ngs.
Personally, I think common sense is going a bit backwards. We fail to have
a gut feeling of how things work, and think the world is always one way. It
isn't an off-on light switch for almost anything, although sometimes it is
close enough to be treated as black or white.
73 Tom
isn't really what most would consider a significant difference.
In my opinion, the choice is mostly a matter of what best fits the supports.
Unless you try to use Tree for an antenna, then you might be 20 dB down.
73 Tom
_
Topband Reflector
ou tell them about all the work or they "like" a
particular antenna you are using.
73 Tom
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Topband Reflector
e
the open end of a short antenna in a resistance.
The real reason antennas in trees make people happy is the loss in the
system making them happy is not really noticeable to them. I can't notice 6
dB loss at times, unless with an A-B test or by measuring things.
73 Tom
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Topband Reflector
ower levels, 10 dB loss in a 100-foot cable might be
unnoticeable.
73 Tom
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Topband Reflector
<<>>
Perhaps you have a temperature sensitive component in the phasing system?
That would explain the change.
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Topband Reflector
Well Tom, you surprise me since I thought in the past you were one of
those
who felt tree losses were minimal and part of mythology for HF/MF. I
guess you changed your mind now that others have shown different.
I think they are minimal, if the tree is not right next to the antenna. I
never
l has an effect that people "feel" or find
useful, so it all works at some level.
73 Tom
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Topband Reflector
n "It has an effect. I read it
somewhere. Next topic."
73, Tom
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Topband Reflector
This discussion involves current scientific research of the D and E layers
of the
ionosphere that are within the thermosphere and parts of the mesophere.
The D and E layers profoundly impact Topband propagation.
I think the problem is the completely off-topic political rants started,
instead
eople who like magic 43 foot verticals would disagree with.
Instead we have only reports and measurements that trees cause increased
loss, and all those multiband single length antennas. :)
73 Tom
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Topband Reflector
n't, like a
toggle switch being on or off. It is often a case of how much it is or
isn't. Some things that are way over in the "isn't meaningful" column get
publicity as being "is", just because they are not perfectly zero or
infinite.
73 Tom
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Topband Reflector
ctors, or having
resonance effects with saltwater jets at low frequencies. At the same time,
even crummy soil has a profound effect on EM fields and other things when
cross sectional area is large enough.
There is a danger that people will not understand the big picture, and write
more seawater an
n how the dense foliage
was created in the model, and why it would likely model like a real forest.
I'm not especially fond of someone's models of someone else's proposed
models, that can get a little sketchy in translations.
73 Tom
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Topband Reflector
with all these switching supplies.
73 Tom
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Topband Reflector
u add capacitors to. I used a system that had F
connectors, eithernet, telco, and power.
This is thousands of times more effective than throwing beads at it and just
hoping common mode impedances are so low the beads do something.
73 Tom
I recently had an internet wireless antenna/unit installed a
member the
characters that touched their lives. I still can hear W6VSS pounding in to
Ohio with his 25 watts on 1999 kHz, when I could just barely hear W6YY with
two half waves in phase on top of a 450-foot tower on some mountain.
73 Tom
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Topband Reflector
real estate. I could not imaging what it would take to make
one for 160, buts its a safe bet that a 4-square will be a lot easier
to install/require less real estate. Paul has a 4-square for 160
among other antennas for Topband.
Tom - VE3CX
On Fri, Jul 26, 2013 at 11:07 AM, Shoppa, Tim wrote
They do indeed sometimes help reduce the QRN from some thunderstorms,
particularly if they are in a nearby state (higher angle) and
perpendicular
to the desired direction. But they are only 580' (1λ on 160 and a 3 dB
beamwidth of 90 degrees). And I do have one Beverage that seems to have a
degr
I think rhombics were sometimes chosen for receiving, because they are a
type of wave antenna like the Beverage but with a sharper pattern. But how
the two compare, I can't say.
