Finally - I've broken ground on the obsy

[dmahon]

Managed to get the new shed installed - I can have my garage back now, it was full of stuff.

Smoothed off the concrete and cut off the excess plastic - covered the holes with some polythene and weighted it down with bits of brick.

[Gina]

That looks neat

[Derick]

Don't forget to leave a small gap around the pier base to prevent any vibration being transmitted to the pier. Polystyrene foam board makes a good gap filler.

Yes really important!!!!

[dmahon]

I really do wonder how much evidence base there is for that - how much vibration does 3 tonnes of several foot thick concrete transmit? But, I've done it anyway as I hope can be seen from the last photo (1 inch thick polystyrene all around the pier block)

[dmahon]

Just got my kit out for the first time since the end of April. Setting it up on a level slab has made a difference already - I normally image either from the patio, though I have done a lot from the site of the planned observatory too to make sure the view was adequate. Today after slewing to a star or two to setup the mount, the chosen star was actually on the sensor straight away and Elbrus could plate solve it.

Now, how much better is it going to be when I don't have to carry everything in/out and plug all the cables in. In fact, I'm now wondering whether to go for an entirely automated solution where I don't even have to leave the house at all, just press a few buttons from my study!

[dmahon]

Concrete stabilised and treated to two coats of masonry paint. A spades width around the edge has been filled with pea shingle - you always need more than you think. Fortunately Wickes have a deal when you buy 10 bags or more, so I bought 10 (and needed them).

[dmahon]

And another update.....

DOME ORDERED!

[JamesF]

That's looking very smart. Be careful one of the neighbours doesn't nip over the fence one night and paint a bright yellow "H" on it

James

[tony]

That's looking very smart. Be careful one of the neighbours doesn't nip over the fence one night and paint a bright yellow "H" on it

James

joking aside, coming along nicely now

[kirkster501]

All gone quiet......?  What dome did you order?

[dmahon]

Pulsar dome on order, deposit paid and awaiting delivery.......

[red dwalf]

looks very impressive, the Pulsar domes look very nicely made, was thinking of one myself but alittle too expensive for me so went down the roll off roof route, real pain to build but now it`s done life is so much easier, like you say no more carrying you gear in and out, just turn on the power and you up and running in no time.

[dmahon]

Yes, it involved a bit of saving up. Then there's all the extras (like electrics) - and when you need the best part of a 100m reel of 10mm SWA, plus a trench digging, plus conduit (so you never have to dig the trench again), it all adds up.

The DIY route isn't cheap either though, having bought some wood recently, especially when you set out to do a good job (and most on here are well, or over, engineered).

[red dwalf]

too true, a 100 meter real of 10mm swa can`t be cheap, could you not have put 10mm twin and earth inside the conduit, might have saved a few quid, i`ve used conduit before , the water tight stuff so it should be fine, may be it`s buiding regs. anyway it`s certainly a long way from the house.

[RT65CB-SWL]

Quote JamesF: "...If you're going to put power cables in trenches then you might as well drop networking in at the same time."

If you have not got your power cables and networking cable in, it maybe worth putting a 'line booster' in too, as CAT5 n/w cable signal maybe or can be 'lossy' in runs of over ten metres or more, if you you want to have PC in the house as well as the observatory.

[yesyes]

solid Cat5 (not the stranded type used for short patch cables) is fine to 100m. Though make sure it's proper shielded cable, especially if it runs parallel to a power cable for a considerable length. Better use Cat6 for Gigabit Ethernet.

[dmahon]

Since I'll be digging a trench I'm going to put three lots of conduit in for power, water and "other cables". To be fair, I'll probably use powerline adapters (as I do now) for networking, as I'd have to use one from the house end of the conduit to the router anyway! That or use a directional wireless antenna which would be fine over 100m. But you never know what cables you might want in future so.I'll put unshielded cat 5e in as that gives the best "value". I don't have networking equipment that will terminate the shielding and cat 5e will do gigabit for half the price of cat 6. In 10 years, if we haven't gone over to wireless completely, I can pull better cable through the conduit if it becomes useful.

