As long as all ports are terminated properly, they both are reciprocal devices--they work the same on RX as they do on TX. If ports are mismatched, different things happen between A and B (and that's true for both RX and TX) Device A will show mismatched impedances at all other ports, and may no longer evenly divide power. Device B will show no mismatch at the 3 input/output ports, but power will be dissipated in the port 4 load. Note that a properly designed Device A will not be mismatched on RX at the split ports.
The main advantage of Device B is the relaxation of the requirements of precise impedance control. -- Scott Townley NX7U Gilbert, AZ DM43di
---- Joop & Tineke Verdoes joop.verdoes@nameplanet.com wrote:
OM-s As I got so much truely valuable and usable feedback on my hybrid power divider/combiner questions, I now dare to ask the following.
For making circulary polarised yagis one needs to split 'things' over two yagis There are basically two ways to split power A- use a 36 ohm power splitter, often a piece of waveguide with one connector on one end(for the TRX) and two connectors (for the Yagis) on the other end B- use a 70 (75) ohm hybrid power splitter/divider, which has 4 ports, one extra for a terminator. The TRX sees just 50Ohm.
A- and B- are both fine for SPLITTING power. In both cases the TRX sees 50ohm, although there are two 50ohm connected in parallel and the other side of the divider. So both are fine for transmit.
But...... A- Is ONLY a power splitter seen from the transmitter's side, it does present a mis-match as seen from the yagi, so on receive things are less than optimal B- Does work both ways, it presents a nice 50ohm port to the yagi, but the RX signal is split between the RX and the other yagi, so the signal that goes to the RX is 3db down.
Does anybody have a view on how "bad" A- is vs B-?
Have fun Joop, PA1JAV
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