Topband: terrain effects

[Steve Flood]

My Montana QTH is a river bottom surrounded by mountains.  To my NE and SW, the terrain "masks" the horizon up to 16 degrees.  To the NW and SE (along the valley), the masks are only up to about 10 degrees.  My old QTH in Idaho was much worse with terrain masks between 12 and 22 degrees all around the horizon.

I played around with a ARRL handbook terrain program a while back and it showed some significant "attenuation" of all arriving HF signals given my terrain features.  While not adhering to good experimental procedures, I've sort of confirmed this yearly during summer outings to the highest ridgetops when signals - especially DX - are tremendously stronger.

So my questions are, do these same effects apply to medium frequency waves?  I haven't bothered with a vertically polarized TX antenna yet due to very poor ground (rocks!) and rocky steep mountains around me.  Larry W7IUV encouraged me to try it anyway a couple years back but I haven't yet.  For the time being, I try to get by with a full size dipole at 70 feet, 100 watts,  and various RX loops (this year using the K9AY design).  Does my terrain absolutely preclude the use of vertically polarized TX (in other words - a waste of time?).

Also - I've thought about running beverages but would have to put them along a sidehill - that is, along the contour of a mountain slope.  And I've thought about running one right up the slope behind the house which is about a 15 degree incline but goes on for 2 miles to the ridgeline.  Will beverages perform in this scenario.  The ground is certainly poor enough.

Thanks for any thoughts - Steve KK7UV