Butchering FSS Stacked LNB for FTA

[bidaw]

Have a question that someone can hopefully help me out with before putting much effort into it.

I have been playing around with cascading my FTA setup in my war room to watch multiple channels off of one lnb run to multiple recvrs. Here's the rub. Example, my dish is pointed to 97W, IA5. RG6 to my CNX-V1 recvr tuned to a vert freq watching show #1, I run it to my Twinhan 102g via IF out to watch show #2 on the same polarity, the IF out to my Buzz recvr to watch a different show #3 same polarity, and IF out to my Nexus-S to watch show #4 vertical as well. All of this works great! But I can only watch channels on the polarity of the initial box of the cascade.

My question is this:

If I was to replace my standard linear lnb on the 90cm dish pointed at 97W that I am cascading with now...with one of those FSS stacked lnb's off of an old superdish...you know, the ones that were aimed at say 105W, and edited my transponder list in my recievers to modify the 97W horizonal freqs to veritcal...would I be able to cascade all signals down to my setup to get all channels on that bird because I converted all freqs to one polarity due to the stacked lnb?

In theory I am almost certain that this would work, but I am looking for some thoughts here on this proposed setup.

Thanks in advance for any assistance you can provide.

 

[Anole]

been thinking about that, too

I don't see why not.
Just so long as all those front-end receivers pass the full bandwidth down the cable.
You might run into attenuation of the very high frequency signal.
Maybe someone who has tried this will have practical experience.

What I'd thought about doing, was putting stacked LNBs on several dishes, then routing them through a Dish DP-34 switch.
Then, any of 4 receivers* could send a diseqc command to pick from up to three birds.
The gotchas might be:
1) powering the switch (not a big deal)
2) limit of three inputs (LNBs)
3) and the fact that the stacked LNBs aren't quite Invacom noise level.

I located some of the 121/119 LNBs and was all set to pick them up.
DP-34 switches for cheap, too.
But, I've been having second thoughts about the whole idea.

Picture of the LNB and horn shown here.


*Actually, the Dish DP-34 diesqc switch is cascadeable to three switches.
This gives four outputs per switch, for a total of 12 receivers.

 

[Tron]

I'm not sure that a FTA receiver can control a DP34... that might present an issue.

 

[Anole]

You can't run 13-18 volt switching commands through it.
So, all your LNBs would have to be band-stacked.
You power it with 20 volts, or so.... which is good for long cable runs...


As for controlling the dp34, it's just diseqc commands.
I use a Twinhan Starbox, but the theory is the same.

 

[bidaw]

Thanks for the quick reply. It just so happens that I have a DP34 laying around here somewhere. Yeah, after I posted last night...or was it this AM? anyway, I did some googling on stacked lnbs and answered my own question, and I am almost certain that this will work! Thanks for the heads up on the dp34, the only thing I might have a problem with on that is more cable runs! Ha...I already have 2 thru the house...whats a couple of more! As for powering the switch, I think a buddy of mine has a dp power adapter...I have also read somewhere that the Pansat's have enough juice to power it as long as it is on port 1. I have one or two of those around here too. So I should be golden, thanks guys!

 

[RVD420]

An FTA reciever can control an DP 34.
DP34 uses Diseq commands.

You could also use a DP FSS LNB.

The DP FSS LNB has all of the TPs on 18v bandstacked.

Then all you need to do is blindscan.

As long as your FTA box can tune the IF 950-2150 you will be good to go.

But realistically if you just want IA-5 I would just use a DP FSS LNB, a 4 way high frequency splitter, and 3 DC blocks.

This way one fta box powers the LNB, and the whole freq. range would be able to be seen by all of the other fta boxes.

 

[Anole]

The other thing you might consider is any reduction of the signal level.
You can see the splitter idea (as well as the loop-through, I assume) will reduce signal level to each receiver.
Only you can decide if that is acceptable.
I mentioned above that the band-stacked LNB is no Invacom...

I'm not aware if the DP-34 switch amplifies the signal at all.
Nothing I've ever read suggests that it does, but it's one heck of a big piece of equipment, with a relatively high original price.
Never cracked one open to see.

I'd use a dead/decomissioned/junker/free Dish receiver to supply power to one output port of the DP34.
And so far as I know, you can power it on any and all ports.

For me, the switch is the cheapest, simplest, quickest solution to this discussion, at a local price of $15, used.
Your mileage may vary.

 

[Mr Tony]

The DP FSS LNB has all of the TPs on 18v bandstacked.

actually its 13v

It takes the H polarity stuff, puts it at a higher frequency and makes it V. I know with a DBS LNB, the H polarity stuff is in the 13XXX range

 

[Anole]

bandstacked FSS lnbs

Well, today was the actual swap meet.
The guy with the LNBs didn't bring them - just all his other stuff.
I should have called him yesterday, but I let it slip by me.
Maybe next month I'll track him down and get some 121/119 band-stacked LNBs

I did notice the 121 horn under the cover.
It's a tall oval, and not very large.
Really suited to the SuperDish. Or, some other elliptical dish.
Not the round Fortec 36" I have.
Wish I had one so I could look into alternate horns.

