The 90 degree hybrid is a third type of hybrid combiner,
distinct from the 0 degree and 180 degree types. It
is typically used for 4 square phasing. All 3 combiners
basically have a 3 dB insertion loss for signals having
appropriate phase conditions.
What you say is true to the extent that using a 90
degree combiner for two signals that are in phase
will result in a 3 dB loss. You would not normally
want to do that.
Rick N6RK
On 2/10/2021 2:25 PM, P H via Topband wrote:
My impression is that a hybrid combiner, which introduces 90 degree shift
(hence two identical signals of amplitude A fed to its inputs will give in
total a signal with the amplitude of 1.41*A) is 3dB less efficient in
comparison to a simple combiner where A+A gives 2*A at the output.
Do you have any thoughts on this?
A loss of 3 dB may be like "to be or not to be" of a QSO on 160 meters.
Regards
Piotr, SP2BPD
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