New house, new dish project

[Huevos]

Got my bracket done for declination control!

No bearings or bushes then, just mild steel against mild steel?

 

[Captain Jack]

Hardly needs it for what it will be used for. Just a load of grease and it will be fine. It's already an overkill with the sizes of rods and eyes used....

 

[Huevos]

I wasn't saying it's not strong enough, just there might be a bit of free play even with grease. That will get multiplied at the ends of the arc with the dish hanging on it. A nicer solution might be to use a bolt with a shank rather than just a threaded rod.

 

[RimaNTSS]

I would use there bolts with cone head, like on attached picture. 10-12mm would be enough. It allows to diminish play at all.

 

[Captain Jack]

There will be nuts on both ends, on the outside of the threaded rod and the inside, so will be the same as having bolts with the added sturdiness. I might need to put a single washer in between the hinges as there's a tiny gap which would create a small play so it should eliminate this.

 

[Huevos]

There will be nuts on both ends, on the outside of the threaded rod and the inside, so will be the same as having bolts with the added sturdiness. I might need to put a single washer in between the hinges as there's a tiny gap which would create a small play so it should eliminate this.

Well you'll know if your theory is correct because if not there will be a big clonk as the dish goes over the centre of the arc.

 

[Captain Jack]

Where's your optimism, Huevos? ;)

 

[Huevos]

Where's your optimism, Huevos? ;)

I'm from an engineering background and I would never consider using threaded rod as a bearing surface, and no amount of grease is going to change that.

 

[Captain Jack]

It'll be fine. It will only move small amounts and rather rarely too...

 

[Archived-1]

When I do get round to doing mine, this is what I will do simples :-).

 

[Captain Jack]

That's what I thought of doing but not suitable for my needs. I will only have 2 positions - 1 for Ku and another for C. You cannot do this if you adjust inclination as it will screw up the arc tracking. You have to do it using declination so the arc is tracked correctly for both "positions".

Your method is fine for simple fine tuning though.

 

[Archived-1]

 

[Captain Jack]

Here is the result. It all works! The only issue I have is that the 10" jack I am using has a potentiometer as opposed to a reed sensor, so I have to drive the dish manually. Thus, I ordered a new 8" jack with a reed sensor and a new 24" heavy duty jack from hm-sat.

View attachment 57292 View attachment 57294 View attachment 57293

C band results are encouraging and are marginally better than what I used to get on my Fibo. Logged a new to me satellite today - 40.5W, though I am finding it generally weak. What are the strong transponders there?

Also, is anything catchable on 50W, 55W and 58W in C-band on a 1.2m-ish dish? I notice they are linear, so I would have to remove the plate. Will also play about with a VS T-plate as mine just sits in the throat and T-plate is supposed to give better results. Unless someone has one lying around?

Another thing - what can I cover the LNB with? At the moment it's just a plastic bag but I want something more tidy/permanent. I'll also try and create a sturdier C band LNB holder. It's alright at the moment but it's not fixed to the holder very well and tends to wobble a little.

Looks like it will an ongoing project with little improvements here and there...

 

[sonnetpete]

Another thing - what can I cover the LNB with? At the moment it's just a plastic bag but I want something more tidy/permanent. I'll also try and create a sturdier C band LNB holder. It's alright at the moment but it's not fixed to the holder very well and tends to wobble a little.

Looks like it will an ongoing project with little improvements here and there...

Something like this CJ? It's actually a couple of mm too small but I'm sure it would do....



(Incidentally the coffee is atrocious)

 

[Captain Jack]

Something like that, yes! I've been looking at tupperware stuff with lids on. The outer diameter of the feedhorn is 16cm (or 15.9cm) so if it's somewhere around that size, it should be fine.

 

[pride21]

hi CJ i use the small pots of trifle you get in super markets it fits tight and easy to take off,had mine about two years now.

 

[hexah]

The old C band LNBs came with a similar kind of plastic thing to stop the spiders getting in.

They would, of course, manage to squeeze in the weep holes as they were a bit bigger than they needed to be for this part of the world.

I hate to admit just how many years I used plastic bags.

 

[Captain Jack]

More updates. Received my heavy duty 24" jack - dear Lord, it's huge! It's bigger and heavier than the 36" one. There was a problem with it missing the counts though - I had to adjust the reed sensor inside to make it see every pulse. Even with that, it seems to be miscounting as it lands a bit short of the stored position. I am pretty sure it's to do with pretty tight ball bearing thing on the main bracket, which I am having trouble loosening, so I put my 36" back on. Will see if I can loosen it but the 36" one is doing the job OK. Why don't these ball bearings not arrive already greased up and loose on new jacks?!

More things... Decided that my threaded bar for the declination adjustment was giving me a little play at extremes so I bought some spherical bearings as well as needle bearings. The needle bearings arrived first, so I put those in place of the threaded bar and put a steel tube through that, tightened by normal M8 bolts. The result is a very smooth, play-free movement. Happy with that.

View attachment 57486

Next - C band LNB polariser plate construction and a cover.

 

[RimaNTSS]

24" jack is huge.... I was impressed when received 36" heavy duty jack, that is even huger
TBH I do not understand why you wish to operate 1,2m dish with > than 18" jack. But your hardware is great looking, congratulations.

 

[Captain Jack]

I couldn't find a heavy duty 18" jack to buy - that's the only reason. I don't need it any bigger than that in reality. And I wanted a heavy duty one for stability though it's probably an overkill!