GP for 7 MHz. |
I used a loop
on 7 MHz and it worked fine except in northern and
southern direction. So I decided to put up a GP to
cover all directions. The radiator is attached to a
tree and at the top it has a fishing rod with a hook
to fix it to the tree. |
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GP for 14
and 18 MHz. |
Limited space
for antennas made me to make a GP for 14 and 18 MHz.
Switching bands is done by controlling 2 relays which
are housed in a plastic box placed at the bottom of
the radiator. There are 4 radials for each band. SWR
is perfect for both bands and for 18 MHz condenser C
will do the trick. |
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Reversible
deltaloop for 7 MHz. |
When beeing
active from Gotland Island (IOTA EU-020) I have a lot
of space to put up antennas. Pretty high trees are
perfect for support points. When YV0D (Aves Island)
should be active in july 2004 I constructed a 2 el
loop for 7 MHz and put it up in direction to the
Caribbean. By adjusting a condenser I could get
some gain and there were no problem working them with
S9 signals. |
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3 el wire
yagi for 21 MHz. |
I got a nice
pile-up when using 100 W and this antenna pointed to
Japan. It is extremly lightweight so erecting it at
the top of a 10 m al-mast mast is done by hand. |
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Bobtail
for 7 MHz. |
The Bobtail
fed at the bottom of the middle tail and the next
antenna the Double Extended Zepp behave in a very
same manner. The gain and the radiation pattern is
comparable but if I have to choose I pick the Double
Extended Zepp. |
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Double
Extended Zepp for 7 MHz. |
Normally the
whole antenna is horizontal but I bent down the ends
of the antenna to fit between the two trees and it
worked nicely. |
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Hexbeam
for 21 MHz. |
In a contact
with a KL7-station I first heard about the Hexbeam
antenna. He said it looks like an umbrella turned
downwards without cloth and can withstand strong winds. I got
curious about the antenna and constructed one for 21
MHz. It worked at the first try and was a very
lightweight beam antenna. |
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Moxon
antenna for 14 MHz. |
This antenna
is a very kind one and often works at the first try. I
have tried several types ( vertical and horizontal) on
different bands and all have worked nicely. |
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Reversible
Moxon
antenna for 7 MHz. |
This antenna
is also called FBA (Flip Beam Antenna) and direction
of the antenna can be changed using relays or a switch.
Signals increase/drop 3-4 S-units when changing
direction. |
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Spitwire
for 7 MHz. |
Talking about
silent antennas this one will count. The antenna is
based upon a construction by W1FV and K1VR called "the
Spitfire" using the mast as radiator. As I use
wire for the radiator I think Spitwire is more
adequate. It uses switches to enable the antenna to
change direction. The gain is about 4 dB and the F/B
is about 20-25 dB, very excellent. |
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Fork antenna
for 7 MHz. |
Even a more
silent antenna is the Fork antenna. it has a F/B value
about 25-30 dB and a gain about 3-4 dB. With a
matchingbox containing 1:6 balun och condensers you
can obtain a SWR 1:1. |
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Veebeam
antenna. |
This antenna
is working nicely on all bands using an antenna tuner
between the 600 ohm ladder and the transceiver. Some
gain is also obtained. |
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Vertical
Moxon antenna for 28 MHz. |
There are
some reasons why you should endfeed your vertical
Moxon antenna. You don´t need a hanging coaxcable from
your radiator. You get an antenna with less windbreak
and an antenna in good balance. You just need to
voltage-feed the radiator with a simple LC parallel
resonant circuit like you feed a Bob Tail antenna or a
Half Square antenna. |
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Vertical
Moxon antenna for 14 MHz. |
This vertical
Moxon is also endfeded. The parallel
resonant circuit in this antenna uses a piece of RG8
coaxcable as a condensor. Remember to keep the open
end of the RG8 secured from water (rain) because of
high voltage. On 25 june 2011 this one helped me with
FO/F6CTL in Marquesas island. |
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Halfsquare antenna for 10 MHz. |
Due to QRM
into my neigbours HI-FI speakers using the Bobtail
described above I replaced it with a Halfsquare
antenna placed 15 meters out of houses. Using a link
with capacitor in serie the SWR is perfect zero. It
works fine even to the south but best directions are
west/east. The horizontal part of the antenna is
hanging in south/north direction. |
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Linear loaded
antennas. |
When space is
limited one has to design and build shortened antenna.
