About Channels Master and C band Lnb

[djgeo_gr]

good afternoon to all friends
i has one channel master dish 3,05 and i am intrested to add it C band Lnb
the issue is what I get and 2 bands
u see it in the photo that i has one invagom for ku band
I want to put the lnb for C band
my dish is pravolic
Now I want to ask friends who have dealt with C must buy 2 lnbs for C that i has h/v and L/R
I will need to put with patent 2 lnb right left from the center of k band lnb
What is your opinion about the best C band Lnb
_http://img85.imageshack.us/img85/6827/p1010048z.jpg

 

[Vipersan]

Hi Djgeo....
You are extremely lucky that you have such a big dish to use ..
You may well get away with a combined C/Ku H/V switched LNB as used in the USA on BUDs ..
The gain is notoriously lower than a single dedicated lnb on ku reception ...but unless you intend to use the dish for fringe reception in ku ...the combination lnb will most likely be adequate.
The problem I can forsee with using a combined H/V lnb is that IF you intend to go after Circular polarised signals in C band ..this will require a depolarizing plate to be inserted in the lnb throat ...and consequently this will have dramatic effects on the linear polarised ku signals ..
Thus it will have to be removed physically when receiving ku.
Other alternatives would include a Corotor type feed with orthomode outs/feeds for seperate ku / C lnbs ..but these are not H/V switched ..so you would in effect need 2 ku lnbs attached ..and 2 C band LNBs..
But ..the depolarising plate could be mechanically positioned to have minimal effect when receiving linear.
The final alternative is to use 3 seperate lnbs at the focus ...1 C band with plate for circular ...1 C band lnb without plate for linear ...and 1 ku lnb for linear ..
With this arrangement only 1 of the 3 lnbs could exist at the true fucus ..
The other 2 ..displaced to either side ...and requiring repositioning of the dish to allow them to be used...
Effectively between 2 and 6 degrees inaccuracy of centre focus.
I hope this covers all possibilities ...
But in the end ..its up to you ..and what you intend to receive.
rgds
VS

_http://www.chaparral.net/store/

_http://www.sadoun.com/Sat/Order/LNBFS/C-Band-LNBF.htm

 

[remlap]

Think there is a Chaparral wideband KU Corotor forsale in the classifieds section that's in Greece.

 

[Vipersan]

Think there is a Chaparral wideband KU Corotor forsale in the classifieds section that's in Greece.

If you choose this option ..you will need a receiver capable of driving the corotors servo motor.
So and older receiver to fully drive it..
Modern receivers ..(low cost don't usually have this facility)

 

[Costactc]

I would opt for a wideband corotor as well but as stated above you will need a receiver to flip polarity with servo motor. I'm not quite sure what is available in Europe but here in North America the old pansat receivers have that option then you loop out to the receiver you want to use. The only issue I can see is are there ku lnb for corotor that are universal? When I used that type of feed in the past the ku side was limited to 11700-12200.

 

[remlap]

Yes there are full universal corotors from Chaparral there's one for sale in the classified here.

 

[Costactc]

Yes there are full universal corotors from Chaparral there's one for sale in the classified here.

Good to know, I wasn't aware of that.