Noise Reducing Antennas
Alfred E. Newman
identical to noise reducimg antenna ideas found in articles by Denzil
Wraight and me which were published in DX News in 1991. Denzil's article
was titled "Interference Reducing Antennas For The BCB," and mine was
"Inverted L Noise Reducing MF/VLF Antenna." Denzil and I used twinlead
rather than coax. However, Mark Connelly published descriptions of similar
noise reducinmg antennas using coax in DX News later in 1991. These
articles are available from The National Radio Club http://www.nrcdxas.org/
as reprint A69. Contrary to what John claims, these kinds of noise reducing
antennas are not very effective against noise at SW frequencies much above 6
MHz. These types of noise reducing antennas were invented by F. R. W.
Strafford in or about 1936, and he discusses these and other types of noise
reducing antennas for short waves in "Screened Aerials," Wireless World,
November 25, 1937, pages 516 - 518.
Best regards,
Dallas
RHF
Long ago John Doty corrected me on the 'fact' that he did not "Invent"
these Antennas or the Design Concepts of these Low Noise Antennas.
However, within this Forum {Rec.Radio.Shortwave} his 'articles'
{Writings} and his 'name' are/is the most often cited reference
concerning this topic.
This is why I say {write}
"Low Noise SWL Antenna" using the 'design concepts' that were
popularized by John Doty.
READ - Three "Must" Links to Read -wrt- Low Noise SWL Antenna
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/message/949
NOTE: John Doty's 'articles' {Writings} and his 'name' are/is
available freely on the Web (WWW) and thus Millions may View and Read
them.
AEN - ? Have you consider 're-printing' your 'articles' {Writings} on
the Web (WWW) and making them Free for All to View and Read ?
AEN - Doing so, may provide you with the recognition that you so justly
deserve.
TBL: As to whether, the "Low Noise" Antenna 'design concepts' work
well for Shortwave Listener (SWL) Antennas: They have improved my
Shortwave Listening with good signal levels and much lower noise. What
more can I say: "I Ain't No Elmer !"
Enjoy Listening to your Radio/Receivers with your Antennas.
iane ~ RHF
.
All are WELCOME at the Shortwave Listener (SWL) "Antenna Ashram"
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/message/502
Some Say: On A Clear Day You Can See Forever.
I BELIEVE: On A Clear Night . . .
You Can Hear Forever and Beyond, The BEYOND !
[ With the a SWL Antenna of your own making. ]
.
.
Alfred E. Newman
I am puzzled. If, as you wrote, John corrected you on the 'fact' that he
did not "Invent" these Antennas or the Design Concepts of these Low Noise
Antennas, then presumably he told you who did. So why have he and you
neglected to mention that in your writings?
It was Denzil Wraight, in fact, who rediscovered Strafford's work on noise
reducing antennas, and who discovered by trial and error reasonable turns
ratios for the antenna matching transformers (Strafford does not discuss
that in his articles). So it is Strafford and Wraight that Doty plagiarized
and you failed to cite. Denzil used a vertical noise reducing antenna,
wrote me about how well it worked, and included a copy of Strafford's
Wireless World article. First I constructed a "top fed" vertical version
with mast almost touching my house. I didn't expect it to do much fow man
made noise in the MW band (my main interest), but to my surprise it did. In
my case, there was little, if any, difference noise reduction between
mounting the vertical mast almost touching my house, or 100 feet away. So
this kind of noise reducing antenna is ideal for DXers with limited space.
Next I implemented an inverted L version of Strafford's noise reducing
antennas. If I recall correctly, the first L was about 100 feet horizontal
and 15 feet vertical. I experimented with both base feed and top feed.
Both gave excellent noise reduction in the MW (and VLF) band(s). Both
Denzil and I used twin feed instead of coax because twin feed tends to pick
up less local nois than coax. Denzil and I wrote two separate articles for
DX news (The National Radio Club http://www.nrcdxas.org/ reprint A69) that
were published in the early summer of 1991. I had sent Mark Connelly
preprints of our arfticles, and he developed coax feed versions of
Strafford's noise reducing antennas. According to Mark, the coax feed
variant picked up little, if any additional noise compared to the twin feed
version. At one point in these experiments I tried shielded twin lead, but
found no further noise reduction (or increase).
