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Mount Stu Observatory mkII


powerlord

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1 minute ago, EarthLife said:

Also, metal sheds make for very nice faraday cages ;) .. could be good, could be not so good.

If you have any wireless comms between shed/house etc using antennas inside the shed then communication could be severely restricted. if it becomes a problem then just mount say any wifi antennas on the outside of the shed.

fair point, but I ran Gb ethernet to the current plastic obsy, so will just be moving the cable to new one - not an issue - I also have a wifi repeater in the obsy (for tablets, phone, alexa, cameras, etc) and that will also be being moved.

stu

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13 minutes ago, powerlord said:

fair point, but I ran Gb ethernet to the current plastic obsy, so will just be moving the cable to new one - not an issue - I also have a wifi repeater in the obsy (for tablets, phone, alexa, cameras, etc) and that will also be being moved.

stu

That's one of the best solutions for sure.

For anyone who's not sure about network comms between buildings you can also use a mains powerline ethernet pair if they have a mains supply to there out building, although it might make the local radio hams a little angry if the mains wire run is above ground (they emit a lot of HF nasties).

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50 minutes ago, EarthLife said:

That's one of the best solutions for sure.

For anyone who's not sure about network comms between buildings you can also use a mains powerline ethernet pair if they have a mains supply to there out building, although it might make the local radio hams a little angry if the mains wire run is above ground (they emit a lot of HF nasties).

And from what I hear about radio hams, they'll probably manage to collude to work out where the noise is coming from and come have a chat if it bothers them lol.

I've heard they are a very knowledgeable set of people, as to be allowed to use the equipment at all you have to go through a lot of training and courses. One lived opposite me for a while and had a big antenna going from house, to garage, to fence to house, and apparently talked to people around the world using it. Didn't speak to him much however.

 

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2 hours ago, EarthLife said:

Also, metal sheds make for very nice faraday cages ;) .. could be good, could be not so good.

If you have any wireless comms between shed/house etc using antennas inside the shed then communication could be severely restricted. if it becomes a problem then just mount say any wifi antennas on the outside of the shed.

I was worried about this when planning my shed, but I have a few low-powered ESP devices running temp sensors and the roof motor logic and haven't so far had any problems accessing a wifi access point outside the shed.   My AP isn't that far away, so it may be that range is restricted if you were looking at longer distances.

As you say wired ethernet should ideally be the first choice (and that's what the astro PC uses).  

 

Edited by adyj1
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Condensation in obsys seems to be something that inadvertently gets designed into the construction.  I'm of the mind that people often over think it and then end up chasing their tail trying to manage it.  The key is simply sufficient ventilation, but there has to be a high refresh rate.  My obsy is a converted garden summerhouse (roll off roof) wooden construction. Despite the climate here doing its best, I've never had any condensation and don't use a dehumidifier, no vapour barrier on walls etc.  Everything is uninsulated (walls , roof, windows etc) but there is a large refresh of air as the roof overhangs the walls leaving an adequate gap all round the perimeter (octagonal frame & roof). If you are determined to use a metal skinned construction I would go over the top to make sure you have maximum natural ventilation (high and low ventilators). 

Jim

Edited by saac
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For my plastic obsy, and again, I'll be simply moving this to my new one, I use an in fan and an out fan, controlled by humidity and temp sensor and alexa tasks.

if humidity above X, fans go on and keep air being refreshed and moving. it also does a great job of keeping it from getting hot.

 If it goes above a certain humidity over that, fans go off, and dehumidifier on.

it's worked a treat for last year.

 

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15 hours ago, saac said:

Condensation in obsys seems to be something that inadvertently gets designed into the construction.  I'm of the mind that people often over think it and then end up chasing their tail trying to manage it.  The key is simply sufficient ventilation, but there has to be a high refresh rate.  My obsy is a converted garden summerhouse (roll off roof) wooden construction. Despite the climate here doing its best, I've never had any condensation and don't use a dehumidifier, no vapour barrier on walls etc.  Everything is uninsulated (walls , roof, windows etc) but there is a large refresh of air as the roof overhangs the walls leaving an adequate gap all round the perimeter (octagonal frame & roof). If you are determined to use a metal skinned construction I would go over the top to make sure you have maximum natural ventilation (high and low ventilators). 

Jim

This hasn't been my experience with my thin metal roof. There is currently way more ventilation than I originally planned (NB: must fill that two-inch gap that goes all the way along the top of the back wall) , and the condensation from the roof inside was like raindrops until I put some foil bubble insulation sheets up. 

