In gusty winds, TV signals disappear and can only be restored by
powering the receiver off and on again. Or at least that's the only way
I've discovered so far to restore normal operation.

The setup is a little unusual: a satellite internet link (which
continues to work throughout the gusts, so dish pointing isn't the
issue), a DVB-S LNB offset by the appropriate amount so that it 'sees'
the Astra 2A-B-D satellites instead of the Europasat internet satellite
which the dish is aimed at, a dish motor so that I can look at other TV
satellites if I don't mind losing the internet connection, a
multiplexer on the roof to combine DAB, FM, terrestrial and satellite
signals, and a matching demultiplexer beside the receiver.

It all works perfectly if the wind isn't blowing, but gets into some
odd state where the TV signal goes from 90% signal strength and 73% signal
quality to near zero strength and zero quality after a variable number
of gusts.

The coax downlead for TV is about 20 metres long and has a
copper-coated steel inner and a foil and braid outer.
I used the best coax only for the internet connection, which might have
been a mistake.
I wish now that I'd used top quality solid copper coax instead of stuff
with a copper coated steel inner, which must be more prone to
electrolytic corrosion and may have a higher resistance.

In desperation I may try replacing/remaking all the 'F' type coax
connectors, though I'm not sure why a poor connection would give the
odd effects in question.

Does a dish motor automatically drive a dish back to the original
position if a gust moves it a fraction of a degree away?
That, happening repeatedly, might (I suppose) overload the power supply
from the receiver, or cause a sudden drop in voltage which could
confuse the TV LNB.

The dish, motor, and receiver are all Fortec Star, which work well
enough in simpler setups.

Has anyone had similar experiences?


--
Windmill, Use t m i l l
J.R.R. Tolkien:- @ S c o t s h o m e . c o m
All that is gold does not glister / Not all who wander are lost

On Fri, 20 Sep 2013 03:56:08 GMT, Windmill wrote:

Does a dish motor automatically drive a dish back to the original
position if a gust moves it a fraction of a degree away?

It might if the system really knows, via some form of feedback where
the dish is but I don't think they do. Just align the dish to
satellites each end of the arc it can see and it just motors x amount
to find the ones in between. There could be some form of signal
strength feeback to "peak the alignment" when about in the right
place but that couldn't be used to keep the dish aligned as it
doesn't provide information about which way to move the dish.

Next time it happens move the dish to another sat and back again?

--
Cheers
Dave.

Yes, the dish movers are just dead reckoning things. If its possible to
actually physically move the dish with gusts of wind then the dish needs to
m be more securely mounted in my view.
Brian

--
From the Sofa of Brian Gaff Reply address is active
"Dave Liquorice" wrote in message
ll.co.uk...
On Fri, 20 Sep 2013 03:56:08 GMT, Windmill wrote:

Does a dish motor automatically drive a dish back to the original
position if a gust moves it a fraction of a degree away?

It might if the system really knows, via some form of feedback where
the dish is but I don't think they do. Just align the dish to
satellites each end of the arc it can see and it just motors x amount
to find the ones in between. There could be some form of signal
strength feeback to "peak the alignment" when about in the right
place but that couldn't be used to keep the dish aligned as it
doesn't provide information about which way to move the dish.

Next time it happens move the dish to another sat and back again?

--
Cheers
Dave.

On 20/09/2013 04:56, Windmill wrote:

The setup is a little unusual: a satellite internet link (which
continues to work throughout the gusts, so dish pointing isn't the
issue), a DVB-S LNB offset by the appropriate amount so that it 'sees'
the Astra 2A-B-D satellites instead of the Europasat internet satellite
which the dish is aimed at,

Just a guess here, but if the dish itself isn't moving maybe the arm
holding the offset LNB is? Possibly it's giving corrupt data packets to
the receiver which doesn't like it?

Couple of our old Sky digital boxes locked up with a similarly noisy
input...

Lee

You cannot assume its not dish movement, it might well be that the aiming is
better for the main sat, and a bit off or weaker for the offset one.
Brian

--
From the Sofa of Brian Gaff Reply address is active
"Lee" wrote in message
...
On 20/09/2013 04:56, Windmill wrote:

The setup is a little unusual: a satellite internet link (which
continues to work throughout the gusts, so dish pointing isn't the
issue), a DVB-S LNB offset by the appropriate amount so that it 'sees'
the Astra 2A-B-D satellites instead of the Europasat internet satellite
which the dish is aimed at,

Just a guess here, but if the dish itself isn't moving maybe the arm
holding the offset LNB is? Possibly it's giving corrupt data packets to
the receiver which doesn't like it?

Couple of our old Sky digital boxes locked up with a similarly noisy
input...

Lee

In article , Lee
scribeth thus
On 20/09/2013 04:56, Windmill wrote:

The setup is a little unusual: a satellite internet link (which
continues to work throughout the gusts, so dish pointing isn't the
issue), a DVB-S LNB offset by the appropriate amount so that it 'sees'
the Astra 2A-B-D satellites instead of the Europasat internet satellite
which the dish is aimed at,

Just a guess here, but if the dish itself isn't moving maybe the arm
holding the offset LNB is? Possibly it's giving corrupt data packets to
the receiver which doesn't like it?

Couple of our old Sky digital boxes locked up with a similarly noisy
input...

Lee




If it is a wind problem you can try moving the affected bit around by
hand and if you can repeat the problem then tighten up and realign as
required.

Also are there any trees overhanging the dishes even some metres away at
all, they can really clobber sat signals and even more so when wet...
--
Tony Sayer

In article , Windmill
writes
In gusty winds, TV signals disappear and can only be restored by
powering the receiver off and on again. Or at least that's the only way
I've discovered so far to restore normal operation.

