JIMMIE wrote:

I have heard that burying your cable will keep RF from coming back in
the shack. From what you say it seems like this is possible but at the
expense of using some of your precious watts to warm the ground.

Jimmie

The same is true of any other kind of resistive common mode choke. But
it's an impedance matching situation, so the loss doesn't necessarily
have to be significant. Remember that the loss is I^2 * R where I is the
common mode current and R is the choke resistance. If R is low, the loss
will obviously be low. The choke won't be very effective, however,
unless it also has a substantial amount of reactance. If R is very high,
the loss will also be low because it will cause I to be low. The only
time that loss really becomes a significant fraction of those "precious
watts" is when R is in the vicinity of the effective common mode source
and load impedance. A properly designed common mode choke will have a
high enough impedance (resistive, reactive, or some combination) to
reduce common mode current I to a low value -- that's the objective
after all.

Roy Lewallen, W7EL