Well, Bob has it in a nutshell.
If everything is balanced, then basic physics rules, as always, and the
equal and opposite fields set up by the equal and opposite currents in the
feeder will cancel at all points in space. Thus, no net radiation.
On the other hand, if there is imbalance at one of several possible points
in the system, then the currents will not be equal and opposite. Thus the
fields will not be equal and opposite, and will not cancel at all points in
space, and thus there will be net radiation.
So much is fact.
73 de Gary, AA2IZ
----- Original Message -----
From: "Robert & Linda McGraw K4TAX" <RMcGraw@Blomand.Net>
To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
Sent: Saturday, July 09, 2005 5:39 PM
Subject: Re: [TenTec] "Radiates like Crazy"???? No
> It seems that Curt tried everything with the feed line. However, it would
> appear he did nothing to assure that the load was balanced. That being
the
> case, yes a balanced line with an unbalanced load will have asymmetrical
> currents and thus radiation will occur from the feed line. Same true for
a
> coaxial line with an improper termination.
>
> 73
> Bob, K4TAX
>
>
> ----- Original Message -----
> From: "NJ0IP" <Rick@DJ0IP.de>
> To: "'Discussion of Ten-Tec Equipment'" <tentec@contesting.com>
> Sent: Saturday, July 09, 2005 7:29 AM
> Subject: Re: [TenTec] "Radiates like Crazy"???? No
>
>
> > OK Curt, you don't have to respond, but I wish to.
> >
> > Question: How do you put up a single antenna that should cover ALL
bands
> > reasonably well, and feed it with coax? Please keep in mind that my
> > linear
> > is transistorized and requires a good SWR.
> >
> > I accept everything you say as being the truth - in the situations you
> > guys
> > tried it. There is no question, sometimes RF takes strange ways.
> >
> > I have a neighbor about 5 doors down who was wiping out his own TV
> > although
> > he was only running 100w.
> > We replaced his coax with open wire (ladderline) and used a matchbox and
> > the
> > TVI was gone. He also claims to get out much better now. Prior to that
> > he
> > had tried all sorts of things like low-pass filters, better ground, etc.
> >
> > I don't think this is a matter of being an old timer vs. being new to
the
> > game. That has nothing to do with it. I guess I'm an old timer, though
I
> > don't feel like it. All my gear is very modern (Orion plus Henry Solid
> > State Linear Amp and lots of computers) and I also have about 300 meters
> > of
> > high quality coax which I use to feed beams or verticals when I go on my
> > contest expeditions. I have a choice at home to use either coax or
> > openwire.
> >
> > Here at home I'm challenged by not being able to put up as many antennas
> > as
> > I would like and a tower is out of the question. My XYL and neighbors
> > agreed to one antenna. I sort of hid a second (vertical) antenna
between
> > the trees and got away with it. I feed both antennas with openwire so
> > that
> > I can run them on all bands. They work great and I pretty much hold my
> > own
> > in contests and working DX. I'm not sure how I could accomplish this
> > using
> > coax.
> >
> > I run 750w, our legal limit in Germany, and I don't have any
interference
> > in
> > the TV, Radio, or telephone.
> >
> > And finally, "My dog eats Kennel Ration too." :-)
> >
> > 73
> > Rick
> > DJ0IP
> >
> > -----Original Message-----
> > From: tentec-bounces@contesting.com
[mailto:tentec-bounces@contesting.com]
> > On Behalf Of Curt
> > Sent: Saturday, July 09, 2005 4:44 AM
> > To: Discussion of Ten-Tec Equipment
> > Subject: Re: [TenTec] "Radiates like Crazy"???? No
> >
> > I love it when what happened to me and several others
> > mostly at W3KHW a ham radio club in Pittsburgh is
> > dismissed as silly nonsensical rubbish. I tried
> > everything mentioned here to solve the problem:
> > Twisting. Lengthening and shorting the feed length.
> > Match boxes. Balun and no balun. Making sure it didn't
> > touch anything. Making sure it had no sharp bends.
> > Wrapping it in circles. Straightening it. Name it and
> > it was tried via advice from all the old timers at
> > W3KHW. So finally coax was purchased and problem was
> > solved instantly. This is why I stated ladder line
> > radiates like crazy because it sure as hell did in my
> > situation and several others at W3KWH. Call me stupid,
> > misinformed, insane or whatever does it for you, it
> > doesn't matter because I know what ladder provided me
> > and a few others, nothing but nightmares of RFI and
> > TVI to my neighbors who lived very close to me back
> > then. The other guys had problems with it getting into
> > their homes with RF flying around the house causing
> > family members to complain. I don't care if you have
> > been using ladder for 60 years! For me and a few of
> > my friends it was nothing but headaches. Coax on the
> > extreme other hand was very unforgiving and "never"
> > radiated no matter the configuration applied to it
> > unlike ladder line. Funny how the old timers are the
> > ones who use ladder line, it's not something that is
> > wildly popular these days and neither are the big
> > bands and Frank Sinatra on the top 40 charts anymore,
> > they are a distant memory. Distance as in light years.