The setup is a little unusual: a satellite internet link (which
continues to work throughout the gusts, so dish pointing isn't the
issue), a DVB-S LNB offset by the appropriate amount so that it 'sees'
the Astra 2A-B-D satellites instead of the Europasat internet satellite
which the dish is aimed at, a dish motor so that I can look at other TV
satellites if I don't mind losing the internet connection, a
multiplexer on the roof to combine DAB, FM, terrestrial and satellite
signals, and a matching demultiplexer beside the receiver.

It all works perfectly if the wind isn't blowing, but gets into some
odd state where the TV signal goes from 90% signal strength and 73% signal
quality to near zero strength and zero quality after a variable number
of gusts.

Can you turn off the LNB power on the receiver to separate the potential
of it being an LNB lockup rather than a steering issue?

If it restores the LNB function it could still be a cabling issue with
movement causing transient interruptions to the LNB supply. I don't know
how sensitive LNBs are to such transients.
--
fred
it's a ba-na-na . . . .

On 20/09/2013 04:56, Windmill wrote:
In gusty winds, TV signals disappear and can only be restored by
powering the receiver off and on again. Or at least that's the only way
I've discovered so far to restore normal operation.

Has anyone had similar experiences?

Not me!

My bet is that the problem lies with the cabling, you could connect the
receiver direct to the LNB to see what happens when the wind blows.

If you have a meter you can check the voltage that the receiver is
supplying to the motor/LNB.

The www.digitalspy.co.uk satellite/technical forum can be quite helpful.

--
Michael Chare

"Dave Liquorice" writes:

On Fri, 20 Sep 2013 03:56:08 GMT, Windmill wrote:

Does a dish motor automatically drive a dish back to the original
position if a gust moves it a fraction of a degree away?

It might if the system really knows, via some form of feedback where
the dish is but I don't think they do.

That's probably the case; I suspect (but don't know for sure - maybe
need to dig for the stuff about DisEqC I copied from a library book a
couple of years ago) that the receiver can tell the dish motor to go to
position 5, the dish motor can remember positions and the corresponding
azimuths when it's told to do so by the receiver (so the receiver can
later say 'Goto X' using the appropriate protocol), the dish motor can
have all positions reset (this one does it when you press both the 'Go
East' and 'Go West' manual buttons on the motor at the same time and
then power on (they can't have intended it to be easy!), but probably
the motor can't tell the receiver where it's pointed.

However it's still possible that even if the receiver doesn't know, the
dish motor might remember where it's pointed and move back there if a
gust blows it maybe 0.1 degrees away.

That would depend on the dish motor having some kind of shaft encoder
to tell it it's current position.

Otherwise, there would have to be a stepping motor pointing the dish
by just counting the number of steps. Which doesn't sound very good,
but maybe they do that.
(I'm just trying to guess semi-logically what the design might do).

Just align the dish to
satellites each end of the arc it can see and it just motors x amount
to find the ones in between. There could be some form of signal
strength feedback to "peak the alignment" when about in the right
place but that couldn't be used to keep the dish aligned as it
doesn't provide information about which way to move the dish.

Mmmm - couldn't you do that by moving one way a small amount until the
signal falls a little, then the other way until it rises then falls to
the same amount as before, and then split the difference?
But I doubt if there is such a feature, in this motor/receiver
combination at least.

The motor does have east and west limits which you set from the
receiver, but that doesn't prove that there is any position feedback to
the receiver from the motor.

Next time it happens move the dish to another sat and back again?

I've been reluctant to do that in case something goes wrong. Access to
the roof here is via a hatch in the upstairs neighbour's flat, so I
have to coordinate that with them, and if I can't get the dish pointed
correctly again I would lose satellite internet until I can go up.
(Also, I'm still not really clear about setting motor positions - the
booklet is translated from maybe the Chinese!)
Pointing to a TV satellite has to be fairly precise, but pointing to an
internet satellite has to be super-precise - a 3 watt transmitted
signal has to reach up 22,400 miles to the satellite.
Which is bloody well amazing, but it works.
Another case where Clarke's dictum is spot on: 'Any sufficiently
advanced technology is indistinguishable from magic'.
And very appropriate that it applies to satellites in the synchronous
orbits he suggested long ago.


--
Windmill, Use t m i l l
J.R.R. Tolkien:- @ S c o t s h o m e . c o m
All that is gold does not glister / Not all who wander are lost

"Brian Gaff" writes:

Yes, the dish movers are just dead reckoning things. If its possible to
actually physically move the dish with gusts of wind then the dish needs to
m be more securely mounted in my view.

It certainly moves a little, but not enough to lose satellite internet,
for which the accuracy has to be high.
During/after moderate gusts it seems to vibrate back to its original
position (there's a little bit of 'slop' in the motor gearing, I think,
and the combination of chimney mounting (steel lashing wires) and mast
isn't quite 100% rigid.
I don't think you could get absolute rigidity.


--
Windmill, Use t m i l l
J.R.R. Tolkien:- @ S c o t s h o m e . c o m
All that is gold does not glister / Not all who wander are lost

Lee writes:

On 20/09/2013 04:56, Windmill wrote:

The setup is a little unusual: a satellite internet link (which
continues to work throughout the gusts, so dish pointing isn't the
issue), a DVB-S LNB offset by the appropriate amount so that it 'sees'
the Astra 2A-B-D satellites instead of the Europasat internet satellite
which the dish is aimed at,

Just a guess here, but if the dish itself isn't moving maybe the arm
holding the offset LNB is? Possibly it's giving corrupt data packets to
the receiver which doesn't like it?

But if the arm is moving, why does powering the receiver off then on
again cure the problem for another 10 seconds/10 minutes/20 minutes?
That's what I don't understand.
Of course you could be right; there may be something unusual in the
receiver design which makes it give up after getting some noise.
The TV LNB is actually fairly firmly mounted; I can imagine it moving
and staying in the wrong position if forced, but moving back to the
correct position seems unlikely.


