Disaster!!

[Vipersan]

..In the spirit of further experiment ..
I calculate that when I'm aligned on 62 East ..

I have about 12 'clicks' in hand so working on the principle that at this extreme 5 clicks cover 1 degree at KU
..I _may just be able to get to 64/65E ...
Now to look if there's anything there to point _at_
;)
rgds
VS

 

[Vipersan]

Well according to lyngsat ...
Nothing available around 64 degree to us in the west at KU
but maybe a couple of C-band channels ??
I'll have to wait 'till I re-fit the BSC421
;)
rgds
VS

 

[Vipersan]

Hi friends ..
I'm seriously considering making a permanent bracket on the tripod .
Off to one side of the C band scalar plate ...to carry a small ku lnb ..
I can't use the 'cut-a-hole in the scalar plate and fit the ku' idea I've seen before ...
..as I don't have clearance behind the C band scalar plate.. to allow a sacrificial plate to be used in this way.
If I do attempt this ..
The ku LNB wouldn't be a permanent fixture ..the bracket would remain..so the ku lnb could be mounted when required so as not to reduce gain for C band reception.
It wouldn't be at the focus of course ...but my question is how effective would it be placed say...3 to 4 inches off centre focus.
rgds
VS

 

[Huevos]

Off to one side of the C band scalar plate ...to carry a small ku lnb ..
I can't use the 'cut-a-hole in the scalar plate and fit the ku' idea I've seen before ...
..as I don't have clearance behind the C band scalar plate..

Let's see some photos of that plate and LNB setup. I would use an Inverto Multi-Connect and put it above or below your C-band LNB and use your elevation control to get it on the arc when you want to use it. Have a rethink on drilling the scalar ring plate because you are only going to need about a 20mm hole to get the bullet nose into position and being such a narrow LNB will allow you to get it pretty close to the focal point.

 

[nelson_b]

Hi friends ..
I'm seriously considering making a permanent bracket on the tripod .
Off to one side of the C band scalar plate ...to carry a small ku lnb ..
I can't use the 'cut-a-hole in the scalar plate and fit the ku' idea I've seen before ...
..as I don't have clearance behind the C band scalar plate.. to allow a sacrificial plate to be used in this way.
If I do attempt this ..
The ku LNB wouldn't be a permanent fixture ..the bracket would remain..so the ku lnb could be mounted when required so as not to reduce gain for C band reception.
It wouldn't be at the focus of course ...but my question is how effective would it be placed say...3 to 4 inches off centre focus.
rgds
VS

hi --
when i was experimenting with my alcoa dish last year - this was one of the things i tried -- just to see how effective it was and i must say the results were good -- not much drop in signal strength - on weaker t.p.s at 1 west --
some pics below of the temporary lash up - l.o.l.

regards nelson.b.

 

[Vipersan]

Excellent idea to use a bullet nosed lnb Huevos ..
Before I go any further I'll re-think the idea..
I particularly like the idea of placing below the C band lnb ...but in my case it would have to be mounted above it ...as it would definately foul on the bottom leg of the tripod....
...though I'm not even sure redrilling the rear mount plate ...there would be enough clearance inside the brass tripod support ring ..

Here's a pic to show how it currently looks ..

Could have done with getting higher up ...but you get the idea.
rgds
VS

 

[Vipersan]

hi --
when i was experimenting with my alcoa dish last year - this was one of the things i tried -- just to see how effective it was and i must say the results were good -- not much drop in signal strength - on weaker t.p.s at 1 west --
some pics below of the temporary lash up - l.o.l.

regards nelson.b.

Thanks for the pics Nelson ..
It certainly gives me ideas ...
I could try this sort of setup before commiting to Huevos's bullet nosed lnb ...as this would require physically modifying the lnb support plate.
That's a dinky little ku lnb ..you're using ..
What is it ?
rgds
VS

 

[nelson_b]

That's a dinky little ku lnb ..you're using ..
What is it ?
rgds
VS

its a darkgold - with the feed hacksawed off --
i also did the same with a black ultra -when i returned the dish to k/u - hoping it would be better -- but it was not the case on this dish -
the - darkgold /invacom feed combination won the day by a fraction in the end - for the turksat east beam t.p. that i was setting it up to receive - results could be different on other transponder frequencies though ?

cheers nelson.b.

 

[Vipersan]

Well...whichever method I decide to go with ..
I will definately be mounting the ku lnb above the Cband lnb
that way the V box positions will still be relevant per satellite ...and I'll then just have to alter the elevation with the second motor to compensate..

watch this space
rgds all
VS

 

[wod]

Is there no combined c/ku band lnbs that are good you could use ?

 

[Vipersan]

..sadly the answer is no ..Wod ..
They all perform much the same ..ask Nelson for details
You compromise C band reception ...and seriously compromise ku ..
They tend to be sold for use in the USA ...where the dishes are refered to as BUDs ...
They are usualy oversized ..so you start with a higher gain factor ..and the reduction due to the combo lnb ..then is acceptable.

