Scaler rings on the old Birdview c-band dishes

[alchevy]

The old C-band dishes have a scaler ring around the lnb. The newer offset dishes do not have a scaler ring. Does anyone know if a newer lnbf will work on a prime focas dish with no scaler ring? Rebuilding my birdview 8ft solid dish with single adjustable length arms to the lnbf making a lnbf mount to the adjustable arms but with no scaler ring. In my younger days I think I remember the scaler ring was to help with ground noise or interference. I can't remember anymore. Do you need a scaler ring on a prime focas dish? This is to be a KU dish only.

 

[radio]

There have been many writeups on Birdview conversions here. I used the original struts and milled out the center of the old scalar plate to fit the newer LNBs of today. My results have been very good to excellent, as have those of member nick-jen and others. Search "birdview" and you'll find much to read. Some people modify the struts, most don't. This is just one thread.

http://www.satelliteguys.us/threads...to-FTA-(and-still-on-HITS)?highlight=BIRDVIEW

 

[FaT Air]

The newer offset dishes do not have a scaler ring.

Yes they do. They are small enough, because of the higher frequency, to be 'built in' the new LNBFs. My channelmasters had originally a LNB bolted to a horn feed which gave the desired F/D ratio.

This is to be a KU dish only.

Then a Ku LNBF designed for prime focus should be employed.
An INVACOM ADF-120 FEED HORN to mount a LNB w/ a C-120 flange, GEOSATpro SL1P, or BSC321sp are the 3 options I know of.
A new style Ku LNBF (intended for an offset dish) could be used but will, I would think, perform not as well as the above.

 

[Tron]

As FaT Air said, the scalar rings in Ku-Band LNBFs are built in. They are behind the weather-protective cap, and can be seen on the Invacom LNBFs because the protective cap is transparent.

There is a diffence in scalar rings (C or Ku) designed for prime focus dishes versus those designed for offset dishes. Scalars for offset dishes are conical, and the scalars for prime focus dishes are flat. The scalars built into almost all Ku-Band LNBFs are conical (for offset dishes). There are a couple of Ku-Band LNBFs that have flat scalars and are designed for use with prime focus dishes; The SL1P FaT Air mentioned is sold by SatelliteAV.

 

[alchevy]

Thank you Radio, Fat Air and Tron for responding to my post. I thought there was a difference between C and KU lnbf's but could not remember what it was. As soon as Tron said conical it hit me and I started to remember what the difference was. Have been messing with dishes for about 20 years now I am forgetting many little things as I age. Have read many post on birdview dish modifications but do not remember reading where a prime focus lnbf is needed. I have added the read sensor and put some thin washers in the under sids or the lower side of the dish mount as in central florida I need 4.6 degree declination instead of five. I think the lower side is correct to reduce the declination and the upper side to increase it. Someone may comment on that as I may not remember correctly as I had to reassemble the dish last week and could not remember where I put the washers last time the dish was used. I started to build a mount for one of the lnbf's I have and then something told me to check before I go to far with the lnbf mount build. You guys have saved me a lot of time and work as I started to put an offset lnbf on the dish. I will now look for a prime focas lnbf and start the mount build all over again. Also I read about the 36 to 1 and the 70 to 1 motor for the birdview dish. Can someone fill me in on the difference between them and how to tell which one I have?

 

[phlatwound]

You are correct, adding washers between the bottom plate of the mount and the dish will decrease your declination.

And there should be a tag or label on your motor that indicates the drive ratio, I have seen 37:1, 70:1 and 110:1.

 

[Anole]

I would recommend you get one of our excellent FTA moderators to change the topic of this thread to something mentioning the word: Birdview
Then, post some pictures, and you'll get all the Birdview help you need!

Also, search for Birdview threads; many members have posted a boatload on 'em.
Pendragon even got into the club, and his recent thread might add to all that's gone before:
http://www.satelliteguys.us/threads/264831-Pendragon-vs-the-Birdview

edit: as for an LNB to bolt to the Invacom AF-120 feedhorn, I'm currently exploring how to graft on a SatelliteAV PLL Ku (after a trip to a machine shop).

 

[alchevy]

Thanks for the suggestion Anole. I am working on doing that now. Read a lot of the post on feeds and birdview the last couple of days. Hope Pendragon gets his spoon dialed in. Very insteresting post. I like to tinker with stuff also but on a smaller scale. I had some time today and looking for a good feed for my birdview to get it going again for ku only. Removed the c/ku corotor II and just want to go ku band only. I have a 12 ft mesh dish for c band up and running years ago and still looks good and a 12 ft. solid dish but now have nowhere to put the 12 ft solid dish. Massive mount, post and dish frame. Just playing around, I took one of my cheap $5.00 ku offset lnbf and popped the plastic top off to expose the scaler rings. Took my drummel with a cut off wheel and removed most of the conical rings and ended up with three flat rings on the scaler. Going to put it on the birdview to see what happens. Something that did amaze me is I put it back on my 120cm offset dish and found no difference in signal and quality than before I cut it up. . I thought I would see some reduction in signal and quality but did not. I also put a corotor II scaler ring around the lnbf holding it in place moving it around on the offset dish and it did not seem to make any differencd no matter where I put it. Very unscientific experment but expected to see a difference in signal and quality but did not happen. I am just in the learning stage but like to play. That is what the hobby is for isn't it?