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Back to Faraday cages & powerline adapters.

My first thought (2007 build) was to use a powerline type adapter. It did not work well.
The type and length of mains cable run meant it lost a lot of signal on the way.
Though it is a long run.
Maybe if I had tried other devices I would have found a solution. But I went wireless.

A timber shed wall holds quite a bit of moisture.
Wifi frequency is close to microwave oven frequency - chosen for its absorption by water!
I found that I had to fit a wifi antenna outside the shed to get satisfactory range/signal strength to the house.
I bought a directional antenna to further help with signal strength.
If you download a (free) wifi strength app for your tablet/phone you can establish if there may be problems and can plan your spend.

HTH, David.

 

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  • powerlord changed the title to Mount Stu Observatory mkII

I have lthe shed now - a duramax 8x 8 foot. Bit of an amazon bargain. Was 500, now 330.

Its not a Chinese job - it's a proper hot dip galvanised one.

So next is digging the foundations, but I'm maybe putting that off a bit... Its hard work and boring.. And instead looking at how I'd automate my roof mechanism.. So here's a wee video.

Next week, I'll be ordering a skip for the soil, and digging out.. Garden is on a slope unfortunately - 3.5inover the width of shed, so my plan of a 6" base (2" mot 1, 4" concrete) is not going to be enough, and I'll have to do 8" with 6" concrete. So digging out to a depth of 6.5in top, 3in bottom. Fun.. 😕

 

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On 14/12/2022 at 12:58, powerlord said:

Here's my scale model 'Wendy observatory'.  1:15.

Scope is my biggest 300pds.

Shed is a 6x9 metal on on ebay.. I think this will work, but will need limit control for low east or west.

Everything to scale. Basic eq mount made, so I can move it around and check.

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Lovely design powerlord and those 3d printed models are so cool.  However, it's the sleekit product placement that caught my eye - I can see you and your observatory featuring in one of those amazing Irn Bru adverts, now wouldn't that be something :) 

Jim 

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19 hours ago, saac said:

Lovely design powerlord and those 3d printed models are so cool.  However, it's the sleekit product placement that caught my eye - I can see you and your observatory featuring in one of those amazing Irn Bru adverts, now wouldn't that be something :) 

Jim 

haha - I'm powered by Irn Bru I reckon.

 

So latest update:

Tonight - off down to Essex to pick up my second pier from @Alan White.

Got tomorrow off - digging foundations! woohoo...what fun.... and on friday 13th. I look forward to finding an indian burial ground.

I also have 2 tons of ballast, 14 bags of cement and 1 ton of sub-base hardcore arriving, along with wood to build the concrete containment box.

At this point it is worth mentioning that I have never done anything with concrete ever...

plan is to get the digging all done this weekend, along with laying down to ton of subbase. And hopefully build up the concrete containing box, getting it all level and solid.

Plan to dig 6" deeper around where the two piers are going to be so concrete is thicker there.

Monday, cement mixer and whacker plate arrive for a week, though will be working all week so won't be used till weekend.

Monday night - whack that subbase flat though maybe - so it gets a chance to settle a bit, and I can whack it again later.

Sat/Sun following week: damp proof membrane, fit threaded rods in for the piers, positioniing with a set of 2 wooden tempates per pier (one at 'tobe' concrete level, and one at top of rods so they are as aligned as possible. triple check my concrete box is level, and then the fun begins with mixing and pouring concrete to the depth of 6" (to top of the wooden box). About half way through pour, Im gonna put a layer of galvanised steel mesh across it all for extra strength, then continue mix and pour.

Oh yeh, need to remember and sink a plastic pipe in so I can feed cabling (power, ethernet) in from underground to the side up through to the top corner of concrete base too.

Hopefully by end of weekend, I can cover it with a tarp and leave it for a week so go off.

Any tips from anyone that has done this before greatfully recieved.

I've seen some folk say give the edge of the base a chamfer, but I have no idea how to do that (it's level with the wooden box, and I can't take it off before its set), so I reckon I have to just miss that, and hope internal sealing of the shed base will be sufficient to keep any water pooling on the edge of the base from getting into the shed.

I'm doing it all myself until the concrete, when I'm hoping to rope a friend in to help (though this may require radical insentives beyond the so far offered free coffee and business I fear)- if only because I can forsee needing more than 2 hands at some stage in the proceedings, and with around 3 tons of liquid concrete it all feels like it could go south quite quickly if something goes wrong.

stu

 

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11 minutes ago, powerlord said:

At this point it is worth mentioning that I have never done anything with concrete ever...

 

11 minutes ago, powerlord said:

Any tips from anyone that has done this before greatfully recieved.

When mixing your own concrete, pour water in the mixer first, then cement, followed by ballast. Don't overfill the mixer, lots of little mix's are easier than a few big ones. An over filled mixer won't mix properly. If you're using a standard 1:4 mix then load mixer with 2:8 at a time (assuming you're using a small Bell type mixer).

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39 minutes ago, powerlord said:

I've seen some folk say give the edge of the base a chamfer, but I have no idea how to do that

When the shuttering comes down and the concrete is still green, run an engineering block (a hard brick) down the edge to chamfer.

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thanks - but er maybe I'm being thick.. 1:4 is 2:8 .. so what do you mean here ? Also, good idea about water first, but I don't know how much water I'll need. any idea ? as my method was going to be add water until it looks right (I was going to go for a sort of very very heavy porridge)

and shuttering down - I was expecting to leave it until totally solid. How can I tell when concrete is 'green' ? I assume this means sold enough to take shuttering down but can still scrape away but not sure I'd be confident in knowing where that point is.. knowing me, I'd be too keen and end up with concrete moving everywhere after taking down shuttering!

cheers

stu

Edited by powerlord
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53 minutes ago, powerlord said:

thanks - but er maybe I'm being thick.. 1:4 is 2:8 .. so what do you mean here ? Also, good idea about water first, but I don't know how much water I'll need. any idea ? as my method was going to be add water until it looks right (I was going to go for a sort of very very heavy porridge)

and shuttering down - I was expecting to leave it until totally solid. How can I tell when concrete is 'green' ? I assume this means sold enough to take shuttering down but can still scrape away but not sure I'd be confident in knowing where that point is.. knowing me, I'd be too keen and end up with concrete moving everywhere after taking down shuttering!

cheers

stu

Yes 1:4 is 2:8, what I mean is, don't put more than 2:8 in the mixer because 3:12 would be too much for a small orange Bell type mixer like from hire shops and it wouldn't mix very well. You would end up with dry mix at the back of the mixer. Bucket of water, put 3/4 in, then 2 shovels of cement, let it mix, then 8 shovels of ballast, let it mix, then rest of water till at the right consistency which depends on how wet the ballast is to start with. If it's too dry, add a little water or if it's too wet, add a little cement. Once you've got the first mix how you want it, just repeat. Wetter concrete is easier to pour and will pretty much find its own level. Dry concrete is a nightmare to lay. Also whilst mixing it's a good idea to hold the mixers handles and tilt the drum forward a little which will help with mixing.

The concrete will be solid after a day or two but still green for a week. When floating up to the edge of the shuttering you will create a sharp edge which is weak and can chip so if you rub it down a little with a brick it will create a slight bevel which won't chip as much if it's hit with anything.

Might be stating the obvious but don't put the shovel in the mixer whilst it's turning, folk have had their wrists snapped doing that.

ps. heavy porridge is good. After you've screed the level and it starts to set the water will rise to the surface, that's normal.

Edited by Franklin
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20 hours ago, powerlord said:

I've seen some folk say give the edge of the base a chamfer, but I have no idea how to do that (it's level with the wooden box, and I can't take it off before its set), so I reckon I have to just miss that, and hope internal sealing of the shed base will be sufficient to keep any water pooling on the edge of the base from getting into the shed.

 

Our Civil Works lads put a chamfer on the edge of their concrete plinths by using a chamfer strip fixed to the top of shuttering prior to the concrete pour.

How to Make Chamfered Edge in Concrete - The Constructor

HTH

Regards

Graeme

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 3 tons earth dug out, shuttering in and levelled, and 1 ton of subbase mot 1 (rocks) layed. Whew. 🥵

Mixer and whacker arrive tomorrow. Just need to do whacking before weekend, and sinking threaded rods when amazon delivers them. then at weekend concrete!

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Whacking complete, templates cut and drilled for both piers. Next step, hammering threaded bolts in, then I'll stick some nuts on them to grab the concrete more, and refit template at top concrete level, levelled. That should keep the threaded bolts all parallel through the pour and setting. Pour happening sat. Might have to wait till afternoon as forecast is 1 degree in morning.. 5 midday.

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