Long wire vs. G5RV/dipole
John
I've been using a G5RV for a number of years for my receivers and it
does a very good job. But I notice that many folks here seem to prefer
a long wire. Is there much difference between a long wire compared to
a G5RV or dipole? And if using a long wire: wouldn't a long wire need
to be electrically matched to the receiver? Or, by using a G5RV, am I
essentially using 1/2 of the antenna as a long wire (the center
portion of the antenna jack on the receiver so to speak). Is one
antenna really that much better than the other? As I said, I've been
using a G5RV for quite a long time and I feel I can pick up just about
the same things other folks do; so I don't believe changing to a long
wire would dramatically improve my reception. But then again, I might
be wrong. Any help would be appreciated in understanding the
difference between the antennas a bit better -- if there is any.
John
Maximus
would need to be matched, but the adavantage would show up in less noise and
fewer images etc. A dipole tuned to the bands you most monitor has the same
advantages. In some areas, a long wire may fetch more signal, but it also
gathers more noise. I guess the best thing to say is that each kind of
antenna has advantages, and some may be more advantageous than others in
relation to the receiver.
Strength and Honor
"John" <johndo...@yahoo.com> wrote in message
news:d2af94ae.04022...@posting.google.com...
RHF
The G5RV is a good Antenna and an Off-Shoot of the common Dipole.
ALL TRANSMITTING THEORY ASIDE:
* For SWLs think of the G5RV as a Dual Opposing Inverted "L" Antenna
with common mode vertical (dual element) Leg.
- Here the G5RV is more Omni-Directional.
* For SWLs some specific Frequencies the Top Arms of the G5RV
Antenna function like a Dipole that is 'cut' for that Band or Bands.
- Here the G5RV is very 'directional' Dipole.
Some G5RV WebSite Links:
* G5RV Multi-Band Antenna - by Louis Varney [G5RV]
http://www.qsl.net/aa3px/g5rv.htm
http://www.astrosurf.com/lombry/qsl-g5rv.htm
http://personal.brunnet.net/markf/g5rv-etc.html
* G5RV Antennas - by Gaylen Pearson [WBØW]
http://www.wb0w.com/g5rv/g5rv_antennas.htm
* G5RV Plus - by RadioWorks
http://www.radioworks.com/cg5rv.html
(Using a 1:1 Balun and Line Isolator)
* G5RV Antenna Radiation and SWR Scans - by Art Unwin [KB9MZ]
http://www.roadkill.com/~unwin/G5RV.html
http://www.roadkill.com/~unwin/gr/
* G5RV Antenna by Keith [WB2VOU]
http://www.g3ycc.karoo.net/g5rv.htm
* The G5RV Antenna System Re-Visited - by L. B. Cebik [W4RNL]
Part 1: The G5RV on 20 Meters <http://www.cebik.com/g5rv.html>
Part 2: The G5RV on All HF Bands <http://www.cebik.com/g5rv2.html>
THE LONGWIRE ANTENNA FOR SWLs:
The commonly called 'LongWire' Antenna is actually a "Random Wire"
Antenna that is used by Shortwave Listener's. The most 'common'
form of the Random Wire Antenna used by SWLs is the Inverted
"L" Antenna. This Inverted "L" Antenna Configuration lends
itself to the Low Noise Antenna design that was popularized
by John Doty.
Inverted "L' Antenna Reading List
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/message/374
"LOW NOISE SWL ANTENNA" - by Mark Connelly [WA1ION]
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/message/119
"Another Look at Noise-Reducing Antenna Systems"
Inverted "L" Antenna as an 'available space' SWL Antenna
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/message/54
"LOW NOISE SWL ANTENNA" - popularized by John Doty.
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/message/2
.
.
REMEMBER: "The Shortwave Antenna is 55.5% of the . . .
Radio/Receiver and Antenna/Ground Reception Equation"
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/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/Shortwave-SWL-Antenna/message/502
I BELIEVE: On A Clear Night...
You Can Hear Forever and beyond, The Beyond !
.
= = = johndo...@yahoo.com (John)
= = = wrote in message news:<d2af94ae.04022...@posting.google.com>...
John
.
David
mhz meters through 25 mHz a big-ass long wire works better than
anything else, on average.
starman
>
> It's been my experience that for listening to all the HF bands from 3
> mhz meters through 25 mHz a big-ass long wire works better than
> anything else, on average.
As a long wire (inverted-L) gets longer, it will become directional on
the higher bands. This may not be desirable, depending on what direction
you're trying to receive.
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John
> JD,
>
> The G5RV is a good Antenna and an Off-Shoot of the common Dipole.
>
> ALL TRANSMITTING THEORY ASIDE:
> * For SWLs think of the G5RV as a Dual Opposing Inverted "L" Antenna
> with common mode vertical (dual element) Leg.
> - Here the G5RV is more Omni-Directional.
> * For SWLs some specific Frequencies the Top Arms of the G5RV
> Antenna function like a Dipole that is 'cut' for that Band or Bands.
> - Here the G5RV is very 'directional' Dipole.
>
Thanks for all the responses so far. Yeah, that "dual opposing
inverted L" seems to make a lot of sense. And it is low noise. As for
directional properties: I don't seem to notice any. Maybe I haven't
bothered to experiment enough; but I've noticed that I seem to receive
stations on a par with reception reports I've read here and other
places. As for the top arms being "cut" for certain bands; again,
maybe I haven't experienced all, but I seem to get all I can get on
any band just as everyone else does. Anyways, those are just my
observations. I have always been happy with the G5RV. Some day I'll
need to get a bit more motivated and stretch out a really long wire
and see what difference it makes at my location.
