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.

What are the pros and cons of each?

Max output is 100 watts
MFJ deluxe versa tuner II
Coax fed
Air wound choke ...possible or if needed..
I do have an antenna analyzer for tuneing.

Joe
KI4ILB
solar powered ham radio 24/7

Just a (long wire) connected to the center of the coax, cut to resonate at
160 meters (about 130' if my memory is correct) in other words, one side of
a normal dipole.
Joe

...
... to a long wire cut for mid band
on 160.

What does that mean?

Owen
--

On Tue, 31 Oct 2006 01:25:37 GMT, "Merlin-7 KI4ILB"
wrote:

....
... to a long wire cut for mid band
on 160.

What does that mean?

Owen
--

If you do that, the outside of the coax becomes the other half of the
dipole. Be prepared for some interesting effects in the shack.

Roy Lewallen, W7EL

Merlin-7 KI4ILB wrote:
Just a (long wire) connected to the center of the coax, cut to resonate at
160 meters (about 130' if my memory is correct) in other words, one side of
a normal dipole.
Joe
...
... to a long wire cut for mid band
on 160.
What does that mean?

Owen
--

On Mon, 30 Oct 2006 18:08:57 -0800, Roy Lewallen
wrote:

If you do that, the outside of the coax becomes the other half of the
dipole. Be prepared for some interesting effects in the shack.

Joe,

Getting detail from you is like drawing teeth. I suppose part of the
learning process is learning the factors that are relevant to the
situation.

You did say you would connect the outer of the coax to the tower....
where abouts? Near ground, somewhere else? This makes a difference.

Fundamentally, you are probably on the wrong track connecting a half
wave wire to the centre of the coax... but that depends on what you
connect to the other side of the end of the coax.

If in fact you effectively ground the end of the coax at the outer,
and have the centre connected to the end of your half wave wire, you
will have a very high VSWR on the coax, exacerbating the loss it
already has, and the magnitude of that loss depends on things that you
haven't described... but it can be huge.

If you were to chose the worst length of a wire to connect to a
substantial length of coax inner in that scenario, it is probably a
half wave. What were / are you trying to achieve?

Owen
--

The easiest antenna is Inverted Vee, dipole cut for the middle of the band
where you want to operate, one support, fed with coax (50 ohms), no need to
match anything, just trim the ends to resonate around 1840. Ends can be
zig-zagged to fit the space. With good ground it accentuates the vertical
polarization and low angle component.

Simple and it works. Got one here in a tree.

73 Yuri, K3BU


"Merlin-7 KI4ILB" wrote in message
. ..
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.

What are the pros and cons of each?

Max output is 100 watts
MFJ deluxe versa tuner II
Coax fed
Air wound choke ...possible or if needed..
I do have an antenna analyzer for tuneing.

Joe
KI4ILB
solar powered ham radio 24/7

Merlin-7 KI4ILB ha escrito:

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.

What are the pros and cons of each?

Max output is 100 watts
MFJ deluxe versa tuner II
Coax fed
Air wound choke ...possible or if needed..
I do have an antenna analyzer for tuneing.

Joe
KI4ILB
solar powered ham radio 24/7

About "end fed" or "center fed" 160m halve wave antenna.

I assume that you will have a halve wave for both options and it is a
single band antenna.

The halve wave dipole will probably work well. I would insert a current
mode balun (based on low frequency ferrite), to reduce common mode
current. The VSWR will be that low, that after tuning in the shack the
cable loss will be negligible.

I have doubts about the end fed option. The halve wave end fed wire
will show a VSWR of about 30..40 to your coaxial cable (impedance in
the kOhms range). Of course you can correct this with the tuner in
shack, but I believe, depending on the cable length, most power will be
lost as heat in the cable.

If you still prefer this option, you may do part of the tuning at the
mast. You could build, for example a 50 Ohms to 1 kOhm transformer.
This will not give perfect match, but the VSWR will be in a range that
it can be tuned inside the shack without significant cable loss.

I would not reduce the length of the end fed wire to a quarter wave
(gives better match), because of high ground current (with associated
loss).

I hope this will help you making the best choice.

Wim
PA3DJS

Normal dipole. You need all the height you can get. With the long wire of
course it is dependent on the physical configuration as to whether you get
horizontal or vertical radiation, and you need a ground for it that could
be considerable. In fact MUST be considerable to reduce losses in the
earth.
I had an inverted L up last year, 40 feet vertical and 80 ft mostly
horizontal with 16 radials of about 50 ft, some longer. My inverted vee at
50 feet worked just as good. I almost never could see any difference, and
the inv vee is trivial to feed.

Rick K2XT

Merlin-7 KI4ILB wrote:
#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.

Why not turn your tower into an inverted-L and
gamma feed it? The tower plus the wire connected
at the top would need to be about 130 feet.

Otherwise, go with the dipole. The above #1 antenna,
as described without modifications, would not work
very well.
--
73, Cecil http://www.w5dxp.com

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