Conical scaler

[sanpat]

Going to set up a 6 ft pronelin dish for c band for a friend, is a conical scaler needed for offset dish or would a prime focus scaler suffice ?

 

[primestar31]

Going to set up a 6 ft pronelin dish for c band for a friend, is a conical scaler needed for offset dish or would a prime focus scaler suffice ?

You need a conical scalar for this to work best. Otherwise it won't see the "entire" dish surface when used for a off-set dish.

 

[RimaNTSS]

Otherwise it won't see the "entire" dish surface

Did you mean that it will see much more than dish surface, including lots of ground noise?

 

[primestar31]

Did you mean that it will see much more than dish surface, including lots of ground noise?

No, I did not. A conical scalar is needed for an offset dish used for C-band. Which is the question he asked.

 

[RimaNTSS]

Of course, conical scalar is needed for LNB when used on offset dish. Flat scalar when the same LNB is installed on PFA. If flat scalar is used on an offset dish than it will overilluminate ( see much more than entire dish surface). Is not this the case you meant by saying word "otherwise"? In contrary , if conical scalar is used of PFA then it will underilluminate the dish (will not see entire dish surface). OK, I am not native English speaker, but that is my understanding of the issue.

 

[Titanium]

Scalars are designed to properly illuminate a reflector. An OEM scalar matched by the manufacturer for the band and model would be the best option.

A scalar is simply a mechanical choke designed to match a given frequency for a specific Focal Diameter Ratio (F/D) and reflector shape (round, oval, etc.). It has little to do with a reflector being prime focus or offset.

The Prodelin 1183/1184 model reflectors , both spec a 0.6 F/D and are round (not elliptical or oval), so an off-the-shelf conical scalar should be used as they typically are optimized for this 0.5 - 0.7 F/D range. A flat scalar typically is optimized for a F/D ratio of 0.3 - 0.5 and would over illuminate the Prodelin 1183/1184 model reflector (see beyond the reflector's surface) allowing ground noise and terrestrial interference to directly enter the feed.