There are LNBs, polarity and LOs
[2008-4-22]
There are LNBs and LNBFs
An LNB has no feedhorn and only gets 1 polarity, these are usually used on C/Ku BUDs and commercial Ku systems. These come in Single output only.
An LNBF has a built-in feedhorn and usually gets 2 polarities using Voltage controlled switching. These come in Single and Dual output models.
LNBF's are what we deal with the most so when you see LNB think LNBF.
A standard LNBF can pick up both polarities at the same time but can only send out one polarity at a time because of bandwidth restrictions, ALL North American LNBs output their signal at 950mhz to 1450mhz to the receiver.
A standard LNBF uses Voltage Controlled switching to select the polarity being sent to the receiver, when one of these LNBs receives 13volts from the receiver it sends back V(vertical) polarity transponders, if it receives 18volts it sends back H(horizontal) polarity transponders, this is why you CAN NOT simply add a splitter to run 2 receivers from one LNB output.
The cutoff point in a Voltage Controlled switch is 15.5volts, so below 15.5v you get V transponders and above 15.5v you get H transponders, if you ever have a problem getting H transponders it is probably because the cable to the dish has a problem and is reducing the voltage that can get to the LNB.
A dual LNBF has two outputs but can only get one satellite, it can be used for two receivers, and because it has two outputs it can be used for MORE than two receivers. You use a Multi-switch for this, both outputs of the LNBF are connected to the Multi-switch the Multi-switch assigns one LNBF port as V(13v) and the other as H(18v) so both polarities are now available IN the Multi-switch, Multi-switches come in 4 output, 8 output and 16 output models. The 4 output model is often referred to as a 3x4 switch, the 3rd input is for a TV antenna or cable TV signal.
There are 3 LNB frequency ranges used in North America:
C-band 3.7ghz to 4.2ghz (same as 3700mhz-4200mhz)
Ku-band(FSS) 11.7ghz to 12.2ghz (same as 11700mhz-12200mhz)
High Ku-band(DSS) 12.2ghz to 12.7ghz (same as 12200mhz-12700mhz)
You need a separate LNB for each range, although there are some combination LNBFs coming on the market now.
In North America,
C and Ku(FSS)-Band LNBs ALL use Linear Polarity to receive satellite signals.
High-Ku (DSS) Band LNBs ALL use Circular Polarity.
So look at the frequency range on the LNB label
11.7ghz-12.2ghz is a Linear polarity LNB
12.2ghz-12.7ghz is a Circular polarity LNB
There are also "universal" LNBs they are ALL Linear polarity
10.75ghz-12.75ghz, these have a wider band but still are only used for Ku(FSS) satellite reception.
There are exceptions to all rules there are Circular polarity Ku-band LNBs made for use in Asia same with Circular polarity C-band LNBs these are not commonly available in North American so be careful what you order from overseas shipper.
LOs
The Local Oscillator is built into an LNB as a tuning Baseline.
It is a reference point that you must tell the receiver.
The LO is LNB specific and has nothing to do with an individual satellite.
Example: we are both looking at the same book and I tell you to turn 14 pages ahead, you say from what page do I go 14 pages ahead? I tell you what page, thats the baseline or starting point. Your receiver needs to know the starting point of this LNB in order to tune it correctly.
It would be nice if all LNBs had the same LO but they don't, different manufactures use different LOs, BUT they always put the LO on the LNB label because it is different.
Some standards
DSS LNB - LO 11250mhz (11.25ghz)
FSS(Ku) - LO 10750mhz (10.75ghz)
Universal Ku LNB has 2 LOs, LO1 9750mhz(9.75ghz) and LO2 10600mhz (10.6ghz)
An LNB has no feedhorn and only gets 1 polarity, these are usually used on C/Ku BUDs and commercial Ku systems. These come in Single output only.
An LNBF has a built-in feedhorn and usually gets 2 polarities using Voltage controlled switching. These come in Single and Dual output models.
LNBF's are what we deal with the most so when you see LNB think LNBF.
A standard LNBF can pick up both polarities at the same time but can only send out one polarity at a time because of bandwidth restrictions, ALL North American LNBs output their signal at 950mhz to 1450mhz to the receiver.
A standard LNBF uses Voltage Controlled switching to select the polarity being sent to the receiver, when one of these LNBs receives 13volts from the receiver it sends back V(vertical) polarity transponders, if it receives 18volts it sends back H(horizontal) polarity transponders, this is why you CAN NOT simply add a splitter to run 2 receivers from one LNB output.
The cutoff point in a Voltage Controlled switch is 15.5volts, so below 15.5v you get V transponders and above 15.5v you get H transponders, if you ever have a problem getting H transponders it is probably because the cable to the dish has a problem and is reducing the voltage that can get to the LNB.
A dual LNBF has two outputs but can only get one satellite, it can be used for two receivers, and because it has two outputs it can be used for MORE than two receivers. You use a Multi-switch for this, both outputs of the LNBF are connected to the Multi-switch the Multi-switch assigns one LNBF port as V(13v) and the other as H(18v) so both polarities are now available IN the Multi-switch, Multi-switches come in 4 output, 8 output and 16 output models. The 4 output model is often referred to as a 3x4 switch, the 3rd input is for a TV antenna or cable TV signal.
There are 3 LNB frequency ranges used in North America:
C-band 3.7ghz to 4.2ghz (same as 3700mhz-4200mhz)
Ku-band(FSS) 11.7ghz to 12.2ghz (same as 11700mhz-12200mhz)
High Ku-band(DSS) 12.2ghz to 12.7ghz (same as 12200mhz-12700mhz)
You need a separate LNB for each range, although there are some combination LNBFs coming on the market now.
In North America,
C and Ku(FSS)-Band LNBs ALL use Linear Polarity to receive satellite signals.
High-Ku (DSS) Band LNBs ALL use Circular Polarity.
So look at the frequency range on the LNB label
11.7ghz-12.2ghz is a Linear polarity LNB
12.2ghz-12.7ghz is a Circular polarity LNB
There are also "universal" LNBs they are ALL Linear polarity
10.75ghz-12.75ghz, these have a wider band but still are only used for Ku(FSS) satellite reception.
There are exceptions to all rules there are Circular polarity Ku-band LNBs made for use in Asia same with Circular polarity C-band LNBs these are not commonly available in North American so be careful what you order from overseas shipper.
LOs
The Local Oscillator is built into an LNB as a tuning Baseline.
It is a reference point that you must tell the receiver.
The LO is LNB specific and has nothing to do with an individual satellite.
Example: we are both looking at the same book and I tell you to turn 14 pages ahead, you say from what page do I go 14 pages ahead? I tell you what page, thats the baseline or starting point. Your receiver needs to know the starting point of this LNB in order to tune it correctly.
It would be nice if all LNBs had the same LO but they don't, different manufactures use different LOs, BUT they always put the LO on the LNB label because it is different.
Some standards
DSS LNB - LO 11250mhz (11.25ghz)
FSS(Ku) - LO 10750mhz (10.75ghz)
Universal Ku LNB has 2 LOs, LO1 9750mhz(9.75ghz) and LO2 10600mhz (10.6ghz)
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