Made a start on my petal extensions ..

[Vipersan]

...If this is true ..then all I see is a classic case of ..
The Law is an Ass...
Both structures are pleasing/displeasing to the eye ..depending on your point of view..
A thing of beauty ...or an eyesore
One they cannot make you shift ...the other they can..
One is safe anchored , structuraly sound and less dangerous ...the other not so much..

and yet ..One is legal ..the other illegal...

I rest my case m'lud
;)

 

[Vipersan]

No longer trying to squeeze out those air blisters and creases ..though I will continue to laminate ..
All wings will be removed again when completed to be painted with aluminium paint ...and finished in cream spray paint..
But ..there are definate signs of increased gain ..
For example one of the startimes transponders at 10E topped 13 db today ..thats a significant increase

most dvbs channels have improved between 1 and 2 db..but 8psk refuses to budge ..
perhaps it will when the wing surfaces are smoother ..and the feed is tweaked ..
As yet _no_ changes have been made at the feed end..
Got to go to work now ...but I'll leave you with this pic of 3 laminated wings attached ..avec blisters and creases..
rgds
VS

 

[wod]

What's the size going to be now with the panels on about 2.2metre ?

How are you fixing the addon panels, is there already predrilled holes where the original extension panels would bolt on to ?

 

[Vipersan]

What's the size going to be now with the panels on about 2.2metre ?

How are you fixing the addon panels, is there already predrilled holes where the original extension panels would bolt on to ?

Hi Wod ...
Yes ...and Yes...
The dish is designed to have extension panels fitted ...and I estimate between 2.1 and 2.2 mtres ...
I'll check for certain ..when I get home..
rgds
VS

 

[Vipersan]

Ok ...
quickly grabbed my tape measure...and confirmed the new dish diameter as 218.5 cm ..
Not quite a 2.2 ...and I don't expect it to perform like one ..but would be more than happy if I got around the performance of a 2m ...or even a 2.1 ...but maybe that's being ambitious.
rgds
VS

 

[lanab]

Hmm...why didn't you opt for 2.4m and why only C-band? you could put a Corotor there for both KU and C-band, only bad thing is that Corotors degrades the signal alot on KU-band but doesn't affect C-band.

 

[Lazarus]

Back-yards in Greater Manchester tend not to have the space .............. plus there is the vexed and oft discussed question of Planning (aka "what the eye doesn't see")

 

[lanab]

Ok so the backyard is not bigger than the pictures posted?

 

[Lazarus]

Put it this way, if you read back from before your return to the Forum, you'll find that space constraints have already led to some mods. required to eg Boiler Flue due to physical interference with the dish assembly.

But I act merely as temporary Secretary - I'm sure VS will tell you more in due course.

 

[Vipersan]

Tivu has it right for the most part ..
When the wind blew Christina down ..she was resurrected slightly higher ..and with a small amount of pinched space so she didn't hit walls ...
Back yards on terraced houses tend toward the small ..so space is at a premium ..
I maximise what I can ..and rather well I think.
Petal dishes are notoriously bad in ku ..and I suspect Christina didn't produce much more than the TD110 in this regard ..
So since C band is a passion with me ..and as Nelson will tell you ...open to experiment unlike ku..
Christina is dedicated to what she does best ..
C band ..and I'm rather proud of her refurbishment and accomplishments.
Sad I know ..that I treat the alcoa as a living ..breathing entity ..but I've had her well over 20 years ..and in satellite terms..
..that makes her a working antique.
rgds
VS

 

[Lazarus]

As opposed to some of us VS fans, who are "non-working Antiques" !

 

[Vipersan]

As opposed to some of us VS fans, who are "non-working Antiques" !

..the same applies to me Gordon...
engines ok ...but the chassis is knackered..
;)

 

[lanab]

T
Petal dishes are notoriously bad in ku ..and I suspect Christina didn't produce much more than the TD110 in this regard ..

rgds
VS

They are not that bad if your dish is straight, i had a Winegard 1.8m petalized and it performed marginally better than a good solid spun 1.5m dish, maybe 1.6m....

If you look at test below from the 80's where they tested Alcoa 1.8 you will see the C/N is only like 1dB less than the best solid 1.8m dish, problem people did back then is that they didn't assemble the dish straight, they made the mounting holes larger and tried to force the panels which warped the whole dish, but mounted correctly it will not perform much worse than a solid one and mine was KU-band mesh antenna so it would have performed even worse in theory but keeping the mesh holes under 0.25mm it will not affect signal so much.