Oh, and I did see one with horn which was maybe the size of a US nickel, and had a pointed white cone in it.
Maybe for 105? Or a different superdish LNB?
Don't know if it's circular or linear.
Anyone know what that "horn" is good for?
Or how hard it is to get it aligned with a dish's focal point?

(I did get a new DMS 22khz tone switch for $5)

 

[dem0nlord]

Oh, and I did see one with horn which was maybe the size of a US nickel, and had a pointed white cone in it.

That small LNBF is for 110W on the 105 Superdish. I'm planning on drilling a hole thru the scalar ring of my BUD to put one of those inside the feedhorn cover for DBS stuff. Also the FSS LNB from those assemblies has a bolt on feedhorn, pretty sure it is a C120 flange so you should be able to bolt the appropriate round feedhorn onto it for your round dish.

If you have access to a decent amount of Dishpro stuff, you might scrounge a DPP44 instead of the DP34. They all have the inline power inserter, so no worries about your FTA box not being able to power it.

 

[Anole]

I did see one of the 105's today, but didn't look (or notice) if it also had a bolt-on flange to hook to the LNB.
If not, then it's circular and on the wrong part of the band.
(...of course, if it's circular you wanted...)
If the pipe is removable, then you bolt up the FSS lnb and go to town.

I still want to get my hands on the 121/119 assembly, and see if it makes sense to slice them apart with a band saw...

There were a bunch of DPP44's, but without the power inserters (I could ask).
They were over twice as much as the DP34's, so I didn't take one hostage right away.
The switches are way more robust than the cheapie diseqc junk, but the LNBs are not the lowest noise.
So, it's a trade-off.
I guess the bigger-dish syndrome trumps deaf lnbs and lossy switches, huh?
...or.... "hey buddy, can you spare a PrimeStar?"

 

[dem0nlord]

I did see one of the 105's today, but didn't look (or notice) if it also had a bolt-on flange to hook to the LNB.
If not, then it's circular and on the wrong part of the band.
(...of course, if it's circular you wanted...)
If the pipe is removable, then you bolt up the FSS lnb and go to town.

I still want to get my hands on the 121/119 assembly, and see if it makes sense to slice them apart with a band saw...

There were a bunch of DPP44's, but without the power inserters (I could ask).
They were over twice as much as the DP34's, so I didn't take one hostage right away.
The switches are way more robust than the cheapie diseqc junk, but the LNBs are not the lowest noise.
So, it's a trade-off.
I guess the bigger-dish syndrome trumps deaf lnbs and lossy switches, huh?
...or.... "hey buddy, can you spare a PrimeStar?"

The 105 assembly I have here is from one of the composite dishes rather than the more common metal ones. They are the only ones with the small lipstick 110 LNBF. Both it and the FSS have removable feedhorns. No cutting needed either, they all unbolt from each other. Agree on the switches, they are very reliable.

 

[Anole]

DL -

Relative to drilling your C band horn...
Here's some alternative hardware Iceberg mentioned a couple of months ago...

On the DirecPC dishes, the 2 LNB feedhorns are really long.
The DBS LNB looks like a pencil and behind the LNB was a good 6+ inches to the LNB

I never knew they had anything of interest beyond the dish.

 

[MJFlash]

Hi, Anole!

I run DPP44s here, and they work extremely well (yes, they're powered via a power inserter, and the primary outputs are definitely amplified, though it appears that the trunk outputs apparently aren't). On the Viewsat Ultra, anyway, just select OCS-DP as the LNB type, which indicates to the receiver that the incoming signals are bandstacked, set the relevant DiSEqC ports, and it all just works. At the moment, I'm running with four fixed DP/DPP LNBs, and a motorized Invacom. To handle the fifth input, I use SW21s for the FTA boxes - it selects between one of the DPP44 outputs and the motorized dish. If you only have four inputs, the DPP44 could take care of everything for you.

One important thing to keep in mind with the DPP44 is that the manual says that you must have at least one DishPro+ receiver attached for it to work. Since I'm already running three subbed DishPro+ boxes, I haven't taken the time to search for what the specific technical requirement is for that DPP box, but you should at least be aware of that.

Good Luck!

 

[MJFlash]

Hi, Anole!

While you may well already know this, I'll mention one important limitation when running with a DPP44 - don't place a 22 KHz switch between it and an IRD. In this configuration, the 22 KHz gets confused with the DiSEqC commands, and things don't work at all.

FYI!

 

[dem0nlord]

Hi, Anole!

While you may well already know this, I'll mention one important limitation when running with a DPP44 - don't place a 22 KHz switch between it and an IRD. In this configuration, the 22 KHz gets confused with the DiSEqC commands, and things don't work at all.

FYI!

This would be the same for any diseqc switch.