Question.
I just installed a new longwire antenna. And because I always heard: "'the
more wire the better"' I have installed a sort of long U, doubling my
regular wire lenght...
One end of the U is attatched to an isolator on the first floor and from
there it goes down to the garden to another isolator, and from there it goes
back up to another isolator. The coax goes to a balun and to my ar3000a and
or Kenwood 1000r.
The antenna wires don't touch and they are plastic coated.
did I do the right thing? seems have a lot of interference....
txs
7373
Joost
A balun matches a balanced load (a symmetric antenna such as a dipole) to an
unbalanced source (coaxial cable). Does not make any sense to me to feed a
longwire via a balun. Maybe you are using an "unun" acting as impedance
transformer between 2 unbalanced sides?
The increased interference you mention may be caused by overloading your RX,
especially if it has no preselector in its front end.
Just my 2c worth...
"Markus L" <uo9...@lnubb.pbz> schreef in bericht
news:uKiTd.82$826....@ns2.gip.net...
.
For a Shortwave Listerner's (SWL) Antenna 'bending' the Antenna
Wire Element is not a problem. Using Insulated (Plastic Overed)
Wire has its Advantages and 'stranded' wire is usually easier to
work with then solid. The use of Insulators at the Wire-Ends and
other Mounting Points is a 'good' Construction Technique.
.
READ - Three "Must" Links to Read -wrt- Low Noise SWL Antenna
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/message/949
.
READ - "Low Noise Shortwave Listener (SWL) Antenna
for most Radio/Receivers" [NO Antenna Tuner Required]
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/message/1525
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/message/1024
.
For most Shortwave Listeners (SWLs) who are considering building
and using a Low Noise Inverted "L" Antenna.
.
READ - Inverted "L' Antenna Reading List
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/message/374
.
READ - The 'simple' Answer (in most cases) is the
Low Noise Inverted "L" Antenna
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/message/1785
.
NOTE - When properly laid-out, arranged and constructed;
the Inverted "L" Antenna provides a relatively 'low noise'
"Omni-Directional" Shortwave Listener's (SWL) Antenna.
.
iane ~ RHF
.
All are WELCOME and "Invited to Join" the
Shortwave Listener (SWL) Antenna eGroup on YAHOO !
<http://groups.yahoo.com/group/Shortwave-SWL-Antenna/>
.
Some Say: On A Clear Day You Can See Forever.
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/message/502
.
I BELIEVE: On A Clear Night . . .
You Can Hear Forever and Beyond, The BEYOND !
With a Shortwave Listener SWL Antenna of your own making.
"If You Build It {SWL Antenna} You Will Hear Them !"
.
.
.
"RHF" <rhf-new...@pacbell.net> schreef in bericht
news:1109251659.6...@f14g2000cwb.googlegroups.com...
~~~~~ God gives Peace not war +
"Moi" <te...@test.nl> wrote in message news:cvkn3h$j20$1...@reader11.wxs.nl...
I don't see a ground lead on that one.
How does one ground it?
Large horizontal loops are very broadbanded. If the loop is about 2 X the
wave length on the lowest band you wish to receive then it will perform
better than any dipole, at the same height, cut for one particular band and
its harmonics. Of course the higher the better is always the key for most
any antenna.
Do experiment with the large horizontal loop.
"RHF" <rhf-new...@pacbell.net> wrote in message
news:1109251659.6...@f14g2000cwb.googlegroups.com...
Then how would you explain the performance equivalency of a 2Xwavelength
horizontal loop's performance to that of a 1/2wave dipole cut for same
frequency?
http://www.cebik.com/wire/horloop.html
The advantage of this type of loop is that it performs equally to a dipole
on
multiple frequencies. It is an excellent SWL antenna if you have the
real-estate.
Even a 1Xwavelength H-loop performs very well.
The main disadvantage is that you could buy several hundred better
performing antennas for less than the first year's property taxes for
the land needed to construct the damn thing!
Yeesh. This makes my jokes about a 30-element MW log-periodic sound
practical by comparison.
"clifto" <cli...@clifto.com> wrote in message
news:a6v4f2-...@remote.clifto.com...
> Pull out your calculator. It's not that big.