Again...thanks to all the replies received.
John
CW
these problems.
"starman" <sta...@tech.net> wrote in message
news:403F7E2C...@tech.net...
Mark Keith
> Need a little help here.
>
> I've been using a G5RV for a number of years for my receivers and it
> does a very good job. But I notice that many folks here seem to prefer
> a long wire. Is there much difference between a long wire compared to
> a G5RV or dipole?
Depends...They can be quite the same, "lower bands" or drastically
different, "higher bands" depending on the length of the wire. Also,
you may really mean a "random wire". A true longwire is over one
wavelength or longer. A random wire could be anything...Short, or
long. If it's over one wave long for a certain band, it qualifies as a
true longwire.
And if using a long wire: wouldn't a long wire need
> to be electrically matched to the receiver?
No. Usually not. It's an option. Overkill for most good receivers.
Or, by using a G5RV, am I
> essentially using 1/2 of the antenna as a long wire (the center
> portion of the antenna jack on the receiver so to speak).
A G5RV is a center fed 102 ft dipole, fed with a combo of
coax/choke-balun/twin lead.
It was mainly designed as a 20m antenna. For all band use, G5RV
recommended running ladder line and using a tuner. Same as any other
ladder line fed dipole.
The feedline is NOT intended to be part of the antenna. Calling it
back to back inv L's is quite a stretch...Back to back inv L's would
be both fed from the ground. A normal 1/4 wave inv L mainly acts as a
vertical radiator with a horizontal loading wire. Much more radiation
"current" is from the lower vertical section from the base up, than
from the horizontal wire. Feeders of ladder line or twin lead do not
normally radiate, or act as a vertical antenna element when feeding a
dipole. Being they *should* be balanced, the current cancels. Only
common mode problems would cause feedline radiation. And even if it
did, it would be unlikely to have the mainly vertical pattern of an
inv L. IE: max current at the base, etc...It would be about the same
as a coax fed dipole, with no balun used between the balanced dipole
element and the unbalanced coax. If you stick the center pin only ,
yes, it's about like an inv L or random wire fed from the shack. You
may notice MW and real low HF freq's work better this way...
Is one
> antenna really that much better than the other?
Just depends on what you are using it for.
As I said, I've been
> using a G5RV for quite a long time and I feel I can pick up just about
> the same things other folks do; so I don't believe changing to a long
> wire would dramatically improve my reception.
You are probably right.
But then again, I might
> be wrong.
Nope, I doubt it. :)
Any help would be appreciated in understanding the
> difference between the antennas a bit better -- if there is any.
I prefer center fed dipoles over most random wires because they are
balanced, and it's easier to avoid common mode problems. For
receiving, this usually means a quieter antenna with less shack noise.
They are also complete antennas within themselves, and do not require
a ground, or radials to supply the missing half of the antenna. As far
as pattern, it all depends...Some *real* longwires, IE:
multi-wavelengths long, are quite directional. But even a 10 wave wire
on 28 mhz would have trouble beating my tri band yagi. And the yagi is
rotatable. MK
RHF
JOHN,
There is only way that you will be able to "KNOW For Sure" that
your current G5RV Antenna is Omni-Directional or very Directional
on various SW Bands.
Take the G5RV Antenna down; and re-mount the G5RV Antenna
perpendicular (90*) to it's former position.
Then try listening to your old good stations and next Scan the
SW Bands for new stations that you could not hear before.
IF - The old Stations are 'weaker' and you are hearing NEW
Stations: Then your G5RV is very Directional like a Dipole.
However - If the old Stations 'sound-the-same' and you can not
hear any New Stations: Then your G5RV is Omni-Directional.
iane ~ RHF
.
Mark Keith
Will depend on the band quite a bit though. Will always be pretty
omnidirectional on the low bands, unless the antenna is real high in
wavelength for the band used. "1/2 wave or higher" Max gain will be
straight up for the usual heights involved.
The G5RV acts pretty much as an 1.5 wl dipole on 20m, and should show
broadside gain of 2-3 db over a 1/2 wave dipole. The maximum "clean"
broadside gain will be at about 12 mhz. "appx 5 dbi". This is where
the antenna is an extended double zepp. The pattern is X shaped on
20m, with less gain. On 21 mhz, you will see an X pattern with about
4.7 dbi in four directions. On 28 mhz, you have a six lobe pattern
with max gain in four "x" directions. "about 4.6 dbi". But even with
the lobes and gain, it's quite probable you wouldn't totally lose any
station when turning 90 degrees, due to ground effects, metal in the
area, etc, unless you found a fluke good null by chance. You could
peak a few up though, and probably find a few good nulls, if you could
rotate the antenna.
The G5RV will act the same as any other 102 ft dipole, assuming no
feedline radiation. "Which it shouldn't have". If I were to run a G5RV
for all bands, I'd feed it with ladder line the whole way to the
tuner. I'd dump the coax and choke. Just causes excess loss, and a
quite larger chance of imbalance. MK
starman
>
> Whatever works best for you should be what you use <S>. I think a long wire
> would need to be matched, but the adavantage would show up in less noise and
> fewer images etc. A dipole tuned to the bands you most monitor has the same
> advantages. In some areas, a long wire may fetch more signal, but it also
> gathers more noise. I guess the best thing to say is that each kind of
> antenna has advantages, and some may be more advantageous than others in
> relation to the receiver.
A properly grounded (decoupled) long wire or inverted-L antenna can be
very quiet.
http://www.anarc.org/naswa/badx/antennas/low-noise_antenna.html