Sky+HD box not working with Optima Multiswitch

I have just fitted a Optima MS508 multiswitch. My FoxSat HD works fine
with it but my Sky+HD reports no signal.

If I connect a Promax Prodig-5 to either lead from the switch I get a
good signal. Also if I bypass the multiswitch and connect the LNB
direct to the Sky box it works fine.

Any ideas?

Ashley

--

Ashley Booth wrote:

I have just fitted a Optima MS508 multiswitch. My FoxSat HD works fine
with it but my Sky+HD reports no signal.

If I connect a Promax Prodig-5 to either lead from the switch I get a
good signal. Also if I bypass the multiswitch and connect the LNB
direct to the Sky box it works fine.

Any ideas?

Ashley

I'm feeding the box into a old TiVo. This worked fine until I put in
the switch. Then after it finished trying to record a programme the
remote control from the TiVo (wired via the RF output) brought it to
life!

It appears now to be working ok. Very strange!

--
Ashley

Ashley Booth wrote:
I have just fitted a Optima MS508 multiswitch. My FoxSat HD works fine
with it but my Sky+HD reports no signal.

If I connect a Promax Prodig-5 to either lead from the switch I get a
good signal. Also if I bypass the multiswitch and connect the LNB
direct to the Sky box it works fine.

Any ideas?

Ashley

Switch could be intolerant of out-of-spec or almost out-of-spec 13/18V
or 22kHz. If you can be bothered get a splitter with DC pass on one leg
and use the DC leg to feed the switch whilst monitoring the other leg
using the suspect receiver.

Bill

Bill Wright wrote:

Ashley Booth wrote:
I have just fitted a Optima MS508 multiswitch. My FoxSat HD works
fine with it but my Sky+HD reports no signal.

If I connect a Promax Prodig-5 to either lead from the switch I get
a good signal. Also if I bypass the multiswitch and connect the LNB
direct to the Sky box it works fine.

Any ideas?

Ashley

Switch could be intolerant of out-of-spec or almost out-of-spec
13/18V or 22kHz. If you can be bothered get a splitter with DC pass
on one leg and use the DC leg to feed the switch whilst monitoring
the other leg using the suspect receiver.

Bill

Had a bit more time to play with it.

It appears that the switch is faulty on the Hi Vert circuit.

Here is my analyzer looking at 12207 MHz Vert direct to my LNB:
http://flic.kr/p/e2GnPH

And here it is via the multiswitch:
http://flic.kr/p/e2GnZe

This seems to be a mixture of V & H. I'll check the voltage and tone on
the port with a scope.

Ashley


--

On 12/03/2013 20:31, Ashley Booth wrote:
Bill Wright wrote:

Ashley Booth wrote:
I have just fitted a Optima MS508 multiswitch. My FoxSat HD works
fine with it but my Sky+HD reports no signal.

If I connect a Promax Prodig-5 to either lead from the switch I get
a good signal. Also if I bypass the multiswitch and connect the LNB
direct to the Sky box it works fine.

Any ideas?

Ashley

Switch could be intolerant of out-of-spec or almost out-of-spec
13/18V or 22kHz. If you can be bothered get a splitter with DC pass
on one leg and use the DC leg to feed the switch whilst monitoring
the other leg using the suspect receiver.

Bill

Had a bit more time to play with it.

It appears that the switch is faulty on the Hi Vert circuit.

Here is my analyzer looking at 12207 MHz Vert direct to my LNB:
http://flic.kr/p/e2GnPH

And here it is via the multiswitch:
http://flic.kr/p/e2GnZe

This seems to be a mixture of V & H. I'll check the voltage and tone on
the port with a scope.

Ashley



does the multiswitch have gain/attenuator controls on it? some
multiswitches do.

The signal between the LNB and multiswitch is peaking at 76.8dBuV, but
is peaking at 80.6dBuV after the multiswitch so it looks as the
multiswitch is adding 4dB gain to the signals so it appears to be an
amplified multiswitch

I may be wrong but there appears to be intermodulation artefacts present
on the output at the multswitch.

Twiddling the gain/attenuator knobs on the multiswitch should help.
Failing that put a 6dB attenuator on the inputs to the multiswitch.

As it is, you're starting with a crackingly strong signal anyway so with
4dB gain, its possibly enough to introduce intermodulation artefacts
and/or overdrive the multiswitch

Also there is a limit to how strong a signal you can input into a sat
receiver. This limit can vary from receiver to receiver.