Presently I use top fed inverted L noise reducing antennas as parts of my
phased arrays. Unless you are listening above 16 MHz or so, or have an
insensitive receiver, you don't really need (or want) a big inverted L. Mine
are 15 feet up and 30 feet horizontal. The matching transformer we
used then (and which I still use now) is an Amidon FT-114-75 (the 75
material may have been replaced with J material), 43 turns to 9 turns (at
the center of the 43 turns) #20 enameled copper wire. The twin lead I still
use is Radio Shack speaker wire (#18 stranded, 7 strands of, I think, #26).
It is cheaper ane easier to use than real twin lead, and had about the right
characteristic impedance (about 100 ohms). You'll need a balun (1:1) at
your receiver to convert the balanced lead in to your unbalanced receiver
antenna input (9 bifilar turns of #20 enameled on an FT-114-75 will do).
Like I said before, the noise reducing properties of these kinds of antennas
begin to decline as you go higher in frequency, and above 6 MHz there is not
much noise reduction. If you believe you got substantial noise reduction
above 6 MHz due only to using one of these kinds of antennas, then you are
mistaken. For SW, Strafford recommended doublet antennas for noise
reduction. I do not have much experience with these because I am not much
of a SW listener. What little experience I have suggests that phased arrays
are much more effective at reducing SW noise sources. Unfortunately,there
are no good phasers that you can buy.
As for publishing these articles on the web, that would involve considerable
work. The articles were produced with typewriters, and contain hand
drawings. To convert them to .PDF or other files would be non-trivial, and
would require NRC approval. Anyone who wants these articles can easily
purchase them as reprints from the NRC at the web site above using PayPal or
other methods of payment.
Best regards,
Dallas
"RHF" <rhf-new...@pacbell.net> wrote in message
news:1102356925.4...@c13g2000cwb.googlegroups.com...
Telamon
"RHF" <rhf-new...@pacbell.net> wrote:
> DALLAS {aka: AEN} ,
>
> Long ago John Doty corrected me on the 'fact' that he did not "Invent"
> these Antennas or the Design Concepts of these Low Noise Antennas.
>
< Snip >
Scientists and engineers have been pondering electromagnetism, antennas
and transmission lines for a century so it's hard to come up with
something new.
--
Telamon
Ventura, California
4nradio
http://www.kongsfjord.no and look under the section "The Dallas Files".
I particularly have benefited from his review and mods for the ICOM
IC-746Pro, as it helped me in my decision to buy and modify a IC-756Pro
(which as very similar receive circuitry).
Guy Atkins
Puyallup, WA USA
"RHF" <rhf-new...@pacbell.net> wrote in message
news:1102356925.4...@c13g2000cwb.googlegroups.com...
<SNIP>
> AEN - ? Have you consider 're-printing' your 'articles' {Writings} on
> the Web (WWW) and making them Free for All to View and Read ?
<SNIP>
John Doty
> Hi whatever your name is,
>
> I am puzzled. If, as you wrote, John corrected you on the 'fact' that he
> did not "Invent" these Antennas or the Design Concepts of these Low Noise
> Antennas, then presumably he told you who did. So why have he and you
> neglected to mention that in your writings?
RHF can't tell you because I didn't tell him. I didn't tell him because
I don't know. I know that the principles behind this kind of system were
well understood by radio engineers 70 years ago. I don't know the
original sources.
The idea of using a transmission line to prevent EMI pickup goes back at
least to 1877. According to the February 19, 1881 issue of Scientific
American, the US patent office ruled (in a dispute with Alexander Graham
Bell) that David Brooks had invented the "return wire" as a way to
reduce crosstalk between telegraph and telphone lines (and if someone
were to cite earlier work by, say, Kelvin, I wouldn't be surprised).
>
> It was Denzil Wraight, in fact, who rediscovered Strafford's work on noise
> reducing antennas, and who discovered by trial and error reasonable turns
> ratios for the antenna matching transformers (Strafford does not discuss
> that in his articles). So it is Strafford and Wraight that Doty plagiarized
> and you failed to cite.
I've never heard of either of these people. My approach is apparently
more theoretical: if you understand the physics you don't need to
experiment with turns ratios (it's a "back of the envelope"
calculation). My writing is my own, not copied from anyone. The design
itself is a combination of well known ideas that should be obvious to an
expert: that makes it engineering, not invention.
> Denzil used a vertical noise reducing antenna,
> wrote me about how well it worked, and included a copy of Strafford's
> Wireless World article. First I constructed a "top fed" vertical version
> with mast almost touching my house. I didn't expect it to do much fow man
> made noise in the MW band (my main interest), but to my surprise it did. In
> my case, there was little, if any, difference noise reduction between
> mounting the vertical mast almost touching my house, or 100 feet away. So
> this kind of noise reducing antenna is ideal for DXers with limited space.