Couple of our old Sky digital boxes locked up with a similarly noisy
input...

Interesting info, that. Who knows what goes on in the innards.


--
Windmill, Use t m i l l
J.R.R. Tolkien:- @ S c o t s h o m e . c o m
All that is gold does not glister / Not all who wander are lost

"Brian Gaff" writes:

You cannot assume its not dish movement, it might well be that the aiming is
better for the main sat, and a bit off or weaker for the offset one.

Yeah but .... turning the receiver off then on again restores the
normal signal. Strength 90%, signal quality 73%. (If the receiver is
telling the truth.)

--
Windmill, Use t m i l l
J.R.R. Tolkien:- @ S c o t s h o m e . c o m
All that is gold does not glister / Not all who wander are lost

tony sayer writes:

In article , Lee
scribeth thus
On 20/09/2013 04:56, Windmill wrote:

The setup is a little unusual: a satellite internet link (which
continues to work throughout the gusts, so dish pointing isn't the
issue), a DVB-S LNB offset by the appropriate amount so that it 'sees'
the Astra 2A-B-D satellites instead of the Europasat internet satellite
which the dish is aimed at,

Just a guess here, but if the dish itself isn't moving maybe the arm
holding the offset LNB is? Possibly it's giving corrupt data packets to
the receiver which doesn't like it?

Couple of our old Sky digital boxes locked up with a similarly noisy
input...

Lee




If it is a wind problem you can try moving the affected bit around by
hand and if you can repeat the problem then tighten up and realign as
required.

Difficult; I'd need to run a mains cable up to the roof then take a TV
up there to see what happened. I hope it doesn't come to that.

Also are there any trees overhanging the dishes even some metres away at
all, they can really clobber sat signals and even more so when wet...

As I've found, in a different place where a tenant has a dish on the
wall outside his flat. Fine in winter, variable in summer. I'm thinking
of putting a dish on the roof there, "God willlin', an' if the crick
don't rise", as the country-corny American saying has it.

But here the line to the Astra satellites is completely unobstructed
(the Eutelsat satellite is, luckily, sufficiently high to be 'visible'
above the neighbour's chimney pots).

--
Windmill, Use t m i l l
J.R.R. Tolkien:- @ S c o t s h o m e . c o m
All that is gold does not glister / Not all who wander are lost

fred writes:

Can you turn off the LNB power on the receiver to separate the potential
of it being an LNB lockup rather than a steering issue?

That's an excellent idea. It can be done just by using the remote. And
I'm keen to do as much investigation from ground level as possible,
given the difficulty of getting onto the roof.

If it restores the LNB function it could still be a cabling issue with
movement causing transient interruptions to the LNB supply. I don't know
how sensitive LNBs are to such transients.

I don't even know what's in an LNB. There must be something like a
tuned cavity and a gallium arsenide transistor or IC to generate the
local oscillator frequency (the specs usually seem to talk about a
stability of +/- 2 MHz, which I suppose isn't much as a percentage of
10 GHz).
And there's some sort of polarisation switch, apparently selectable by
changing the DC supply voltage from the receiver down below, and some
sort of 22KHz modulated tone, also from the receiver, though I've
forgotten what that does in an LNB (frequency selection? LNB selection
when there are multiple LNBs ?).


--
Windmill, Use t m i l l
J.R.R. Tolkien:- @ S c o t s h o m e . c o m
All that is gold does not glister / Not all who wander are lost

Michael Chare mUNDERSCOREnews@chareDOTorgDOTuk writes:

On 20/09/2013 04:56, Windmill wrote:
In gusty winds, TV signals disappear and can only be restored by
powering the receiver off and on again. Or at least that's the only way
I've discovered so far to restore normal operation.

Has anyone had similar experiences?

Not me!

My bet is that the problem lies with the cabling, you could connect the
receiver direct to the LNB to see what happens when the wind blows.

If this was something I did regularly I suppose I'd need to buy a
battery-powered satellite receiver. Otherwise it's difficult to get
mains and a receiver up to the roof (I have only an ex-wife so
can't get her to call up to me!), so I'm trying to avoid that approach
if possible.

If you have a meter you can check the voltage that the receiver is
supplying to the motor/LNB.

I've been thinking about that. To properly measure voltage, current,
etc., I'd need a low pass filter to separate the DC from the UHF or SHF
(I suppose it might be called). Maybe a tiny one-turn coil and a 10,000
pF. capacitor, or two of them to measure current (with another 1000pF
cap to bypass the TV signals).


The www.digitalspy.co.uk satellite/technical forum can be quite helpful.

Thank you for that link. I'll give it a try.

--
Windmill, Use t m i l l
J.R.R. Tolkien:- @ S c o t s h o m e . c o m
All that is gold does not glister / Not all who wander are lost

On Sun, 22 Sep 2013 01:25:28 GMT, Windmill wrote:

Can you turn off the LNB power on the receiver to separate the
potential of it being an LNB lockup rather than a steering issue?

That's an excellent idea. It can be done just by using the remote.

Worth a try but there ain't much to "lock up" in an LNB, not unless
they are using a sledge hammer to crack a nut.

I don't even know what's in an LNB. There must be something like a
tuned cavity and a gallium arsenide transistor or IC to generate the
local oscillator frequency (the specs usually seem to talk about a
stability of +/- 2 MHz, which I suppose isn't much as a percentage of
10 GHz).

Yep LO of some sort.

And there's some sort of polarisation switch, apparently selectable by
changing the DC supply voltage from the receiver down below,

Yep, magnetic some how in the feed horn/wave guide.

and some sort of 22KHz modulated tone, also from the receiver, though
I've forgotten what that does in an LNB (frequency selection?

Think it's justa 22 kHz tone on or off. Selects which block of
frequencies to send down as the IF signal. Lo-Band or Hi-Band.