Regards

Stephen

On 12/03/2013 22:20, Stephen H wrote:
On 12/03/2013 20:31, Ashley Booth wrote:
Bill Wright wrote:

Ashley Booth wrote:
I have just fitted a Optima MS508 multiswitch. My FoxSat HD works
fine with it but my Sky+HD reports no signal.

If I connect a Promax Prodig-5 to either lead from the switch I get
a good signal. Also if I bypass the multiswitch and connect the LNB
direct to the Sky box it works fine.

Any ideas?

Ashley

Switch could be intolerant of out-of-spec or almost out-of-spec
13/18V or 22kHz. If you can be bothered get a splitter with DC pass
on one leg and use the DC leg to feed the switch whilst monitoring
the other leg using the suspect receiver.

Bill

Had a bit more time to play with it.

It appears that the switch is faulty on the Hi Vert circuit.

Here is my analyzer looking at 12207 MHz Vert direct to my LNB:
http://flic.kr/p/e2GnPH

And here it is via the multiswitch:
http://flic.kr/p/e2GnZe

This seems to be a mixture of V & H. I'll check the voltage and tone on
the port with a scope.

Ashley



does the multiswitch have gain/attenuator controls on it? some
multiswitches do.

The signal between the LNB and multiswitch is peaking at 76.8dBuV, but
is peaking at 80.6dBuV after the multiswitch so it looks as the
multiswitch is adding 4dB gain to the signals so it appears to be an
amplified multiswitch

I may be wrong but there appears to be intermodulation artefacts present
on the output at the multswitch.

Twiddling the gain/attenuator knobs on the multiswitch should help.
Failing that put a 6dB attenuator on the inputs to the multiswitch.

As it is, you're starting with a crackingly strong signal anyway so with
4dB gain, its possibly enough to introduce intermodulation artefacts
and/or overdrive the multiswitch

Also there is a limit to how strong a signal you can input into a sat
receiver. This limit can vary from receiver to receiver.

Regards

Stephen



I've done some digging for a table that shows what the min and max
strengths should be for various signal types:

How much signal do I need?

Min dBuV Max dBuV C/N ratio db
Analogue TV PAL 60 80 43
Digital UHF DTT 45 65 26
FM (stereo) 57 74 45
FM (mono) 40 74 25
DAB (Band II) 45 70 20
Sat IF analogue 47 77 15
Sat IF digital 47 77 12

So I reckon your LNB signals are too high for the multiswitch to handle
properly without introducing distortion.

Stephen H wrote:

On 12/03/2013 22:20, Stephen H wrote:
On 12/03/2013 20:31, Ashley Booth wrote:
Bill Wright wrote:

Ashley Booth wrote:
I have just fitted a Optima MS508 multiswitch. My FoxSat HD
works fine with it but my Sky+HD reports no signal.

If I connect a Promax Prodig-5 to either lead from the switch
I get a good signal. Also if I bypass the multiswitch and
connect the LNB direct to the Sky box it works fine.

Any ideas?

Ashley

Switch could be intolerant of out-of-spec or almost out-of-spec
13/18V or 22kHz. If you can be bothered get a splitter with DC
pass on one leg and use the DC leg to feed the switch whilst
monitoring the other leg using the suspect receiver.

Bill

Had a bit more time to play with it.

It appears that the switch is faulty on the Hi Vert circuit.

Here is my analyzer looking at 12207 MHz Vert direct to my LNB:
http://flic.kr/p/e2GnPH

And here it is via the multiswitch:
http://flic.kr/p/e2GnZe

This seems to be a mixture of V & H. I'll check the voltage and
tone on the port with a scope.

Ashley



does the multiswitch have gain/attenuator controls on it? some
multiswitches do.

The signal between the LNB and multiswitch is peaking at 76.8dBuV,
but is peaking at 80.6dBuV after the multiswitch so it looks as the
multiswitch is adding 4dB gain to the signals so it appears to be an
amplified multiswitch

I may be wrong but there appears to be intermodulation artefacts
present on the output at the multswitch.

Twiddling the gain/attenuator knobs on the multiswitch should help.
Failing that put a 6dB attenuator on the inputs to the multiswitch.

