Just a quickie ...

Vipersan · May 23, 2015

Having got fed up of mopping out my C1PLL on the offset dish after some rain ...
I temporarily clothed it in a bread wrapper and lastic bands ..
Didn't look very pretty but worked ok ..
recently found this on fleabay:-
http://www.ebay.co.uk/itm/320930124...49&var=510069446740&ssPageName=STRK:MEBIDX:IT
The 15cm version for about £3.50 delivered is a perfect fit when the curved lip is trimmed down a little..
and signal reduction is less than 0.5db
This wont appeal to many ..but if like me you want the benefit of a T plate dielectric plate (1db gain advantage over conventional plates) ...accomodation of the plate whilst keeping out the rain is a must have..
Thus I can keep the waveguide open in all weathers ..and the dome is easily removed..
Looks good too
;)

scopus · May 23, 2015

Great stuff VS

Archive-8 · May 23, 2015

I use a Tupperware lid, and zip clips :-) £2.99 from Tesco. It's microwave safe.

Llew · May 23, 2015

Yes, had my T-plate in the Titanium when we had a hailstorm the other day. I could see the hail bouncing around the LNB, but there didn't appear to be any that found their way into the feedhorn opening, luckily.

That bowl looks to be just the job VS, Chris's Tupperware too. Ta for the tips ;)

Vipersan · May 23, 2015

Chris1979 said:
View attachment 78480
I use a Tupperware lid, and zip clips £2.99 from Tesco. It's microwave safe.

Great stuff Chris ...but no use for me ...on account I need extra height for the T plate ..
Superb tho' if using a conventional dielectric plate.
;)

Vipersan · May 23, 2015

So ..to continue this thread a bit ..
Recently bought another gibby offset ku lnb extension bar..
Of course these never make provision for C band lnbs ...
So why not make one ?
I had a spare ku clamp left over so cut it up to make a Cband clamp to clip on the bar ..
More to do obviously ...but looking quite do-able ..
You can see the original ku clamp ..and the Cband cut up one side by side..
rgds
VS

Vipersan · May 24, 2015

Ok ..
Slept on it an came up with this simple adaptation ..
Cast a ring in liquid plastic larger than diameter needed ..
Drilled and tapped fixings and threaded lnb support bolt holes ...
Looks ok ..but need to buy some shorter M3 stainless bolts to replace the ones currently supporting the lnb ..
They just look silly ..
lol
but a result is a result..
rgds
VS

Llew · May 24, 2015

Good result VS. Wish my dreams could be as useful

Vipersan · May 24, 2015

So ...
probably the last photos on this project..
The new C band offset mount has replaced the old one ..
the ability to tilt the C1PLL to the centre of the dish and securely lock it has gained me another 0.5db from 3676R 40E ..
now at 10.9db on the F15 occasionally 11db
..
of course ..
this is without it's deep dish cover ..as this is being used to mold an RTV silicon gasket seal off the dish ..
Probably taking overnight to fully cure..
rgds
VS

Topper · May 24, 2015

Heavens re photograph #2 there must have been a lot of tumeric in last night's curry

Vipersan · May 25, 2015

These are the last 2 photos I promise ..
Silicon gasket cured to perfection this morning ..and a perfect fit..
lithium greased the outer ring of the feed to aid removal if needed ..and popped it in place ..
Lets see the Manchester rain get past that ...
lol
rgds
VS

Llew · May 28, 2015

I found the ideal cover for mine from the pots'n'pans aisle at Asda.

It's a food storer with a detachable, airtight lid. With the bottom half inch cut off, it's a perfectly tight seal when forced into the feedhorn, and the lid is easily snapped on or off.

(Although the pics don't show it, the T-plate is actually proud of the feedhorn, like VS's, so I needed something similar to completely cover everything).

Testing on the Gibby,I don't see any significant drop in signal with the lid on.

Archive-8 · May 28, 2015

Llew said:
I found the ideal cover for mine from the pots'n'pans aisle at Asda.

It's a food storer with a detachable, airtight lid. With the bottom half inch cut off, it's a perfectly tight seal when forced into the feedhorn, and the lid is easily snapped on or off.

(Although the pics don't show it, the T-plate is actually proud of the feedhorn, like VS's, so I needed something similar to completely cover everything).

Testing on the Gibby,I don't see any significant drop in signal with the lid on.

View attachment 78715 View attachment 78716 View attachment 78717

Nice attachment you have there :-)

Vipersan · May 28, 2015

Just out of curiosity Llew ..
Do you also experience a flat gain across the spectrum of between 1 and 1.5 db with your T plate ?
Also ..
have you tried the polyethylene rough chopping board T plate ?
..and how does it compare with your perspex one ?
rgds
VS
..btw ..
nice 'hat' your feed now has ..
;)

Gonna get 2 of those ..
1 for my Cband feed ..and one for my breakfast cereal ..
Nice

Archive-8 · May 28, 2015

@Llew and @Vipersan does you're plate make a big difference compared to the default plate?

Llew · May 28, 2015

Vipersan said:
Do you also experience a flat gain across the spectrum of between 1 and 1.5 db with your T plate ?

I'll check that out tomorrow VS.

Vipersan said:
have you tried the polyethylene rough chopping bard T plate ?

I did try that one when I first set up for C-Band using the Triax TD88, but I found no significant difference to using the small dielectric slab.
I've lost that T-plate now, but I'll cut another one to try on the Gibby in due course.

Regarding the food container hat, be careful when removing the bottom, as the container isn't perfectly cylindrical - it increases in diameter towards the top. I guess I was lucky in my measurement from the bottom (~1/2 inch) in that it wedged perfectly into the feedhorn and won't come out in a hurry.

Vipersan · May 28, 2015

Chris1979 said:
@Llew and @Vipersan does you're plate make a big difference compared to the default plate?

I have tried many times to disprove the effectiveness of my T plate design ..
but I cannot ..
It always ...at least for me...gives about 1db extra sometimes more over a standard 'untuned' plate ..
The only other design which also gives extra performance is the Doktor of Sat plate design + variations ..but this appears to be tuned giving improvements in performance in specific areas of the C band spectrum...where as mine is a flat gain improvement accross the spectrum.
Hope this helps you decide..
My experiences were born out by NelsonB who saw much the same improvements.
but it appeared more effective on larger dishes.
1.5 mtre and above
rgds
VS

My theory ..fwiw..is that the T plate matches the lnb feed better on some dishes by sort of sticking out a tongue into the space above the lnb throat .. catches and funnels extra signal into the feed throat ..
Signal that might not make its way in otherwise particularly on a bad offset feed/dish match.
It cant produce more signal than is there ..but simply catches and therefore converts more..
hope that makes sense..

Llew · May 28, 2015

Chris1979 said:
@Llew and @Vipersan does you're plate make a big difference compared to the default plate?

Certainly Chris. A minimum +1dB on some channels for me on 40W - the difference between lock and no lock with my tiddly 1.2M dish.

Archived-1 · May 28, 2015

Chris1979 said:
@Llew and @Vipersan does you're plate make a big difference compared to the default plate?

Interesting read here Chris

.

https://www.satellites.co.uk/forums/threads/dielectric-plate.115537/

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