LNB selection when there are multiple LNBs ?).

Got me there, I've always assumed that LNB switching was done
manually or possibly part of the DiscEq protocol.

--
Cheers
Dave.

On Sun, 22 Sep 2013 00:47:41 GMT, Windmill wrote:

There could be some form of signal strength feedback to "peak the
alignment" when about in the right place but that couldn't be used
to
keep the dish aligned as it doesn't provide information about
which way
to move the dish.

Mmmm - couldn't you do that by moving one way a small amount until the
signal falls a little, then the other way until it rises then falls to
the same amount as before, and then split the difference?

How do you know that the signal fall, or rise, is due to the movement
and not some other external factor, heavy rain, dish icing, sun
outage, bird perched on LNB...

Pointing to a TV satellite has to be fairly precise, but pointing to an
internet satellite has to be super-precise - a 3 watt transmitted
signal has to reach up 22,400 miles to the satellite.

3 W ERP or 3 W of RF into a 20 dB gain dish? (350+ W ERP...)

--
Cheers
Dave.

On 22/09/2013 02:36, Windmill wrote:
Michael Chare mUNDERSCOREnews@chareDOTorgDOTuk writes:

On 20/09/2013 04:56, Windmill wrote:
In gusty winds, TV signals disappear and can only be restored by
powering the receiver off and on again. Or at least that's the only way
I've discovered so far to restore normal operation.

Has anyone had similar experiences?

Not me!

My bet is that the problem lies with the cabling, you could connect the
receiver direct to the LNB to see what happens when the wind blows.

If this was something I did regularly I suppose I'd need to buy a
battery-powered satellite receiver. Otherwise it's difficult to get
mains and a receiver up to the roof (I have only an ex-wife so
can't get her to call up to me!), so I'm trying to avoid that approach
if possible.

If you have a meter you can check the voltage that the receiver is
supplying to the motor/LNB.

I've been thinking about that. To properly measure voltage, current,
etc., I'd need a low pass filter to separate the DC from the UHF or SHF
(I suppose it might be called). Maybe a tiny one-turn coil and a 10,000
pF. capacitor, or two of them to measure current (with another 1000pF
cap to bypass the TV signals).


The www.digitalspy.co.uk satellite/technical forum can be quite helpful.

Thank you for that link. I'll give it a try.


The next time you have a problem, before you power off, try switching to
a channel of the opposite polarity. The change in DC voltage might just
help.

Some satellite receivers don't really supply enough current. This can be
a problem if you have multiple items connected, such as switches, motors
or even cheap meters.


--
Michael Chare

In article , Michael
Chare mUNDERSCOREnews@chareDOTorgDOTuk.? scribeth thus
On 22/09/2013 02:36, Windmill wrote:
Michael Chare mUNDERSCOREnews@chareDOTorgDOTuk writes:

On 20/09/2013 04:56, Windmill wrote:
In gusty winds, TV signals disappear and can only be restored by
powering the receiver off and on again. Or at least that's the only way
I've discovered so far to restore normal operation.






Just a thought. You say that this plays up until you reboot the system
and then it seems to be OK.

Just wondering if something in the sat RX is making it drift then when
re booted it corrects that alignment problem.

Might be an idea to watch it carefully under "fault" conditions whilst
getting SWMBO to re boot it and looking for and movement from it?...
--
Tony Sayer

tony sayer writes:

In article , Michael
Chare mUNDERSCOREnews@chareDOTorgDOTuk.? scribeth thus
On 22/09/2013 02:36, Windmill wrote:
Michael Chare mUNDERSCOREnews@chareDOTorgDOTuk writes:

On 20/09/2013 04:56, Windmill wrote:
In gusty winds, TV signals disappear and can only be restored by
powering the receiver off and on again. Or at least that's the only way
I've discovered so far to restore normal operation.






Just a thought. You say that this plays up until you reboot the system
and then it seems to be OK.

Just wondering if something in the sat RX is making it drift then when
re booted it corrects that alignment problem.

Might be an idea to watch it carefully under "fault" conditions whilst
getting SWMBO to re boot it and looking for and movement from it?...

My ex-SWMBO and I have for a long time now been separated by the Pond!

And when recently the BBC played that song sung by Rex Harrison about the
disasters caused by 'letting a woman into your life', I found myself
shouting my agreement.
A replacement SWMBO is therefore wildly unlikely.

But if all else fails I'll maybe need to take an old LCD monitor with a
VGA input fed by an S-video to VGA converter up onto the roof and force
the reboot by turning the receiver's power on and off (should be able
to do that with a long mains cable).
I'd need some way to send the video up to the roof (did I see ads for
VGA over Cat5 drivers somewhere?). Or take the reciver up also.

Far cheaper than a SWMBO!

But the first thing to do is to re-make all coax connections, I think.

--
Windmill, Use t m i l l
J.R.R. Tolkien:- @ S c o t s h o m e . c o m
All that is gold does not glister / Not all who wander are lost

In article , Windmill spam-no-
lid scribeth thus
tony sayer writes:

In article , Michael
Chare mUNDERSCOREnews@chareDOTorgDOTuk.? scribeth thus
On 22/09/2013 02:36, Windmill wrote:
Michael Chare mUNDERSCOREnews@chareDOTorgDOTuk writes:

On 20/09/2013 04:56, Windmill wrote:
In gusty winds, TV signals disappear and can only be restored by
powering the receiver off and on again. Or at least that's the only way
I've discovered so far to restore normal operation.






Just a thought. You say that this plays up until you reboot the system
and then it seems to be OK.

Just wondering if something in the sat RX is making it drift then when
re booted it corrects that alignment problem.

Might be an idea to watch it carefully under "fault" conditions whilst
getting SWMBO to re boot it and looking for and movement from it?...