As it is, you're starting with a crackingly strong signal anyway so
with 4dB gain, its possibly enough to introduce intermodulation
artefacts and/or overdrive the multiswitch

Also there is a limit to how strong a signal you can input into a
sat receiver. This limit can vary from receiver to receiver.

Regards

Stephen



I've done some digging for a table that shows what the min and max
strengths should be for various signal types:

How much signal do I need?

Min dBuV Max dBuV C/N ratio db
Analogue TV PAL 60 80 43
Digital UHF DTT 45 65 26
FM (stereo) 57 74 45
FM (mono) 40 74 25
DAB (Band II) 45 70 20
Sat IF analogue 47 77 15
Sat IF digital 47 77 12

So I reckon your LNB signals are too high for the multiswitch to
handle properly without introducing distortion.

Thanks for those figures. I had 53-80dBuV as the range.

A reason for the high input is that there is only about 5m of cable
between the LNB and the multiswitch.

There are no gain controls on the multiswitch.

Why is only 1 of the 4 circuits affected by the high signal?

I have no attenuators that pass the DC and tone. I might try the old
damp rag over the LNB trick when I've time.

Ashley

--

On 12/03/2013 23:16, Ashley Booth wrote:
Stephen H wrote:

On 12/03/2013 22:20, Stephen H wrote:
On 12/03/2013 20:31, Ashley Booth wrote:
Bill Wright wrote:

Ashley Booth wrote:
I have just fitted a Optima MS508 multiswitch. My FoxSat HD
works fine with it but my Sky+HD reports no signal.

If I connect a Promax Prodig-5 to either lead from the switch
I get a good signal. Also if I bypass the multiswitch and
connect the LNB direct to the Sky box it works fine.

Any ideas?

Ashley

Switch could be intolerant of out-of-spec or almost out-of-spec
13/18V or 22kHz. If you can be bothered get a splitter with DC
pass on one leg and use the DC leg to feed the switch whilst
monitoring the other leg using the suspect receiver.

Bill

Had a bit more time to play with it.

It appears that the switch is faulty on the Hi Vert circuit.

Here is my analyzer looking at 12207 MHz Vert direct to my LNB:
http://flic.kr/p/e2GnPH

And here it is via the multiswitch:
http://flic.kr/p/e2GnZe

This seems to be a mixture of V & H. I'll check the voltage and
tone on the port with a scope.

Ashley



does the multiswitch have gain/attenuator controls on it? some
multiswitches do.

The signal between the LNB and multiswitch is peaking at 76.8dBuV,
but is peaking at 80.6dBuV after the multiswitch so it looks as the
multiswitch is adding 4dB gain to the signals so it appears to be an
amplified multiswitch

I may be wrong but there appears to be intermodulation artefacts
present on the output at the multswitch.

Twiddling the gain/attenuator knobs on the multiswitch should help.
Failing that put a 6dB attenuator on the inputs to the multiswitch.

As it is, you're starting with a crackingly strong signal anyway so
with 4dB gain, its possibly enough to introduce intermodulation
artefacts and/or overdrive the multiswitch

Also there is a limit to how strong a signal you can input into a
sat receiver. This limit can vary from receiver to receiver.

Regards

Stephen



I've done some digging for a table that shows what the min and max
strengths should be for various signal types:

How much signal do I need?

Min dBuV Max dBuV C/N ratio db
Analogue TV PAL 60 80 43
Digital UHF DTT 45 65 26
FM (stereo) 57 74 45
FM (mono) 40 74 25
DAB (Band II) 45 70 20
Sat IF analogue 47 77 15
Sat IF digital 47 77 12

So I reckon your LNB signals are too high for the multiswitch to
handle properly without introducing distortion.

Thanks for those figures. I had 53-80dBuV as the range.

A reason for the high input is that there is only about 5m of cable
between the LNB and the multiswitch.

There are no gain controls on the multiswitch.

Why is only 1 of the 4 circuits affected by the high signal?

I have no attenuators that pass the DC and tone. I might try the old
damp rag over the LNB trick when I've time.

Ashley




If you are actually using a QUATTRO LNB with the multiswitch, there will
not be any tone or voltage switching between the QUATTRO LNB and the
Multiswitch so you can use normal attenuators between the QUATTRO LNB
and multiswitch.

If you happen to have a special multiswitch that is expressly designed
to work with a QUAD LNB, then yes there will be 22KhZ and voltage
switching from the multiswitch to the QUAD LNB to make the Quad LNB
emulate a QUATTRO LNB.

