Birdview DMX 741u

[DWTexas]

I have a 8' 6" solid Birdview dish with a Dmx 741u LNB. When I installed the new scaler ring it bolted right on top of the old ring. I was glad of that because the bolts on the struts of the old one were very rusty and I was afraid they would break, if I tried to take it off. When I put the new LNB in, it fit perfect into the old scaler ring, But inside the old ring about a half inch from the bottom of it, there is a 1/8 inch lip. So I push the lnb down as far as it would go. So it sets about a 1/2 inch up inside the old ring. It has worked good on most satellites. But on a few satellite, it will not pick up some channels or has very low S & Q. I also have noticed that if I move the lnb to fine tune ,moving it left or right it, makes no difference at all on the S & Q. So I was wondering if this could be caused by the lnb not going all the way to the end of the scaler ring and maybe affecting focal distance. Any advise would be greatly appreciated and thanks. Oh yea I have never been able to get over 90% signal on any satellite.

 

[skysurfer]

In my experience, the focal point of the birdview is the dish-facing side of the birdview scaler ring.

I slid my corotor throat into the birdview scaler ring and set it such that the focal point part of the corotor throat (1/8" inside the front edge) is flush with the dish-facing side of the birdview scaler ring and I have excellent performance.

If you can't get the focal point area of your feedhorn/LNB to the dish-facing side surface of the birdview scaler, then it would make sense that you would have some poor signals (probably Ku affected more than C, but still not optimum for either band) and you will have to do a mod to fix that or go to a different plan.

 

[DWTexas]

Thats what I thought I needed to do . So I guess, I will have to do a little modification to the inside of the scaler ring. To get feedhorn fush on the bottom of the scaler ring facing the dish.Maybe a drimel tool. Because I just need to take off about a half inch all the way around and about a 16th in thickness. Hey thanks for the info. Any other suggestions about taken off the lip on the inside of the scaler ring. Would be appreciated.Thanks again

 

[1beertap]

I have 8.5' birdview with a dmx741. I have installed it to be 1/8 inch sticking out on the dish side of the birdview scalar. This seems to be the sweet spot for best signal quality on my dish. I did not use the scalar that came with the lnbf as I made L brackets with holes to hold it in place. Also, make sure zero (0) on the lnbf is facing toward the ground when dish is at true south.

 

[skysurfer]

Any other suggestions about taken off the lip on the inside of the scaler ring. Would be appreciated.Thanks again

you may want to file more than using a grind wheel.

I had to take off about 1/16" or so all around to make the corotor throat fit. The grind wheel quickly clogged up with aluminum pieces that were hard to dig out with a pick tool.

I ended up filing to the rough shape and then finishing up with the grind wheel and dressed the grind wheel every so often to clean up the aluminum pieces (melted aluminum that cools and solidifies in the valleys of the abrasive material?)

 

[DWTexas]

The hole in the the scaler ring is 2 5/8 same as the dmx. Except for the 1/16th or so that sticks out in the bottom of the ring. I was thinking of getting a 2 5/8" hole saw bit and just drill the last 1/2" or so out. Very carefully with it on the dish. I really would like to keep the BirdView scaler on the dish because of the size of it and I know I would prob break a strut getting it off. Thanks again guys for the info. I will let you know how it turns out.

 

[Anole]

don't re-invent the wheel:

Please look back through the Birdview related threads for some help.
I don't have all the details book marked, and can't remember everything, but...
I think it was Phlatwound who described how he used a hole saw to enlarge the scalar hole...
Others have taken the scalar to a machinist who used a hand grinder with a router-like tip (not a wheel) to open up the hole by hand.
Others have used a file, I believe.
You can spin it on a lathe to easily bore the hole to any size needed.

Check back through the threads for all the ideas that were tried.
Obviously some of the techniques are better than others.
Linuxman was probably the first one here to write extensively about Birdviews on the forum.
Might want to start with his.

And you are right, breaking the scalar support struts is a real possibility.
Stogie5150, and maybe Phlatwound have written extensively on the problem and the cures.

 

[skysurfer]

Others have used a file, I believe.
...
And you are right, breaking the scalar support struts is a real possibility.
Stogie5150, and maybe Phlatwound have written extensively on the problem and the cures.

I used a file (and finished with a grind wheel to smooth up the inside).

I didn't break any struts but one of the struts was broken. I just filed it flat on the end that was broken off, drilled a hole down the center into the end, and used a screw and washer to fix it.

The pics I posted in another thread show the fixed strut attached to the scaler ring and the filng and strut fixes I did were also posted in other threads on this site.

 

[DWTexas]

Well got it done in about an hour. I left the ring on the sat and used a file bit that goes in a drill. The bit is about 1 inch long and about 1/2 wide. Looks just like a file. Worked very well no clogging on the file, but you need wear some gogggles. Lots of small shavings.
I moved the LNBF down the throat, it gave me more signal and a better balance in S&Q. Thanks again for the help and Info