160 meter antenna pros and cons
 

"Merlin-7 KI4ILB" wrote in
:

I have 2 wire antennas that I am thinking about putting up..

#1 A long wire with the shield of the coax grounded to the tower at
the feed point with the center of the coax connected to a long wire
cut for mid band on 160.

#2 a normal dipole cut for mid band 160.

Take a dipole's worth of wire. Run it vertical for as far as you can, then
horizontal. Feed it with a quarter wave of ladder line at the bottom end.
The ground isn't too important....a 3/8" copper pipe driven in should do it.
Tune the line as balanced. Cut it for the part of the band you use the most.

The higher you bend it, the better. Halfway is probably a good compromise
between DX needs and local working.


--
Dave Oldridge+
ICQ 1800667

160 meter antenna pros and cons
 

Hello Joe!

One easy thing that you might try, is to slope a 1/4-wave wire from the
top of your tower, connecting your coax to the wire, and coax shield to
the tower at the feedpoint, this way your tower will be the "other leg"
of the dipiole, or a "counterpoise". Then just trim the 1/4-wave wire
for swr.


73 de Hans, SM3PXG





Merlin-7 KI4ILB wrote:
Thanks everyone.
I will be changeing my QTH next summer but was trying to get up something
for 160.
My back lot has enough room (and trees) to place 1 side of the dipole from
my tower. It would need to have a bend in it to make it fit but it is
possible.
The front of the house is a problem, theres nothing there but the power
lines...
Is it possible to put a slinkie on just one side of the dipole or would I
need to make both sides exactly the same?
I could wrap a lot of wire around something (with the loops spaced apart a
bit) on one or both sides of the dipole.
I am just trying to get up something for 160 for 9 months or so.

The fan dipole I have up now is about 66 feet long (each side from the
tower) 66tower66.

I do not know what would happen if I ran the 160m dipole 70 feet or so and
bent the ends in the same direction (towards the back yard)

My back yard is 120' by75' (the fan dipole I have up is at an angle) The
tower (feed point) is in the middle of the 120'side 75' from the back of the
lot.

Any ideas? It will only be up for 9 months or so...
Thanks
Joe

160 meter antenna pros and cons
 

HS wrote:
One easy thing that you might try, is to slope a 1/4-wave wire from the
top of your tower, connecting your coax to the wire, and coax shield to
the tower at the feedpoint, this way your tower will be the "other leg"
of the dipiole, or a "counterpoise". Then just trim the 1/4-wave wire
for swr.

The ARRL Antenna Book says that works if the tower is 1/4WL
tall or taller. A 1/4WL tower on 160m would be about 130 feet
tall. If the tower is less than 1/4WL tall, it seems to become
the major radiating portion of the antenna. I just modeled a
33 foot tower and a 100 foot wire on 1.9 MHz. That total length
is just about 1/4WL and winds up looking something like a gamma
fed inverted-L. The feedpoint impedance at the top of the tower
is low at ~8 ohms.

Such an antenna has a 50 ohm feedpoint impedance somewhere
along that horizontal wire. In my 33'-101' version above, the
50 ohm feedpoint is about 40' from the open end of the 100' wire.
And, of course, the feedpoint currents are unbalanced.

100' total
+-----------------------FP---------------
| 60' 50 ohm 40'
|
|33' tower
|
|
+-----GND
--
73, Cecil, http://www.qsl.net/w5dxp

160 meter antenna pros and cons
 

I may try this approach, my tower is only 50' or so but It has guys on it,
The guy that goes out to my back yard is about 75' or so but is also
connected to the chain link fence that winds all thru the block that I live
on. (not sure what effect the fence will have if any)
Just a note: the guys do little more than keep the tower from swaying (rhon
25) when I am working on antennas etc.
I have radials everywhere and ground rods and there tied into the chain
link fence ( I lost count of how many)
After I get it up, I can connect my antenna analyzer and see what kind of
readings I get.
When I make the feed point connection I can make it in a way that I could
remove the shield from the tower and change it into a normal dipole. I am
not sure where I could run that end but maybe I can sweet talk a neibor..

Am I NuTz?

I love playing with antennas...

Joe
"Cecil Moore" wrote in message
. ..
HS wrote:
One easy thing that you might try, is to slope a 1/4-wave wire from the
top of your tower, connecting your coax to the wire, and coax shield to
the tower at the feedpoint, this way your tower will be the "other leg"
of the dipiole, or a "counterpoise". Then just trim the 1/4-wave wire
for swr.

The ARRL Antenna Book says that works if the tower is 1/4WL
tall or taller. A 1/4WL tower on 160m would be about 130 feet
tall. If the tower is less than 1/4WL tall, it seems to become
the major radiating portion of the antenna. I just modeled a
33 foot tower and a 100 foot wire on 1.9 MHz. That total length
is just about 1/4WL and winds up looking something like a gamma
fed inverted-L. The feedpoint impedance at the top of the tower
is low at ~8 ohms.

Such an antenna has a 50 ohm feedpoint impedance somewhere
along that horizontal wire. In my 33'-101' version above, the
50 ohm feedpoint is about 40' from the open end of the 100' wire.
And, of course, the feedpoint currents are unbalanced.

100' total
+-----------------------FP---------------
| 60' 50 ohm 40'
|
|33' tower
|
|
+-----GND
--
73, Cecil, http://www.qsl.net/w5dxp