adding second lnbf question

[nasko]

Hi all,

This subject is probably beaten to death by I guess my searching capabilities are very limited on Monday morning
I though I'd like to complicate my life by adding a second LNBF. Would somebody explain the steps involved. I've seen that there is a bracket for two LNBs that I need to buy. My question is: how do I aim the second LNBF to the satellite plus how is the elevation adjusted? Is there any marking on the dual LNB bracket to help pointing the second LNB?

Thanks!

 

[PSB]

You don't aim it the dish does, mount the 2nd LNB as close to the same height and distance away from the dish as your KU LNBF, point the 2nd LNB as close as you can to where the focal point is on the dish, then you are done. Go back to the receiver, and motor the dish until you hit the DBS satellites, they are very strong so you will soon land on them, remember you have to change your L.O. to 11250 for a DBS LNBF, then just enter the coordinates of a DBS live transponder and motor until you get quality!

This is of course for a motorized dish for a fixed dish then yes you would have to mess with the LNB and bracket to hit the satellite you are looking for.

 

[TuxCoder]

I made my own bracket by bending two PC expansion slot filler plates and it works great. Use the existing 1/2" fold at the top to 'hug' the back corner of your existing LNB, and at the point where it's near the front of the LNB, bend it so the remaining length runs back away from the dish. Leave some room though, don't "flatten" it at the bend. My bend is a smooth turn of about 5/8" diameter, and not quite 180 degrees.

Then I ziptied two of those brackets to my existing LNB and once they were secured, ziptied the new LNB on there.

Also, if it's a DBS LNB, you have some forgiveness to keep in mind since DBS is a much more powerful signal. If one LNB or the other has to 'sacrifice', make it the DBS one. Like, first and foremost, leave the Ku one in the main position directly at the end of the LNB arm and strap the DBS one on the side of the Ku one. Don't switch them. Also, I didn't have any more short RG6 pieces but a short run of RG59 is less of a problem on the DBS one than the Ku one.

That brings up the question of a switch. What kind of switch are you going to be using to switch between the two LNBs? DiSEqC, 22kHz, 12V, manually operated A/B selector, old fashioned disconnect/reconnect?

 

[Mr Tony]

I just ziptied a DBS LNBF to a dish fixed at Galaxy 10 for Dish audio. Had to crack the top of the houseing to expose the neck and then ziptied the two together at the neck and hose clamped the 2 together. I had 75 signal but once I got the 2 close as possible, it went to 105

 

[nasko]

My intent wasn't to put a DBS LNB. I have a non-motorized dish aimed at Telstar 5. I wanted to put a second LNB to get possibly AMC1 or 4 since they aren't more than 10° apart (From Telstar5). Read somewhere that 13° is the widest angle between satellites that you can do with 2 LNBS.
From what I understand you basically "wiggle" the second LNB until you hit the desired satellite, correct?
If this scenario is possble I'd like to use a diseqc switch to change between lnbs.
Tux do you mind posting some pictures of your setup? Thanks

 

[TuxCoder]

My stuff above still applies, except for the few lines starting with "if it's a DBS LNB..."

Setting it up on a fixed dish to see both at the same time is a little trickier. You lose the luxury of 'wiggling' it electronically from the comfort of your recliner.

 

[nasko]

You don't aim it the dish does, mount the 2nd LNB as close to the same height and distance away from the dish as your KU LNBF, point the 2nd LNB as close as you can to where the focal point is on the dish, then you are done. Go back to the receiver, and motor the dish until you hit the DBS satellites, they are very strong so you will soon land on them, remember you have to change your L.O. to 11250 for a DBS LNBF, then just enter the coordinates of a DBS live transponder and motor until you get quality!

This is of course for a motorized dish for a fixed dish then yes you would have to mess with the LNB and bracket to hit the satellite you are looking for.

Sorry to keep this thread alive but I still need to clarify one question.
There is about 5° elevation difference between the satellites I am trying to get (my dish is currently pointing at IA5 and I am trying to add another LNBF for AMC1). How do I aim the second LNBF to make up the difference? Adding a motor as an alternative is not an option for now.

 

[TuxCoder]

Since it's already pointed to IA5 and you're adding AMC1, it's important that you put the new LNB on the eastern side of the existing one; the new one goes on the "left" if you're standing behind the dish facing south.

And I'm not multi-LNB expert, but I would just start out with them side by side and try to get a signal. If anything, I believe you would need to slightly move (not just rotate) the new LNB higher with respect to the reflector if AMC1 is the lower elevation of the two for your area, or move it lower if AMC1 is the higher elevation of the two. This might take some imagination to picture, but it matches the concept of offset vs. prime focus dish, and signals bouncing into the LNB, etc.

And if all else fails, first mark the current scales and azimuth on your dish and pole, then try to point the dish between the two azimuths for IA5 and AMC1 and set its elevation to between the two. The azimuth is a little more complicated though since one LNB is centered and the other is off to one side.

Good luck though, I am definitely a fan of simplification, higher LNB to dish ratios, only if signal doesn't suffer.

 

[talrudeboy]

hey TuxCoder , Whats up
Do you have pics of that Braket?

<---------------PC Tech with access to tons of those slot fillers for Pcs

 

[TuxCoder]

Sorry for the long delay in response. My approach described above didn't work out when I went to move the DBS LNB to the other side, since my FSS LNB is sort of P shaped on the back (see pic 3 below). Also, my cheap brackets were getting rusty by the time I took them down to do that reconfiguration. So I had thrown them away at that time. But I have plenty of brackets, so I re-made them (see pic 1). It's a good quick solution though. Be sure to leave a bit of an angle between the long stretches when bending them back. I can't recreate my ziptying fanciness when I had those brackets up there but just be creative. Also, I had ripped the brackets off some old ISA cards and kept them (see pic 2... ISA, not PCI, notice the board screws are on the opposite side from PCI--a subtle difference). With the extra tabs and screw holes on those, one could be perhaps a little more creative.

 

[talrudeboy]

In pic #3 I do not see the bracket

 

[Mr Tony]

looks like that 1x2 and zipties are the bracket

Thats how I got 91 & 82 for ExpressVu on one 24" dish

 

[TuxCoder]

Like I said above, these brackets didn't work when I moved the other LNB to the western side (a few weeks ago), where there's an indentation from the "P" shape of my primary FSS LNB. So Iceberg's right, my new "bracket" is that piece of wood. But in the spirit of further documentation I went ahead last night and made up more brackets to photograph. I'll sell them for the right price.