Welcome HOME to SatelliteGuys! We are America's Most Popular Satellite Forum!

        

Page 1 of 2 12 LastLast
Results 1 to 6 of 9

Thread: Problems Installing Chaparral Superfeed Single Polarity Feed Horn

  1. #1
    Join Date
    Dec 15th, 2007
    Posts
    16
    Post Thanks / Like

    Problems Installing Chaparral Superfeed Single Polarity Feed Horn

    I just purchased a Chaparral Single polarity C-band Feedhorn, (SuperFEED) and am a bit confused how to fine tune polarity with this feedhorn. We only require horizontal polarity on our fixed prime focus dish, however, I was under the impression that the throat would be rotatable much like other Chaparral feed horns I have used. The picture and description on chaparral's website did not indicate it was a single welded piece. This makes it nearly impossible to reposition the LNB one or two degrees in either direction. The only way to adjust is to use the different screw holes to re-position the entire feedhorn - which would change everything by 15 to 20 degrees.

    I'm installing a Norsat 3000 series c-band LNB and would appreciate any suggestions on how fine tuning polarity can be accomplished using this feedhorn.

    Or.... did I buy the wrong Feedhorn for this dish?Click image for larger version. 

Name:	superfeed.jpg 
Views:	66 
Size:	5.2 KB 
ID:	60323

    Thanks in advance.


  2. # ADS
    Register Today & This Ad Goes Away! Syndicated Advertisement
    Join Date
    Always
    Posts
    Many

    Reigster at SatelliteGuys
     
  3. #2
    Join Date
    Sep 8th, 2008
    Location
    Cavalier, North Dakota
    Posts
    1,305
    Post Thanks / Like
    You could try slotting the screw holes a bit.

  4. #3
    Join Date
    Jan 8th, 2005
    Posts
    3,290
    Post Thanks / Like
    I'm not familiar with that particular feedhorn, but I wonder if the probe inside the feedhorn is fixed or if it can be turned to set the proper skew?

  5. #4
    Join Date
    Dec 15th, 2007
    Posts
    16
    Post Thanks / Like
    Thread Starter
    Actually the Chaparral "Superfeed" doesn't have a probe inside the feedhorn, due to the fact that it's a single polarity feedhorn, there's just a large opening at the back end of the unit for placement of the LNB. Nothing inside the cavity.

  6. #5
    Join Date
    Oct 12th, 2008
    Posts
    1,075
    Post Thanks / Like
    If you happened to have a buttonhook support, this adjustment could be child's play. If you have support arms, it's sometimes possible to twist the feed a bit back-and-forth, meaning the arms will no longer point at the center of the feed. This will affect the focal point somewhat, but for small adjustments it probably won't matter. If I had to rotate between two polarities with a single polarity feed, I'd probably cobble together some form of slip plate.

    One of the other downsides of feeds like this is they have a fixed f/D. I suppose you could cut off the scalar and substitute another. I've picked up extra scalars for around $5-10 from a couple of dealers. The nice thing about feeds like this is they have extremely low losses.

  7. #6
    Join Date
    Jan 1st, 2009
    Location
    Ontario
    Posts
    750
    Post Thanks / Like
    assuming you have a polar mount dish (although without an actuator arm or in other words a fixed dish) I think you better aim the dish to true south and install the Feed horn and LNB as 0 skew (make sure it is properly set for 0 horizontal) then using some sort of pipe or metallic broom simulating an actuator arm simply "move the dish" to the exact position it will have if it had an actuator arm. I know it sounds easy but it is not , but if your polar mount was already setup (it has declination and polar elevation set already) all you have to do is find true south and the "move" the dish manually pushing using the pipe or broom "actuator".

    I hope this all makes sense?.

Page 1 of 2 12 LastLast

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •