IF Frequencies

[mbarnes]

In looking at various equipment, I see that the typical LNB outputs an L-band IF between 950 and 1750 mhz. But I see receiver specs with input range of 950-2150 MHz. Why does the receiver have a wider bandwidth than the lnb output?

Just wondering.

 

[Mr Tony]

Here in the US we dont use the extended band of KU. Extended would be from 12.2-12.750. In Europe they do. So its not needed here.

Easiest way to figure out frequency range is to take IF frequency and add the LNB LO freqnency

standard
10750+1750 IF =12500
KU Band stops at 12200

DBS runs from 12200-12750 here in North America but the LNB LO is 11250
11250+1750 =13000

LNB's for Europe you'll see 950-2150 IF freqency

10600 (most LNB"s are Universal) +2150 =12750

 

[Larry1]

You can use a stacked LNBF. For the StarChoice, the specs are


Starchoice LNBF Specs:
* Input - 11.7 to 12.2 Ghz
* Output - 950 to 1450 (V) and 1525 to 2025 (H)
* Max Noise Rating - 0.8dB
* Gain 50 (lower IF) to 62dB (higher IF)
* Cross polarity isolation - 27dB Min.
* Power consumption - 200mA, 10,5 to 24 Volts (nominal 13V recommended)
* Operating temperature - -32°C to + 52°C
* 54mm in diameter

or you can use a Dish Stacked


The DishPro high band is 1650-2150MHz. Just for reference, the low band is 950-1450MHz



Since the tuner can tune from 950 to 2150 the receiver can tune the vertical and horizontal frequencies. No need to change the voltage on the coax cable to switch the output of the LNBF. Both Vertical and Horizontal frequencies are on the coax at the same time. Due to this you can use High Frequency splitters instead of switches to connect multiple receivers that have access to all frequencies available at all times. One receiver can be tuned to a vertical channel while another is tuned to a horizontal. However, the higher the frequency, the greater the loss in the cable and the more inportant the quality of the connections. With a regular LNBF, you select either the horizontal frequencies or the vertical frequencies and can not have both available on the coax at the same time. To connect up two or more receivers with the ability to access horizontal or vertical channels, (independantly) you would need multiple output LNBF and switches.