FSS Band Stacked Issues

[fafhrd2]

I was playing with a Dish Pro FSS Stacked lnbf from a Superdish I got a few days ago. Hooked the unit up directly to a 76 cm dish pointed at 97 W and receiving good quality using a DMS 0.3 db bullet type lnbf. When I substituted the bandstacked lnbf, I had to wrap some padding around the throat to enable proper fit to mounting bracket. Used these settings on receiver setup: LNB Type--Single Stack. LO freq.--10750/10175 Ghz. 22 Khz--Off. DiSecq-- Off. Then selected strong transponder like 12177 or 11991 - a vertical tp at any rate. No quality level reception. Tried skewing or rotating the lnb and moving it in and out to find focal point, but no luck. Now I understand these lnbfs may only have 0.7 or 0.8 db noise capability??
Do you have to use them in conjunction with a Dish Pro 34 Multiswitch? I have one still attached to the elliptical dish.

 

[Corrado]

Try manually selecting the LO freq. 13850mhz and rescanning V.

 

[Mr Tony]

if you are trying to aim a dish put the LNB LO to 10750 first

If you have a stacked option try 10750/11250. I've seen that work on my Pansat 1500. But otherwise 13850 works too

 

[pendragon]

My Pansat 9200 has the same stacking option you indicated. It works fine with Superdish FSS LNBs, although one has to translate the H frequencies. I've tried entering a custom LO, but the 9200 will not reliably scan the H range (upper 500 MHz) with one.

The frequency accuracy of these LNBs isn't stunning, so I've had to compensate from time to time with some offsets for known transponders. I can imagine the NF isn't blindingly impressive either, but many Ku LNBFs greatly exaggerate this specification. There are other specifications that are also important, but I've not had problems with the Superdish FSS LNBFs compared to my more expensive LNBFs, and I have around 16 on a toroid.

From the photo it looks like you've got the feed mounted at the correct angle with respect to the LNB - that shouldn't change. Are you feeding 18V from the receiver (set to H, even though you are receiving V)? These LNBFs are kind of power hungry. I can't think of a lot left to check if substituting another LNBf works. You may just have a dumpster-grade LNB.

 

[Anole]

possibilities:

Here are a number of thoughts:
- are you sure you have the actual LNB with "FSS" on the label?
- are you sure you reattached the feedhorn properly?
- if the feed horn is rotated on the LNB out of its proper orientation, it won't get signals. It has two detent positions.
- I understand from previous posts the NF is around 0.7db, and remember... these work fine for FSS on a smallish SuperDish!
- you do not -need- to use the DP-34 switch, and I would take it out of the test.

 

[Tron]

The frequency accuracy of these LNBs isn't stunning, so I've had to compensate from time to time with some offsets for known transponders.

I've noticed this as well. As much as 3-4 mhz off on the vertical (non-stacked) transponders, and as much as 8-10 mhz off of what the horizontals should be (given the 24600 minus the Horizontal TP frequency formula) after a blind scan. Still, they work well with no other issues. I use 10750 as my L.O., and blind scan vertical only.

 

[fafhrd2]

Thanks very much fellas! I will try varying frequencies and rotating feed to alternate position, etc.