Imagine my surprise when my MW loop turned out to be only 1341 feet in
diameter, needing only 33 acres to hold it (41-1/3 if you own the entire
square the circle is inscribed in).
We'd need about 36 poles to hold it half a wavelength, or 1,054 feet,
off the ground.
Maybe we could rent Arecibo... is it big enough?
I don't think anyone is going to go through the trouble of building a H-loop
for the MW BCB. The original post inquired about the feasibility of a
longwire shaped into a "U". He was almost there by a few yards short of a
better performing horizontal loop.
The point of the discussion, and the links I included,
show that a modest horizontal loop has the same dB gain as a dipole AT
THE SAME HEIGHT. The loop advantage is that the dipole performs optimally
on its fundamental and harmonics ONLY, while the H-Loop performs equally
well on all frequencies at and above about its one wavelength circumference.
Read the links and learn.
Well said. A horizontal dipole is optimal only between 1/4 wave to
preferably 1/2 wave height above ground. Anyone who thinks erecting a
horizontal loop at 1/2 wave height is easy, we've got a bridge in Arizona to
sell you. These horizontal loops are used, but they are typically strung
between the tops of several tall telephone poles erected in a circle.
Nothing you see in a hobbyists backyard.
Jack
I would suggest that very few persons actually mount there longwire or
dipoles at the optimum heights.
And even a modestly sized H-loop, say about 80 to 100 Ft in circumference,
would easily fit around the eaves of a roofline as I have actually done.
While a dipole or longwire strung on top of my roof could hardly stretch
across maybe 50 ft at best.
And the dipole/longwire would only be at its optimum - tuned , regardless of
height, at its 1/2 wave frequency and its harmonics. While the H-loop would
be tuned from the 1 wavelength resonance all the way up to 30mHz and beyond!
To give you a more practical comparison the difference is like a 1/2 wave
vertical for a tuned frequency of , say 500mHz, and a discone with a tuned
range of about 30mHz to 900mHz. Roughly equal gain at 500mHz for both
antenna's AT THE SAME HEIGHT. But stray away from 500mHz with the 1/2 wave
vertical and performance drops significantly compared to a discone on any
other frequency. No comparison!
>From what you have written here; I soumds like
you built yourself a SkyWire Loop Antenna.
.
"SkyWire Loop Antennas" Forum {eGroup} on YAHOO !
SKYWIRE => 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 per Side = "SPACE"
80 Meter Band = 268 Feet Loop = 67 Feet per Side = 'Space'
40 Meter Band = 141 Feet Loop = 35 Feet per Side = space
20 Meter Band = 71 Feet Loop = 18 Feet per Side
10 Meter Band = 35 Feet Loop = 9 Feet per Side
.
Some SkyWire Loop Antenna Messages to Read :
* Using a SkyWire Horizontal Loop Antenna ? One or Two WaveLengths
Size ?
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/message/191
* SkyWire Horizontal Loop Antenna = Height ?
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/message/184
* "SkyWire" Horizintal Loop Antenna is 'by design' an All "Omni"
Directional Antenna
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/message/151
* SkyWire Loop Antenna Balun (Baluns in General)
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/message/122
* Which BALUN for the SkyWire Loop Antenna ?
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/message/121
* Loop Antennas: SkyWire -vise- Rhombic
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/message/76
* "SkyWire" Loop Antenna
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/message/55
.
Look Up In The Sky ! - its a bird - its a plane - its sure big !
NOooo It's A SkyWire Loop Antenna ! ! ! and its everywhere . . .
.
Once again for those who are interested in Learning More about
the SkyWire Loop Antenna Check-Out the eGroup on YAHOO !
SKYWIRE => http://groups.yahoo.com/group/SkyWires/
.
give me land lots of land to build antennas on, don't CCR me in ~ RHF
.
.
On Sat, 26 Feb 2005 16:06:57 -0500, "Jack Painter" <223...@cox.net>
wrote:
Many folks here are missing the point. It doesn't have to be 2X wavelength
or
even 1X wavelength. Just string up a horiz. loop anywhere you can and as
long as you can make it. Don't worry about height above ground or if it is
in a
circular, square or trapezoid, or what have you, configuration. If it is
anywhere
near as high as your proposed longwire or dipole it will work just as well
but
over a much broader swath of frequencies. Think of its performance as much
like a discone antenna at VHF & UHF - no gain over a half-wave vertical but
very broadbanded. The H-loop "generally" has omni-directional
characteristics
where as a dipole or longwire has definite nulls and peaks around the
compass.
