10 GHz LNB EXT OSC MK3

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.