@RDP I just watch your video (Happy Farmer) on the other thread--

A lot of the time, your bow is moving closer to the fingerboard—this will diminish the sound of the bow.  You should try to move your bow more centered between the bridge & the fingerboard—I think you’ll find it easier to get sound that way.

Also, you may find yourself skidding the bow at an angles sometimes—that’s when you’ll hear a more scratchy sound.  This can happen when you’re focusing on what your left hand is doing—makes it harder to focus on the bow hand (my teacher calls this “kerflooey”—messing up one hand while focusing on the other).

Practicing with long bows on open strings is a good thing to do (I do it all the time).  By doing this, you can focus on what a full bow stroke feels like without the distraction of what you need to be doing with your left hand. The bow feels different at different points (at the tip, at the frog, etc.,).  Being able to distinguish this will help you learn how to control it at different points.

My teacher calls this exercise “80 bows” (use long, full bows; steady--each bow even & not fast, moving to each string without a break):

Bow 4 times on the G string (i.e., up, down, up, down is 4), then 4 on the D, then 4 on the A, then 4 on the E—then reverse 4 on the E, 4 on the A., etc., 

Once you get back to the G & finish the 4, then start over but now do 3 times on the G, 3 times on D, etc., up & down.  Then start over on the G doing 2 times, up & down etc.,

Then on the G one time, up & down.

When you first start doing this, you may have to stop because you find you need to adjust your position, etc., but you should aim to do all "80" bows in a row at a steady pace.