One way to do this is to use the linear loaded
koncept. By using 450 ohms ladder lines as stubs the
construction is a piece of a cake. I have used a
griddip meter to adjust the lengths of the stubs to
obtain the demanded frequency. Below you can find
dimensions for antennas for 7, 14 and 28 MHz. All
antennas are 70 % of normal lengths. |
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Rotatable
loop for 14 MHz. |
This simple
antenna is working extremly well. Compared to a Double
Extended Zepp at same hight and same direction it has
more gain and less noise. So it is a very attractive
antenna for portable use on both receiving and
transmitting side. |
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Vertical
dipole for 14 MHz. |
Tired of
noise from your house? Well, one way to get rid of it
is to move your antenna into the wood. One of the real
simple antenna to build and to erect is a vertical
dipole. If you use a tree as a tower it is really a
piece of a cake. A quater wave electrical length of 75
ohm (3.5 m) is used to match 50 ohm coax to the balun
and antenna. The antenna has low gain but also very low
elevation angle, 16 degrees, which is good for long
distance QSO´s. |
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Mini Horse (MH)-antenna. |
- kicks like
a grown-up horse |
- takes the
space of a pony |
- broad as a
highway |
Ever looked
for an antenna which has good gain, nice F/B, 50 ohms
matching, excellent bandwidth, small turning radius
and great mechanical stability? This antenna is for
you! If you need a nec-file to play with just send me
a mail. |
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Compact Moxon
antenna for 7 MHz. |
This antenna
only needs 2 trees or masts to be hanged up in the
air. It works nice with about 5 dB gain and 13 dB F/B
hanging 12 meters above ground. More gain and better
F/B if you can put it higher. |
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A 40/30/20
meter vertical on a flagpole. |
If you are in
a hurry getting on the air or don´t want to disturb
your neighbours with ugly antennas this antenna can be
the solution. It is a vertical tribander fixed to the
flagpole with radials on the ground. Traps are made of
coax cable using VE6YP coax trap program. |
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A 17/15/12/10
meter vertical on a fishing rod. |
Vertical
antennas with only 2 elevated radials are simple but
also quite good antennas for DXing. Another advantage
is that it can be placed where there is no good ground
or at the edge of your lawn so you can cut your grass
without thinking of radials on ground. The traps also
shortens the antenna a bit. |
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A 40 meter
vertical with 2 elevated radials. |
As mentioned
above vertical
antennas with 2 elevated radials are simple and very
cheap antennas for DX-ing. This one works fine from
7.0 to 7.2 with SWR < 1.5. If you use bare wire you
should prelong the elements with 4%. On 15 september
2010 I worked ZS8M using this antenna. |
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A reversible
vertical for 15, 12 and 10 meters. |
If you use
the same concept as above and apply some electrical
short circuit units (6 pieces) you will get a
reversibel antenna for the higher bands. This one
helped me with VU4PB and 5M2TT on those bands. |
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Slope Loop for 10 meters. |
This antenna
is in perfect balance focused to a mast by some
fishing rods. The antenna is a 2 el Delta Loop with
sloping elements. The gain of the antenna is like a 3
element yagi and the front to back ratio is about 8
dB. |
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2 el phased
vertical for 40 meters. |
Combining 2
verticals with 2 elevated radials each and 3 pieces of
coaxcables gives you a phased vertical. Gain is 2-3 dB
over a simple vertical and F/B is about 15 dB. |
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2 el Diamond
Loop for 10 meters. |
This antenna
might be the smallest 2 element antenna with a turning
radius less then 1.6 meters. It gives a gain of 4 dB
over a dipole and the F/B is about 15 dB. It needs a
balun transformer 2.25:1 to match the 20 ohm impedans
at the loading point. |
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2 el yagi for
21, 24 and 28 MHz. |
Solarcycle 24
is here and the higher bands will hopefully be in good
shape. This antenna is small and perfect for portable
use. Elements are made of 1 mm insulated wires
supported by fishing rods. Gain is about 4-5 dB and
F/B is about 8-12 dB. Best performance on 28 MHz. |
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Dipole for
10, 14 and 18 MHz. |
By using
simple switches you can easily build a dipole for 3
bands. A piece of plexiglass and some connecting
devices will do the job. Put one end of the antenna
close to one of the trees for easy let down of the
antenna for changing band. |
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