[JamesF]

I think that makes a lot of sense.  I've done some very long cat5e runs in my time, even with stranded cable, and it seems to be pretty reliable.  Our house is long and narrow and I have a number of cable runs that must approach 50m without a problem.  I'm not sure I can see a compelling reason to use cat6-compliant cable unless you can also comply with all the other requirements (for example, I seem to recall that to have a cat6-compliant installation you have to ensure that all bends in the cable have a given minimum radius and so on, though if that's been relaxed Chris may well know more about it than me).

James

[SnakeyJ]

No need to go over board with the separation of the data and power as you're SWL is effectively screened, though good practice to allow a little.    Cat5e cable will run gigabit ethernet as will cat6 - the problem you will have is that most of these cables are for internal use only and duct grade (as opposed to external grade) Cat5e/Cat6 cable is very rare.    You can use either the external or internal cable, provided they are not submerged in water as this will quickly rot internal and external grades - best bet would be to run it through a length of blue water pipe and seal both ends once it's in place.   The external grade is suitable for catinary use or clpping along fascia, wall or fence (UV stable and water resistant), just not long term submersion.

That painted slab is a thing of great beauty and makes my own efforts look extremely second rate

Sounds like all the real work is done now, so hope the dome arrives quickly - should be up and assembled in a day!

[Derick]

Quote JamesF: "...If you're going to put power cables in trenches then you might as well drop networking in at the same time."

If you have not got your power cables and networking cable in, it maybe worth putting a 'line booster' in too, as CAT5 n/w cable signal maybe or can be 'lossy' in runs of over ten metres or more, if you you want to have PC in the house as well as the observatory.

Actually, a Cat5e should give you over 100 feet  (30 meters) without any problems whats so ever... 

[Derick]

solid Cat5 (not the stranded type used for short patch cables) is fine to 100m. Though make sure it's proper shielded cable, especially if it runs parallel to a power cable for a considerable length. Better use Cat6 for Gigabit Ethernet.

Cat5 won't give you 300 feet (100meters) Cat5e might but depends on the surroundings... but we used to install repeaters every 250 feet if i'm not mistaken! 

[Derick]

No need to go over board with the separation of the data and power as you're SWL is effectively screened, though good practice to allow a little.    Cat5e cable will run gigabit ethernet as will cat6 - the problem you will have is that most of these cables are for internal use only and duct grade (as opposed to external grade) Cat5e/Cat6 cable is very rare.    You can use either the external or internal cable, provided they are not submerged in water as this will quickly rot internal and external grades - best bet would be to run it through a length of blue water pipe and seal both ends once it's in place.   The external grade is suitable for catinary use or clpping along fascia, wall or fence (UV stable and water resistant), just not long term submersion.

That painted slab is a thing of great beauty and makes my own efforts look extremely second rate

Sounds like all the real work is done now, so hope the dome arrives quickly - should be up and assembled in a day!

Cat5e won't give you a proper Giga network persay... The cable should be straight all the way long not curved and the connector should be flawless to give your that kind of bandwidth with that cable(if you ever manage to get it)! If it is the bandwidth you are looking for, go ahead for a Cat6 cable wich will be more permissive specially if you got some curves from point A to B.

[SnakeyJ]

Cat5e won't give you a proper Giga network persay... The cable should be straight all the way long not curved and the connector should be flawless to give your that kind of bandwidth with that cable(if you ever manage to get it)! If it is the bandwidth you are looking for, go ahead for a Cat6 cable wich will be more permissive specially if you got some curves from point A to B.

Sorry Derrick, but Cat 5e is rated for for Gigabit ethernet up to 100m, allowing 90m for the permanent link in solid UTP and up to 10m in standed UTP patch/fly leads.    This was ratified by ANSI back in 99 and is certified by TIA, ISO and BS/EN certifying authorities.   In practice using good quality cable, connectors your can push this a little further perhaps 20% under ideal circumstances, but with all test thresholds being met, other than exceeded length.

However standed cable is subject to higher attenuation and so 30-35m is probably about right with this type of cable.