Also my petalized Winegard had the famous "buttonhook" which sagged down so you need guy wires to have the focus spot on centered, otherwise you would loose another dB or so....

You have any instrument to compare it to any other dish at home?

My old Winegard below, you will see the bad buttonhook, i hated it.

 

[Vipersan]

They are not that bad if your dish is straight, i had a Winegard 1.8m petalized and it performed marginally better than a good solid spun 1.5m dish, maybe 1.6m....

If you look at test below from the 80's where they tested Alcoa 1.8 you will see the C/N is only like 1dB less than the best solid 1.8m dish, problem people did back then is that they didn't assemble the dish straight, they made the mounting holes larger and tried to force the panels which warped the whole dish, but mounted correctly it will not perform much worse than a solid one and mine was KU-band mesh antenna so it would have performed even worse in theory but keeping the mesh holes under 0.25mm it will not affect signal so much.

Also my petalized Winegard had the famous "buttonhook" which sagged down so you need guy wires to have the focus spot on centered, otherwise you would loose another dB or so....

You have any instrument to compare it to any other dish at home?

My old Winegard below, you will see the bad buttonhook, i hated it.

I suspect you're right about poor assembly ...
Poor girl was never 100% after the fall ...but got her fairly fuctional again ...certainly good enough for Cband
..and half the problem with ku was the lack of a matched ku feed ..
it didn't come with one ...just a straight tube feed ..and mechanical polariser ..
results were certainly acceptable at that time ...but the TD110 does more than enough in ku for what I need.

..another interesting test I made was to mount a ka band lnb at the focus ..
The results were about 2db better than an 80cm offset..
Certainly not really suitable for ka ..unless its a mighty powerfull signal.

cheers
VS

 

[BM300]

Just a reminder, to reduce the load on the motor and extend its life, it is a good idea to fix a counter-weight behind the dish.
I am sure that you know that it will make the dish movement much smoother.

 

[Vipersan]

Just a reminder, to reduce the load on the motor and extend its life, it is a good idea to fix a counter-weight behind the dish.
I am sure that you know that it will make the dish movement much smoother.

thanks for the reminder BM ..though the wings weigh very little ...light enough to hang on a finger ..
the increased surface area will increase the wind loading however...and this has to be considered ..
Normally I just steer the dish into a suitable position in strong wind conditions ..and of course ..the added mount pole braces to the walls help counter any movement..
The only thing that could really suffer is the actuator..and this is replaceable should the worst happen ..
The main dish is solid ally and would be most unlikely to suffer any more than it did prior to the added wings..though in theory winds could rip a wing off if strong enough.
That is why I shall be keeping my mould ..just in case I ever have to manufacture a replacement.
..the folded back edges to form a tray on the petal extensions themselves help provide structural rigidity plus bracing on the underside of each wing.

The Three already fitted will get a bit of a test ...as the winds are quite strong and blustery here atm ..
and from the East ..and blaady cold too ..
This has caused me to down tools for the moment ..so the project is temporarily halted
rgds
VS

 

[Vipersan]

Just a quick point of interest ..
The number of Left and right circular channels/transponders I can receive _without_ a depolarising plate of any kind has almost doubled with the 3 wings attached..
for example ...at 20 East I can now get 80 - 85 % of the channels just using H/V switching and no plate in the lnb throat..
I'll make a full list when I'm not busy..
rgds
VS

 

[Captain Jack]

How many extensions do you have stuck on at the moment? 3 still?

 

[Vipersan]

Hi CJ ..
attached the 4th this morning ..but not tested yet ..
Oddly the 4th doesn't quite fit as well as the previous 3 ..
distorted slightly on curing ..but I'll tweak it to fit better ..eventually ..
Still ..its good enough to test.
I'll post a pic later..
raining constantly atm ...and I'm now in work.
What I can tell you is that the startimes tansponder referred to previously at 10E that briefly touched 13 db on a dry day ..

Went over 13 db in the rain ..but no further tests for now.
rgds
VS

 

[Vipersan]

Still raining here ..thats almost non stop for 2 days..
I'm cold ..and I ache like I've got flu...so no more till the rain stops.
Here is the pic I promised earlier..
The obvservant amongst you will notice the slight curve discrepency ..but luckilly the wings are still flexible enough to correct this whe bolted up tight..
Off for a lie down ..
catch you later

rgds
VS