My ex-SWMBO and I have for a long time now been separated by the Pond!

Ah!, sorry I thought there was another with you;!...


And when recently the BBC played that song sung by Rex Harrison about the
disasters caused by 'letting a woman into your life', I found myself
shouting my agreement.

Funny that a mate of mine has just that outlook he treats them as
expendable and mean just isn't the word for it either! .

And guess what as soon as ones gone there another turns up there!

.. round him like files;!...


A replacement SWMBO is therefore wildly unlikely.

But if all else fails I'll maybe need to take an old LCD monitor with a
VGA input fed by an S-video to VGA converter up onto the roof and force
the reboot by turning the receiver's power on and off (should be able
to do that with a long mains cable).
I'd need some way to send the video up to the roof (did I see ads for
VGA over Cat5 drivers somewhere?). Or take the reciver up also.

Far cheaper than a SWMBO!

Not got a mate who could look at this whilst being re booted at all?..

But the first thing to do is to re-make all coax connections, I think.


--
Tony Sayer

On 22/09/2013 02:25, Windmill wrote:


I don't even know what's in an LNB.

Probably not what you want but...
http://www.admac.myzen.co.uk/quad_lnb/

--
mailto:news{at}admac(dot}myzen{dot}co{dot}uk

tony sayer writes:

In article , Windmill spam-no-
scribeth thus
tony sayer writes:

In article , Michael
Chare mUNDERSCOREnews@chareDOTorgDOTuk.? scribeth thus
On 22/09/2013 02:36, Windmill wrote:
Michael Chare mUNDERSCOREnews@chareDOTorgDOTuk writes:

On 20/09/2013 04:56, Windmill wrote:
In gusty winds, TV signals disappear and can only be restored by
powering the receiver off and on again. Or at least that's the only way
I've discovered so far to restore normal operation.






Just a thought. You say that this plays up until you reboot the system
and then it seems to be OK.

Just wondering if something in the sat RX is making it drift then when
re booted it corrects that alignment problem.

Might be an idea to watch it carefully under "fault" conditions whilst
getting SWMBO to re boot it and looking for and movement from it?...

My ex-SWMBO and I have for a long time now been separated by the Pond!

Ah!, sorry I thought there was another with you;!...


And when recently the BBC played that song sung by Rex Harrison about the
disasters caused by 'letting a woman into your life', I found myself
shouting my agreement.

Funny that a mate of mine has just that outlook he treats them as
expendable and mean just isn't the word for it either! .

And guess what as soon as ones gone there another turns up there!

.. round him like files;!...

Not how it works for me. But I don't treat them as expendable, I treat
them as unexploded bombs.

A replacement SWMBO is therefore wildly unlikely.

But if all else fails I'll maybe need to take an old LCD monitor with a
VGA input fed by an S-video to VGA converter up onto the roof and force
the reboot by turning the receiver's power on and off (should be able
to do that with a long mains cable).
I'd need some way to send the video up to the roof (did I see ads for
VGA over Cat5 drivers somewhere?). Or take the reciver up also.

Far cheaper than a SWMBO!

Not got a mate who could look at this whilst being re booted at all?..

I stopped going to the pub 10 years ago; too expensive.
And anyway a lot of the people I knew or was related to have 'shuffled
off this mortal coil' (Shakespeare obviously was observant about the
old gits' gait).

But the first thing to do is to re-make all coax connections, I think.

--
Windmill, Use t m i l l
J.R.R. Tolkien:- @ S c o t s h o m e . c o m
All that is gold does not glister / Not all who wander are lost

alan writes:

On 22/09/2013 02:25, Windmill wrote:


I don't even know what's in an LNB.

Probably not what you want but...
http://www.admac.myzen.co.uk/quad_lnb/

I should look on wikipedia. Always forget how much info is available
on-line nowadays (when you can find it).

--
Windmill, Use t m i l l
J.R.R. Tolkien:- @ S c o t s h o m e . c o m
All that is gold does not glister / Not all who wander are lost

(Windmill) writes:

fred writes:

Can you turn off the LNB power on the receiver to separate the potential
of it being an LNB lockup rather than a steering issue?

That's an excellent idea. It can be done just by using the remote. And
I'm keen to do as much investigation from ground level as possible,
given the difficulty of getting onto the roof.

If it restores the LNB function it could still be a cabling issue with
movement causing transient interruptions to the LNB supply. I don't know
how sensitive LNBs are to such transients.

More info at last: Using the remote as you suggested to turn LNB power
off then on again restores function just as powering the receiver off
then on again does.

I put my trusty old Avo Mk. 8 on the receiver cable without doing this
properly (no low pass filter to the meter) but the receiver continued
to work anyway, as sometimes happens when you ignore what should really
be done.

I saw 12.5 volts going up to the roof, and no change in DC voltage when
things repeatedly stopped working during some rainy gusts.
Later (did I change the channel? Didn't think so, but maybe I must have
done) I saw 19.5 volts, and no more failures although the rain and wind
has died down.

It's still working, which is annoying because I've done nothing to fix
whatever is wrong, so it must still be wrong.
Maybe it'll fail again during the next gale.

Seems likely that I really should remake all the F connector
connections when I can next get up on the roof.

Was unhappy to discover when hooking up the Avo that not only does the
cable have just copper-coated-steel inner conductor, but that the outer
braid over the foil can't be soldered because it is (I think) aluminium
braid.
Which sounds to me like an accident waiting to happen.

--
Windmill, Use t m i l l
J.R.R. Tolkien:- @ S c o t s h o m e . c o m
All that is gold does not glister / Not all who wander are lost

On Sat, 5 Oct 2013 15:57:41 GMT, Windmill wrote:

I saw 12.5 volts going up to the roof, and no change in DC voltage when
things repeatedly stopped working during some rainy gusts.
Later (did I change the channel? Didn't think so, but maybe I must have
done) I saw 19.5 volts, and no more failures although the rain and wind
has died down.

