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Fist off the standard disclaimer; this is a little tutorial on how to possibly destroy your perfectly good (if all too common) DirecTV LNB! Do not attempt this unless... well, you know- you're over 11, have your parents and/or kids' permission, are Vulcan and have two hearts... Whatever.

Big thanks to sidha for giving the original method. Following his suggestions will undoubtably work better. Consider this the way of going about things if you have none of the proper tools or parts

STEP ONE:
Find an old DirecTV LNB.
http://www.dwarchive.net/mod/mod1.jpg
Here's my unsuspecting old dish, hanging out behind the house. You're goin' DOWN, LNB! Well, down in frequency anyway..

The LNB off mine happens to be the "easy-to-mod" kind:
http://www.dwarchive.net/mod/mod2.jpg
Namely: California Amplifier P/N: 15057 LOT NO: 02385
I highly recommend you seek out a similar model, as most others are purposely tamper-resistant, and a REAL pain to mod, or even take apart.

STEP TWO:
Crack it open. Just prying with a screwdriver should do it.
http://www.dwarchive.net/mod/mod3.jpg
Don't worry about being a bit rough with the screwdriver; no vital parts exposed yet.

STEP THREE:
Remove the feedhorn cap.
http://www.dwarchive.net/mod/mod4.jpg
As you can see from the picture, now you can see the teflon (looks like plastic to me) "wedge" glued in the throat of the feedhorn. We want this out to convert from circular to linear polarization.
WARNING! Attempting to pull it out with pliers results in this:
http://www.dwarchive.net/mod/mod9.jpg
The wedge is fairly brittle and easily pulls apart that way. Keep reading for a better method of extraction...

STEP FOUR:
Pry the back cover off the LNB.
http://www.dwarchive.net/mod/mod5.jpg
The cover is held in place with some rubbery sealant that is easily scraped away on my model. It's there to keep the weather out, not you

Now we can see the innards of the beast:
http://www.dwarchive.net/mod/mod6.jpg
Note the tuning screw. A vey simple mod is to adjust this screw to skew your frequency coverage by up to 23Mhz, says sidha; then the very uppermost Ku transponders might be findable with a blind search.

STEP FIVE:
If you're like me and don't have the 'right' tool to loosen the backplate screws, I suggest using some pliers and carefully giving each a half-twist or two. Once loosened that much, they turn smoothly and can easily be unscrewed/removed with your fingers. Once done, we now have this:
http://www.dwarchive.net/mod/mod7.jpg
Note the ceramic "puck" under where the tuning screw was. To lower our frequency, we need to add to this puck. A reverse mod some may be familar with is sanding this puck down, raising the freqency, and converting this for other uses (as discussed here ).

STEP SIX:
Remove the teflon wedge. The best way seems so be carefully using a flathead screwdriver to break the wedge's glue seal, then (again, carefully!) from the reverse side, using a flathead screwdriver and a hammer, driving the wedge out, like so:
http://www.dwarchive.net/mod/mod8.jpg
Yes, I said be very careful, but if you do crack it up a bit rest easy knowing mine looks like a dog chewed on it, and there is about 5-10% physically missing, but it still works at least as well as it did previously.

STEP SEVEN:
Add ceramic to the 'puck' to lower the frequency.
Sidha tells us to use a 'donor' LNB and cut/shave bits off to add to this modded one. Having no donor LNB, I looked around my junk pile for some suitable ceramic. Hrmmm...
http://www.dwarchive.net/mod/mod10.jpg
Yes, here's what I was looking for:
http://www.dwarchive.net/mod/mod11.jpg
I'm sure using another LNB for donor parts is much more suitable, but this seemed to do the job Now, break it!
http://www.dwarchive.net/mod/mod12.jpg
Try and get some decent-sized chunks. I also made sure the chunks had no metal in them, just ceramic; it might not matter in small quantity, but I wasn't taking chances.

STEP EIGHT:
Add the ceramic bits to your 'puck.'
Sidha recommends superglue or the like. Not being able to find any in the house at the time, I tried to think of what other substance I had that could 1) go on in a very thin layer and 2) be sticky enough to keep the bits in place. I finally found some thermal paste that seemed to suit nicely. Again, I trust in sidha that superlue or epoxy are better choices. With enough of a beating, I imagine the paste could loose its' grip on the ceramic.
Okay, so, I coated the puck a bit:
http://www.dwarchive.net/mod/mod13.jpg
... and then added some ceramic chips:
http://www.dwarchive.net/mod/mod14.jpg
Your goal should be about 30% more cermaic added on to the 'puck.' I did a lot less this time, becuase I'm lazy. Actually, I wanted to finish writing this up and get things working before 4am Try and add as much as you can around the edges, and only thin peices on top... there's lots of space around it, but not much height-room to add.

STEP NINE:
Reassemble the LNB. This is (sort of) where Part One of the tutorial ends. I can offer some helpful hints, but those with recievers capable of blind scanning should be pretty well off now; SOME part of the Ku band should be within your reach if you added enough ceramic. Fine tuning with the set screw can be done to adjust your frequency range- also, when putting everything back together, watch that the set screw doesn't crush your now-higher 'puck.' Here is a little proof-of-concept I've developed from my non-blind-scanning Twinhan card:

I've had my dish locked on Echo7 the entire time I did this mod. Not as easy as it sounds, I practically have to hang off the dish to remove/reinstall the LNB First, I put the wedge back in to restore circular polarization. I fired up ProgDVB, and tried pulling up Echo7:
http://www.dwarchive.net/mod/mod15.jpg

As you can see, I got nothin'. Why would this be? We've changed the LO on the LNB! So I'm way off frequency trying to pull in the transponders. I didn't add much ceramic to the puck, so I shouldn't be that far off. Adjusting bit by bit, and checking the same transponder each time, I finally arrived at:
http://www.dwarchive.net/mod/mod16.jpg
Yes, the LO is now set 180Mhz below normal. And we get:
http://www.dwarchive.net/mod/mod17.jpg
Incedentally, this is the best quality I've ever gotton off this dish. Actually, I've never had more quality than signal... weird, huh?

The bottom line is, I now have a functioning new LO! With more ceramic, it would drop lower and lower; with time, patience, and some tuning screw adjustments I can achieve 10750. With the wedge removed, we have a Ku-band capable DirecTV dish! Yay!

I'll continue to work on this. Hopefully sidha will offer more advice, and I'll write up a Part Two when I successfully lock into a linear polarized Ku bird. In the meantime, I hope his little guide helps everyone! It's a fun project anyway, and the parts are sure easy to come by

CharredPC