= = = "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 !
..
..

(RHF) wrote in message om...
= = = "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?


A year or so ago I had to come up with a replacement for an ageing
vertical antenna for my amateur radio station...After researching, I
decided to put up a full wave loop cut for 80 meters..Im going to
quote some sentences from this article, which you should check out:

http://www.bloomington.in.us/~wh2t/loop.html

"To determine the approximate length in feet of a Full Wave Loop
antenna use the formula 1005/Freq in Mhz = length in feet. For 160
meters a full wave loop antenna resonant at 1.9 Mhz would be about 529
feet long.

For the 75 meter band a full wave loop antenna resonant at 3.85 would
be about 261 feet long. A full wave for 3.9 Mhz = 257 Feet 8 inches. "

I happened to design mine for the 75/80 meter band.

"This type of antenna doesn't depend on an efficient ground system for
efficient performance. The impedance of a Full Wave Loop antenna is
theoretically in the vicinity of 100 ohms.

Connect one end of the wire to the coax center and Connect the coax
shield to the other end of the wire. Be sure and seal the end of the
coax against water. Form the wire in a loop and run it horizontally to
trees or whatever supports are handy. Be sure to insulate the wire
from the supports. "

Now, this antenna works great on receive and transmit on everything
from 75/80 meters and up (10-80) for transmit, the meager automatic
antenna tunner in me bloody kenwood ts450sat tunes it..amazing..and
the one band that sometimes gives me a bit of trouble is 15 meters,
where I have to use the external tuner..

And it hears really good everywhere my radio will go (general
coverage)...mine is only up an average of about 20 ft..

So, if you have the room I'd seriously consider a full wave loop..good
luck..

Steve
kb8viv

= = = (Steve) wrote in message
= = = . com...
(RHF) wrote in message om...
= = = "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?


A year or so ago I had to come up with a replacement for an ageing
vertical antenna for my amateur radio station...After researching, I
decided to put up a full wave loop cut for 80 meters..Im going to
quote some sentences from this article, which you should check out:

http://www.bloomington.in.us/~wh2t/loop.html

"To determine the approximate length in feet of a Full Wave Loop
antenna use the formula 1005/Freq in Mhz = length in feet. For 160
meters a full wave loop antenna resonant at 1.9 Mhz would be about 529
feet long.

For the 75 meter band a full wave loop antenna resonant at 3.85 would
be about 261 feet long. A full wave for 3.9 Mhz = 257 Feet 8 inches. "

I happened to design mine for the 75/80 meter band.

"This type of antenna doesn't depend on an efficient ground system for
efficient performance. The impedance of a Full Wave Loop antenna is
theoretically in the vicinity of 100 ohms.

Connect one end of the wire to the coax center and Connect the coax
shield to the other end of the wire. Be sure and seal the end of the
coax against water. Form the wire in a loop and run it horizontally to
trees or whatever supports are handy. Be sure to insulate the wire
from the supports. "

Now, this antenna works great on receive and transmit on everything
from 75/80 meters and up (10-80) for transmit, the meager automatic
antenna tunner in me bloody kenwood ts450sat tunes it..amazing..and
the one band that sometimes gives me a bit of trouble is 15 meters,
where I have to use the external tuner..

And it hears really good everywhere my radio will go (general
coverage)...mine is only up an average of about 20 ft..

So, if you have the room I'd seriously consider a full wave loop..good
luck..

Steve
kb8viv

STEVE,

Check-Out the "SkyWire Loop Antennas" eGroup on YAHOO !
http://groups.yahoo.com/group/SkyWires/

Dr. Ace [WH2T] is one of the Moderators of the eGroup.
http://www.bloomington.in.us/~wh2t/loop.html

A Critical requirement for a SkyWire Loop Antenna is "LAND" & Space.

SkyWire Loop Antenna Size per Square Side:
160 Meter Band = 529 Feet Loop = 132 Feet Side = "SPACE"
80 Meter Band = 268 Feet Loop = 67 Feet Side = 'Space'
40 Meter Band = 141 Feet Loop = 35 Feet Side = space
20 Meter Band = 71 Feet Loop = 18 Feet Side
10 Meter Band = 35 Feet Loop = 9 Feet Side

give me land lots of land to build antennas on, don't CCR me in ~ RHF
..

Hi RHF, I used to subscribe to it but I tend to change hobbies in the Summer
LOL..Anyway, last year I remember we were trying to have a net (so to speak) on
hf and it never really materialized. When summer hit I was back into my other
hobby of motorcycles..I should resubscribe though, if I remember correctly
there was a pretty good group there..Thanks again for the invite..

Steve
kb8viv