> Next I implemented an inverted L version of Strafford's noise reducing
> antennas. If I recall correctly, the first L was about 100 feet horizontal
> and 15 feet vertical. I experimented with both base feed and top feed.
> Both gave excellent noise reduction in the MW (and VLF) band(s). Both
> Denzil and I used twin feed instead of coax because twin feed tends to pick
> up less local nois than coax.
If you're getting less pickup with twin lead than coax, there's
something amiss with the way you're using the coax. In general, coax
picks up much less than twinlead. The EM field of coax is confined
within the cable. The field of twinlead surrounds the cable, making it
much more susceptible to to external coupling.
> Denzil and I wrote two separate articles for
> DX news (The National Radio Club http://www.nrcdxas.org/ reprint A69) that
> were published in the early summer of 1991. I had sent Mark Connelly
> preprints of our arfticles, and he developed coax feed versions of
> Strafford's noise reducing antennas. According to Mark, the coax feed
> variant picked up little, if any additional noise compared to the twin feed
> version. At one point in these experiments I tried shielded twin lead, but
> found no further noise reduction (or increase).
I got to know Mark a few years after I wrote the article. His approach
is similar to mine, but there are some important differences. He uses
transformers for isolation as well as matching. I shunt the common mode
current to ground at the ground stakes, while absorbing the common mode
energy by burying the coax between them.
Mark never accused me of intellectual theft.
>
> Presently I use top fed inverted L noise reducing antennas as parts of my
> phased arrays. Unless you are listening above 16 MHz or so, or have an
> insensitive receiver, you don't really need (or want) a big inverted L. Mine
> are 15 feet up and 30 feet horizontal. The matching transformer we
> used then (and which I still use now) is an Amidon FT-114-75 (the 75
> material may have been replaced with J material), 43 turns to 9 turns (at
> the center of the 43 turns) #20 enameled copper wire. The twin lead I still
> use is Radio Shack speaker wire (#18 stranded, 7 strands of, I think, #26).
> It is cheaper ane easier to use than real twin lead, and had about the right
> characteristic impedance (about 100 ohms). You'll need a balun (1:1) at
> your receiver to convert the balanced lead in to your unbalanced receiver
> antenna input (9 bifilar turns of #20 enameled on an FT-114-75 will do).
>
> Like I said before, the noise reducing properties of these kinds of antennas
> begin to decline as you go higher in frequency, and above 6 MHz there is not
> much noise reduction. If you believe you got substantial noise reduction
> above 6 MHz due only to using one of these kinds of antennas, then you are
> mistaken. For SW, Strafford recommended doublet antennas for noise
> reduction. I do not have much experience with these because I am not much
> of a SW listener. What little experience I have suggests that phased arrays
> are much more effective at reducing SW noise sources. Unfortunately,there
> are no good phasers that you can buy.
I measured 36 dB of EMI reduction at 25 MHz with one of my antennas. If
you're not getting good EMI reduction at SW there's some important
difference between your approach and mine.
>
> As for publishing these articles on the web, that would involve considerable
> work. The articles were produced with typewriters, and contain hand
> drawings. To convert them to .PDF or other files would be non-trivial, and
> would require NRC approval. Anyone who wants these articles can easily
> purchase them as reprints from the NRC at the web site above using PayPal or
> other methods of payment.
The trouble is that most people who are interested will never even know
what to order. Allowing your work to be freely published on the web is a
good way to get it circulated. Credit for ideas tends to flow to those
whose disseminate them, regardless of precedence or the desires of the
people involved.
>
> Best regards,
>
> Dallas
-jpd
RHF
"RHF" are my 'initials' and for most of my work life I was "RHF"
DALLAS - Now I say that "I am a Work-A-Holic in Recovery;
Living Retired, Healthy and Free in OK-Land, Cali-4-Ni-A."
- "RadioHighFreq" on Yahoo eGroups.
- "Retired-Health-and-Free" on eBay.
- My eMail Address for Rec.Radio.Shortwave is
<rhf-new...@pacbell.net>
Anyone what to guess what my initials are ? ? ?
DALLAS ? So tell me Dallas why do you post here as "Alfred E. Newman"
?
