DIY 2nd hand satellite dish install

Hi,

Got an old satellite dish from a neighbour, it is a good 20in in diameter and is well over 10 years old. Set it up and plugged it in.... nothing. The signal strength meters on the humax boxes admin menu report nothing at all. Perhaps I sould say I am tryng to pick up freesat.

Anyway I suspect the LNB, a grundig "aus 25", is to old for the humax and want to buy a more modern LNB. My question is: are the LNBs physically interchangeable? Most of the dishes seem to use a collar to hold the LNB, is this true? Are they all the same diameter?

I feel quite confident about the dishes direction given advice on the internet and observation of where my neigbours have their freesat dishes pointing. As for elevation, I noted that the LNB was not mounted at the central point of the dish and so assumed that the dish should be vertical with the off center LNB positioning sorting things out.

Reply to
Fergus McMenemie
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You might find it "un-aided" but you're picking up a signal from something the size of a transit van 22,000 miles above Lake Victoria

This site might help

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you might need to resort to a sat finder meter

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I feel quite confident about the dishes direction given advice

You need to be within a degree or better, rather than just in the same general direction followed by adjusting for a better picture like you can with an aerial.

Yes, most dishes are offset, so will be looking higher up at the sky than a direct view from behind, no elevation markings on the mount?

Reply to
Andy Burns

You will be extraordinarily lucky to pick anything up if the dish has been installed purely by estimation, no matter how well done. The margin for error is very slight, no more than a very few degrees in both elevation and azimuth.

If you have left the vertical alignment alone you may be able to pick something up by very slowly moving the aerial in azimuth. This can be a really tedious process depending upon your receiver as the digital ones can take minutes to lock onto a new signal and don't always tell you they are doing anything in the meantime.

You can get simple signal strength meters such as

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it is probably worth getting that or a similar device for your initial setup particularly if you have altered the vertical alignment. You _can_ align it all by using just the freesat box alone but it can easily take you many hours and much annoyance.

When using the signal strength meter note that if you pick up something on it but your Freesat box still shows nothing it does not mean the LNB is dead but that you have probably picked up the wrong satellite. Some Freesat receivers only show Freeesat channels and refuse to respond at all to other signals.

Reply to
Peter Parry

On Wed, 26 May 2010 15:05:21 +0100 someone who may be snipped-for-privacy@twig-me-uk.not.here (Fergus McMenemie) wrote this:-

As Andy said a meter can be very useful. It is generally best to set the elevation about right, get the direction right and then adjust the elevation precisely. Only small adjustments are needed when in the right direction.

Generally there is an offset of 20 degrees in elevation, because of the offset of the LNB. Dish elevation depends on where you are, in Scotland the dish is likely to be horizontal or even pointing down slightly. Further south the dish will be pointing up a little.

Reply to
David Hansen

which Satellite you want.

Reply to
Fergus McMenemie

Thanks for both answers but both missed the point! The dish and its LNB are very old. Possibly before digital TV sat broadbcasts. Will the same LNB do? Will the Humax Foxsat work with such and old LNB?

If I have to buy a new LNB, how standard are the fittings. Is this

40mm collar thing a standard?

Thanks Fergus.

Reply to
Fergus McMenemie

Never having done this before I was wondering if the "absolute zero" on the satellites signal strength display was significant. Do they read a total zero or do they show a 5-10% noise level when off beam? I would be expecting

Reply to
Fergus McMenemie

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember snipped-for-privacy@twig-me-uk.not.here (Fergus McMenemie) saying something like:

Pretty much, yes. If the old LNB is old enough it will only be a standard of the day one, what you need is a modern Universal which has extra bandwidth. Assuming the old one still works, it would actually give you some channels, just not all. If it's giving nothing at all, it's likely banjaxed - not surprising, really.

Reply to
Grimly Curmudgeon

Have X-posted you to alt.satellite.tv.europe.

If it is really old it may be an analog LNB.

Your assumption about vertical positioning may not be correct. My dish ( a modern one I fitted recently) is not vertical. I used a satellite finder from Maplin - even then I found the wrong satellite first.

I did have an analogue system years ago with a tin dish and I set that up using the satellite decoder and a small TV but I was standing on my balcony which made things a lot easier.

HTH

Dave R

Reply to
David WE Roberts

It should work. If it is the one Noah used to get BBC and ITV only on the Ark then it is possibly covering an incomplete frequency band, the band extended a decade or more ago . The very early LNB models wouldn't pick up Astra 1d (I think - its a long time ago!). If the LNB has a frequency of 10GHz marked it is an early model. If it has

9.75 or "universal" it is a later one. You may have to set the LNB frequency in the foxsat if you can if it is 10GHz as the default will now be 9.75.

The 40mm collar is fairly standard although I think some 40mm fixing LNB's need an adapter clip with very early Sky provided mini dishes.

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If the Foxsat has two aerial inputs then get a dual LNB such as
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connect both to the receiver. If your present LNB is single output and the Foxsat is a PVR then you will need a dual LNB to be able to record one channel while watching another.

