Advice Needed Is there a variation in optimum Dish elevation with the seasons????

[jeallen01]

I seem to recall, quite recently in some thread or other, that there could be a benefit from making a slight variation to the dish elevation angle during some months of the year.

That intrigued me because I would have thought that with most sats being geostationary then the angle would be constant throughout the whole year - or is it maybe something to do with the Earth "wobbling" on its rotational axis, &/or some other factor(s)?

I'd not heard of this before and would appreciate any info &/or experience on the subject.

 

[Channel Hopper]

The geostationary satellites maintain a close proximity to the equatorial arc, and will vary only as a result of gravitational and solar energy forces, plus their own momentum above/below the line, this is on a daily rather than seasonal basis.

No earth station as I understand has seasonal adjustments for tracking satellites, so it not reasonable to assume anyone with a standard set up would either, though there two are exceptions to this

1) The difference in ambient winter/summer temperatures on aluminium structures can cause the reflector to align differently, and so an elevation motor might offset this effect.

2) (from personal experience) . A 1.4m dish installed on a large paving slab at a clients address, next to a stream in their garden, was affected by the biomass in the soil expanding in the spring and contracting in the late autumn, I fitted a small motor on the elevation to allow remote adjustment for this effect rather than travel the 85 miles each six months to compensate.

 

[jeallen01]

CH

Many thanks - very interesting!

I don't think my dishes would be affected by either of those factors because they are not that big nor are they aluminium, and the sub-soil is very stable and dry London clay.

 

[Lazarus]

.... A fault on an Underground Leccy cable though ....... Kaboom!

 

[jeallen01]

.... A fault on an Underground Leccy cable though ....... Kaboom!

I think that would result in the need for rather more than a slight realignment - or do you have "personal experience" of the issue (Leccy cable fault = Kaboom, I mean )?

 

[Channel Hopper]

.... A fault on an Underground Leccy cable though ....... Kaboom!

It's not just cabling that causes pavement explosions in London though, there is a lot of decomposing (and not decomposing) material underground. Houseowners pouring waste oil into the drains, restaurants 'storing' fat for months in some dubious places, sewers clogged with an exponential mass of debris that turns into 'fatbergs'. There was a report by the mayor a few years back that mentioned what should be done to improve air quality in London, hinting at harbouring biodiesel in strategic passages underground to save the need for buses to drive and refuel at the depot.

 

[Lazarus]

I think that would result in the need for rather more than a slight realignment - or do you have "personal experience" of the issue (Leccy cable fault = Kaboom, I mean )?

Far too many instances of investigating, in my former life, injuries and death resulting from catastrophic faults in high fault-level areas, sadly.

One surprising and fortunate case was at a new (under construction) major sub-station where a guy penetrated a short underground section of 132kv cable in an open trench and survived without anything but brown trousers: The Protection was so robust and fast that virtually no energy was dissipated.

London, however, has a largely ageing infrastructure with high fault-levels and dubious protection.

 

[jeallen01]

Far too many instances of investigating, in my former life, injuries and death resulting from catastrophic faults in high fault-level areas, sadly.

One surprising and fortunate case was at a new (under construction) major sub-station where a guy penetrated a short underground section of 132kv cable in an open trench and survived without anything but brown trousers: The Protection was so robust and fast that virtually no energy was dissipated.

London, however, has a largely ageing infrastructure with high fault-levels and dubious protection.

Moral? Don't mount your sat dishes where there is "almost anything" "potentially dangerous" of those types in the ground below!
AFAIK there's nothing like that below mine - but, then, what do I (or anyone else) actually know?;)

Interesting how this thread has gone in a totally different direction ("Down", not "Up") to what I first envisaged!

 

[Channel Hopper]

Interesting how this thread has gone in a totally different direction ("Down", not "Up") to what I first envisaged!

A solid foundation is key to a good installation. My second example confirms this, but there was no alternative to the siting owing to trees and the house walls being tiled in viable alternative locations.

 

[jeallen01]

A solid foundation is key to a good installation. My second example confirms this, but there was no alternative to the siting owing to trees and the house walls being tiled in viable alternative locations.

Understand what you mean. My main pole is a 2" steel scaffolding pole concreted into 2x old chimney pots (!) - one below ground and one above it - and, as I said, the subsoil is hard/dry London clay and not very far down. Still had to brace it 1/2 up against (next door's!) fencing post though as the wind can still move the dish a bit otherwise. Not had any problems with that in around 15-20 yrs