Michael
2011-05-10 13:13:36 UTC
I've been wanting to build a Lazy H antenna for 10 meters for some
time now. Last summer I purchased a new house with some land, and I
decided to give the Lazy H antenna a try. According to the ARRL
handbook a Lazy H antenna with 1/2 spacing between the top and bottom
elements has 5.9 db gain over a half wave dipole. At 5/8th wave
spacing between the top and bottom elements the ARRL antenna handbook
claims the Lazy H is suppose to have 6.7 db gain over a 1/2 dipole.
In the real world I have found the Lazy H to actually have less gain
than a 1/2 wave dipole at both 5/8th wave spacing and 1/2 wave
spacing.
I viewed the W8JI web page concerning the Lazy H. I used 450 ohm
ladder line between the top and bottom elements, and I center fed that
piece of ladder line with another 100 foot run of 450 ohm ladder line
back to the shack. The ladder line runs perpendicular away from the
Lazy H. I attached the ladder line to the balanced line input on my
Dentron MT-3000 antenna tuner.
Dentron MT-3000
http://www.eham.net/reviews/detail/868
The first thing I noticed is I have to turn the antenna matching
adjustment all the way to the right to get the SWR to come down, and
the transmitter matching to about 3 o'clock. I've never had to turn
the antenna matching adjustment that far for any other antenna to
match. I also hooked the ladder line to my Drake MN-75 antenna tuner
with the 4:1 balun installed and the adjustments on the Drake antenna
tuner where about the same as the Dentron MT-3000.
The top wire on the Lazy H is at about 45 feet. I also have a coax
fed 1/2 wave dipole for 10 meters at about 30 feet. I live near
Charleston, South Carolina, and I have both the dipole and the Lazy H
broadside to southern California.
I did multiple A/B comparisons between the 1/2 wave 10 meter dipole
and the 10 meter Lazy H and this is what I found.
Charleston, South Carolina to Arkanasas via sporaic E skip
- The dipole easily out performs the Lazy H
F layer skip....
Charleston, South Carolina. to Arizona
- The dipole easily out performs the Lazy H
Charleston, South Carolina to California
- The dipole easily out performs the Lazy H
Charleston, South Carolina to Hawaii
- The dipole and the Lazy H are about the same
When sporadic E skip rolled in from Ohio the Lazy H demonstrated the
expected null to the North.
I have rechecked all the connections and they are correct. I verified
the connections with an ohm meter and the top left element is
connected to the bottom left element. The top right element is
connected to the bottom right element. There is no connectivity
between the left and right elements which is what the handbook shows.
There is no twist in the ladder line that connects the top and bottom
elements. This is a center fed Lazy H, and not a bottom fed Lazy H. I
verified the Lazy was in fact pointing in the correct direction by
rotation my dipole to null out signals coming from California. I
noted the direction with my compass, and then I made sure the Lazy H
was broadside to that direction on the compass.
Has anyone seen real world gain with the Lazy H on 10 meters verses a
dipole? My experience shows it consistently lags behind the 1/2 wave
dipole even through the Lazy H is 10+ feet higher than the dipole.
I also built an extended double zepp for 10 meters with a 450 matching
section to a 1:1 balun and then to coax, and the extended double zepp
consistently out performs the dipole in it's preferred direction.
time now. Last summer I purchased a new house with some land, and I
decided to give the Lazy H antenna a try. According to the ARRL
handbook a Lazy H antenna with 1/2 spacing between the top and bottom
elements has 5.9 db gain over a half wave dipole. At 5/8th wave
spacing between the top and bottom elements the ARRL antenna handbook
claims the Lazy H is suppose to have 6.7 db gain over a 1/2 dipole.
In the real world I have found the Lazy H to actually have less gain
than a 1/2 wave dipole at both 5/8th wave spacing and 1/2 wave
spacing.
I viewed the W8JI web page concerning the Lazy H. I used 450 ohm
ladder line between the top and bottom elements, and I center fed that
piece of ladder line with another 100 foot run of 450 ohm ladder line
back to the shack. The ladder line runs perpendicular away from the
Lazy H. I attached the ladder line to the balanced line input on my
Dentron MT-3000 antenna tuner.
Dentron MT-3000
http://www.eham.net/reviews/detail/868
The first thing I noticed is I have to turn the antenna matching
adjustment all the way to the right to get the SWR to come down, and
the transmitter matching to about 3 o'clock. I've never had to turn
the antenna matching adjustment that far for any other antenna to
match. I also hooked the ladder line to my Drake MN-75 antenna tuner
with the 4:1 balun installed and the adjustments on the Drake antenna
tuner where about the same as the Dentron MT-3000.
The top wire on the Lazy H is at about 45 feet. I also have a coax
fed 1/2 wave dipole for 10 meters at about 30 feet. I live near
Charleston, South Carolina, and I have both the dipole and the Lazy H
broadside to southern California.
I did multiple A/B comparisons between the 1/2 wave 10 meter dipole
and the 10 meter Lazy H and this is what I found.
Charleston, South Carolina to Arkanasas via sporaic E skip
- The dipole easily out performs the Lazy H
F layer skip....
Charleston, South Carolina. to Arizona
- The dipole easily out performs the Lazy H
Charleston, South Carolina to California
- The dipole easily out performs the Lazy H
Charleston, South Carolina to Hawaii
- The dipole and the Lazy H are about the same
When sporadic E skip rolled in from Ohio the Lazy H demonstrated the
expected null to the North.
I have rechecked all the connections and they are correct. I verified
the connections with an ohm meter and the top left element is
connected to the bottom left element. The top right element is
connected to the bottom right element. There is no connectivity
between the left and right elements which is what the handbook shows.
There is no twist in the ladder line that connects the top and bottom
elements. This is a center fed Lazy H, and not a bottom fed Lazy H. I
verified the Lazy was in fact pointing in the correct direction by
rotation my dipole to null out signals coming from California. I
noted the direction with my compass, and then I made sure the Lazy H
was broadside to that direction on the compass.
Has anyone seen real world gain with the Lazy H on 10 meters verses a
dipole? My experience shows it consistently lags behind the 1/2 wave
dipole even through the Lazy H is 10+ feet higher than the dipole.
I also built an extended double zepp for 10 meters with a 450 matching
section to a 1:1 balun and then to coax, and the extended double zepp
consistently out performs the dipole in it's preferred direction.