That is normal, the voltage sent to the LNB determines which polarity
signal to receive. The lower being vertical. Curiously I thought the
"acceptable ranges" where 12.5 to 14.5 V and 15.5 to 18 V.

Was unhappy to discover when hooking up the Avo that not only does the
cable have just copper-coated-steel inner conductor, ...

Hum, see recent thread about CCS phone cable. It has a significantly
higher resistance than copper, like about 7 times higher. If the
cable is long there could be an appreciable voltage drop across it.
Current is probably 100 mA or more depending on the LNB.

... but that the outer braid over the foil can't be soldered because it
is (I think) aluminium braid.

One wouldn't normally solder F-types, they either screw on, crimp or
have a compression fitting.

Which sounds to me like an accident waiting to happen.

You can't beat copper (well silver probably would but...)

--
Cheers
Dave.

Was unhappy to discover when hooking up the Avo that not only does the
cable have just copper-coated-steel inner conductor, but that the outer
braid over the foil can't be soldered because it is (I think) aluminium
braid.
Which sounds to me like an accident waiting to happen.

I think you'll find most all the cable TV nets in the UK use ally foil
cables there not quite as bad as you might think terminated properly..
--
Tony Sayer

"Dave Liquorice" writes:

On Sat, 5 Oct 2013 15:57:41 GMT, Windmill wrote:

I saw 12.5 volts going up to the roof, and no change in DC voltage when
things repeatedly stopped working during some rainy gusts.
Later (did I change the channel? Didn't think so, but maybe I must have
done) I saw 19.5 volts, and no more failures although the rain and wind
has died down.

That is normal, the voltage sent to the LNB determines which polarity
signal to receive. The lower being vertical. Curiously I thought the
"acceptable ranges" where 12.5 to 14.5 V and 15.5 to 18 V.

Quite likely it will be 16 when it gets through a demultiplexer then 25
meters of cable then a multiplexer then the motor, before reaching the
LNB.
In fact I had wondered if voltage drop was the cause of the problem,
but that doesn't easily explain the 'works for days / fails every few
minutes' scenario I'm seeing.

Was unhappy to discover when hooking up the Avo that not only does the
cable have just copper-coated-steel inner conductor, ...

Hum, see recent thread about CCS phone cable. It has a significantly
higher resistance than copper, like about 7 times higher. If the
cable is long there could be an appreciable voltage drop across it.
Current is probably 100 mA or more depending on the LNB.
Plus 300 mA if the motor is turning, but of course then the LNB is
less relevant.

... but that the outer braid over the foil can't be soldered because it
is (I think) aluminium braid.

One wouldn't normally solder F-types, they either screw on, crimp or
have a compression fitting.

No, I meant that, so as to get access to the centre conductor, I had
cut in half a short piece of cable with an F connector on one end and a
connector plus F-to-F adaptor on the other, then tried to solder the
two braids together again.
I should have explained properly.
The centre conductors soldered easily, but for the braid I had to use a
little 2 A. terminal block.
It still gave the receiver an adequate signal, though I would not have
been surprised if it hadn't.

Which sounds to me like an accident waiting to happen.

You can't beat copper (well silver probably would but...)

I remember radar stuff which used a lot of silver, and even rhodium.


--
Windmill, Use t m i l l
J.R.R. Tolkien:- @ S c o t s h o m e . c o m
All that is gold does not glister / Not all who wander are lost

tony sayer writes:

Was unhappy to discover when hooking up the Avo that not only does the
cable have just copper-coated-steel inner conductor, but that the outer
braid over the foil can't be soldered because it is (I think) aluminium
braid.
Which sounds to me like an accident waiting to happen.

I think you'll find most all the cable TV nets in the UK use ally foil
cables there not quite as bad as you might think terminated properly..

Yebbut this wasn't just aluminium foil; the braid was also aluminium
and so wouldn't solder.
Re-checking the cable specs, I see that it does say 'aluminium wire
braid over foil'.
Either I didn't spot that, or they've produced a more detailed
description in the years since I ordered the reel of cable.


--
Windmill, Use t m i l l
J.R.R. Tolkien:- @ S c o t s h o m e . c o m
All that is gold does not glister / Not all who wander are lost

In article , Windmill spam-no-
lid scribeth thus
tony sayer writes:

Was unhappy to discover when hooking up the Avo that not only does the
cable have just copper-coated-steel inner conductor, but that the outer
braid over the foil can't be soldered because it is (I think) aluminium
braid.
Which sounds to me like an accident waiting to happen.

I think you'll find most all the cable TV nets in the UK use ally foil
cables there not quite as bad as you might think terminated properly..


Yebbut this wasn't just aluminium foil; the braid was also aluminium
and so wouldn't solder.
Re-checking the cable specs, I see that it does say 'aluminium wire
braid over foil'.
Either I didn't spot that, or they've produced a more detailed
description in the years since I ordered the reel of cable.



Invariably they crimp that sort of cable. You can use screw on F types
with it.

I don't think theres a soldered connection most anywhere in the local
cable network!..

--
Tony Sayer

tony sayer writes:

In article , Windmill spam-no-
scribeth thus
tony sayer writes:

Was unhappy to discover when hooking up the Avo that not only does the
cable have just copper-coated-steel inner conductor, but that the outer
braid over the foil can't be soldered because it is (I think) aluminium
braid.
Which sounds to me like an accident waiting to happen.

I think you'll find most all the cable TV nets in the UK use ally foil
cables there not quite as bad as you might think terminated properly..


Yebbut this wasn't just aluminium foil; the braid was also aluminium
and so wouldn't solder.
Re-checking the cable specs, I see that it does say 'aluminium wire
braid over foil'.
Either I didn't spot that, or they've produced a more detailed
description in the years since I ordered the reel of cable.



