Hi there, I am trying to build a longwire antenna for use in the 20 meter
band to 70 meter band area. I was looking for advice on what materials to
use for the antenna and the lead in lines. I will hook it up to a Drake r8B
radio. What is the minimum height it has to be? Where to ground it?.
Actually, does it have to be grounded if the radio is grounded at the
outlet?

I am a little limited in space as my yard is only 75 feet long and there are
power lines at the front. I assume that they are the source of an irritating
hum on the receiver on certain frequencies.

Thanks for the help in advance.

Pierre

A google search of "dipole antenna" gave about 48k hits.

I think the following url will be of help:
http://www.angelfire.com/mb/amandx/dipole.html

The Alpha-Delta Sloper will give you very good wide band coverage. It
can be seen at http://www.universal-radio.com/catalog/sw_ant/3377.html

=========

Pierre Vachon wrote:

Hi there, I am trying to build a longwire antenna for use in the 20 meter
band to 70 meter band area. I was looking for advice on what materials to
use for the antenna and the lead in lines. I will hook it up to a Drake r8B
radio. What is the minimum height it has to be? Where to ground it?.
Actually, does it have to be grounded if the radio is grounded at the
outlet?

I am a little limited in space as my yard is only 75 feet long and there are
power lines at the front. I assume that they are the source of an irritating
hum on the receiver on certain frequencies.

Thanks for the help in advance.

Pierre

Hi Pier

- Try getting a portable SWR & walking around your lot, putting it to a " Blank
" frequency and checking where you hear noise, and where you don't

You should also check to see swhere on your lot you pick up 20 - 70 meter
frequencies your interested in

Try this both in the daytime, and at night..
THEN
You'll be able to put an antenna in the ": Noise Free areas"

Dan / NYC ( Sangean 606A, Jwin M14, Icom R-75 )



In article , "Pierre Vachon"
writes:

Subject: Antenna design
From: "Pierre Vachon"
Date: Mon, 11 Oct 2004 18:58:03 -0400

Hi there, I am trying to build a longwire antenna for use in the 20 meter
band to 70 meter band area. I was looking for advice on what materials to
use for the antenna and the lead in lines. I will hook it up to a Drake r8B
radio. What is the minimum height it has to be? Where to ground it?.
Actually, does it have to be grounded if the radio is grounded at the
outlet?

I am a little limited in space as my yard is only 75 feet long and there are
power lines at the front. I assume that they are the source of an irritating
hum on the receiver on certain frequencies.

Thanks for the help in advance.

Pierre

Pierre,

Unless you have a transformer nearby, the powerlines won't necessarily be
the cause of the hum you mention. They can certainly cause noise, when
something is loose or dirty. But not usually a hum.

Use a portable SW radio to track it down. Walk around with it to see if the
hum gets louder or softer.

Mark.


"Pierre Vachon" wrote in message
. ..
Hi there, I am trying to build a longwire antenna for use in the 20 meter
band to 70 meter band area. I was looking for advice on what materials to
use for the antenna and the lead in lines. I will hook it up to a Drake
r8B
radio. What is the minimum height it has to be? Where to ground it?.
Actually, does it have to be grounded if the radio is grounded at the
outlet?

I am a little limited in space as my yard is only 75 feet long and there
are
power lines at the front. I assume that they are the source of an
irritating
hum on the receiver on certain frequencies.

Thanks for the help in advance.

Pierre

"Pierre Vachon" wrote
Hi there, I am trying to build a longwire antenna for use in the 20 meter
band to 70 meter band area. I was looking for advice on what materials to
use for the antenna and the lead in lines. I will hook it up to a Drake
r8B
radio. What is the minimum height it has to be? Where to ground it?.
Actually, does it have to be grounded if the radio is grounded at the
outlet?

I am a little limited in space as my yard is only 75 feet long and there
are
power lines at the front. I assume that they are the source of an
irritating
hum on the receiver on certain frequencies.

Thanks for the help in advance.

Pierre

The minimum height above ground is about 1 millimeter ;-) That's where
Hurricane Isabel dumped one of my long wires last fall. It took over a week
to clear debris away before I could get it back up in the tree it was pulled
out of. It still received quite well in the meantime, even laying on the
ground. Of course the higher the antenna, the better it receives. At an
angle of more than 45 degrees, there is very little effect on the direction
the sloping wire points. At an angle of more than about 75 degrees, you are
approaching a "vertical" which is known for it's higher background noise.
Not desirable in DX work.

You didn't say if you are going to use a Balun transformer at the antenna
and coax feedline to connect to the radio. *If* you do, then you can
certainly ground the shield of the coax at the balun (even ground the unused
side of the balun), and shield ground the coax again before it comes into
your home. That can certainly help reduce noise. If the coax shield is not
grounded, the home electrical ground can "feed" noise from the radio, out
the coax shield, and back into the coax center conductor at the antenna
connection. Shield grounding does prevent this from happening. It is also
required in order for any static or lightning protection device to work
properly, should you use those devices.

