A loop should be cut at approx. lambda/10, so with a circumference of 16m
or
a radius of 5m !
Too bulky for a small garden
==============================

What prevents it being cut with a circumference LESS than 16m.
---
Reg, G4FGQ

"Reg Edwards" wrote in message
...
A loop should be cut at approx. lambda/10, so with a circumference of
16m
or
a radius of 5m !
Too bulky for a small garden
==============================

What prevents it being cut with a circumference LESS than 16m.

Indeed, there isn't anything on 160M that's going to NOT be a compromise
here.

Why not try a double layered loop? Feed with a 4:1 balun about 1/4 of
the way from the corner on the 40 ft side, make a spiral, and send the
other side back to the balun. Separate the two layers by about 10
feet, get it at least 15 feet off the ground at the bottom, and it
should work.

In that small of a garden, you're going to have to compromise.. might
as well get as much wire in the air as you can.

-SSB

M3 wrote:
Hi,

Any designs for a small antenna to work on 160M? My garden is approx 40ft x
17ft.

Post links here.

Thanks.

sideband wrote in message . com...
Why not try a double layered loop? Feed with a 4:1 balun about 1/4 of
the way from the corner on the 40 ft side, make a spiral, and send the
other side back to the balun. Separate the two layers by about 10
feet, get it at least 15 feet off the ground at the bottom, and it
should work.

In that small of a garden, you're going to have to compromise.. might
as well get as much wire in the air as you can.

-SSB

I don't think double layering will have much change, except for where
it's resonant. It should still act pretty much the same as a single
turn loop of that size.
Myself, I think he would be best off going with a very high
performance short vertical. A loop is gonna be a skywarmer, and a
lukewarm one at best. I would layer the garden with almost solid
metal, preferably copper wires, or whatever, and run the best,
tallest, lowest loss vertical he could get away with. I'd top load it
if at all possible. That will greatly improve the current
distribution.
With a good vertical, he would at least have a chance of having a
decent signal.
For long haul, nothing else he could install would touch it. I like
the inv L idea, but I assume he can't do that for some reason.

M3 wrote:
Hi,

Any designs for a small antenna to work on 160M? My garden is approx 40ft x
17ft.

If you line that garden with a lot of radials under the ground, you
could have acceptable losses for what you have to work with. Most loss
is directly at the base of the vertical. Plant a lot of radials lining
the garden, and you will do ok. MK

There's something called an EH-antenna... despite many claims it is not a
wonder antenna, but it does get you on the air... it's not a substitute for
a dipole or beam though (I saw a 160m 2 element quad.. that was a monster,
but I digress).

www.eh-antenna.com

Somewhere I saw someone's test of one at some low band... 80 or 160m I
forget which... It was pretty good sized, but tiny compared to say, a
dipole. 2-3' in diameter, looked to be about 10-15' tall. no real good
'scale' photos.

I have seen a couple of 'how to build' articles on the web, but don't have
them handy I'm afraid.

Unfortunately nothing is going to work really well... given your space
limitations. I'd go for as much of a vertical as I could, and run ground
radials in the garden, or maybe a ehem 'long' wire run around two sides of
the property maybe?




--

"M3" *** wrote in message news:4081ab53.0@entanet...
Hi,

Any designs for a small antenna to work on 160M? My garden is approx 40ft
x
17ft.

Post links here.

Thanks.

Cecil Moore wrote in message ...
Reg Edwards wrote:

Pity the poor ham who puts an Isotron on a ten foot pole
for field day.

And the same pays for the EH antenna, see
http://home.earthlink.net/~calvinf15...est_report.pdf

73 Ivan OK1SIP

Also the EH antenna have to follow the laws of nature. The laws of nature is
inthing You can disobey, and get a few Years of prison. It is simply impossible!

So, the EH antenna does not work according the way the inventors claim.
Of course, it radiates. But:

The main radiating element of a "good" EH antenna system is the feeder (koax)
shield. Not the antenna itself.

So, if You have a short feeder, the antenna will radiate very poor (however, it
of
course radiates). And the EH antenna is NOT CHEAP!.

There are some other types og antennas:

1) The Isotron antenna, which is a Q-tank, thus radiates poorly as well,
but the inventors to my knowledge does not make any un-scientifical claims.
You can work some stations with it, it might be a "salvation" if You are
real eager to get on 160, and does not want to do a massive work Yorself.

2) The magloop, an interesting but complex way to make a small antenna.
It WORKS, efficiency is not good, but amazing results can be achieved!

3) DCTL, in fact a magloop, but is NOT recommended for 160.

4) A dipole made of 2 commercially bought mobile whips including coils:
Works, efficiency is not good.

5) A mobile whip.
It is small, and a built in small coil with low Q. Not my kind of tea.

6) Ultra-shortened ground plane aka monopole. A capacitive antenna, which can
be used, if You have good nerves (HIGH VOLTAGE!) and a variometer. Look
what the european 136kHz (LW) hams are achieving! I would recomment this type!
(of COURSE low efficiency, but one can use hi-Q coils, which outperforms
other set-ups)

No type is GOOD for 160m if You have resticted space...

Tyas_MT wrote:

There's something called an EH-antenna... despite many claims it is not a
wonder antenna, but it does get you on the air... it's not a substitute for
a dipole or beam though (I saw a 160m 2 element quad.. that was a monster,
but I digress).

www.eh-antenna.com

Somewhere I saw someone's test of one at some low band... 80 or 160m I
forget which... It was pretty good sized, but tiny compared to say, a
dipole. 2-3' in diameter, looked to be about 10-15' tall. no real good
'scale' photos.

I have seen a couple of 'how to build' articles on the web, but don't have
them handy I'm afraid.

Unfortunately nothing is going to work really well... given your space
limitations. I'd go for as much of a vertical as I could, and run ground
radials in the garden, or maybe a ehem 'long' wire run around two sides of
the property maybe?

--

"M3" *** wrote in message news:4081ab53.0@entanet...
Hi,

Any designs for a small antenna to work on 160M? My garden is approx 40ft
x
17ft.

Post links here.

Thanks.

M3 wrote:
"Any designs for a small antenna to work on 160M ?"

Small antennas are inefficient.

Medium wave broadcast stations have operated from small plots with some
satisfaction. They once commonly operated from building tops in the
middle of the city.

Building top antenna systems were most often short verticals worked
against a ground plane. The broadcaster only wanted vertically polarized
radiation, radiated at an extremely low angle.

DXers want low-angle radiation too, but not 0-degree radiation. A
horizontal wire must be 1/2-wave high for low-angle radiation; more if
conductivity is good under the antenna.

The shortest vertical antenna with a groundplane has a null in its
radiation pattern directly overhead but most radiation is at low angles.

The efficiency of a vertical antenna over real earth is bad without an
excellent ground system. U.S. medium-wave broadcasters approach 100%
efficiency using 1/4-wave towers and 120 radials near the earth`s
surface. As antenna efficiency is: radiation resistance divided by the
sum of radiation resistance plus loss resistance, the short vertical
antenna (whip) has a low radiation resistance and poor efficiency. The
efficiency formula has a small numerator, thus a small quotient.

As most mobile operators have found, the short vertical antenna is not
the best choice. It is the only choice for an extremely restricted
space.

How can the best use be made of a small garden space? Jerry Sevick,
W2FMI is pictured adjusting his 6-foot high 40-meter vertical on page
6-24 of my 19th edition of the ARRL Antenna Book. There are several
other options in chapter 6 of the "Antenna Book". Get it or a similar
book and study applicabilities to your situation.

Antennas scale to most wavelengths.

Best regards, Richard Harrison, KB5WZI