive solution. At a minimum you could swap the head amp for a passive splitter and hope you have enough signal to run everything. At the other extreme it'd probably cost you around £60 in materials to upgrade everything (aerial, splitter & cable), plus the labour to install it. You'd probably pay £150-£200 for an aerial installer to put in a completely new set up (inc materials).
Before you do that though I would definitely check a few things -
1) your current set-up definitely has a fault. The PSU you bought looks as if it should do the job, but the Humax PSU on/off should not be an issue and suggests that something is wrong with the way the masthead PSU is working or connected. This all needs double checking - are all connections going to the correct places; are all the earths nicely connected; are all the centre cores on those F-connectors the right length and not bent, and are there NO shorts where a small piece of braid is in the wrong place.
2) is your aerial pointing the same way as your neighbour's (is the interference because your aerial's poorly aligned?)
3) Have you tried an external earth on the UHF lead to reduce the interference?
4) does your house (and not your neighbour's) have any obstructions to the transmitter which may explain why you have an active system, when your neighbour's are passive?
5) do you already have good quality cables? The thing you are looking for is a second outer screen - made of foil, and around the outer braid. This will influence how much of an upgrade you need to do if you want to change it all over to a passive system.
Good luck!
You can't do that Colin, the aerial system is designed to 'see' 75 ohms at the ends of the cables. The aerial is designed to feed into 75 ohms and each piece of equipment presents a load of 75 ohms to the cable thereby correctly terminating it. A distribution amplifier or passive splitter maintains this 75 ohm match but simply twisting three cables together results in 75/3 ohms presented to each arm of the system causing a mismatch. This will result in signal reflections in the cable system which, if analogue, would produce ghosting. What it's doing to the digital signal I wouldn't like to guess.
Colin
If it was as simple as that Colin then a passive splitter would be no more than a box housing three (or more) terminals simply wired together.
PS. I'm still trying to get that data to you, stay with me.