🚀 go-pugleaf

regarding the following figure:


                50 ohm
           =============
25 ohm  //               \\   25 ohm
========  A             B  ============
        \\               //            |
          ===============             ---
              50 ohm                  | |
                                      | | 25 ohm
                                      | |
                                      ---
                                       |
                                      GND


i think this is what you have when you launch a wave down the
coax:

a signal of voltage v and current i travels down the first
length of coax.  it encounters the 25 ohm 'T' splice and sends
a signal of voltage v and current i/2 down each branch with
no reflection.  

if the two branchs are equal in length, the signals travel
and meet at splice B.  this gets a little tricky.  a wave front
traveling along the south branch would approach splice B and
see an approx. 17 ohm impedance (50 and 25 in parallel).  the
reflection generated from a 50 to 17 ohm mismatch is about 
1/2 the incident wave so at the splice, the signal is reflected
back down the south branch with voltage 1/2 v.  as it happens,
the other branch has provided a boost of 1/2 v as well at precisely
the same time and therefore a signal of v is created at splice
point B (works the same from either branch).


that boost is because of the mismatch, i.e., half of the signal was
reflected, half transmitted.  the reflected signal is exactly cancelled
by the other branchs transmitted signal.  at splice B, your left with
the newly created copy of the signal which is free to travel down
the 25 ohm coax in its original form (+/- capacitive/inductive effects
due to bad solder job.

d