High stability 10GHz LNB. 
PARI-O (Power And Reference Inserter - OCXO) 

The PARI-O consists of a modified 10GHz LNB for outdoor use and an indoor unit that feeds power and reference signals to it and extract IF signal for use by an external receiver. 
This forms a high stability low phase noise 10Ghz down converter unit that can be used for any 10GHz reception in general including for Oscar 100 satellite reception.



  • Size: 290x305x33 millimeter

  • Power usage: 10W Max, 3W typical.  (12V 600mA at startup, 250mA after one minute of warm-up)

  • Weight: 222 gram

  • Frequency accuracy: better than 10 ppb - typically 2 ppb*

  • Frequency drift at 10GHz due to temperature variation is typically less than 2Hz.  

  • Calibrated against in-house Rubidium standard before delivery.

  • Comes delivered with modified commercial 10GHz LNB and power supply.

  • Single 75ohm coax between LNB and indoor unit.

  • Can be frequency re-calibrated by user if needed 

* ppb=parts-per-billion



The PARI-O (Power And Reference Inserter - Ovenized crystal oscillator) is a Low Noise Block amplifier/Down-converter for Oscar 100 reception.

The LNB is a commercial unit that has been modified to make it's internal local oscillator highly frequency stable as needed for Single Side Band reception on the 10GHz band.

This product was primarily designed for used as a Oscar 100 satellite down converter but it can be used to down-convert the entire 10 GHz amateur band. The gain goes down slightly with frequency so it has the highest sensitive on the band edge around 10.5GHz were the Oscar 100 is being operated.

The Local Oscillator in the LNB operates at 9.750MHz so use the formula - Input frequency minus 9,75 GHz to calculate the IF frequency.

When receiving the narrow band transponder from the Oscar 100 satellite the IF frequency will be 739.5MHz to 739.9MHz 
When receiving signals at 10.368GHz the IF frequency will be 618MHz.

This IF output can be processed by a converter/transverter or sent to a SDR receiver.

The product consist of three units.

1 The LNB/10GHz down-converter.

2 The indoor unit that connects to the LNB and extracts IF signal.

3 A power supply that feeds the two units.

The reference signal for the LNB is being feed up to it in the same coax cable that it is using for power and IF signals.

This signal is generated in the indoor unit by a high quality Japan made OCXO.
The result is a very low noise and stable down-converter with virtually no frequency drift.

The same reference signal that is sent to the LNB is also available on three SMA connectors on the indoor unit. This can be used to frequency lock transverters or SDR receivers.
It can also be used in the up-link chain to make sure your transmitted signal has a stable reference source.

The OCXO is the same as used in my Frequency Standard product and it will be calibrated by my in-house Rubidium clock before delivery.
Reference outputs are a 10MHz square wave with 13dBm in 50ohm. 


The unit is typically is accurate down to around 2 parts per billion, this means that on 10GHz will be off in frequency less than 20Hertz.

The drift due to temperature changes is a magnitude lower than this, typically the short term temperature drift is less than 2Hz at 10GHz.

The low drift is partly due to having the reference oscillator indoors and being feed remotely and partly because of the high quality OCXO.

The unit is ready to be put on the air and the user only needs to connect the two units with standard 75ohms coax and connect the receiver or SDR to the IF output.

The indoor unit can be desk or wall mounted.

The power supply included is a 12V power supply with a Euro plug but the unit can accept 8 to 20V on it's DC input.

This makes it possible to switch LNB receive polarization electrically.

Receive polarization change occurs when the LNB voltage goes above 17V.

Minimum voltage is 8V - the LNB stops working at this voltage.

Maximum voltage is 20V - the heat dissipation of the unit will be excessive if going above 20V, permanent damage to the LNB happens somewhere above 22V.

Power consumption is around 600mA at warm up going down to around 250mA after the OCXO has warmed up.

The initial warm-up to heat up the oven takes about 1 minute but it is recommended to allow it to settle at the correct frequency by giving it 10 minutes of warm  up..

Connectors of the indoor unit.

The internals of the Indoor unit

The picture shows how to hook-up the unit.

Screenshot of the narrow band transponder as viewed by a SDR connected to the IF output. The Antenna is a 80cm parabolic reflector in South Sweden. The lower beacon is exactly at 739.550MHz due to the exact frequency of local oscillator in the LNB

The LNB that is used is a commercial unit that has been modified for external reference insertion.
Type brand is Golden Media GM-201. I picked this one after testing  a few PLL units that seemed suitable.
The Golden media was a low cost unit that had the most sensitivity when receiving the Oscar 100 Signal at 10.489GHz. See this video for the selection test.
Each LNB have been dissembled and modified by removing and adding components to make it suitable to receive the PLL reference frequency from the remote unit instead of using the original 25MHz crystal.
The modification is done using hand tools and microscope due to the small size of the internal components.

After the modification a new weather seal has been applied and it is then tested and put back in the original box.
It can not be used as a regular LNB, it must be connected to the PARI-O indoor unit to operate so if you have similar LNBs make sure you don't mix this one with the others.

LNBs during the rebuild process. The Spectrum analyzer shows the 740MHz IF signal from the LNB. The 10GHz signal comes from the top signal generator set at 10.489GHz. This signal is feed to a 10Ghz antenna that sits in the upside-down connector to the left. It then enter the wave-guide of the LNB on the table. Every rebuilt LNB has been tested in this setup.

The indoor unit and the LNB comes calibrates, tested and ready to be used. The included 12 power supply has a Euro plug but it can operate from 110V so just add a suitable adapter-plug if you live outside Europe.


The calibration trimmer on the front adjusts the frequency on the internal 10mHz OCXO.

It should not be adjusted without suitable instruments that can measure the 10MHz output to a high degree while it is being adjusted.

My Frequency Calibrator can be used for that https://www.zachtek.com/1019
The long time aging or drift of the unit is very low so there should be no need for re-calibration until a few years of use.

© by ZachTek.