Social Feed

QPH 031 Combined Circular and Linear LNBF Test Results

(Please note that this review is being conducted by an Invacom Distributor. Units are currently available for dealer testing and will be available in mid May for resale. Satelliteguys.us gets exclusive scoop on this first review!)


A single LNBF is now able to simultaneously receive both circular and linear polarity satellite signals. The performance on each polarity type is outstanding. Invacom has managed to improve their champion performance linear FSS LNBF and combine it with a circular DBS / DSS LNBF that outperforms any circular LNBF that we have ever tested. Both the circular and linear polarities are rated 0 .3dB NR / 55 dB gain typical, featuring suppressed harmonics and less than 1 MHz drift.

The LO (Local Oscillation) frequency for the circular outputs is 11250 and 10750 for linears. Standard 13 /18 volt switching controls the two circular RHP/LHP outputs and the two linear outputs are V/H switched. Linear input frequency range is 11.7 - 12.2GHz, circular 12.2 - 12.7GHz.

The real world test consisted of a Fortec Lifetime Ultra, Dish Network Model 508 PVR, GEOSATpro 90CM (36") dish, GS120 USALS compatible motor, GS 2x1 DiSEqC switch, SW21 switch, Dish Network legacy single output LNBF and the QPH 031 CP/LP LNBF.

To start the test we mounted a legacy type Dish Network LNBF on the 90CM dish as a bench mark. A spot beam on Echostar 7 at 119W was peaked at 40% level on the Dish Network receiver. The Invacom QPH 031 LNBF was then mounted, boosting the previously marginal signal to over 60% level.

Next we connected the Ultra and mounted a Fortec FSKUv 0.4 dB NR universal LNBF on the dish and peaked the quality on a weak AMC4 transponder to 52%. When the QPH 031 was substituted and the quality climbed to 68%.

While the Fortec Lifetime Ultra was viewing programming on AMC4 a DirecTV RCA DRD450 receiver was connected to the QPH 031. One fixed dish with one LNBF and we were now watching DirecTV programming and AMC4 at the same time. Transponder changes on either receiver produced no lower signal or quality readings on the other receiver. This indicates excellent isolation on the outputs, which minimizes loss of signal quality with multiple receiver installations.

Next, one each of the linear and circular polarity outputs were connected to the 2x1 DiSEqC switch. The switch output was then looped through the DiSEqC compatible horizon to horizon dish motor and connected to the Fortec Lifetime Ultra. All of the linear polarity satellites had been previously activated on the Ultra, so to add circular polarity, the satellites were made active and the DiSEqC was simply set to the correct input for the circular output of the LNBF. Two minutes later the motor was zipping from satellite to satellite and seamlessly switching between the linear and circular signals. Stopping on Echostar 7 at 119W, we performed a FTA scan and were watching NASA TV and Angel One within minutes. Moments later, we were surfing through the ethnic and religious channels on IA5 ( Telstar 5 ).

Using the traditional method of mounting a linear and circular LNBF side by side produces signal loss to the LNBF mounted offset from the factory LNBF clamp. It often takes a bit of time to mount the second LNBF, determine the number of degrees that the second LNBF is offset then entering that offset for each satellite location. Multi-satellite installations will now be much easier for the novice or for self installation.

In conclusion, this is the most fun that I have had testing satellite gear in a long time!