DALLAS - Here is what John Doty 'posted' :
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
- - - - - -
John Doty Jan 11, 2004 @ 7:35 pm show options
Newsgroups: rec.radio.shortwave
From: j...@w-d.org (John Doty)
Date: 11 Jan 2004 19:35:33 -0800
Local: Sun, Jan 11 2004 7:35 pm
Subject: Re: N8KDV Random Wire Antennas -&- N8KDV Ten-to-One (10:1)
Matching Transformer
Reply | Reply to Author | Forward | Print | Individual Message | Show
original | Report Abuse
N8KDV <n...@nospam.iserv.net> wrote in message
<news:4000D076...@nospam.iserv.net
>...
> Also, I'm afraid to point out that the
> design pre-dates the John Doty concept. (as far as I know).
True. There was nothing really new in my design. I wrote up the design
because I hadn't seen a good clear explanation of nonresonant wire
antennas with effective common mode decoupling. The article has been
posted on several web sites and published in several newsletters:
people seem to find it helpful. But it doesn't represent an invention,
it's just a piece of writing.
John Doty
"You can't confuse me,
but an unreliable news server can make posting difficult!"
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
- - - - - -
DALLAS - Here is my 'reply'
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
- - - - - -
RHF Jan 12, 2004 @ 1:47 am show options
Newsgroups: rec.radio.shortwave
From: rhf-m...@pacbell.net (RHF)
Date: 12 Jan 2004 01:47:14 -0800
Local: Mon, Jan 12 2004 1:47 am
Subject: Re: N8KDV Random Wire Antennas -&- N8KDV Ten-to-One (10:1)
Matching Transformer
Reply | Reply to Author | Forward | Print | Individual Message | Show
original | Report Abuse
JPD,
I guess I will have to to change my attribution line.
FROM: Low Noise Antenna Design Concepts
- written by John Doty
TO: Low Noise Antenna Design Concepts
- as popularized by the writings of John Doty
http://www.anarc.org/naswa/badx/antennas/low-noise_antenna.html
Build-It-YourSelf and Hear the Difference.
>From the Association of North American Radio Clubs (ANARC) WebSite
and the Rec.Radio.ShortWave (NG) WebPage.
IMHO: No one can deny that your Writings about the Low Noise Antenna
Design Concepts have 'helped' to "Popularize" those design concepts.
iane ~ RHF
.
.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
- - - - - -
About "POPULARIZE" : Legendary "Henry Ford" may not have invented or
engineered
the Automobile; but no one can dispute that he was a prime figure in
POPULARIZING
the Automobile in the USofA by making a 'basic and reliable'
Automobiles like the
Model "A" and "T that were Economically Affordable for many Americans.
One could make the same statement about Bill Gates and MicroSoft;
MS-DOS
and Windows.
DALLAS - I Remain 'rhf' ~ RHF - aka - a Really Happy Fella :o)
.
.
Mark Keith
>
> John Doty's noise reducing antenna ideas from his 1993 posting are virtually
> identical to noise reducimg antenna ideas found in articles by Denzil
> Wraight and me which were published in DX News in 1991.
Decoupling a feedline is decoupling a feedline....
Denzil's article
> was titled "Interference Reducing Antennas For The BCB," and mine was
> "Inverted L Noise Reducing MF/VLF Antenna."
Is that an oximoron? Seriously...Using an omnidirectional antenna to
reduce *noise* on those bands is kinda counterproductive seems to me...
Denzil and I used twinlead
> rather than coax. However, Mark Connelly published descriptions of similar
> noise reducinmg antennas using coax in DX News later in 1991. These
> articles are available from The National Radio Club http://www.nrcdxas.org/
> as reprint A69. Contrary to what John claims, these kinds of noise reducing
> antennas are not very effective against noise at SW frequencies much above 6
> MHz.
Uhh...Decoupling a feedline is decoupling a feedline. No matter what
frequency...
You can do it at 440 mhz just fine... All my antennas are well
decoupled, and that includes from MW to 440 mhz.
> These types of noise reducing antennas were invented by F. R. W.
> Strafford in or about 1936, and he discusses these and other types of noise
> reducing antennas for short waves in "Screened Aerials," Wireless World,
> November 25, 1937, pages 516 - 518.
Decoupling the feedline has been around for quite a while...
I guess I have one issue though, and yes, I am anal retentive...I object
to *any* antenna being called a "low noise" antenna. Why? Cuz they don't
exist. These is no such thing. They should describe all of these types
of decoupled antenna schemes as "examples of better decoupled antenna
*systems*. The lower noise has nothing to do with the antenna itself.