I would guess that my H-loop is about at least 70-75 meters in circumference
at an average height of about 20 ft. It is strung around the edge of my
roof in
a large "L" configuration with the wire tucked under the roofing shingles at
strategic locations - invisible! It has survived several seasons of severe
weather and hasn't budged. I use it for SWLing as well as transmitting on
80-10 meters using a vintage Johnson Matchbox - sweet!
Compared to a dipole or a longwire it doesn't experience those "dips" in
reception on certain bands. Any "dips" that do occur are not as deep and
an antenna matchbox will easily make up for it.
Where anyone obtained the idea you must use dozens of 75+ ft telephone poles
around 100 acres of real-estate has simply never built or used a horiz.
loop.
> Granted, it would undoubtedly work better at greater height, my horizontal
> loop encircles a small section of my woods at varying heights of anywhere
> from 6 feet to (maybe) 15 feet. I ran about 475 to 500 feet of wire,
> hanging it off available tree branches as I went, in what is more or less
a
> square with somewhat bulging sides. I couldn't tell you exactly how much
> wire I used, other than I used enough to form a loop through the woods. I
> couldn't tell you it's impedance. I feed it with coax through a home-made
> 1:1 transformer. I have no complaints with it's performance.
>
> I think there's this expectation by folks new to the hobby that everything
> has to be "labratory" perfect or it's a waste of time. In my experience, I
> have found that wire antenna's are *very* forgiving of imperfections.
> Granted, they will not perform as well as something carefully constructed
> in a labratory environment, but they will *still* work - and there's even
> odds (or better than even) they will work better than expected!
>
> My rule of thumb is: "As much wire as you reasonably can, as high as you
> reasonably can." In different situations, that could be 30 feet of wire at
> house-eave level -or- a 2wl horizontal loop at 1wl above dirt. Just do
> what you can, and are interested in trying, and don't sweat the details
> until *after* you establish a baseline.
>
> -=jd=-
> --
> My Current Disposable Email:
> jd77...@HATpostmark.net
> (Remove YOUR HAT to reply directly)
(( Comments inserted between text ))
--
While it sounds like you have little more than a cloud warmer there (if
otherwise please do advise), you're right that it costs very little to run a
few hundred feet of wire anywhere you can get it. The result could be a
good listening antenna. What it won't normally be is a good transmitter,
unless it meets mimimum design conditions.
Also, don't you worry what kind of RF you illuminate the house with? It
looks to me like people inside could be as close as 2 or 3' from your
antenna, and at most HF frequencies that is way too close to 100+w transmit
power.
--
> Compared to a dipole or a longwire it doesn't experience those "dips" in
> reception on certain bands. Any "dips" that do occur are not as deep and
> an antenna matchbox will easily make up for it.
>
> Where anyone obtained the idea you must use dozens of 75+ ft telephone
poles
> around 100 acres of real-estate has simply never built or used a horiz.
> loop.
>
--
That would be me. I have seen one in use, just never replicated by a
hobbyist (yet). Without the near 1/2 wave design-elevation, a horizontal
wire antenna becomes NVIS (or cloud warmer). We've all heard of people
doing this with their rain gutters for years, but that doesn't translate to
a worthwhile effort when compared to most achievable antenna designs.
--
True enough.
Jack
I couldn't memorize 1 wpm of Morse code in the Boy Scouts, doubt that it is
going to happen 35 years later ;-) I'm on the air for the USCG and they
don't care if we know code or not. A smaller and smaller number of older
chiefs and officers who were hams for a hundred years still know code in the
guard - not much interest in it or radio in general by younger generations,
even when they operate them for a living. Computer networking is what
drives the communication business today, the radios themselves seem a small,
mostly forgotten part of it.
Sorry to have gotten off-topic with the longwire - for listening it is
certainly the most forgiving of any configuration imaginable.
Jack