Good luck,

Jack

= = = "Pierre Vachon" wrote in message
= = = ...

Hi there, I am trying to build a longwire antenna for use in the 20 meter
band to 70 meter band area. I was looking for advice on what materials to
use for the antenna and the lead in lines. I will hook it up to a Drake r8B
radio. What is the minimum height it has to be? Where to ground it?.
Actually, does it have to be grounded if the radio is grounded at the
outlet?

I am a little limited in space as my yard is only 75 feet long and there are
power lines at the front. I assume that they are the source of an irritating
hum on the receiver on certain frequencies.

Thanks for the help in advance.

Pierre

PV,

Your simplest 'design' would be a "Low Noise" Antenna in the
'form' of an Inverted "L" Antenna. Since you have Power Line at
the front of the Yard. Consider running your Coax Cable to the
Back-End of the Yard (Possibly a Corner?). Construct an Antenna
Support at this 'spot'. I like to us Top-Rail as a Free-Standing
Antenna Support. Next at this back-of-the-yard 'location' install
a Ground Rod. Then 'mount' a Matching Transformer on the Top
of the Ground Rod. (This is your Primary Grounding Point for
your Antenna and Ground System.) Connect the Antenna Wire Element
and Coax Cable to the Matching Transformer (Balun/MLB). Route/Run
the Antenna Wire Element 'up' to the Top of the Top Rail and
'out' toward the front yard. Near the front of the Yard find
or build a second Antenna Support. (Top Rail Again?)

Some people like "Exact Numbers". So since you mention the
70 Meter and 20 Meter Bands; consider 'cutting' your Inverted
"L" Antenna to be a Quarter Wave Length on Top-Horizontal-Arm
for your Lowest Band and a Quarter Wave Length on the
Bottom-Vertical-Leg or your Lowest Band.
* 80 Meter 1/4WL = 67 Feet Top-Horizontal-Arm
* 20 Meter 1/4WL = 18 Feet Bottom-Vertical-Leg
Total Length of the Antenna Wire Element = 85 Feet.

READ: Antennas - Five Things to Consider : Antenna, Balun,
Ground, Coax & Planning
http://groups.yahoo.com/group/Shortw...a/message/1544

The SWL Versions of the Inverted "L" Antennas can be any size
because they are in-fact simply Random Wire Antennas that are
'designed' to Fit the available space.
http://groups.yahoo.com/group/Shortw...nna/message/54
Inverted "L' Antenna Reading List
http://groups.yahoo.com/group/Shortw...na/message/374
'About' the Inverted "L" Antenna = http://tinyurl.com/5aw9a
'Sizing' the Inverted "L" Antenna = http://tinyurl.com/5cqf8
The 'Low Noise' Inverted "L" Antenna = http://tinyurl.com/5953c

About - TOP RAIL as a "Free Standing" Antenna Support
http://groups.yahoo.com/group/Shortw...na/message/201
http://groups.yahoo.com/group/Shortw...enna/message/3
..
..
REMEMBER: "The Shortwave Antenna is 55.5% of the . . .
Radio/Receiver and Antenna/Ground Reception Equation"
http://groups.yahoo.com/group/Shortw...na/message/288
A Shortwave Antenna is "Equally" Important for Good Reception [.]
..
..
iane ~ RHF
..
Some Say: On A Clear Day You Can See Forever.
http://groups.yahoo.com/group/Shortw...na/message/502
I BELIEVE: On A Clear Night...
You Can Hear Forever and beyond, The Beyond !
..
..

Pierre Vachon wrote:

Hi there, I am trying to build a longwire antenna for use in the 20 meter
band to 70 meter band area. I was looking for advice on what materials to
use for the antenna and the lead in lines. I will hook it up to a Drake r8B
radio. What is the minimum height it has to be? Where to ground it?.
Actually, does it have to be grounded if the radio is grounded at the
outlet?

I am a little limited in space as my yard is only 75 feet long and there are
power lines at the front. I assume that they are the source of an irritating
hum on the receiver on certain frequencies.

Thanks for the help in advance.

Pierre

A real longwire antenna is much longer than what you are thinking of
building. The antenna you describe is called a 'random wire' or
inverted-L. This kind of antenna is not tuned for a specific band or
range of frequencies. In fact, it performs well throughout the shortwave
spectrum. See the following website for instructions on building a good
low noise inverted-L antenna. I use this kind with my R8B.

http://www.anarc.org/naswa/badx/ante...e_antenna.html


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"starman" wrote in message
...
Pierre Vachon wrote:

Hi there, I am trying to build a longwire antenna for use in the
20 meter
band to 70 meter band area. I was looking for advice on what
materials to
use for the antenna and the lead in lines. I will hook it up to a
Drake r8B
radio. What is the minimum height it has to be? Where to ground
it?.
Actually, does it have to be grounded if the radio is grounded at
the
outlet?

