Domestic IRS Problems

[excollier]

Last week I installed 3x Freesat receivers to a newbuild house. I noticed that the quad-output LNB was not outputting the Vertical high frequecies, but I got the other three ( V-low, H-low and H-high ) and got the setup working in two of the three rooms, and a good signal level in the third, although I did not test the receiver
Yesterday I returned to install an aerial so that the customer could receive RTE along with his UK satellite channels.
To achieve this I used a quattro LNB and a 5x4 Triax multiswitch, as the customer only has 1 cable to each room, I also added triplexed(sat, UHF, FM/DAB ) outlet plates.
Once again I seem to be missing V-high frequencies from the satellite outputs on the plates.This varies from 48% PQ in two of the rooms to 0% PQ in the third room, which was the troublesome room at the first attempt, also the satellite picture keeps coming on and off, alternating with the terrestrial transmission (which is fine throughout the house). The customer commented on this effect before I returned to add the aerial and multiswitch. The satellite signal shows no fluctuation or intermittent signs on the meter, it is steady and constant.
The V-high from the LNB to the multiswitch input is fine at 86% PQ.
Could anyone tell me what causes this ( I suspect the cable to the most troublesome room is the culprit ) any pointers will be gratefully received.
Also as an added question, as this is a single dwelling, with only three rooms using the multiswitch, do I need to add earth bonding? From what I can gather a small install like this does not need it, but I am unsure of where I stand on this.
Thank you in advance

 

[Channel Hopper]

If you are not getting the V High, then the switch is not sending out the 22kHz and 13V signal, even though it is receiving it in from the fourth port of the LNB.

I don't know about the Triax multiswitch, but if it isn't powered by an external source (relying only on the voltage from the receivers) then you should try another that is powered, as I have replaced similar types to remove some weird effects on wallplates.

Earthbonding is not a requirement for satellite equipment in a single dwelling (yet)

 

[Robbo]

Sounds to me like the quatro lnb isn't working right, if you are getting no Vert H, directly at the LNB.

 

[satelliteman]

The V-high from the LNB to the multiswitch input is fine at 86% PQ.

Worth trying another switch in that case.

 

[excollier]

I am getting V-H at the lnb and at the input to the multiswitch, and at good strength too. What I am not getting is V-H in one room and a low reading for it in 2 other rooms.The multiswitch has it's own power supply, so that is not the cause, possibly it isn't sending any power to that particular output on the lnb, but that wouldn't explain the fact that I am getting 48% at the other 2 rooms, but none at all in the third room. Maybe the switch is faulty as mentioned above, I will just have to try aother switch.
thanks for the word on earth bonding, finding an earth point in a new house attic these days is nigh on impossible, houses are almost totally plumbed with plastic these days, as is my own.
Thanks for your help all..

 

[satelliteman]

Try swapping over the subscriber feeds first to see or at least the free port available.

 

[rolfw]

So if I get this right, you are measuring with a meter, the input to the switch on all four ports of the quatro and also from the outputs from the switch and they are all similar, perhaps with a small loss due to the switch insertion loss?

But all of the outlets in the rooms are showing poor signal strength on vertical high only? Or on other polarities/bands as well? What sized dish are you using?

 

[excollier]

Thanks a good idea and an obvious one that I hadn't thought of. But it doesn't explain the low readings in the other two rooms.
This is the multiswtch I used, _http://www.vanjak.com/product_details.php?category_id=657&item_id=713
and the lnb _http://www.vanjak.com/product_details.php?category_id=626&item_id=1407

 

[excollier]

So if I get this right, you are measuring with a meter, the input to the switch on all four ports of the quatro and also from the outputs from the switch and they are all similar, perhaps with a small loss due to the switch insertion loss?

But all of the outlets in the rooms are showing poor signal strength on vertical high only? Or on other polarities/bands as well? What sized dish are you using?

Yes you are right there,only low on V-High, I am using a 60cm dish, which is giving very good readings on all four ports of the lnb.
I did not measure at the switch outputs, as I am distributing UHF with it as well, I am not sure if the combined signal woul damage the sat meter, but I suppose I could disconnect the aerial first and then take measurements, I will be going back tomorrow night so I will try all these ideas, and try to isolate the problem,
thanks for your ideas and thoughts.

 

[rolfw]

That's the most important place to measure, as if that is wrong, then everything after it will be wrong. What meter are you using?

 

[excollier]

That's the most important place to measure, as if that is wrong, then everything after it will be wrong. What meter are you using?

A Lacuna MkIV, which is quick and simple to use, I have been using it for two years now, many happy customers.

 

[rolfw]

As you say, you can always remove the terrestrial feed, but unless you have a very strong UHF signal, it shouldn't be a problem, I normally take measurements without removing the UHF input. Measure each output and see if there are any differences, plus compare the difference between input and output strength.

I'm presuming that the downleads are satellite quality and that you've checked the connections on the outlet plates, as 50% of outlet plates I've checked have been badly connected.

 

[excollier]

I suppled and fitted the outlet plates myself, but the cabling to the rooms was supplied and fitted by an electrician. The usual very cheap RG6 type double screened stuff but thin and the f-plugs are a loose-ish fit on it. Luckily the troublesome room is an upstairs bedroom, so should be relatively easy to re-cable with Webro WF100 which is all I ever use, or Triax TX100, both quality cables.
These are the outlet plates I used so I can add FM later
_http://www.vanjak.com/product_details.php?category_id=60&item_id=74

 

[satelliteman]

As you say, you can always remove the terrestrial feed, but unless you have a very strong UHF signal, it shouldn't be a problem,

Second that and then it mainly only causes problems in the low band

 

[rolfw]

Global kit is OK, more than likely the cheap cable, I've found it to lose 15-20db at UHF over relatively short runs, so God help you on IF.

 

[excollier]

Second that and then it mainly only causes problems in the low band

I can see why that would be so, that's why the V-high is puzzling.
Any way I will learn a lot from this one, my first multiswitch.
Could the multiswitch be earthed via the earth terminal in a mains power socket?

 

[rolfw]

Well whether it's vertical high or vertical low, the IF range is the same, it'll be the lower frequencies in either band, those that have an IF of not much over 950Mhz

 

[Channel Hopper]

I suppled and fitted the outlet plates myself, but the cabling to the rooms was supplied and fitted by an electrician. The usual very cheap RG6 type double screened stuff but thin and the f-plugs are a loose-ish fit on it. Luckily the troublesome room is an upstairs bedroom, so should be relatively easy to re-cable with Webro WF100 which is all I ever use, or Triax TX100, both quality cables.

You could try running a receiver on a similar length of quality cable (just run it down the stairs for the time being). If it works at the end of the line then you know not to pay the electrician.

 

[satelliteman]

I can see why that would be so, that's why the V-high is puzzling.
Any way I will learn a lot from this one, my first multiswitch.
Could the multiswitch be earthed via the earth terminal in a mains power socket?

No need to earth bond. It's a three point domestic set up as briefly mentioned in post #2.

 

[excollier]

I tested the multiswitch, and only one output is giving satisfactory output for V-high, and the one output is giving no V-high at all.
The room that was giving the "on/off" satellite picture was narrowed down to a faulty tv set, after all other components were eliminated one by one.
Now all I have to do is replace the multiswitch and the system will be fully operational.
Thanks to you all for your help and suggestions