I have a few questions and I thought that this may be the group that could
help. I have a nice sized backyard and would like to construct an antenna
that would give me good performance on 80-10m bands.

Well, you could build a full wave loop/delta loop...you'd need 3 good mounting
points up as far as you can get em..In my case I used trees in the
backyard..the height in my case was anywhere from 10 ft to about 30 ft...the
loop works great and will work everything from 10-80 with a tuner...the lowest
swr your likely to find is about 1.7:1..

The length to get it resonant at about the middle of 80 meters is aprox 250ft
using insulated wire, around 260ft using bare antenna wire..the equation is
1005/freq..but subtract about 5% if you use insulated wire..just works out that
way..you can feed the loop with plain ole coax like I did...good luck es 73's
de kb8viv.

Steve