Rhombics, because of the many small lobes, have poor directivity. As such,
they are not exceptionally good receiving
And that's where the term "California Kilowatt" came from. I'm told his
rhombics were loud mostly for that reason. I forget what tubes were in his
amp, but they sure weren't 6V6s. ;-)
When I was bumming around in the 60's, I visited some west coast stations
with large wire antennas with excepti
r 80M.
I can't imagine why anyone would have one today. Here is an analaysis of
Rhomics.
http://www.w8ji.com/rhombic_antennas.htm
73 Tom
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Topband Reflector
The persistence of easily more than half a year of loud QRN in the
evenings
on 160, perhaps 3/4 of the year, has generated the *expectation* that no
one is on. The expectation of activity is what generates activity. The
band is clearly open to some degree at various times any night, even in
Jul
term, and for the overall good, it makes no sense at all to mix
incompatible modes, or especially to mix significantly different bandwidths.
Anyone with an ounce of common "radio" sense should be able to think about
this, and understand the potential problems
Sorry I identified "Corcom" incorrectly.
I checked a sample and the actual filters that I used were Delta
Electronics 05DRCG5.
http://c1170156.r56.cf3.rackcdn.com/UK_DEL_05DRDG3_DS.pdf
That's better. That is a filter that suppresses CM and DM signals via
capacitors, but it still looks like
Sorry I identified "Corcom" incorrectly.
I checked a sample and the actual filters that I used were Delta
Electronics 05DRCG5.
http://disti-assets.s3.amazonaws.com/quistelectronics/files/datasheets/4322.
pdf
Tom
-Original Message-
From: Topband [mailto:to
our common sharing of a pole transformer.
73 Tom
_
Topband Reflector
- Original Message -
From: Tom Boucher
To: 160 reflector
Sent: Tuesday, July 23, 2013 6:30 PM
Subject: Inv-L joy
What bothers me about putting the actual antenna wire across the tree is that
it is then very close and in fact touching the tree. I'm not sure what loss the
tree
of these into a box with outlet on it but I
figured that the long plug in cord from the noise generator (power supply)
would allow too much noise radiation, so I didn't try it.
Tom
-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of ZR
Sent: Sunday,
On 7/21/2013 8:49 AM, Tom W8JI wrote:
I can't understand why throwing some ferrite beads at a problem, or
changing the supply, are the only two solutions.
Many times, if not most times, a few .01 uF line voltage rated bypass
capacitors are significantly better than a sting of cores,
not built correctly. Some fail to address
the common mode, others fail to address the differential mode. But the
poorest and most unreliable system of all is the system that just throws
beads at a problem.
73 Tom
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Topband Reflector
earth, and not little charged
particles hitting out antennas and making a tiny spark. Even the noise pitch
is almost always unrelated to quantity of particles.
73 Tom
All good topband ops know how to put up a beverage at night.
_
Topband Reflector
the antenna makes a great deal of difference, as does the
height.
73 Tom
All good topband ops know how to put up a beverage at night.
_
Topband Reflector
impedance and
transmission line effects doesn't work. It is really a more complex answer
that requires looking at the system. Voltage and current are not even in
phase, so we also have to know if the element is driven by voltage, current,
or someplace between.
73 Tom
All good t
ea, or why they might want less gain, since they get
more gain with that null cone that gives much better F/R. Perhaps the
problem is years and years of not wording things properly in our handbooks,
or not thinking through the problem, has confused people.
73 Tom
All good topband ops know how
ift between the elements is some value greater than 90 degrees. I
can't think of a reason to pick 90 degrees as a target value, unless it is a
system designed to protect something on groundwave that happens to be
straight in line with the elements.
73 Tom
All good topband ops know how to
-matched termination.
With that in mind, a 71 degree long line might produce considerably
different phase shift than the electrical line length, and the user probably
wants phase to be some other value than 90 degrees (if the user understands
arrays and patterns).
73 Tom
All good topband ops
I have a simple switchable coaxial BOG running NE-SW. I have often
noticed that it is not bothered much by rain. In fact, I would consider
this a valid "selling point" of the BOG. Having said that, even on a
rainy day, the longer 2-wire beverage up about 5' still hears slightly
better (even with t
* Are your radials resonant? For the purposes that you are attempting,
they need to be, in order to maintain the phase relationship between the
driven element and the parasite.
