Chris,

Bill Schwab wrote:

snip


You mean C:\docs\davit_calc2.jpg? If so, isn't that the pin you said
doesn't act on the beam? If that's the case, then we're back to the
missing horizontal force.


The pin does not transmit the horizontal component of the tension to the
top end of the column, if you accept the idealised joint I proposed.
This does not mean that the pin is unable to transmit any horizontal
force to the column. It does provide a horizontal reaction which opposes
the compression in the horizontal beam. This is a subtlety of the
idealised joint, which you may like or dislike, but the FBD is
consistent with the idealisation.

I call it quits.

What you describe is almost certainly either unsupported, or statically
indeterminate. Even if you have designed something that is determinate,
it is by no means a simplification relative to the what was presented to
you in your mechanics classes. If you think the pinned frame is
complicated, you didn't learn the material.