Getting Started On C Band

[Archived-1]

C band questions please is it just a case of changing your lnb to try for this please are is there more to it ?

 

[Huevos]

c band Q please is it just a case of changing your lnb to try for this please are is there more 2 it ?

LNB diameter is 65mm compared to 40mm for Ku band. You need to attach the C-band LNB so the centreline of the LNB is in the same position as the Ku band LNB is.

 

[Captain Jack]

Yes and you need an offset feedhorn along with a depolariser plate for most C band stuff over Europe. If you want both on the same dish, put another jack arm for elevation control and a C band LNB above your Ku band one.

 

[Huevos]

If you want both on the same dish, put another jack arm for elevation control and a C band LNB above your Ku band one.

No need for two actuators. Just put the LNBs side-by-side and they will both be on the arc and can be allocated individual DiSEqC 1.2 positions. If you have an elevation actuator that would need to be controlled separately, so it wouldn't be a position the receiver could access automatically. Also, if I did have 2 actuators the second one would be a declination actuator, not elevation (like my Fibo). BTW, if you put a C-band LNB and feedhorn above the Ku-band LNB that would make a shadow on the dish; placed side-by-side that doesn't happen.

 

[Captain Jack]

Thanks Huevos, that helps.

The problem with Channel Master dishes is that the LNB holder arms get in the way, so you would need to devise a way to move them aside. And with the LNB on the side - does that not give a worse signal anyway, or does it not matter in C band that much?

 

[Huevos]

The problem with Channel Master dishes is that the LNB holder arms get in the way, so you would need to devise a way to move them aside. And with the LNB on the side - does that not give a worse signal anyway, or does it not matter in C band that much?

Nelson has got that covered. Just move the those arms down. If you do a search you'll find pictures of his dish somewhere.

Re: worse signal... Obviously the best spot for the LNB is right at the focal point... but if that is not possible (because the Ku LNB is in the way), whether the C-band LNB is above or to the side is irrelevant as far as signal collection is concerned (as long as the dish is aligned to compensate for the offset). With my 1.5m dish the C-band LNBs are 2º off centre (i.e receive from 4º off centre) so not miles off. And as the dish size increases they would become less off centre.

 

[Captain Jack]

Yeah, I might consider nelson's method of doing this - the only way is to experiment

BTW, why would you adjust the dish declination rather than the whole mount elevation?

 

[Lazarus]

Gentlemen, I am going to move all the C Band implementation Posts when I've finished my Coffee - worthy of a separate Topic and so as not to distract from 11W reports.

 

[Lazarus]

Done it: I can further Edit the Topic Title if necessary.

 

[Channel Hopper]

The problem with Channel Master dishes is that the LNB holder arms get in the way, so you would need to devise a way to move them aside. And with the LNB on the side - does that not give a worse signal anyway, or does it not matter in C band that much?

There was a modification for Channel Master dishes to allow the side feeds an uninterrupted view, Whether it is an official mod I can't tell.

 

[Captain Jack]

The bar looks fairly official... http://www.satellites.co.uk/forums/topic/137744-wanted-channel-master-multifeed-kit-606701/

 

[Archived-1]

thankyou lads, would it be worth trying with my 1.2, I know a bigger dish is recommended, but do I stand a chance please.

 

[Channel Hopper]

Only you can be the judge of that. You will get channels of course (and some data feeds)

 

[Analoguesat]

You will certainly get some tp's from 20E - I managed 3 tp's on a 1m Orbital last summer. And that was with the lnb / mount very roughly using yes more zip ties!

http://www.satellites.co.uk/forums/topic/154589-first-attempt-at-c-band/

 

[remlap]

Should get some from 5W too and if you're lucky maybe the BBC transponder on 1W.

Also the Linear Libyan channels at 3e are an easy catch.

 

[Archived-1]

thanks again I will give it a go, its something new to play with :-),

I also found this thread interesting,

http://www.satellites.co.uk/forums/topic/127408-fixing-c-band-lnbf-on-a-ku-band-channel-master-12m-dish/

 

[Lazarus]

thanks again I will give it a go, its something new to play with :-),

I also found this thread interesting,

http://www.satellites.co.uk/forums/topic/127408-fixing-c-band-lnbf-on-a-ku-band-channel-master-12m-dish/

Having seen the way the split-off Topic is going, I'm going to further amend the Title :-righton

 

[Kveys]

thanks again I will give it a go, its something new to play with :-),

I recommend C-band also. After more than 20-years (dx kind?) with KU-band I found new "motivation" from 4Ghz. Many, many new channels and maybe less satguys using it, its interesting again to find surprises and changes by channels..?

 

[Huevos]

why would you adjust the dish declination rather than the whole mount elevation?

The axis of a polar mount is supposed to be parallel with the axis the planet turns on. If it is not parallel (because the actuator changes its angle) it will not track the arc properly. Also changing the inclination does not have a uniform effect across the arc, and also interferes with skew. On the other hand if the actuator adjusts declination, skew is unaffected, and for any given actuator setting the dish will track a line across the sky that is 100% parallel to the arc. So once you work out that 2º is 15 clicks on the actuator that number is valid for the whole arc, no matter what satellite you are receiving from. With an inclination actuator that is not the case, and requires a different actuator setting for each satellite.

 

[Captain Jack]

Thanks Huevos! Explains perfectly...