I'd guess that a brick wall would lower the resonance somewhat (due to
the brick's dielectric constant), but not introduce a significant amount
of loss. But that's a guess.

What I'd do, of course, is model the antenna with EZNEC (the free demo
program would be adequate). That would tell me where the antenna would
be resonant without the brick wall. Any major deviation from that could
be attributed to the brick wall. Of course, you'd have to include your
coil in the model, including its loss if you want to determine the
antenna loss, and the feedline to account for its impedance
transformation and consequent effect on resonance. To determine the
antenna loss I'd look at the bandwidth with EZNEC and compare it to the
measured bandwidth -- if the real antenna is considerably broader,
there's extra loss from somewhere that's not in the model.

If you don't think it's worth the effort to model, you might just try
doubling the distance from the wall and remeasuring. I'm not sure that
would be enough to really tell, but if the resonance changes noticeably,
then the bricks are having an effect. And if the bandwidth decreases
appreciably, then the bricks are contributing loss.

Roy Lewallen, W7EL

Ken Bessler wrote:
What effect would a brick wall have on a HF antenna?
I'm talking 1-2" distance from the bricks, folks. The
wire used is 22 ga stranded insulated speaker wire.
Now no lectures about power - I run QRP. :-) The
station is well grounded to a copper baseboard heater
pipe and all components have short runs (12" or less)
of 1/4" braid line going to a common point. From there
it's 1/4" braid (26" long) to the pipe. I can touch any
part of the system while transmitting and see no change
in SWR.

I cut an inverted V 66'7" per leg 133'2" overall. It's fed
with 12' of rg8x coax with a 6 turn 2-5/8" dia coil at the
feedpoint. The apex of the antenna is roughly 25' up. The
ends of the antenna are at chest height. The antenna is bent
around the corner of my building 90 degrees (I'm in a
corner unit). The last 8' of each leg bends again 90 degrees.

The antenna resonates as follows:
============
2.130 2:1 swr
2.715 1:1 swr (flat)
3.620 2:1 swr
============
8.970 2:1 swr
9.210 1.8:1 swr
9.390 2:1 swr
============
12.230 2:1 swr
13.040 1.9:1 swr
13.850 2:1 swr
============
15.930 2:1 swr
============
20.970 2:1 swr
22.745 1.2:1 swr
24.520 2:1 swr
============

If I figure 468/133.1666666667 I get 3.514.393 mhz
for resonance How come the antenna is so far off?
Could it be the height? Not that I'm complaining - I
like the low resonance and my Z11 autotuner will take
this antenna down to 1.8 mhz real easy. Although at
that freq I expect the antenna will radiate a NVIS
signal due to low HAAT.

Any ideas???

72's de Ken KG0WX