The older Cat 5 standard supports operation at 100Mbs full duplex, but both Cat 5e and Cat 6 support full duplex 1000Mbs or Gigabit ethernet.    Although Cat 5e cable is certified to 100Mhz frequency, where as Cat 6 is certified to 250Mhz - though in practice the additional bandwidth is not used and manufacturers have skipped cat 6 for Cat 6e which is certified for 500Mhz and can support 10 Gigabit ethernet out to 90M permanent link.      There are few benefits to be returned from Cat 6, though it can support lower transmit power (due to reduced cross talk - more twist and dielectric separator) and bigger conductors - the bigger conductors are also beneficial with the higher power requriements of newer POE standards 802.3at and beyond, where bundles of Cat 5e can start to warm up.    A few years ago there was some talk about certifying Cat 6 for 10G ethernet to a reduced length 35m, which might have been quite handy within server and data farms, though problems with the high levels of cross talk (and particularlay Alien Cross Talk in unsheilded installations) led to no agreement or ratification.

Generally these cables are designed for internal use, though you can source UV stable water resistant PVC sheathed cables which can be used for external/catinary applications.    It is very difficult to source duct grade cables, suitable for prolonged submersion - though all the major manufacturers promise, it seems there is little call and I've been quoted leads of 10-12 weeks and minimum orders of 50-100 boxes!

Usually we would recommend fibre optic cables for any external and duct works - Costs are pretty cheap nowadays, even for preterminated solutions and compatible SX/LX fibre gbics are available for around £ 20 / end.    Quite often external buildings may have their own earth (by design or accident), so there is also the risk of stray current leakage over copper cables.    I can't think of an example were we have seen problems or damage attributed to stray current flow and I know many clients who operate such links for external portacabins/outbuildings.    However wiring regs are quite strict on this so worth a mention.

[IanL]

  I can't think of an example were we have seen problems or damage attributed to stray current flow and I know many clients who operate such links for external portacabins/outbuildings.    However wiring regs are quite strict on this so worth a mention.

Lightning strikes (even indirect) will cause plenty of problems.  You may think it a remote possibility but first hand experience:

- I once had a whole bunch of kit fried across several floors by an indirect strike.  It was the transceivers that went, not the PSUs, this was entirely due to induction as there was no cabling external to the building. This was a properly certified professional installation (CAT 3), not a homemade set-up.

- Many years ago as a student, one of the guys on the course had his green screen terminal literally go up in flames in the lab due to a strike on an external serial cable installation between the comp-sci building and the adjacent computer building.

I suppose it depends on the value of the kit at each end of the cable, but for a long run like that I'd be sorely tempted to use fibre otherwise it is just a big antenna collecting plenty of energy and directing it straight in to the back of your expensive laptop.  It might cost a bit more but getting a pair of fibre->ethernet media converters and a matching pre-made fibre cable is pretty much plug and play - just connect the ethernet cables from your device at each end (switch/router/computer) to the converter's ethernet ports and plug the fibre cable in to the other ports.

[SnakeyJ]

Interesting experience and cautionary tales there Ian.   Most of our installation side is industrial and public sector and designed/specified to EN 50173/50174, but at the lower end (mainly thinking small primary school's and small businesses) a lot of these links still go in as copper (often wired up by smaller electrical contractors), particularly as 'temp' portacabin blocks are added around the sites.

I've certainly seen plenty of lightning damage through telephone wiring to ADSL and older modems, lots of mains spiked equipment and back in 96 I saw the entire comcentre of Mulinational Brigade Rear HQ fried by direct lightning strike to the top of the building!    Though not personally seen anything directly attibutable on copper LAN networks in 20 years - though probably a statistical blip (as I search around for some wood to grasp).

Worth noting that lightning surge protectors are available for RJ45 terminated cables from around £ 10+ / end -  http://www.amazon.co.uk/Ethernet-Network-Thunder-Lightning-Arrester/dp/B007Q01FHY/ref=pd_sim_sbs_ce_3

Though the amount of protection is limited and they need direct earthing.

However if you are only running a cheap 8 port switches and a router and don't connect anything expensive, then I suspect most would accept the risks of running unprotected. But as more equipment is wired in (big TV's, media centres...) people should definitely be aware.