If you are indeed using a QUAD LNB, then you will need power passing
attenuators, i.e ones that allow DC passthrough.

Stephen.

Stephen H wrote:

On 12/03/2013 23:16, Ashley Booth wrote:
Stephen H wrote:

On 12/03/2013 22:20, Stephen H wrote:
On 12/03/2013 20:31, Ashley Booth wrote:
Bill Wright wrote:

Ashley Booth wrote:
I have just fitted a Optima MS508 multiswitch. My FoxSat
HD works fine with it but my Sky+HD reports no signal.

If I connect a Promax Prodig-5 to either lead from the
switch I get a good signal. Also if I bypass the
multiswitch and connect the LNB direct to the Sky box it
works fine.

Any ideas?

Ashley

Switch could be intolerant of out-of-spec or almost
out-of-spec 13/18V or 22kHz. If you can be bothered get a
splitter with DC pass on one leg and use the DC leg to feed
the switch whilst monitoring the other leg using the
suspect receiver.

Bill

Had a bit more time to play with it.

It appears that the switch is faulty on the Hi Vert circuit.

Here is my analyzer looking at 12207 MHz Vert direct to my
LNB: http://flic.kr/p/e2GnPH

And here it is via the multiswitch:
http://flic.kr/p/e2GnZe

This seems to be a mixture of V & H. I'll check the voltage
and tone on the port with a scope.

Ashley



does the multiswitch have gain/attenuator controls on it? some
multiswitches do.

The signal between the LNB and multiswitch is peaking at
76.8dBuV, but is peaking at 80.6dBuV after the multiswitch so
it looks as the multiswitch is adding 4dB gain to the signals
so it appears to be an amplified multiswitch

I may be wrong but there appears to be intermodulation artefacts
present on the output at the multswitch.

Twiddling the gain/attenuator knobs on the multiswitch should
help. Failing that put a 6dB attenuator on the inputs to the
multiswitch.

As it is, you're starting with a crackingly strong signal
anyway so with 4dB gain, its possibly enough to introduce
intermodulation artefacts and/or overdrive the multiswitch

Also there is a limit to how strong a signal you can input into
a sat receiver. This limit can vary from receiver to receiver.

Regards

Stephen



I've done some digging for a table that shows what the min and max
strengths should be for various signal types:

How much signal do I need?

Min dBuV Max dBuV C/N ratio db
Analogue TV PAL 60 80 43
Digital UHF DTT 45 65 26
FM (stereo) 57 74 45
FM (mono) 40 74 25
DAB (Band II) 45 70 20
Sat IF analogue 47 77 15
Sat IF digital 47 77 12

So I reckon your LNB signals are too high for the multiswitch to
handle properly without introducing distortion.

Thanks for those figures. I had 53-80dBuV as the range.

A reason for the high input is that there is only about 5m of cable
between the LNB and the multiswitch.

There are no gain controls on the multiswitch.

Why is only 1 of the 4 circuits affected by the high signal?

I have no attenuators that pass the DC and tone. I might try the old
damp rag over the LNB trick when I've time.

Ashley




If you are actually using a QUATTRO LNB with the multiswitch, there
will not be any tone or voltage switching between the QUATTRO LNB and
the Multiswitch so you can use normal attenuators between the QUATTRO
LNB and multiswitch.

If you happen to have a special multiswitch that is expressly
designed to work with a QUAD LNB, then yes there will be 22KhZ and
voltage switching from the multiswitch to the QUAD LNB to make the
Quad LNB emulate a QUATTRO LNB.

If you are indeed using a QUAD LNB, then you will need power passing
attenuators, i.e ones that allow DC passthrough.

Stephen.

I am using a quad LNB. I've found a 10dB attenuator that came with the
analyzer that passes DC but not sure about the tone.

Will try fitting it tomorrow (I mean today!)

Ashley

--

Stephen H wrote:

The signal between the LNB and multiswitch is peaking at 76.8dBuV, but
is peaking at 80.6dBuV after the multiswitch so it looks as the
multiswitch is adding 4dB gain to the signals so it appears to be an
amplified multiswitch

They all amplify except for a few specialist ones that require external
pre-amplification. They have to amplify because the internal losses are
high; about 20dB is normal.

Bill