Invariably they crimp that sort of cable. You can use screw on F types
with it.

I don't think theres a soldered connection most anywhere in the local
cable network!..

I'm now thinking that the cause of my problems may well be that it's
difficult to get a good connection to aluminium.
A terrestrial antenna usually won't need power, so this stuff might be
fine for that, but dish motor and LNB could take going on for 1/2 amp.

This is another case of 'what I think I know is now wrong'.

Once upon a time, RG6 cable had copper inner conductor and tinned
copper braid outer, and that's what I thought I was ordering.
But this junk has copper-coated steel inner conductor and aluminium foil
outer with aluminium braid wire over that.

Maybe there's still some hope, though, short of replacing all the
cable.

You say that screw-on F type connectors can be used with it.
Is there some special approved method of making the connection?
Maybe folding back the foil as well as the braid over the outer
insulation, instead of remving the foil and leaving only the braid as I
did, and then screwing a suitable-sized connector over that?

--
Windmill, Use t m i l l
J.R.R. Tolkien:- @ S c o t s h o m e . c o m
All that is gold does not glister / Not all who wander are lost

On Wed, 9 Oct 2013 04:01:29 GMT, Windmill wrote:

You say that screw-on F type connectors can be used with it.
Is there some special approved method of making the connection?
Maybe folding back the foil as well as the braid over the outer
insulation, instead of remving the foil and leaving only the braid as I
did, and then screwing a suitable-sized connector over that?

There may be something in one of Mr Wrights articles, I'd be
surprised if there wasn't:

http://www.wrightsaerials.co.uk/articles/index.shtml

I remove the foil fold back the braid evenly, trim the inner
insulation with a sharp blade soit's smooth, sqaure and projects
about 1 mm beyond the folded back braid. Screw on the connector until
the inner insulation is firmly against the flange in the connector.

F-types outside need to be completely wrapped in self amalgamating
tape once mated, they are not damp proof let alone weather proof!

--
Cheers
Dave.

In article , Windmill spam-no-
lid scribeth thus
tony sayer writes:

In article , Windmill spam-no-
scribeth thus
tony sayer writes:

Was unhappy to discover when hooking up the Avo that not only does the
cable have just copper-coated-steel inner conductor, but that the outer
braid over the foil can't be soldered because it is (I think) aluminium
braid.
Which sounds to me like an accident waiting to happen.

I think you'll find most all the cable TV nets in the UK use ally foil
cables there not quite as bad as you might think terminated properly..


Yebbut this wasn't just aluminium foil; the braid was also aluminium
and so wouldn't solder.
Re-checking the cable specs, I see that it does say 'aluminium wire
braid over foil'.
Either I didn't spot that, or they've produced a more detailed
description in the years since I ordered the reel of cable.



Invariably they crimp that sort of cable. You can use screw on F types
with it.

I don't think theres a soldered connection most anywhere in the local
cable network!..

I'm now thinking that the cause of my problems may well be that it's
difficult to get a good connection to aluminium.

Well if you saw the crimp connectors they use;!..

A terrestrial antenna usually won't need power, so this stuff might be
fine for that, but dish motor and LNB could take going on for 1/2 amp.

This is another case of 'what I think I know is now wrong'.

Once upon a time, RG6 cable had copper inner conductor and tinned
copper braid outer, and that's what I thought I was ordering.
But this junk has copper-coated steel inner conductor and aluminium foil
outer with aluminium braid wire over that.

Well if you have a duff connection then you have a duff connection, have
a look at the joints in the system and make sure there're well wrapped
in self welding tape! and theres no water ingress anywhere along the
cables if the outer sheathing has been damaged or slit etc....


Maybe there's still some hope, though, short of replacing all the
cable.

You say that screw-on F type connectors can be used with it.
Is there some special approved method of making the connection?
Maybe folding back the foil as well as the braid over the outer
insulation, instead of remving the foil and leaving only the braid as I
did, and then screwing a suitable-sized connector over that?

You can do that, have a practice..
--
Tony Sayer

"Dave Liquorice" writes:

On Sun, 22 Sep 2013 01:25:28 GMT, Windmill wrote:

Can you turn off the LNB power on the receiver to separate the
potential of it being an LNB lockup rather than a steering issue?

That's an excellent idea. It can be done just by using the remote.

Worth a try but there ain't much to "lock up" in an LNB, not unless
they are using a sledge hammer to crack a nut.

I don't even know what's in an LNB. There must be something like a
tuned cavity and a gallium arsenide transistor or IC to generate the
local oscillator frequency (the specs usually seem to talk about a
stability of +/- 2 MHz, which I suppose isn't much as a percentage of
10 GHz).

Yep LO of some sort.

Don't know why, but looking on Wikipedia is often thelast thing that
occurs to me.
When finally I did, I found out that the oscillator was somethoing
called a 'dielectric oscillator', not a transistor at all. Now I
suppose I need to look that up in turn.

And there's some sort of polarisation switch, apparently selectable by
changing the DC supply voltage from the receiver down below,

Yep, magnetic some how in the feed horn/wave guide.

That's what I thought, and seemingly that was once the case (which
maybe explains those LNBs whose spec gives an operating lifetime for
the number of polarisation changes) but according to Wikipedia they now
just use two probes at right angles, one to receive the horizontal
signals and one to recive the vertical, with the switching presumably
being done by choosing which probe you want to take the signal from.

and some sort of 22KHz modulated tone, also from the receiver, though
I've forgotten what that does in an LNB (frequency selection?

Think it's justa 22 kHz tone on or off. Selects which block of
frequencies to send down as the IF signal. Lo-Band or Hi-Band.

LNB selection when there are multiple LNBs ?).

Got me there, I've always assumed that LNB switching was done
manually or possibly part of the DiscEq protocol.

