Setting up conical feed questions

[jcardani]

Hi All,

I will be seting up a conical feed on my Fortec 1.2m soon and have some questions.

First, where should the feed be positioned on the LNB (at what F/D line?) Should it be lined up with .6 since the dish is a .6F/D? Iceberg's pictures on his review of the conical feed appears to not be at .6 but it's hard to see. BTW I have the DMX741 C/Ku band LNBF and not the GeoSatpro he was using. I want to make sure the dish is illuminated properly.

Also, is the focus point the same for C and Ku band with this LNB?; ie if I set the focal length both C and Ku would be correct.

Thanks

Joe

 

[brentb636]

I think you'll have to play a little , Joe. Once I got a signal on my lnbf WITHOUT the scalar, I optimized that manually. Then I put the scalar cone on the lnbf . Beginning at the very end and moving away from the dish, my best spot seems to be about 1" to 1 1/2" from the mouth of the feedhorn. I use STO on Gal 23 (121W) as a target since it's loaded with power. Since , by definition, this C-band lnbf is mismatched to a Ku band dish, I wouldn't rely too much on trying to "calculate" the sweet spot. It's quicker to actually determine it logically in incremental fashion.

 

[brentb636]

I also believe you will have to sacrifice some Ku Quality to optimize the C-band Quality. I don't for a minute think that there is one spot that is perfect for both.

 

[jcardani]

Hi Brent,

Thanks for your help!

Joe

 

[Mr Tony]

my LNB is set up almost like Brent's in regards to the depth of the LNB

I'll take a pic of mine later

 

[brentb636]

This pic from your review shows it , Tony.
http://www.satelliteguys.us/attachment.php?attachmentid=36905&d=1240887166

 

[Mr Tony]

true. But that dish has been moved now to 121 and the LNB is pushed a little farther in