Reply to
Peter Parry

Your aiming accuracy needs to be within just a few degrees for both horizontal and vertical. An offset dish aimed at Astra should be roughly vertical for most of the UK. A decent compass (making allowance for magnetic variation) and a bit of wood should get it pointing in the correct horizontal direction. The signal meter in most receivers is almost useless, because they respond too slowly to be useful - use an inline meter. Obvious really, but the dish also needs a clear view of the sky, in the direction it is aimed.

Reply to
Harry Bloomfield

You are wasting your time, you can pick up a freesat HD system for under £70,including dish,LNB, Decoder and cable.

Yours may be an old Analogue system, the LNB or decoder may be knackered.

Reply to
Camdor

This might help:

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Reply to
PeterC

Unlike the good old analogue days, a digital satellite cannot be set by watching the picture. With digital nothing shows up until you are very, very close to the correct position. Then you can only optimise the position if you have a read-out of the signal strength AND the quality.

The collar on most standard universal LNBs is 40mm but some have serrations on them which need to be filed off to fit an older clamp.

Older (intended for analogue) LNBs cannot tune the whole K band. That is why universal LNBs were developed. The Humax - if it is a FreeSat model

- needs to tune to all transponders to function correctly.

LNBs can be had on eBay or from Lidl for around a fiver. If you are wanting the Freesat channels then a 50/60 cm (~20") dish should be OK.

Good luck.

Dem

Reply to
Demonic

That's a 50cm dish, which should be adequate for the UK, but almost certainly you're not getting a signal because the dish isn't aligned on any satellite cluster, see below.

Most LNBs should fit in most dishes, although I have heard there are oddballs.

No! First thing to note: Pointing a sat dish is not like pointing a TV aerial, where anything within about 5-10 degrees of correct will get a signal, probably an adequate one. As you have found, if you just look at your neighbours' dishes and try and judge it by eye, you'll probably get no signal, or if you're lucky enough to do so it'll almost certainly be the wrong cluster of satellites. You need to *measure* it! Accurately! Initially to within about a degree! (a)

As for elevation, you have what is known as an offset dish. A characteristic of these dishes is that the elevation required for them is reduced by the offset angle, but the precise elevation will still depend on the site location and the longitude of the target satellite (more correctly, satellite cluster), which for Freesat is 28.2E

First, I suggest you read the General Introduction in the section of my site linked above, then enter you location's details into the Satellite Alignment Calculator. From there, as explained in the Introduction:

1: To get the azimuth (horizontal direction) you can either use the Calculator's internet mapping to print out an aerial photo of your house and use the marker on it to point the dish, or else use the settings from the Calculator with a hardcopy map or a compass. 2: If the dish has a scale, you can set the elevation (vertical direction) from the Calculator directly on the scale, if not, things get more difficult, especially if, which I doubt from your description above, the dish is a mini-dish, wider than tall. I suspect that from its age it's a conventional offset dish, slightly taller than wide, in which case measure the width and height and feed these into the Calculator, which will work out an approximation for the offset and adjust the elevation figure accordingly, then use one of the three methods from the Introduction to set the elevation - click on 'The Dish Has No Scale'.

(a) To keep constant station with respect to a spinning planet, here of course Earth, the laws of physics dictate that such a orbit MUST be exactly around its equator at an exact and specific radius that depends on the planet's rate of spin, here 24hrs. This means that space in such 'geo-stationary' orbit is limited, and demand has led to satellites orbiting together stacked up in clusters which appear to a dish on Earth as one satellite, and above populated areas clusters are only about 2-3 degrees apart. Consequently, dishes have to be big enough to have the resolution to pick up only the cluster they are aimed at, not its neighbours. This means that the 'target' for aiming the dish is very small indeed.

Ah! That's why I didn't see the original.

To be accurate, there's no such thing as an 'analogue' LNB. As the other respondent has pointed out, what he needs is a *Universal* LNB, whereas he might have an older one which can't cover the whole band.

Which exactly bears out my point above! Thank you!

Reply to
Java Jive

Hmmmm that looks a very useful site.

Thanks for the help everyone!

Reply to
Fergus McMenemie

Reply to
Peter Parry

My box generates Strength and Quality bars on the screen, so I arranged a large mirror so that I could see the screen from up the ladder, then 'rock'-tuned the dish. This involved finding the signal, checking that it was the correct satellite (Astra 2) and then moving the dish around so that it was in the middle of the range that gave the best figures. This allows things to move/drift a bit without the signal deteriorating too easily.

Now, if there were a way of 'seeing' through heavy precipitation...

Reply to
PeterC

All I've seen either have the round 40mm collar, or are the sky push in type. Adaptors are available to enable the roud type to fit a sky dish. However, sky (oval) dishes have LNBs supposedly optimised for that type of dish, sa compared with the more standard circular dishes.

Lidl had some suitable LNBs (40mm) last week for under £3. You may find somewhere that hasn't sold out. I got two.

Reply to
<me9

I /am/ using an old analogue dish. It is larger (80cm) than the sky ones. It works perfectly with a new universal LNB. 40mm collar is standard apart from proprietry sky digital dishes.

Reply to
<me9

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