Using Receiver Power Dividers

[TXHarleyDude]

Anyone out there have any experience utilizing a 2-Way "Power Divider" instead of a Splitter to provide isolation to a single cable fed LNB such as a DishPro Twin connected to two single tuner receivers?.

While a power divider such as a CM2212IFD looks like a splitter, the two output terminals have a diode in each leg. The 2212IFD will pass DC power from any output to the single input. There is a 0.8V drop across the diodes which are included to prevent one receiver from passing power back to another receiver. They are particularly useful in CATV headends as the multiple receiver LNB powering provides redundancy against losing LNB signals due to a receiver failure. Unused outputs are terminated to achieve optimum flatness, return loss and isolation. They are rated at 1000 ma Max thru current, and have a rated freq. range of 950 - 2150 MHz.

Seems like a simple way to feed two receivers over one cable from an LNB.

 

[PATECO]

This will work fine for A DirecTv Stacked lnb for 101° or for a Dishpro Single or Dual pointed at 119°only, but will not work for DPtwin DPPtwin DPquad or any other multisat LNB . The reason is that DirecTV Stacked LNB and Dispro Single and dual, have all of the frequncies from one sat 101° or 119° stacked on a single cable. Twin or quad lnbs look at two locations 119° and 110° therefor the cable can only contain one location at a time.

Directv's new SWM (Single Wire Multiswitch) can also use this power dividing splitter, but the wire only contains the signal from 8 transponders at a time each transponder frequency is assigned to a specific tuner in your home.

 

[PBX_Guy]

This will work fine for A DirecTv Stacked lnb for 101° or for a Dishpro Single or Dual pointed at 119°only, but will not work for DPtwin DPPtwin DPquad or any other multisat LNB . The reason is that DirecTV Stacked LNB and Dispro Single and dual, have all of the frequncies from one sat 101° or 119° stacked on a single cable. Twin or quad lnbs look at two locations 119° and 110° therefor the cable can only contain one location at a time.

Directv's new SWM (Single Wire Multiswitch) can also use this power dividing splitter, but the wire only contains the signal from 8 transponders at a time each transponder frequency is assigned to a specific tuner in your home.

Another of several possible ways to explain the technology of the SWM-8 is to say that it establishes up to a maximum of 8 concurrent virtual coax cables within one common physical cable. The signal carried by each virtual coax is controlled by the 1 specific tuner assigned to it by the IRD (set top box). Up to 8 physical tuners can share in the one physical coax via a special but relatively inexpensive splitter ($20) , but no 2 physical tuners can ever share the same virtual coax. (it simply won't work).

"Power dividers" are common in MDU (Multi-Dwelling Unit) systems, though I've never heard them referred to by that name. They're simply known as diode-steered splitters. The term "power divider" is more synonomous with the co-phasing of multi-array transmitting antennas in VHF, UHF and terrestrial microwave service where it's vital that the signals are addative in phase. The co-phased antennas, when properly oriented on the mast, provide improved signal gain via a compressed radiation pattern. When the entire multi-stack array is oriented toward the same direction it serves to provide much more directivity (narrower beamwidth) in addition to gain. Alas, I digress. I'm just the telephone man.

 

[TXHarleyDude]

Power Dividers appear to come in three flavors. One type will pass DC power from one output to the LNB input. Thus only one receiver supplies LNB power and controls any voltage switched polarization selection.

The second type will pass DC power from all outputs to the LNB input. Thus all receivers can supply LNB power.

The third type will pass DC power from any output through a diode to the LNB input. The diode prevents one receiver from passing power back to another receiver. This is the type of Power Divider I am considering as far as this discussion; and I believe it should work with all DishPro LNB’s.

DishPro offers two LNB Types. DishPro Plus (DPP) which uses a technique called “Bandtranslating” that will only work with Dual-Tuner receivers. This is because the software for the dual tuner receiver tells the tuners where to look for their signal. Tuner 1 uses the lower band (950-1450 MHz) for all Odd transponders, while Tuner 2 uses the upper band (1650-2150 MHz) for all Even transponders. And, DishPro (DP) which uses “Bandstacking” to put the Odd (119) and Even (110) transponders at different frequency ranges (950-2150 MHz) to allow both to travel down one cable without interfering with each other.

Let’s now consider the DP Twin LNB which has an internal DP21 type switch to allow feeding two receivers via two coaxial feed lines. We could use two 2-Way diode coupled Power Dividers or two 2-Way diode coupled Splitters to keep the two receivers DC isolated from each other; thus providing optimum power to the LNB from either or both receivers. We can now see that while Power Dividers are not splitters, there are some splitters that may be utilized for DC power isolation.