On Jul 5, 3:55 pm, Wimpie wrote:
On 5 jul, 18:42, Michael wrote:



I've seen the Lazy H mentioned in many antenna books over the years,
so I decided to try one on 10 meters. According to the ARRL handbook
the Lazy H is two collinear elements stacked on above the other, Each
collinear element is made up of two 1/2 wave elements. I chose to
use 5/8 wave spacing between the top and bottom elements. I connected
the top and bottom elements with 450 ohm 16 gauge stranded ladder line
(window line). After building the antenna I verified connectivity
between the top and bottom right elements and the top and bottom left
elements. I color coded the end insulators on each side so I could
easily see which top and bottom elements were connected to each other.
The antenna book says to connect the 450 ohm ladder line from the
antenna tuner to the middle of the 450 ladder line that connects top
and bottom elements. Ok done. Now I put up the antenna and make sure
the top and bottom elements are in phase. That is both left connected
elements are on the left and both right connected element are on the
right. I also make sure there is no twist in the ladder line
connecting the top and bottom elements. I also checked the other
ends of the 450 ohm ladder line feeding the antenna has connectivity
at the antenna, and the left and right sides of the ladder line do not
have connectivity. The 450 ohm ladder line feeding the antenna is
about 200 feet long.
Now I bring the 450 ohm feedline in to the house, hook it to my
Dentron MT-2000 antenna tuner with the 4:1 balun inside, tune it up,
and it sucks! Both my half wave horizontal dipole and my Solarcon
Max-2000 blow it away on incoming skip even in the preferred direction
of the lazy H. I rechecked my connections and the lengths of the
elements and spacing and they are correct. I did take in to account
the velocity factor of the 450 ladder line that connects the top
elements to the bottom elements. The antenna book says the length of
the 450 ladder lien between the antenna and the antenna tuner can e
any lenght.
The bottom element is at least 1/2 wave of the ground, and the top
element is 5/8ths wave above that. What did I do wrong?

Michael

Hi Michael,

Normally spoken the feedline between top to bottom elements is
0.5lambda long, without twist, feeding in the middle. The path from
feedpoint to end of the radiation elements is 0.75 lambda, giving an
almost real low input impedance (on order of 30 Ohms, depending on
thickness of radiating elements). In fact you have two full wave
dipoles fed in phase that give most radiation (ground ignored)
perpendicular to the array (bidirectional). There is a vertical null

Why choosing 5/8 lambda vertical element spacing? You create a
vertical lobe and a null in the elevation radiation pattern under
about 53 degrees. You also get a strong reactive input impedance, but
this may not be a problem with the ladder line.

Did you do some indicative field strength measurements (diode
detector) to find out whether it (and the elements) do(es) radiate
(comparing to the other antennas)? It may also reveal some hidden
things.

Maybe somebody knows a loss figure for your ladder line (at 28 MHz) to
assess the losses in the line (200ft part) because of bad VSWR.

Best regards,

Wim
PA3DJSwww.tetech.nl
When you remove abc, the mail does work.

Hi Wim,
According to the ARRL handbook the highest gain is achieve with a
5/8ths wave spacing between the upper and lower elements. The
handbook gives the following figures for estimated gain.

3/8 wave spacing = 4.4 dbd
1/2 wave spacing = 5.9 dbd
5/8 wave spacing = 6.7 dbd
3/4 wave spacing = 6.6 dbd

EZNEC shows a similar gain peak with a 5/8th wave spacing between the
top and bottom elements.

It seems to works on 14 MHz (stacked dipoles at 14 MHz), but on 10
meters the single 10 meter dipole blows it away.