Just wondering...........

What would be best for my next receiving antenna.

1) A long wire , coax feed (no balun ) about 80 feet, ( earthed coax braid)
15mtrs from house.

or

2) A Long dipole, about 80 feet each side.

Noisy here at times.

What do you reckon?

Best Regards

Jeff

I'd go with the random wire, unless you either have a favorite band to cut the
dipole for (49 meters perhaps), or can feed the dipole with twin lead.

jw
wb9uai

If I had property big enough, I'd have a horizontal antenna running
north-south and another east west. I'd have them connected to a switch and
they would be as long as space permitted, and as high as I could get them.

Lots of people use an antenna sloping at an angle from high to low as long
as at least a 1/2 wavelength of the middle frequency of the band in
question.

Another good antenna is a "V" shaped antenna supported from the middle such
that the length can be as near to 1/2 wavelength of the center frequency of
the band of interest.

However, if a coat hanger gets you the desired reception, then you are home
free s. I don't mean to ridicule ! For receiving, length is not critical -
it IS if you are transmitting, and it becomes very important in relation to
the power output of your transmitter - meaning if there is a significant
mismatch, you can kiss off your radio g.

A wire suspended in space has a specific length. That length can be equated
to the distance between the crests of waves that defines a particular
frequency. If you want to listen to 60 meters 3.28 ft x 60=1968 feet for a
full wavelength. A receiving antenna can be as short as 1/4 of that length
and still present efficient reception of a signal in the 60 meter band,
especially if recieving conditions are good and the broadcaster is using
200,000 watts or more. At the same time, if you have a good receiver and a
good antenna and good conditions, you can have five or six good signals all
arriving at the antenna at the same time. Some signals may be lightening
crashes, or unwanted signals, such as noise from your refer or the
neighbor's computer or car ignition. You have no conrol over that, and the
longer the antenna, the more energy imparted to the wire, and thus the
reciever. You cannot control that, but if you are fortunate enough to have
some audio processing equipment included in your equipment, you might be
able to minimise te unwated sounds.

My antenna is not just one wire. I am fortuante to have an understanding
property manager, and I have three wires of at least 80 feet between my
apartment and a convenient tree running approximately north-south. I also
have a wire slung up into a fir tree up to at least 80'. The 3 wires are
connected together and connect to coaxial cable to the center connector, The
other wire slung up into the fir tree, is connected to the braid of my
coax. the receiver is grounded to an earth ground. There is a cell tower in
the area, and someone has a constant computer signal, and I get hit on
various frequencies. I still listen S. Any length of wire at least 30 feet
to 75 feet in length will make a good antenna. But to be completely
scientific and get the optimum response, calculate the frequency at the
center of the band of most interest, and put up an antenna at least 1/4 of
the wavelength. I always use INSULATED wire. That protects the wire and
protects you from unfortuante accidents involving contact with power lines -
not a good scenario .
"J999w" wrote in message
...
I'd go with the random wire, unless you either have a favorite band to cut
the
dipole for (49 meters perhaps), or can feed the dipole with twin lead.

jw
wb9uai

"Maximus" wrote:

A wire suspended in space has a specific length. That length can be
equated
to the distance between the crests of waves that defines a particular
frequency. If you want to listen to 60 meters 3.28 ft x 60=1968 feet for a
full wavelength.

60 meters = 196.8 feet

A center-fed dipole for 60 meters (5 MHz) would be slightly less than half
that length (about 94 ft).

Art Harris N2AH

J999w wrote:

I'd go with the random wire, unless you either have a favorite band to cut the
dipole for (49 meters perhaps), or can feed the dipole with twin lead.

jw
wb9uai


The long wire would be best if your are going to tune a broad spectrum
of the the bands. Attached to a tuner or pre-selector these wires work
very well. Dipoles are great but are tuned to certain frequencies and
drop off as you tune away from them.

More info on the AMANDX site listed below

--
73 and Best of DX
Shawn Axelrod

Visit the AMANDX DX site with info for the new or experienced listener:

http://www.angelfire.com/mb/amandx/index.html

REMEMBER ON A CLEAR DAY YOU CAN HEAR FOREVER

"JEFF UK" wrote in message ...
Just wondering...........

What would be best for my next receiving antenna.

1) A long wire , coax feed (no balun ) about 80 feet, ( earthed coax braid)
15mtrs from house.

or

2) A Long dipole, about 80 feet each side.

Noisy here at times.

What do you reckon?

