DMX741 F/D Ratio Scale

[ats144]

I am a bit of a noobie but i'm learning pretty quick. I obtained a late 80's model 10 foot unimesh dish. The polar mount was really rusty and the actuator was frozen solid. It's amazing what one can accomplish with a bit of patience and alot of elbow grease. The dish is up now and aligned pretty good on c-band. I was having trouble with Ku signals. I read that the original Chapparal feedhorn was not much good anymore as it is only analog. I got a WS Int. DMX741 to replace it but I am unclear about the F/D ratio scale. My dish has a ratio of .4. The scale on the LNB dosen't seem to correspond to anything. The center of my dish is 10 feet up and I live in Florida so my elevation is way up there. This puts my feedhorn out of reach when installed, so trial and error is out of the question. Can anyone help me with this?

[Babadem]

Originally Posted by ats144

I am a bit of a noobie but i'm learning pretty quick. I obtained a late 80's model 10 foot unimesh dish. The polar mount was really rusty and the actuator was frozen solid. It's amazing what one can accomplish with a bit of patience and alot of elbow grease. The dish is up now and aligned pretty good on c-band. I was having trouble with Ku signals. I read that the original Chapparal feedhorn was not much good anymore as it is only analog. I got a WS Int. DMX741 to replace it but I am unclear about the F/D ratio scale. My dish has a ratio of .4. The scale on the LNB dosen't seem to correspond to anything. The center of my dish is 10 feet up and I live in Florida so my elevation is way up there. This puts my feedhorn out of reach when installed, so trial and error is out of the question. Can anyone help me with this?

I don't have much experience with C-Band LNBs, but try using Calculator for F/D ratio of a prime focus antenna from here. You might find other tools that may be useful on the site. Here also is a PDF document of DMX741U that may give you some ideas. I hope this helps.

[RDosetareh]

My dish has a ratio of .4. The scale on the LNB dosen't seem to correspond to anything.

The F/D #s on the outside of the DMX LNBF are in tenth.

[ats144]

Originally Posted by RDosetareh

The F/D #s on the outside of the DMX LNBF are in tenth.

Thank you. It seems so obvious now.

[RDosetareh]

You are very welcome! Did you get it up and running?

[ats144]

Not yet. I will get it back up this weekend. I'll keep you posted.

[RDosetareh]

Makes for a good weekend project. I hope the weather cooperates with you.