Hair Brained Scheme II

[jollyrgr]

I'm trying to add Ku to a 7.5' mesh dish with only a C-Band feedhorn. I tried using a DirecTV LNBf but was told that these are cicular polarized and not linear polarized. So I purchased a 0.3Ku "electronic" LNBf.

Even with a LINEAR 0.3Ku I'm not getting anything from G10R. I get a signal strenght of 94 out of 100. But no QUALITY reading at all.

Can a LNBf be simply mounted next to the C-Band feedhorn? Is the focal point that critical if using an LNBf offset slightly from the center? My thinking is that using something meant for a 36 inch disk should surely work on a 7.5' dish by just being in the ball park.

Also, what is considered normal for polarity switching? My receiver does 14 volts and 18 volts (both with and without a resistor). Does this make a difference? Can physical position make this matter? I've tried several positions near the focal point and oriented the LNBf different directions. I get a solid tone on the Sat Finder; I just can't get a QUALITY reading.

(FYI, this same receiver on a C/Ku big dish feedhorn works as expected.)

 

[rkrenicki]

with and without a resistor?

are you talking about +22k? If so, you must be refering to your MSR1500.. that is for tone inject.. that enables a 22khz tone to be sent down the wire for 22k switches or for universal LNBs

What kind of LNB are you using? If this is a universal one (which most 0.3db ones are) then you will need to use either 14v+22k or 18v+22k (depending on the polarity) and use 10600 (or, in your case, 10600000) for your LO frequency.

The Ku LNBs on your C/Ku setup probably use 10750 (or 10750000 for your MSR) and that simply wont work on a universal... Uni's also default to the low band, so will require the 22khz tone to select the high band.. (since only european satellites use the lowband.. and the only viewable from here is PAS9 for Cubavision)

 

[Mr Tony]

it sounds like a MSR1500 with the options of 14, 13+22k, 18, 18+22k

Things to remember are the LO frequency and the frequency have to have 3 zeroes added to them (again, if this is a Quantum MSR1500, Viacast 2000)

Also, since the KU band is next to the C-Band, you will have to nudge it a little (also, KU has to be fine tuned even if you had a combo c/ku lnb)

With the quantum (and I hope both of us are right that you have one) easiest thing to do is program in the following

11805000 freq
18 polarity
4580 symbol rate
The LO frequency would be 10750000 UNLESS its auniversal. If it is, then the numbers above are different.

Scan the TP you just entered and you'll probably get "no signal". Hit "info" and it will show signal 94 and quality low....now fine tune. When the signal is picked up (even for a second) the info bar will disappear. Then you know your close. Hit info and fine tune some more

But all of the above may be bunk until we know what LNB and receiver you have

 

[Mr Tony]

also, since it truly isnt at the focal point, the KU is probably at 127 or 119 (depending on what side of the C-band you put it on)

 

[jollyrgr]

LNBf Info

Thanks for the replies. I had assumed the 22k was a resistor for current limiting and not an injection tone. This is the MSR1500. I shall give the referenced numbers a try. I do know about the three zeros and have had this receiver working on a regular C/Ku "big dish" feedhorn on both C and Ku LNBs. It is the LNBf that is giving me issues.

The LNBf is an "XTREME 0.3dB LNBf" Digital Ku Band Single LNBf. Here is a "datasheet" on the item:
http://www.worldwidesatellites.com/ebay/xtremespecs.pdf

Out of curiosity why the different LO frequency? The data sheet states the 10750 MHz but I'm supposed to use 10600MHz? Is there some reason for using the lower frequency?

 

[PSB]

With the Extreme the L.O. IS 10750 as its a STANDARD KU LNBF

 

[rkrenicki]

Or, in your case, it would be 10750000

The 10600 (or 10600000) would be for a Universal LNB, which most 0.3db LNBs are with the exception of the Invacom Quad Polar, and the Xtreme (which is news to me, I thought it was a Uni)

EDIT: Also, since this is not a Uni, it does not matter of tone inject is on or off, since the LNB will igonore it, so just use the 14v and 18v settings for polarity.

 

[Mr Tony]

ulta

If he adds the 22K to the setup in the menu it will screw it up....just use 14 or 18

 

[rkrenicki]

would it? it never bothered my DMSI Standard... but nonetheless it is unnecessary, which is why I suggested using 14 and 18 naked too