Only the decoupling of the line, coax or ladder line. And to top this
off, if you are in a quiet area with no noise to pickup, using the
decoupling schemes will not do *anything* at all to reduce noise. The
performance will be exactly the same. IE: out in the woods, running
battery power, etc...A *true* noise reducing *antenna* would work
anywhere, but again, as far as I'm concerned, they don't exist. The on;y
way to really reduce noise using the antenna itself, would be to change
polarity. That would reduce an opposite polarized signal about 20 db or
so...
As far as the decoupling losing effectiveness over a certain freq, thats
a design issue with the decoupling scheme being used. Balun, chokes,
etc...BTW...I include the so called "shielded loops" with the "misnamed"
antenna group. In all tests I've ever run, I've never seen any
indication a shielded loop is any *quieter* to noise pickup than a
regular open loop. But the reason there is not due to decoupling of the
feedline per say, although a lack of decoupling can effect the overall
balance. It's due to the shielded loop providing inherent good balance
due to it's design. But if you have an open loop just as well balanced,
it will null noise sources just as well as a shielded loop. A shielded
loop is not any quieter to far field noise, than any other loop if you
are not using it to null the noise source. It *could* do a better job of
nulling that source, *if* the balance on the open loop was poorer, but
again, this is a design issue..You can design the open loop to be just
as balanced. MK
John Doty
> I guess I have one issue though, and yes, I am anal retentive...I object
> to *any* antenna being called a "low noise" antenna. Why? Cuz they don't
> exist. These is no such thing. They should describe all of these types
> of decoupled antenna schemes as "examples of better decoupled antenna
> *systems*.
One trouble is that many potential readers wouldn't understand such a
pedantic article title.
> The lower noise has nothing to do with the antenna itself.
> Only the decoupling of the line, coax or ladder line.
You can't decouple the line from an unbalanced antenna that lacks a
counterpoise. You can argue that really isn't an antenna (and I would
agree!), but such things are sold as "antennas". The most commonly
recommended "antenna" for the newbie is a "random wire", technically
only half of an unbalanced dipole. Even professionals aren't immune from
this technical error: unbalanced dipoles are often called "monopoles"
even though Maxwell's equations forbid a true monopole antenna.
Even if a counterpoise is present, the design of the antenna influences
your ability to effectively decouple it from the line. Ungrounded but
unsymmetrical antennas (like "slopers") are particularly troublesome.
> And to top this
> off, if you are in a quiet area with no noise to pickup, using the
> decoupling schemes will not do *anything* at all to reduce noise. The
> performance will be exactly the same. IE: out in the woods, running
> battery power, etc...A *true* noise reducing *antenna* would work
> anywhere, but again, as far as I'm concerned, they don't exist.
In the article in question, I wrote, "The real trick with a shortwave
receiving antenna system is to keep your receiver from picking up noise
from all the electrical and electronic gadgets you and your neighbors
have". Plainly, I was not talking about receiving systems out in the woods.
I'm a professional physicist: I can be as fussy and pedantic as you'd
like. Unfortunately, that rarely leads to effective communication. SWL's
write to me to tell me that following my advice has improved their
reception, and several DX websites host copies of my article. I like to
think that shows I've communicated something that matters to people. You
seem to know quite a bit about this stuff: why not write up *your*
approach to these issues?
-jpd
Telamon
Low noise antennas exist and one type is a shielded loop. The noise
improvement is from local noise sources not distant radiating far fields.
Inefficiently radiating local noise sources tend to spread out the
electric field where the magnetic field stays closer to the source.
These are induction fields not radiating fields. It is well known that
local noise source problems are due to common mode inductive electric
field pickup.
Mono-poles (Marconi 1/4 wave) and dipoles are examples of voltage
sensitive antennas. Loop or folded dipoles are examples of antennas
more sensitive to magnetic fields than electric.
A Mono-pole is great at picking up common mode electric fields and is
the worst type in noisy areas. It is very insensitive to local magnetic
fields.
Small unshielded loops are good at picking up local magnetic fields and
poor at picking up local electric fields. Shielding the loop makes it
even less sensitive to local electric fields.
Decoupling the unbalanced transmission line allow a balanced antenna to
stay that way. The balanced antenna is less sensitive to local common
mode electric fields.
Decoupling the transmission line helps prevent noise picked up on it's
outer shield from coupling to the antenna or noise from the mains
supply, through the radio and coax from coupling to the antenna.
If you don't live in the woods and if you or your neighbors have
electrically noisy electronic devices that radiate poorly but still
generate spread out electric common mode fields then the worst type to
best type relative to another is:
1. 1/4 wave Marconi mono-pole electric field sensitive unbalanced.
