Fortec 120cm mod for the BSC621 LNB (PDF)

[scottc98]

All,

As promised, here is the pics and description on how I modded my Fortec 120cm dish to optimize both KU and Cband for the BSC621. Use this new thread for comments/questions.

Thanks!

Scottc98

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Please refrain from posting this PDF anywhere! I would like it only listed here and on Sadoun's forum (since Jamal was key helper in this setup). If people want it, they can add a hit to these two locations
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[Anole]

good job !

Interesting solutions to all the problems.
Great documentation.
A+ for creativity, too.
You really made it look easy.

I'd always wondered what the problem was with those dual-band LNBs, and you say just moving it back is all it takes?
That's just too easy.

But the one thing you didn't document...
...where did you find the conical scaler ring?
The Sadoun web page still lists it as "will arrive soon".

 

[scottc98]

Thanks for the comments! I'm probably going to clean up everything with some fresh paint once I'm completely done tweaking (90% sure its staying as is; cutting the main arm is the one thing I'm debating). I'm really suprised that the lnb location was all it was. I do think that the scaler ring does diminish the KU signal a tad. Its because of this that I am still debating on the cutting the main arm to allow the ring to be moved back more. Wondering if that will help.

As far as the Scaler ring......Craigslist Found a backhaul yahoo member selling the ring from AZ. He was using it on his channelmaster 5 footer but the lnb mount conflicted with the ring and he gave up.

Been mentioning the rings to jamal when I stop in at Sadoun, but no real ETA. Let me track down some old emails from the AZ guy and I'll see where he picked it up from

 

[Anole]

feedback

You have plenty of good pictures from the side, which fully shows the problem and solution.
There are no shots facing the horn, though.
Can you put your camera at the focus... or better yet, down where the arm meets the dish, and shoot up at the scaler ring?
You have the benefit of knowing exactly how everything fits together, and we have only your pictures.

If you did cut the arm, that wouldn't really allow the scaler to go away from the dish very far, would it?
At what point would it run into the side support arms?
If that's a problem, maybe you can spread the side arms at the point where they connect to the main LNB arm, to gain more clearance.
Spacers, maybe? Or, something more creative?

As for cutting the LNB arm, it looks like a necessary evil.
Here's how to repair it if you should decide to restore the dish to stock:
Get some square tubing that will slide inside the existing LNB arm... say, six inches.
(worst case - fold one up out of sheet metal)
Slip it into place, and secure it with some sheet metal screws (or whatever suits you).
Leave about a saw-kerf between the old arm and the cut-off piece when re-attaching.
If you are really anal, go ahead and fill the kerf gap with bondo, calking, or whatever.
Shoot it with some paint.

 

[scottc98]

As far as the requested pics: did you want a pic looking into the scalar ring? I'll see about getting a few more angles for everyone. (need to borrow the camera from a co-worker).

Cutting the arm: It would allow the ring to be moved back a lot IMO. The 2nd pic on the pdf should show that. The side arms should't interfear with the ring after moving the side arms down, and grinding the tops. Cutting the main white bar should alllow me to move the ring back a good 3/4 in. The holes you see on the white bar on the 2nd pic is the original holes for the side arm to connect to the main arm. Changing that and grinding the tops (used a dremel tool for that) did take care of the side arm clearance for the ring.

To restore the bar if I cut it. I am just thinking about getting a new LNB arm all together. I may talk to jamal to see if I can get a spare to buy, or see if I can get one on loan to make exact measurements. Then I may just replicate the entire arm for a easy switch out between a normal KU lnb config and a BSC621 config.

EDIT:

talked to my co-worker and got the camera for another day. I'll take multiple shots tomorrow. If there are any requests, please make them by 1pm est. I've got to leave for work by 2:30pm. That should give me time to upload the pics and create another PDF for the extra shots

 

[Anole]

pix suggestions

Often, when a picture is taken dead-on (from the side, or front, etc), you don't get the perspective ya might with a 3/4 shot.

I'd like one peeking over the top of the dish, looking at the scaler and arms.
That's assuming you don't zoom in too much.
Oh, and maybe a top view, looking down onto the scaler.
There just wasn't enough info shown, to know whether the side support arms would hit the scaler, in the pix I saw.

Showing how things are related to each other (at least with an establishing shot) makes understanding the close ups easier.
And you've pretty much got that covered.

I try to take a whole bunch, from every which angle, then pick the best ones later.
I managed to select maybe 2 or 3 out of a dozen, when I posted some shots of an LNB holder I whipped up.
None were really side/front/top views.
There was an establishing shot, pretty much showing the whole dish (as you have), then one or two 3/4 views of the bracket and LNB in close-up.

One last thought:
When you re-do the PDF, is it possible to put a blank line between pictures?
The way they run together is sometimes amusing with one picket fence slanting to the left, and the one below it slanting to the right.

edit:
Okay, upon closer inspection of all the pix, it looks like the scaler will clear the support arms and move back a good inch or more.

Was looking at the bolts you used to secure your stack of square tubing to the LNB arm.
If you were to use carriage bolts for that, and file the hole square in the top of you LNB arm, that would make them easy to secure.
...and it kinda looks like maybe you did.

Really great job, and wonderful pix - I just needed to look more closely.
.

 

[scottc98]

Here are the new pics...

 

[jayelem]

Cool Dog .......

 

[Wescopc]

Great work scottc98. Thanks for your report.
Bob

 

[Anole]

It's nice working with big pictures you can zoom in on.

The fifth and maybe fourth picture clearly show that the scaler will clear the side arms, if you are able to slide it farther onto the LNB and away from the dish.

Great job.

 

[Anole]

follow up

How about a little update on this project?
You gettin' any... signals...?
Make any other improvements?
Order a 6' dish, yet?
Get good Ku performance outta that BSC621?