Seems that the protocol modulates the 22KHz tone (on and off in a
binary pattern, I think I now remember seeing) to tell which switch
what to do.

I'm learning - trouble is I'm forgetting almost as fast!


--
Windmill, Use t m i l l
J.R.R. Tolkien:- @ S c o t s h o m e . c o m
All that is gold does not glister / Not all who wander are lost

"Dave Liquorice" writes:

On Sun, 22 Sep 2013 00:47:41 GMT, Windmill wrote:

There could be some form of signal strength feedback to "peak the
alignment" when about in the right place but that couldn't be used
to
keep the dish aligned as it doesn't provide information about
which way
to move the dish.

Mmmm - couldn't you do that by moving one way a small amount until the
signal falls a little, then the other way until it rises then falls to
the same amount as before, and then split the difference?

How do you know that the signal fall, or rise, is due to the movement
and not some other external factor, heavy rain, dish icing, sun
outage, bird perched on LNB...

Pointing to a TV satellite has to be fairly precise, but pointing to an
internet satellite has to be super-precise - a 3 watt transmitted
signal has to reach up 22,400 miles to the satellite.

3 W ERP or 3 W of RF into a 20 dB gain dish? (350+ W ERP...)

IIRC the specs say 3 watts of RF, which is apparently the maximum
allowable under EU rules for a dish of 1 metre or was it 85 cm., unless
the site has a special licence to operate at higher powers.

Maybe it is 350W ERP, but the field intensities in the largish beam
can't be all that high. Calling it 350 watts makes it sound alarming,
but what would it be in the beam of a 5 megawatt radar (pulsed, of
course)? It would be something horrendous, but there used to be jokes
(I *think* they were jokes) about guys who temporarily sterilised
themselves by standing in the beam for a few seconds.

--
Windmill, Use t m i l l
J.R.R. Tolkien:- @ S c o t s h o m e . c o m
All that is gold does not glister / Not all who wander are lost

Michael Chare mUNDERSCOREnews@chareDOTorgDOTuk writes:

On 22/09/2013 02:36, Windmill wrote:
Michael Chare mUNDERSCOREnews@chareDOTorgDOTuk writes:

On 20/09/2013 04:56, Windmill wrote:
In gusty winds, TV signals disappear and can only be restored by
powering the receiver off and on again. Or at least that's the only way
I've discovered so far to restore normal operation.

Has anyone had similar experiences?

Not me!

My bet is that the problem lies with the cabling, you could connect the
receiver direct to the LNB to see what happens when the wind blows.

If this was something I did regularly I suppose I'd need to buy a
battery-powered satellite receiver. Otherwise it's difficult to get
mains and a receiver up to the roof (I have only an ex-wife so
can't get her to call up to me!), so I'm trying to avoid that approach
if possible.

If you have a meter you can check the voltage that the receiver is
supplying to the motor/LNB.

I've been thinking about that. To properly measure voltage, current,
etc., I'd need a low pass filter to separate the DC from the UHF or SHF
(I suppose it might be called). Maybe a tiny one-turn coil and a 10,000
pF. capacitor, or two of them to measure current (with another 1000pF
cap to bypass the TV signals).


The www.digitalspy.co.uk satellite/technical forum can be quite helpful.

Thank you for that link. I'll give it a try.


The next time you have a problem, before you power off, try switching to
a channel of the opposite polarity. The change in DC voltage might just
help.

Doesn't seem to. In fact the behaviour is becoming more random all the
time. It has worked steadily for about 30 hours now.

Some satellite receivers don't really supply enough current. This can be
a problem if you have multiple items connected, such as switches, motors
or even cheap meters.

That could well be a part of the problem, but when I can next negotiate
with the upstairs neighbour I've decided to replace at least the LNB to
motor and the motor to multiplexer cables with real copper 125 cable
instead of the aluminium braid wire on the so-called RG6. Yuck!

--
Windmill, Use t m i l l
J.R.R. Tolkien:- @ S c o t s h o m e . c o m
All that is gold does not glister / Not all who wander are lost

"Dave Liquorice" writes:

On Wed, 9 Oct 2013 04:01:29 GMT, Windmill wrote:

You say that screw-on F type connectors can be used with it.
Is there some special approved method of making the connection?
Maybe folding back the foil as well as the braid over the outer
insulation, instead of remving the foil and leaving only the braid as I
did, and then screwing a suitable-sized connector over that?

There may be something in one of Mr Wrights articles, I'd be
surprised if there wasn't:

http://www.wrightsaerials.co.uk/articles/index.shtml

I need to have a look. Using a different PC.

I remove the foil fold back the braid evenly, trim the inner
insulation with a sharp blade soit's smooth, sqaure and projects
about 1 mm beyond the folded back braid. Screw on the connector until
the inner insulation is firmly against the flange in the connector.

That's roughly what I did. But the crappy coax I bought has just a few
strands of aluminium braid which makes me wonder about the quality of
the contact with the F plug body.

F-types outside need to be completely wrapped in self amalgamating
tape once mated, they are not damp proof let alone weather proof!

I used silicone rubber sealant on most of the connections, but there
were a couple where I didn't (because I needed to muck about with a
satellite meter aligning on the satellite, and thought I might need to
repeat the process).

However the setup, which worked initially (months ago), failed before
it rained, and has behaved oddly ever since. Right now it's been in a
working state for hours, but may fail during the next gale.

I lost my self-amalgamating tape (read: put it in a safe? place) but
now have more, so when I get the chance I'll use that on the new
interconnections I plan to make.

Going to have to find my birth certificate; the TV licencing people
claim to be unable to verify my age by contacting the DWP with my NI
number, and I don't want them on my top :-)



--
Windmill, Use t m i l l
J.R.R. Tolkien:- @ S c o t s h o m e . c o m
All that is gold does not glister / Not all who wander are lost