Bill Ogden wrote:
For the first time in many years I have been listening a lot on the
low
bands (160/80/40). It seems there is much more background noise than
when I
was in my teens, but that may be my selective memory at work. I am
in the
far suburbs trying to use a half-sloper and an inverted V -- both
with the
peak at about 53 feet. I think most of the noise is "natural"
(except for a
15Khz harmonic every now and then.)

I started reading about small loops for receiving on 160 and 80. In
particular I have been reading about:

(1) the 4-turn loop on 4-foot cross arms (W1FB),

Mine is closest to this one...Mine is a 44 inch per side diamond, using
5 turns.

(2) the 4-turn coax loop (in a 9-inch diameter) (W1FB),

I have to wonder how he is tuning 4 turns on a 9 inch form?

Seems it would tune quite high in freq...

I have a 16 inch circular loop, but it takes about 12 turns to tune
MW..

(3) an 18-inch ferrite rod unit described by G2BZQ

Worst of the bunch, no doubt....

All of these were described as better receiving antennas "in the
house" than
the authors' more conventional outside antennas. W1FB thought the
9-inch
loop was better than the 4-foot unshielded loop and apparently did
not think
much of ferrite-stick antennas.

What is the experience of those on this newsgroup? Are these
antennas
really better (in the house, and even in the basement) than
conventional
outdoor antennas?

Depends on the use, and also depends on the source of the noise.
If the noise source is local, they can work very well to null that
noise. If the noise is just general atmospheric noise, the results
won't
be as good. Yes, the nulls are very sharp.

Are they significantly better when used outside and
perhaps elevated a bit?

I've heard of people elevating, but myself, I'm not really convinced
it makes any difference. I keep mine on the floor, here in the shack
on stands, so I can rotate them. They work fine , even on the ground.

I realize they are inconvenient because they must
be tuned even for small frequency changes. It seems they are very
directional for nulls but fairly broad for other responses. Is the
same loop
good for 160 and 80 (and maybe even 40)?

Ok for 160, but not really sure about the other bands. I use mine more
for MW use than anything...But mine does work 160m. The *best* time
for
a loop is actually in the daytime for MW ground wave use. They work
great
for that. They do help at night a bit as far as nulling some noise, or
unwanted stations, but the nulls on a skywave signal as not near as
deep
as for ground wave. To have a better idea if it's worth a try, will
probably depend on the source of your noise. If it's a local source,
could be worth a try. You can null that source down to nearly nothing..
But if you have multiple sources of noise, the results won't be as
good.
A loop won't be in the leaque of say a beverage or whatever, for say
160m dx...
MK