NEW version: 10 GHz LNB EXT OSC MK3

wiki order

This new Bias Tee Box MK3 offers two LNB reference signal options. The first is an internal (very accurate and stable) TCXO - this can be used if you cannot connect an external 10MHz source. If you do have an external 10MHz precision signal source - e.g. GPSDO - this will give you an accurate and stable reference signal for the PLL in the LNB. The reference signal is sent to the LNB together with the IF signal from the LNB via a coaxial cable. In this MK3 version, the reference signal is multi-filtered by quartz filters, ensuring both signal purity and reduction of possible harmonic components. The result is a much cleaner IF signal and noticeably better PLL phase noise (compared to the previous version or the competition), even when using a lower quality 10MHz reference source (GPSDO). This is particularly beneficial for weak signals at and below the noise floor - EME. A specially designed diplexer in the Bias Tee box separates the reference signal (25MHz) from the IF signal ( > 600MHz) and the DC power supply to the LNB. The LNB power supply still guarantees polarization switching capability and switching to H-pol is indicated by a front panel LED (supply voltage above 18V). The power supply is protected by a special electronic fuse that protects the box in the event of a short circuit in the coaxial cable. The input from the LNB also has HV protection by gas discharge tube and antiparallel diodes. The IF signal from the LNB passes through the frequency and power diplexer to the variable attenuator. This allows the conversion gain of the LNB to be adjusted to avoid overdriving the RX. In this MK3 version, the ATT trimmer is positioned so that the gain can be conveniently adjusted on the front panel of the box. The RX output is again protected by diodes, and there is a super-fuse that will disconnect the unit if there is a strong signal on the RX port - a signal from an incorrectly connected TX and levels above 20mW - protecting the box and LNB from destruction. The main difference from the older version is the filtering of the 25MHz reference signal. X-tal filters are used to achieve the best possible filtering. One before the buffer amplifier and one after it. Another one is directly in the LNB. Thanks to this filtering, better phase noise and signal clarity is achieved even with a worse 10MHz signal source.

OLDer version: 10 GHz LNB + Bias Tee with TCXO or 10 MHz reference input (9750 MHz LO) for GPSDO - QO-100 and tropo


This is the Ku band 10 GHz LNB (Low Noise Block) with external reference input. LNB needs external 25 MHz reference for internal PLL. This signal is feeded by the same one coaxial cable as IF down. Special small Bias Tee box with TCXO (25 MHz) or 10 MHz reference signal (GPSDO) works as DC injector and also 25 MHz source for the LNB. There is also variable attenuator for IF signal which allows you to change IF signal from 0 to maximum. High Pass Filter and 25 MHz Notch Filter at IF line. You can still switch between V and H polarisation by the supply voltage. You can use it for QO-100 satellite and also for Tropo contesting / DXing.

Main functions:

Technical parameters:

LNB local oscillator:				9750 MHz (with 25MHz source)
Conversion gain of a LNB:			> 50 dB
LNB IF:						739 MHz for 10 489 MHz (QO-100), 618 MHz for 10 368 MHz (TROPO/EME)
Reference 10 MHz input power:			- 3 dBm to + 13 dBm
Stability with 10 MHz reference:		depends on reference source
Stability with 25 MHz TCXO (0,2 ppm):		0,2 ppm (X 390)
25 MHz cut off to RX output port:		> 50 dB
Frequency error with TCXO:			max. 3 KHz, typ. less than 1 kHz (after 5 minutes) 
DC power:		       			+12 V for Vertical polarisation - NB and  +15 V for Horizontal - WB
Bias Tee IF loss:				typ. less than 3.5 dB (filter + notch + ATT)
Variable Attenuator on IF:			1 dB to NO signal
⚠ NOTE: This Bias Tee box is designed for 10 MHz external reference source but you can also use internal 25 MHz TCXO, which is 0,2 ppm. Frequency error is max. 3 kHz.

⚠ NOTE: Do not forget that the quality of the 10 MHz signal source has got final effect on the quality of the output signal. With added phase noise multiplying by PLL.

Block diagram of the Bias Tee BOX:

LNB bias tee block diagram



Set Includes:

RF adapters


LNB Bias Tee BOX with TCXO / 10 MHz reference input
MKII. rev 1.2 sch pcb Files267 MANUAL MKII
rev 0.3 sch pcb Files267 MANUAL ver 0.x
3D printed POTY adapter STL file
rev 0.1 11-2019 picture Files669
We believe open source is a better way of doing things.
View and download the Shield Schematic and PCB Kicad/Eagle CAD files,
LibreCAD .DXF, or Inkscape .SVG files.
The hardware designs are released under the
Attribution-NonCommercial 2.0 Generic