I am a little limited in space as my yard is only 75 feet long and
there are
power lines at the front. I assume that they are the source of an
irritating
hum on the receiver on certain frequencies.

Thanks for the help in advance.

Pierre

A real longwire antenna is much longer than what you are thinking of
building. The antenna you describe is called a 'random wire' or
inverted-L. This kind of antenna is not tuned for a specific band or
range of frequencies. In fact, it performs well throughout the
shortwave
spectrum. See the following website for instructions on building a
good
low noise inverted-L antenna. I use this kind with my R8B.

http://www.anarc.org/naswa/badx/ante...e_antenna.html

Hmm. That brings up a question that I'd thought of earlier, but
when I was writing my posts, I forgot to put it in.

How do you figure out the impedance of various random
wires of different gauges?? John Doty's article mentioned
an 18 gauge wire hung more than a few feet above the
ground, but I'm just curious what sort of differences there
would be using, say, 14, 16 or 22 gauge wire in a similar
scenario. I can't imagine trying to test it without a load of
some sort.

--Mike L.

Michael Lawson wrote:

"starman" wrote in message
...
Pierre Vachon wrote:

Hi there, I am trying to build a longwire antenna for use in the
20 meter
band to 70 meter band area. I was looking for advice on what
materials to
use for the antenna and the lead in lines. I will hook it up to a
Drake r8B
radio. What is the minimum height it has to be? Where to ground
it?.
Actually, does it have to be grounded if the radio is grounded at
the
outlet?

I am a little limited in space as my yard is only 75 feet long and
there are
power lines at the front. I assume that they are the source of an
irritating
hum on the receiver on certain frequencies.

Thanks for the help in advance.

Pierre

A real longwire antenna is much longer than what you are thinking of
building. The antenna you describe is called a 'random wire' or
inverted-L. This kind of antenna is not tuned for a specific band or
range of frequencies. In fact, it performs well throughout the
shortwave
spectrum. See the following website for instructions on building a
good
low noise inverted-L antenna. I use this kind with my R8B.

http://www.anarc.org/naswa/badx/ante...e_antenna.html

Hmm. That brings up a question that I'd thought of earlier, but
when I was writing my posts, I forgot to put it in.

How do you figure out the impedance of various random
wires of different gauges?? John Doty's article mentioned
an 18 gauge wire hung more than a few feet above the
ground, but I'm just curious what sort of differences there
would be using, say, 14, 16 or 22 gauge wire in a similar
scenario. I can't imagine trying to test it without a load of
some sort.

Don't worry about it. The gauge of the wire will have an extremly minimal
effect, and besides, there are so many other variables as well.

dxAce
Michigan
USA

http://www.iserv.net/~n8kdv/dxpage.htm

In article ,
"Michael Lawson" wrote:

"starman" wrote in message
...
Pierre Vachon wrote:

Hi there, I am trying to build a longwire antenna for use in the
20 meter band to 70 meter band area. I was looking for advice on
what materials to use for the antenna and the lead in lines. I
will hook it up to a Drake r8B radio. What is the minimum height
it has to be? Where to groundit?.

Actually, does it have to be grounded if the radio is grounded at
the outlet?

I am a little limited in space as my yard is only 75 feet long
and there are power lines at the front. I assume that they are
the source of an irritating hum on the receiver on certain
frequencies.

Thanks for the help in advance.

Pierre

A real longwire antenna is much longer than what you are thinking
of building. The antenna you describe is called a 'random wire' or
inverted-L. This kind of antenna is not tuned for a specific band
or range of frequencies. In fact, it performs well throughout the
shortwave spectrum. See the following website for instructions on
building a good low noise inverted-L antenna. I use this kind with
my R8B.

http://www.anarc.org/naswa/badx/ante...e_antenna.html

Hmm. That brings up a question that I'd thought of earlier, but when
I was writing my posts, I forgot to put it in.

How do you figure out the impedance of various random wires of
different gauges?? John Doty's article mentioned an 18 gauge wire
hung more than a few feet above the ground, but I'm just curious what
sort of differences there would be using, say, 14, 16 or 22 gauge
wire in a similar scenario. I can't imagine trying to test it
without a load of some sort.

A decrease in the gauge number means an increase in the wire diameter.
If you increase the wire diameter the impedance goes down. If you place
the wire closer to the ground the impedance goes down.

The difference between a step in wire gauge is about 12 ohms.

A 16 gauge wire 5 to 15 feet off the ground ranges from 500 to 600
ohms.

--
Telamon
Ventura, California