Best Regards

Jeff

I'd rather have the dipole I think, but it really doesn't have to be
that large to work well. Would be nice for the lower bands though.
Overall, the dipole will probably give you the best s/n ratios being
it's usually fairly easy to decouple. I'd use a good 1:1 balun or a
coax choke or ferrite beads. If you used a 160 ft 1/2 wave dipole, it
would be resonant at 5.8 mhz as a half wave. 11.6 mhz as two half
waves in phase which is a hi-z feed. About 17.4 mhz as a 1.5 wl
dipole, which is a low Z feed. Other bands will vary... It would work
pretty well on most all the higher bands. The pattern on the upper hf
bands would be multi lobed, and fairly omnidirectional overall. The
mismatch using coax to feed one of these is not worth worrying about
for receiving. The coax loss on any HF band is not enough to lower the
s/n ratio. Not even close unless you have a dead radio or dead coax.
All bands will still have plenty of signal level. But you could use
twin lead and a tuner if you were worried about feedline loss. Another
advantage to the dipole, is you then really have three antennas. The
dipole fed normally. Or you could feed one conducter, "usually the
center pin, by unscrewing the shield and letting ground float" as a
random wire. Or you can tie the center pin to shield at the shack ,
and feed as a single conductor T vertical. Good for 160m, MW, LW,
etc..Myself, I parallel dipoles on the same feedline. Right now, I
have a 80m turnstile, and a 40 dipole on the same coax feed. It's a
good SWL antenna anywhere in the HF spectrum. Sometimes I have
80/40/20. Sometimes 160/80/40. Just depends on the time of the year,
and what I'm working the most. I didn't use a 160 dipole this year, as
I usually prefer my top loaded vertical. MK

Mark, I agree with you on the dipole but expand on it a bit. Build a fan
dipole.
"Mark Keith" wrote in message
om...
"JEFF UK" wrote in message
...
Just wondering...........

What would be best for my next receiving antenna.

1) A long wire , coax feed (no balun ) about 80 feet, ( earthed coax
braid)
15mtrs from house.

or

2) A Long dipole, about 80 feet each side.

Noisy here at times.

What do you reckon?

Best Regards

Jeff

I'd rather have the dipole I think, but it really doesn't have to be
that large to work well. Would be nice for the lower bands though.
Overall, the dipole will probably give you the best s/n ratios being
it's usually fairly easy to decouple. I'd use a good 1:1 balun or a
coax choke or ferrite beads. If you used a 160 ft 1/2 wave dipole, it
would be resonant at 5.8 mhz as a half wave. 11.6 mhz as two half
waves in phase which is a hi-z feed. About 17.4 mhz as a 1.5 wl
dipole, which is a low Z feed. Other bands will vary... It would work
pretty well on most all the higher bands. The pattern on the upper hf
bands would be multi lobed, and fairly omnidirectional overall. The
mismatch using coax to feed one of these is not worth worrying about
for receiving. The coax loss on any HF band is not enough to lower the
s/n ratio. Not even close unless you have a dead radio or dead coax.
All bands will still have plenty of signal level. But you could use
twin lead and a tuner if you were worried about feedline loss. Another
advantage to the dipole, is you then really have three antennas. The
dipole fed normally. Or you could feed one conducter, "usually the
center pin, by unscrewing the shield and letting ground float" as a
random wire. Or you can tie the center pin to shield at the shack ,
and feed as a single conductor T vertical. Good for 160m, MW, LW,
etc..Myself, I parallel dipoles on the same feedline. Right now, I
have a 80m turnstile, and a 40 dipole on the same coax feed. It's a
good SWL antenna anywhere in the HF spectrum. Sometimes I have
80/40/20. Sometimes 160/80/40. Just depends on the time of the year,
and what I'm working the most. I didn't use a 160 dipole this year, as
I usually prefer my top loaded vertical. MK

"CW" wrote in message ...
Mark, I agree with you on the dipole but expand on it a bit. Build a fan
dipole.