> > I will no longer respond to this subject because it's
> > only vanity going back and forth ad nauseam and for
> > what? Mine is bigger than yours..don't think so.
> >
> >
> > Love Curt
> >
> > --- NJ0IP <Rick@DJ0IP.de> wrote:
> >
> >> I fully agree with Stuart. Curt must have made some
> >> strange experience to
> >> cause him to feel that way.
> >>
> >> Ladderline does not radiate like crazy - hardly at
> >> all - if the load at both
> >> ends are symmetrical. Stuart's tip about twisting
> >> it is highly recommended.
> >>
> >> I've used openwire for over 40 years and the
> >> ladderline since about 20 years
> >> now. I have often had cases of it radiating.
> >> Specifically, nearly every
> >> time I tried to feed it thru a balun in front of an
> >> asymmetrical matchbox.
> >> I don't care which side of the matchbox you place
> >> the balun, it still did
> >> not eliminate this radiation - especially when
> >> running a linear.
> >>
> >> I have also had at a truly symmetrical matchbox
> >> (Annecke) for the past 25
> >> years and each time I had the problem above, I
> >> solved it by using my
> >> symmetrical matchbox instead of the jerry-rigged
> >> solution described above
> >> (and still sold by many vendors as "a symmetrical
> >> solution"). Lesson
> >> learned. There are no shortcuts in life and quality
> >> costs money.
> >>
> >> In the meantime I have 4 symmetrical matchboxes with
> >> various power ratings
> >> and I run legal power here and don't have any
> >> problems with feedline
> >> radiation.
> >>
> >> Coax radiates too if it has high SWR on it
> >> (everybody knows that and knows
> >> how to fix it).
> >> Open wire feedline radiates when either of its ends
> >> are not in balance (keep
> >> it in balance and it won't radiate).
> >> These are rules of thumb.
> >> Of course there are rare exceptions to every rule,
> >> but the statement that
> >> ladderline radiates like crazy is blatantly wrong!
> >>
> >> Using ladderline or homebrew openwire is an
> >> excellent way to build a simple,
> >> effective wire antenna which will operate all (or
> >> most) bands.
> >>
> >> If anyone is interested in using openwire /
> >> ladderline feedline but wasn't
> >> sure how to feed it, here is some useful
> >> information:
> >>
> >> In the meantime there are good symmetrical
> >> matchboxes available for all
> >> sorts of power level. The are at least 5 or 6
> >> vendors offering excellent
> >> products for a reasonable price. A recent ARRL
> >> (QST) article described some
> >> of these, but only focused on the U.S. vendors (MFJ,
> >> Palstar). There are
> >> alse several European vendors with great products
> >> too (e.g., U.K. Amp,
> >> Hamware, Christian (DL3LAC), and DL1SWR). Just be
> >> sure the box you are
> >> interested in is truly symmetrical. MFJ and Palstar
> >> both make good and bad
> >> products advertised as suitable for symmetrical.
> >>
> >> 73
> >> Rick
> >>
> >>
> >> -----Original Message-----
> >> From: tentec-bounces@contesting.com
> >> [mailto:tentec-bounces@contesting.com]
> >> On Behalf Of Curt
> >> Sent: Friday, July 08, 2005 11:45 AM
> >> To: Discussion of Ten-Tec Equipment
> >> Subject: Re: [TenTec] "Radiates like Crazy"???? No
> >>
> >> I don't care if you do or don't...you're
> >> wrong!!!!!!!!!!
> >>
> >> --- Stuart Rohre <rohre@arlut.utexas.edu> wrote:
> >>
> >> > I must respectfully disagree that ladder line
> >> > "radiates like crazy".
> >> >
> >> > It is BALANCED line, that means if it is fed from
> >> a
> >> > balanced source and goes
> >> > to a balanced antenna, the currents are equal and
> >> > opposite in each wire and
> >> > their fields cancel within a few diameters of the
> >> > line. See the theory of
> >> > transmission lines in the ARRL Handbooks.
> >> >
> >> > It should cross conductors at right angles, and
> >> > should be twisted every 18
> >> > inches or so, to minimize effects from nearby
> >> > conductors that could
> >> > unbalance it.
> >> >
> >> > If you ever have ladder line "radiating" you are
> >> mis
> >> > applying it in some way
> >> > at one end or the other. Balanced antennas are
> >> > center fed beams, dipoles,
> >> > etc. with line brought off at 90 degrees to the
> >> > antenna wires.
> >> >
> >> > Let's bury these old wive's tales about balanced
> >> > parallel transmission
> >> > lines.
> >> >
> >> > Stuart
> >> > K5KVH
> >> >
> >> >
> >> >
> >> > _______________________________________________
> >> > TenTec mailing list
> >> > TenTec@contesting.com
> >> >
> >> http://lists.contesting.com/mailman/listinfo/tentec
> >> >
> >>
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> >
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