Actually there are three cases that work:
1.) Where a limited size system has radials are exactly resonant
2.) Where
ystem. Perhaps inadequate radials,
coupling from element to element through radials, or too much other stuff
making the array not work.
73 Tom
All good topband ops know how to put up a beverage at night.
_
Topband Reflector
he
shield and the 240 line. That issue happens anytime a feedline crosses
almost anything metal, even a fence or pipe.
73 Tom
All good topband ops know how to put up a beverage at night.
_
Topband Reflector
I have a system with two gamma matched towers that works pretty well. I
did all I could to make them appear to be similar. The gamma dimensions
and capacitance are identical - and I used a loading wire on top of one of
them - making it longer and longer until the match was similar.>>>
Results
Delay lines would, of course, result in almost no gain or F/B with shunt fed
systems, unless someone deviated from normal procedures and compensated for
the transmission line effects of the shunt system.
73 Tom
All good topband ops know how to put up a beverage at night.
_
Topband Reflector
tion, you could certainly make it work. I
phased dissimilar elements many times over the years, with the grossest
mismatch a "T" phased against a shunt fed tower. All it takes is parts and
patience. :-)
73 Tom
All good topband ops know how to put up a beverage at night.
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Topband Reflector
doesn't mean phasing shunt systems
cannot work, or even that the job is difficult. It is just different.
73 Tom
All good topband ops know how to put up a beverage at night.
_
Topband Reflector
Your forgetting that the front end is still broadband and wide open and
being blasted into intermod many times.
Someone would need to have grave noise level issues if noise overloaded the
front end. They would not hear much of anything with or without a loop. Look
at receiver specs for 20 kHz
Actually a properly designed purpose built loop can offer a reduction in
noise from the high Q selectivity offered.
That would only be true if the receiver system noise bandwidth was wider
than the loop's bandwidth. If you had a SkyBuddy with 30 kHz noise BW and
put a 5 kHz wide loop in front,
sorted or mislabeled in distribution. I've seen bags of
100's of 73 mix cores, from normal good distribution, that were 61 or 43.
73 Tom
All good topband ops know how to put up a beverage at night.
_
Topband Reflector
y perfect single band balun with no
beads and no solenoid chokes at all. An 80 meter dipole with a feedline in
air and a ground ~~40-80 feet from the antenna has virtually no common mode
without any balun at all. As a matter of fact, a balun could make it worse.
We need to think about the s
Handbook tuner with poor balance design.
Every system has to be looked at as a system.
73 Tom
All good topband ops know how to put up a beverage at night.
_
Topband Reflector
000 ohms. It is always far better to make the
antenna with a correct feed system, because a proper feed has far less
common mode response without any common mode foolery.
73 Tom
All good topband ops know how to put up a beverage at night.
_
Topband Reflector
depth difference. This means CM noise on the feeder can be
abnormally problematic, because more than the antenna is the antenna!
This throws another wild card in the deck.
73 Tom
All good topband ops know how to put up a beverage at night.
_
Topband Reflector
ansmitters
This is why sometimes loops help, sometimes poorly designed are better than
well designed loops, and quite often they do nothing at all. Sometimes they
make things worse. Most are sold by mythology, like homeopathic medicines.
73 Tom
All good topband ops know how to put up
One
size will never come close to fitting all.
73 Tom
All good topband ops know how to put up a beverage at night.
_
Topband Reflector
Go to http://exax.net/index.html and scroll down the page to "center fed
steerable wave antenna". The diagram shows how you can feed a 2-wire
Beverage in the center, or anywhere along its length. The two
transformers
in the middle have center taps that pass signal currents from one side of
the
After looking at their literature it appears to me that this is nothing
more then two beverages, one in each direction, with the "feed unit"
being, perhaps, a couple relays. I don't see the merit in using RG6 as
the beverage wire: its heavy, will need more supports, and compared to
other solut
Shouldn't you also look at lightning activity on the path between you and
your area of interest? I've found quite often that the day after a big
eastward-moving storm, there is a lot of noise on my path to Europe.