2. 1/2 wave dipole electric field field sensitive balanced antenna.
3. 1 wavelength or larger loop antenna which is a mix of electric and
magnetic field sensitive antenna. This antenna is balanced.
4. 1/10 wave or less loop antenna which is balanced, mostly magnetic
sensitive and has very poor electric field pickup.
5. 1/10 wave or less shielded loop which is generally better balanced
than unshielded and the least sensitive to local noise electric fields.
RELATIVELY SPEAKING "5" is a "low noise" antenna compared to "1" as far
as locally generated noise is concerned.
--
Telamon
Ventura, California
hjs...@cs.com
on noise
reducing antennas,..."
After reading the above statement I don't see where you and Denzil have
created something that could be plagarized. You and Denzil did what a
lot of others have done in the world of amateur radio, and that is to
use, combine and possibly update the work of others.
It is great that you have continued the research on noise reducing
antennas, but by your own words you cannot claim ownership. This
topic has been researched and rehashed for decades. Since Strafford
published in 1937 and is probably long gone from this world, his
descendants should be the ones to raise a complaint. But then again
maybe Strafford used the work of someone else...what do you think.
nm...@wt.net
didn't read it before writing the post, although I think I have read it
some time in the past.
The reason I bring it up, is some seem to get the idea that the
antennas themselves are
"quieter". As far as local noise, and decoupling, I don't consider
adding
decoupling to an antenna, as making it "low noise", even though that
may be an
end result. I just consider that as allowing the antenna to work
properly, without the feedline becoming part
of the antenna. All my antennas are decoupled, and I consider *none* of
them
as being "low noise" antennas. I have no interest in writing articles
per say. I "write"
up my approaches to this, right here on usenet. As far as "incomplete"
antennas, I don't
spend much time thinking about them, as I don't use them. I mean, if
you look at the title,
"Noise reducing antennas", it's very misleading to some. Or could be.
There is no such thing.
nm...@wt.net
> improvement is from local noise sources not distant radiating far
fields.
Of course. To me, this proves my point about the antenna in itself. But
again, I don't
consider adding decoupling as making an antenna or even antenna system
"low noise".
That might be an end result to a guy with loads of local noise, but to
a guy in the woods,
it means nada...His noise level in the woods should still be the same.
As far as #1,
1/4 wave Marconi mono-pole electric field sensitive unbalanced., as
being a worst case,
I would think that depends on how it's set up. IE: grounded at the
base, radials, etc as
John mentioned...I never run "incomplete" antennas. Ever...
My 1/4 wave's are not overly prone to common mode problems, but as I
mentioned, if I use a
1/4 wave, it would be properly installed with the lower "half" of the
antenna included,
either as radials, or at least grounded. A balanced coax fed dipole can
be quite bad, if the operation
of the choke, balun, etc is not functioning properly. This would
usually show up more on bands higher
than it's half wave length. IE: Using a 40 meter dipole on 20 meters,
etc..With the hi Z feed on
20m, a usual 1:1 balun would be fairly useless as far as decoupling the
feedline. MK
BTW, if the type on these post's gets goofy, it's cuz I'm using the new
google "beta" and the line wrapping
has changed, and is driving me nuts...It wants to run off the page
forever, unless I manual hit return, and that
drives me crazy. The "old" google, auto wrapped as you typed. Why do
they always
have to mess up something that works perfectly well as is....Or
was...Overall, I don't
like this new google beta much at all.
nm...@wt.net
> improvement is from local noise sources not distant radiating far
fields.
Of course. To me, this proves my point about the antenna in itself. But
RHF
Its about 'effective communication' as John Doty posted earlier
in this thread.
The average Shortwave Listener (SWL) who owns a Shortwave Radio
and WANTS More-Out-of-It; simply wants to 'know':
- What to Buy and How to Put It Up.
- Or - What to Build and How to Do It.
- NO Rhyme-or-Reason is Required [.]
[ Please - Just Tell Me - What To Do ]
1. So 'suggesting' they Buy a PAR End Fed Shortwave Listener
(EF-SWL) Antenna and 'configuring' the Antenna in the [Shape]
of an Inverted "L" Antenna.
