Aligning a corotor

[Orthoclipse]

I'm wondering if anyone here with a dual C/Ku corotor knows the best way to align it. Up until recently I've aligned mine on a ChannelMaster dish using the Ku signal as a guide. To get the best signal the corotor had to be tilted upwards slightly with the scalar rings set at f/D = 0.42. C-band reception is also OK.

When the corotor is exactly at prime with the scalars set to f/D = 0.4 - which is the correct calculated f/D - the C-band signal improves significantly by 10-20%, but there is absolutely no Ku-band signal, not even on Astra 28E.

Any suggestions?

I've seen some posters on other sites saying that there is a difference between C-band and Ku-band dishes in terms of surface shape i.e. one is slightly more curved than the other. Is they're any truth to that? I've also seen solid dishes on sale in the US such as Prodelin which are sold as either C or Ku dishes, but I always assumed that was more to do with higher surface accuracy needed for Ku rather than a design diffence.

 

[Likvid]

It is a prime focused Channel Master you are using right?

You set the f/d to the f/d of the dish, if you have f/d of 0.40 you have to set the Corotor to 0.40 also.

However adjusting the scalar rings on the corotor doesn't affect Ku-band as much as you think as the Corotor is not working so good with Ku-band.

I used the Corotor on my 3 meter dish once but exchanged it for the Seavey C/Ku and the performance was much better in Ku-band.

There is that Golden ring also you can buy to fit in the center choke, it is primarly used for deep dishes.

The surface on a Ku-band dish needs to be better than C-band, i think it's something like close within 2.54 mm....

When it comes to that C-band dishes are more curved is not true......

Best thing is to buy a high performance solid KU-band dish, then you can use it with excellent results in C-band as well....

 

[Orthoclipse]

It's a prime focus solid ChannelMaster dish. Correct f/D is 0.4 but as I wrote above, when it is "properly aligned" C-band reception is very good, but Ku-band is practically zero.