Ok ..
So this is my first design for what I have called 'The Leech' ....
Its organically grown from my bits box ...
;)
Its nothing more than a mounted C120 feed at the moment ...but the throat is close to the the focal length of the dish ...and it sits clear of the C band feed...
I took care to point it at the centre of the dish but this will need adjustment ..
How much I'm not sure ...
What effect it will have on the C band signals..
again ..no idea as yet ..
But it is clip on ...so is removeable if it presents a problem ..
Comments ...derisory or helpful ...are all welcome ..
I'm in unknown territory with the leech..
rgds
VS

 

[nelson_b]

..sadly the answer is no ..Wod ..
They all perform much the same ..ask Nelson for details
You compromise C band reception ...and seriously compromise ku ..
They tend to be sold for use in the USA ...where the dishes are refered to as BUDs ...
They are usualy oversized ..so you start with a higher gain factor ..and the reduction due to the combo lnb ..then is acceptable.

l.o.l. -- that sums it up nicely

with the k/u leech --
when i was experimenting - just with k/u on the alcoa i found that on the " strong sats " almost any C 120 - original or home made , worked fine -- when just bolted on to the alcoa,s original feed tube with no scalar/ feed .
but to get the best results on weak t.p.s it needed a feed, and after spending many more hours than i should have done on it - i ended up with the l.n.b - tube - and feed-- that is in the picture i posted this afternoon -- the feed is a invacom ajustable feedhorn with the threaded centre cut out so that it would fit over the alcoa,s k/u tube
the position of the feed on the tube is -- critical -
its very sensitive to the slightest adjustment on weak signals --
but as i got very good results in the end - i felt it had been worth it

regards nelson .b.

p.s like the clip on arrangement ------

 

[sonnetpete]

Ok ..
So this is my first design for what I have called 'The Leech' ....

Ah VS, you're really a 'sucker' for punishment, though I'm pleased to see you 'hanging on'............Is that my coat???

 

[Huevos]

VS, if you want to mount the LNB above just use the bullet nose LNB upside down so the cable comes out the top. For a closer look at the LNB have a look at my 28ºE/26ºE on a prime focus dish thread.

 

[Vipersan]

HI huevos ..
I will take a look ..and probably will invest in a bullet nose at some point ..
Need to find a UK supplier ..and need some more 'filling' for the piggy bank ...
Just had a few bills come in ..and with what I've spent recently on the dish and the F15 ...
I need to take a spending break..
I'll have a play around with what I've got to hand for the moment ...but most likely will take your advice at a later date.
thanks m8
I appreciate your help
VS

 

[Huevos]

Just had a few bills come in ..and with what I've spent recently on the dish and the F15 ... I need to take a spending break..

No idea of the cost in the UK, but I buy them for 5.50€ each.

 

[Montafon Guy]

Ok ..
So this is my first design for what I have called 'The Leech' ....
Its organically grown from my bits box ...
;)
Its nothing more than a mounted C120 feed at the moment ...but the throat is close to the the focal length of the dish ...and it sits clear of the C band feed...
I took care to point it at the centre of the dish but this will need adjustment ..
How much I'm not sure ...
What effect it will have on the C band signals..
again ..no idea as yet ..
But it is clip on ...so is removeable if it presents a problem ..
Comments ...derisory or helpful ...are all welcome ..
I'm in unknown territory with the leech..
rgds
VS

Hello Vipersan,


i made several tests like you with 1,8m and 2,4m Alcoa - but the Ku-band Lnc performed like on a 50 - 70 cm dish. ( the Ku-Band Lnc beside a C-Band works only on 1,2 m dishes )

Is that enough for you? ( for me it wasnt )


Regards Montafon Guy!

 

[Vipersan]

Hi Montafon ..
I will be happy with results comparable with a 70 >80 cm dish ..
Its not the dishes main function ...more of an addon to locate satellite positions on the arc ...
Particularly as C band is present on so few birds..
I've so far managed to pull

Thor 5 at 0.8°W
:-11247 V
tp C3 Canal Digital DVB-S

CCTV News
at Signal level around 70%...
So it looks likeThe leech will have its uses ..
..but not for fringe or dx ..reception..
rgds
VS

 

[Montafon Guy]

Hello Vipersan,


so thats an different situation!

On 64 East you can also get C-band for instance the strongest is American Forces Network ( scrambled )
4.094 L SR 3.680 2/3 - good luck!.-)



Regards Montafon Guy!

 

[Vipersan]

Hi friends ..
Spent a couple of days playing with the leech ..
..and whilst it certainly performed reasonably well ...
It did miss a few of the weaker sats ..plus it was often tricky having to take into account the elevation offset ..plus the angular offset which could be handful of degrees when at the extremes of the arc.
So ..in the spirit of experiment ..I decided to attempt a mole instead of a leech...
Working on the same principle as the dual ku/C lnb..sold in the USA ...but since I know these dont perform at all well in KU ...I decided to to come up with an adaption of my own ..
Since I don't want or neccessarily need a permanent fixture ..
This works exceptionally well ..
Just a pity no one makes a smaller c120 lnb that could be placed more centrally ..but It certainly does the job ..though of course it requires manual removal and refitting when needed.
I don't however have to make any changes to the C-band setup.

Having removed the casing from an invacom SNF-031..
I found there was a lot of wasted space inside ..
The lnb itself is relatively small ..though quite heavy.
It still couldn't be used however as access to the F connector was impossible with what I intended to do ..
So ..out came the hacksaw and off came the F connector ...very carefully so as to leave the centre connection insulated and intact.
This was the reduced in height ..and a small hole drilled into the cast casing to allow a small self tapping screw to be used as an ground connection.
A flying lead was then attached so it protudes out to the front ..past the small feed horn assy.

Another block of my favourite expanded foam was the cut to shape and hollowed out to make a stable 'cosy' around the now naked lnb ...
this keeps it from moving around ..and protects the C band probes inside the lnb throat ..

It all has been tested ...
Its very easily inserted and removed ..and performs very very well ..even though the feed is slightly forward of the dish focal point and slighty eccentric.

I can even pick up a fairly stable picture from Asia TV @57East with it.

Here are the pics of 'the mole'

Shown in the BSC422 ..as the BSC421 ..is currently mounted on the dish ..
The principle is the same ..but made for a better photo.

Before and after insertion.
rgds all
VS