PAR Electronics "End Fed Shortwave Listener" (EF-SWL) Antenna
POPCOM=> http://www.popular-communications.com/23HomelandOct04.html
MT=> http://www.monitoringtimes.com/html/mt2003reviews.html
eHAM=> http://www.eham.net/reviews/detail/3707
PAR=> http://www.parelectronics.com/swl_end.htm
UR=> http://www.universal-radio.com/catalog/sw_ant/2205.html
GE=> http://www.grove-ent.com/ANT8.html
Telling the SWL 'what-to-do' in general simple terms.
http://tinyurl.com/66lhs
http://tinyurl.com/683gd
http://tinyurl.com/4qmqw
2. Or simply 'recommending' that they READ three WebPages
to gain some understanding of the "Low Noise" SWL Antenna.
http://tinyurl.com/4kp7m
CONSIDER BUILDING A "LOW NOISE" ANTENNA:
Try building an Improved SWL Random Wire Antenna that uses a
9:1 Matching Transformer (Balun / MLB) then you may not see
any real 'improvement' in your receive signal.
This is the so called "Low Noise" SWL Antenna.
Three "Must" Links to Read -wrt- Low Noise SWL Antenna
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/message/949
[ Please READ These Three Links ]
http://www.anarc.org/naswa/badx/antennas/low-noise_antenna.html
http://www.anarc.org/naswa/badx/antennas/SWL_longwire.html
http://www.anarc.org/naswa/badx/antennas/grounding.html
ABOUT THE "LOW NOISE" ANTENNA 'DESIGN CONCEPTS':
A Random Wire Antenna Element coupled via a 9:1 Matching
Transformer at the Near-End of the Antenna with a Ground
Rod and Coax Cable Feed-in-Line to the Receiver. This is
the basic SWL Antenna that uses the "Low Noise Antenna"
'design concepts' that were {popularized} by John Doty.
.
nm...@wt.net
RHF wrote:
> "N",
>
> Its about 'effective communication' as John Doty posted earlier
> in this thread.
I think I've fairly well communicated my thoughts on the matter...
Thats all I intended to do. But it seems some have problems with even
that..
Every time I post something here, I get a load of @$#^$*%('s climbing
down my back. Get over it! If you disagree with something I say, fine.
I have
no problems with that. But to harp just because I won't dumb myself
down to
your "supposed" r.r.s.w. monkey level status, really starts to grate on
my nerves.
>
> The average Shortwave Listener (SWL) who owns a Shortwave Radio
> and WANTS More-Out-of-It; simply wants to 'know':
I'm not an "average" shortwave listener, and I don't claim to cater to
them.
Actually, I don't claim to cater to anyone....It's not my job.
>
> - What to Buy and How to Put It Up.
That will stir more conflict than this thread....:/
>
> - Or - What to Build and How to Do It.
I think the user should decide that. Not some guy 1000 or more miles
away...
Only he knows what he really wants or needs..I have no problems telling
someone how to build something, but for the most part, it's all been
covered a
zillion times over...Thats why they sell books. Thats why I have books.
>
> - NO Rhyme-or-Reason is Required [.]
I can't live that way myself. I refuse to be "dumbed down" to trained
monkey
level, just because this is a shortwave listeners group. If I get too
technical for some,
"which I really don't think I do", or I get anal retentive because
people
keep calling certain antennas "low noise", they can just ignore it.
Many people *do* want
to know the truth,or maybe a little more detail about certain things.
They may not reply
to any of the posts.
Many people read the stuff,that never actually post. It's not like I
use a bunch of
fancy named mumbo jumbo, or obtuse theories designed to confuse people.
If they want to
call them "lower noise antenna systems", I'd have less problem with
that. But as I
said, I don't consider simply decoupling a feedline as making it a "low
noise" antenna
system. Even if that could be the end result for some. It's just acting
normally without
the common currents screwing up the operation.
If you take a milked down stock 302 ford engine with say 150 hp when
running
normally, and 2 plugs are fouled, allowing only 110 hp out, changing
all the plugs
does not make the engine a blueprinted 400 hp race engine. It will now
run properly with
the new plugs, but it will still be the same stock 150 hp engine. This
probably won't make much sense
to you, but that's a fairly fitting analogy I think...
The decoupled antenna system is just acting normally. The un-decoupled
antenna system
is not. It's a defective system. It would be more accurate to call such
a system a "high noise" system, than
it is to call the decoupled system "low noise". Or to me anyway...
I just want to make sure people understand that the lower noise they
experience
is due to decoupling the feedline from the antenna, and has nothing to
do with
the antenna itself. I'm sure many already realize this. But it seems
fairly obvious many
don't. I'm also sure not *everyone* wants to live in the dark like a
mushroom.
