Thursday, August 20, 2020

 10 GHz LNB with external reference / GPSDO


This is the 10 GHz Low Noise Block (LNB) modified for 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 or 10 MHz reference signal works as DC injector and also 25 MHz Source for LNB. There is also variable attenuator for IF signal which allows you to change IF signal from 0 to maximum. You can still switch between V and H polarisation by supply voltage.

More at: https://remoteqth.com/lnb_gps.php

Main functions:

  • Ku band LNB
    • Very low noise converter
    • External 25MHz PLL reference signal over IF coax cable
    • LO = 9750 MHz: 10489 - 9750 = 739 MHz IF etc
    • V + H pol
    • Supply over one coax
    • Voltage supply +12V for V-pol, +15V for H-pol

  • Bias Tee board
    • DC supply over one coax together with 25 MHz PLL reference signal
    • Build in TCXO with 0,2 ppm as alternative to 10 MHz reference input More in WiKi
    • 10 MHz reference input for very big frequency precision and stability
    • LO = 9750 MHz: 10489 - 9750 = 739 MHz IF etc
    • Variable ATTENUATOR in the bias tee
    • High voltage / current protection
    • Voltage supply +12V for V-pol, +15V for H-pol More in WiKi
    • Bias tee connectors: IN (LNB) = F, OUT = SMA

  • Option: 10 MHz PLL-GPSDO reference source
    • 10 MHz reference source locked to GPS signal More in WiKi
    • RF output typ + 5 dBm
    • HW by BG7TBL, modification by OK2ZAW
    • Including GPS antenna and DC cable
    • Including coax cable with BNC and SMA (abt 50cm)

  • Option: 3D printed adapter for POTY dual band antenna
    • UV stable PETG material
    • 22 mm Cu tube diameter
    • ONLY ADAPTER, not 2.4 GHz antenna!

  • Option: 2-way small splitter box
    • Small splitter for 10 MHz reference signal
    • Splits 10 MHz signal to Bias Tee box and another your device (SDR, TX etc) More in WiKi
    • Low loss 3,5 dB
    • Including coax cable with SMA

  • Option: RTL-SDR receiver with 1ppm TCXO
    • RTL-SDR USB receiver
    • In metal box
    • 1 ppm TCXO for better stability
    • Input SMA connector
    • SMA - SMA cable included (17 cm)
    • Firmware already installed
    • 8 bit, up to 2 MHz of spectrum
    • compatible with: HDSDR, SDR console etc.

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
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
Bias Tee IF loss:				typ. less than 2 dB
Variable Attenuator on IF:			0 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.

Schematic for version 0.3

PCB for version 0.3

Duplexer 25 MHz and High pass filter for IF + ATT
I

Optional GPSDO PLL
Internal TCXO or 10 MHz external reference source
POTY antenna adapter for 22 mm Cu pipe