Thats basically what I have for 80m. But I think it's probably
overkill for just SWL receiving. I think it would be better to
parallel another smaller dipole at twice the frequency of the lower
one. That way you get a low Z feed on a band that would be a high Z
feed using the lower band dipole alone. That in turn gives you one
more 3/4 wave low Z resonance also. I use the fan dipole/turnstile for
a more omnidirectional pattern on 80m. I can also lengthen one leg,
and make it resonant at two points in the band if I want both phone
and cw. The swr curve becomes a W. But normally, I run them both tuned
to the same freq up in the phone band. The 40 dipole is on the same
feedline, so that antenna has six legs total. Four 60 ft legs, and two
32 ft legs. I run it on 160m as a top loaded vertical by shorting the
coax together down at the tuner. It works pretty well as the current
distribution is fairly constant up the 42 ft coax vertical section.
It's top loaded by mainly the four 60 ft wires, but the 40 legs help a
bit also I guess. It beats my 45 ft tall inv L most of the time.
Usually by appx 10 db on the avg meter. Been hanging out on 1.889.50 a
lot lately. We've been building up a pretty good regional group there.
Lots less qrm than 75m...We can talk all night on 160m and not have
any qrm or hecklers.. Can't always say that about 75. MK

MK,

Good Ideas... But You are thinking with your Amateur/HAM Hat On.

Think like a SWLer who whats a Receive ONLY Antenna that will
work well for all directions on All Bands from 500kHz to 30 MHz.

The Dipole is a Great Frequency Specific Directional Antenna
for use by Amateurs/HAMs for Transmitting.

IMHO: The Random Wire Antenna configured as an Inverted "L"
Antenna using the Low Noise design concepts as popularized by
the writings of John Doty. Would serve a SWLer better for a
Receive ONLY SWL Antenna.
http://groups.yahoo.com/group/SWL-AM...na/message/374


iane ~ RHF
..
..
= = = (Mark Keith)
= = = wrote in message . com...
"JEFF UK" wrote in message ...
Just wondering...........

What would be best for my next receiving antenna.

1) A long wire , coax feed (no balun ) about 80 feet,
( earthed coax braid)
15mtrs from house.

or

2) A Long dipole, about 80 feet each side.

Noisy here at times.

What do you reckon?

Best Regards

Jeff

I'd rather have the dipole I think, but it really doesn't have to be
that large to work well. Would be nice for the lower bands though.
Overall, the dipole will probably give you the best s/n ratios being
it's usually fairly easy to decouple. I'd use a good 1:1 balun or a
coax choke or ferrite beads. If you used a 160 ft 1/2 wave dipole, it
would be resonant at 5.8 mhz as a half wave. 11.6 mhz as two half
waves in phase which is a hi-z feed. About 17.4 mhz as a 1.5 wl
dipole, which is a low Z feed. Other bands will vary... It would work
pretty well on most all the higher bands. The pattern on the upper hf
bands would be multi lobed, and fairly omnidirectional overall. The
mismatch using coax to feed one of these is not worth worrying about
for receiving. The coax loss on any HF band is not enough to lower the
s/n ratio. Not even close unless you have a dead radio or dead coax.
All bands will still have plenty of signal level. But you could use
twin lead and a tuner if you were worried about feedline loss. Another
advantage to the dipole, is you then really have three antennas. The
dipole fed normally. Or you could feed one conducter, "usually the
center pin, by unscrewing the shield and letting ground float" as a
random wire. Or you can tie the center pin to shield at the shack ,
and feed as a single conductor T vertical. Good for 160m, MW, LW,
etc..Myself, I parallel dipoles on the same feedline. Right now, I
have a 80m turnstile, and a 40 dipole on the same coax feed. It's a
good SWL antenna anywhere in the HF spectrum. Sometimes I have
80/40/20. Sometimes 160/80/40. Just depends on the time of the year,
and what I'm working the most. I didn't use a 160 dipole this year, as
I usually prefer my top loaded vertical.
MK
..

JEFF-UK,

Here are three Messages to Read:

The "Low Noise" Antenna Design
- as popularized by the writings of John Doty
http://groups.yahoo.com/group/SWL-AM...na/message/519

Inverted "L' Antenna Reading List {A Compilation}
http://groups.yahoo.com/group/SWL-AM...na/message/374

Compilation of "Low Noise SWL Antenna" Messages
http://groups.yahoo.com/group/SWL-AM...na/message/119


iane ~ RHF
..
Some Say: On A Clear Day You Can See Forever.
http://groups.yahoo.com/group/SWL-AM...na/message/502
I BELIEVE: On A Clear Night... You Can Hear Forever and Beyond !
..
..
= = = "JEFF UK"
= = = wrote in message ...
Just wondering...........

What would be best for my next receiving antenna.

1) A long wire , coax feed (no balun ) about 80 feet, ( earthed coax braid)
15mtrs from house.

or

2) A Long dipole, about 80 feet each side.

Noisy here at times.

What do you reckon?

Best Regards

Jeff