I make no apologies for being anal retentive. That is my job. :)
> [ Please - Just Tell Me - What To Do ]
Why? It's not my job....:/ You should already be fairly well set up
anyway
judging from all the links you post ...:)
MK
RHF
All of what you have written defines You 'being' YOU !
{and that is Good}
All of what I have written defines Me 'being' ME !
{and that is Good}
.
i guess we are communicating - pal ~ RHF
.
.
Michael Lawson
"bpnjensen" <bpnj...@yahoo.com> wrote in message
news:1102693091.6...@c13g2000cwb.googlegroups.com...
> Guys Guys - there is both room for, and value in, both approaches.
>
> I'm glad that both of you post here. Keep those antenna tips
coming!
Which reminds me....
I was perusing the ground articles in hard-core-dx.com,
and I was curious about one of the articles there (probably
was one of John's) stating that a good way of eliminating
common mode interference is to ground the shield separately
away from the 9:1 transformer. That I can do easily, but I
was curious about the next statement about attaching the
ground directly to the shield.
My thinking is that it would be smarter to attach the ground
to the shield via a ground block, but the only ground blocks
I can find use the F connectors, not the 239/259 ones. Is it
necessarily a good idea to strip the coating off the coax,
exposing the shield, and clamping that shield to the ground
rod? Seems like you'd be exposing the connection to the
elements, probably hastening the demise of the coax at that
point. Not to mention the changing of the interaction of
the two conductors by changing it's form...
--Mike L.
Jack Painter
"Michael Lawson" <mtl@[REMOVE-TO-REPLY]fuse.net> wrote in message
news:0doud.533$sY5...@fe37.usenetserver.com...
Jack Painter
"Michael Lawson" <mtl@[REMOVE-TO-REPLY]fuse.net> wrote
> Which reminds me....
>
> I was perusing the ground articles in hard-core-dx.com,
> and I was curious about one of the articles there (probably
> was one of John's) stating that a good way of eliminating
> common mode interference is to ground the shield separately
> away from the 9:1 transformer. That I can do easily, but I
> was curious about the next statement about attaching the
> ground directly to the shield.
>
> My thinking is that it would be smarter to attach the ground
> to the shield via a ground block, but the only ground blocks
> I can find use the F connectors, not the 239/259 ones. Is it
> necessarily a good idea to strip the coating off the coax,
> exposing the shield, and clamping that shield to the ground
> rod? Seems like you'd be exposing the connection to the
> elements, probably hastening the demise of the coax at that
> point. Not to mention the changing of the interaction of
> the two conductors by changing it's form...
>
> --Mike L.
http://www.harger.com/catalog2004/4_3_1.pdf has examples of typical Andrews
Wire Co produced shield grounding kits. It is advisable to cover with
waterproofing materials any connection that is exposed to the weather. There
is also no such " changing of the interaction of the two conductors by
changing it's form..."
Btw, my "noise limiting antenna" comes from an old design published in Fine
Tuning's Proceedings, in which one side of a dipole-type Balun is grounded
at the feedpoint (also on the ground) and the longwire antenna is connected
to the Balun's other antenna connection. Coax feedline comes out the bottom
of the Balun, and is shield grounded twice for lightning protection: once at
the Balun and another time before it enters the station.
Besides an excellent and very quiet listening antenna, this is also a
transmitter. It has worked over 500 miles on 2 Mhz and 3,000 miles on 8 Mhz.
Jack Painter
Virginia Beach Virginia
Michael Lawson
"Jack Painter" <223...@cox.net> wrote in message
news:J%sud.3067$7p.1654@lakeread02...
I dredged up my old Halliday and Resnick text, and
took a look. Yes, you are correct. The important part
is the shield surrounding the core.
> Btw, my "noise limiting antenna" comes from an old design published
in Fine
> Tuning's Proceedings, in which one side of a dipole-type Balun is
grounded
> at the feedpoint (also on the ground) and the longwire antenna is
connected
> to the Balun's other antenna connection. Coax feedline comes out the
bottom
> of the Balun, and is shield grounded twice for lightning protection:
once at
> the Balun and another time before it enters the station.
>
> Besides an excellent and very quiet listening antenna, this is also
a
> transmitter. It has worked over 500 miles on 2 Mhz and 3,000 miles
on 8 Mhz.
Thanks for the info.
--Mike L.
Jack Painter
No problem Mike. Btw, the grounding blocks work fine too, I use them under
the house. But out in the field, and on towers particularly, the coax shield
ground kits can be easier to handle. Nothing stopping you from making your
own kit either, I just like Andrews products, already cut for your size
cable, etc.
Cheers,
Jack