That's right, Pete. With good directional receiving antennas, other than
reall
Last time I was at Dayton 2 years ago, there was a webcam set up in
the Contest Supersuite. Not sure what the plan is for this year, but
if so, it may be a chance to check out what you are missing out on.
Then again, time to start planning for next year :-)
Tom - VE3CX
On 5/8/13, Gary Smith
I'm interested in your comment about LMR400 and soldered braids, Tom. I
understand the point about shield current flowing on the insde of the foil
or braid closest to the center conductor, but if the shield connection is
faulty, oxidized, or has high resistance, then it seems to me the
top of foil that has a poor electrical and
pressure connection to the foil is not a good connection point. This is why
LMR400 is problematic when the braid is soldered to a PL-259. The very same
cable is great with a crimp connector, if the cable is clean (not tarnished
or corroded) inside.
CATV installers use almost 100% quad shield in order to keep the signals
inside and not cause interfering leakage (egress); FCC specs are adamant
about that. These specs go back to the 70's. In more recent years the
cable also must keep local RFI (ingress) out.
While they do use tape foil shie
the issue caused by overlaying a foil shield with braid, and
soldering to the braid?
73 Tom
All good topband ops know fine whiskey is a daylight beverage.
_
Topband Reflector
ennas and replace all the F
connectors and particularly the F to 259 adapters with something else, but
what? BNCs?
BNC's are worse yet, as a general rule. They rely on spring pressure for the
shield path. Look into a type match error between the cable you have and the
connectors, or a connector inst
I wouldn't attempt to tune the radials exactly to resonance, because that
will be most difficult to achieve due to a number of reasons... the worst
that may happen is that just one radial is exactly resonant, as it will
take (almost) all the return current and diminish the effect of
(horizontal
you
get a few good reports, or work a new country, it would prove a 20 dB
increase. :-)
73 Tom
All good topband ops know fine whiskey is a daylight beverage.
_
Topband Reflector
s not properly designed to be sealed, like standard coax or
ladder line, is a mistake. As said above, it is much better to leave
something not flooded or pressurized open.
73 Tom
_
Topband Reflector
Been reading in ON4UN low band dxing book about mulitable element receive
arrays for 160 meters. I'm a little confused about 180 deg phase inverters,
and flip transformers are these two the same thing?
I never heard of "flip transformers" before, but in context of the
application I immedia
on films look **exactly** like carbon
composition resistors!!
73 Tom
_
Topband Reflector
e, light, thick, and does not weigh the lines
down.
73 Tom
_
Topband Reflector
ennas because of wind vibration or some other fatigue. Due to weight
restrictions, I almost have to use aluminum wire in some places.
73 Tom
_
Topband Reflector
er I installed the dipole
here and compared it to a vertical and other antennas for a year or two, I
finally remembered how well my old 1/4 wave vertical worked. :)
This was eye opening to me.
73 Tom
_
Topband Reflector
matter
how nice it would be if there actually was one.
73 Tom
_
Topband Reflector
l and work upwards, not cut things.
An A-B test comparison to a stable reference would be simple and reliable.
73 Tom
_
Topband Reflector
uckle out of
"I took down an antenna and put up another one and it was difference"
statements. It takes a long time period of many direct A-B comparisons to
reach dependable conclusions.
73 Tom
_
Topband Reflector
ook at Rudy N6LF's clear published warnings about (mis)use of his data, and
then look at how his cautions are ignored as people selectively use the data
they want from his articles as absolutes.
73 Tom
_
Topband Reflector
ve is a good source for that particular test condition. Most
people seem to miss this:
http://www.antennasbyn6lf.com/2012/02/elevated-radial-ground-systems-some-cautions.html
What he writes isn't often what people actually paraphrase.
73 Tom
_
Topband Reflector
Yes Tom, I was going to mention the polyprop guys as well. Worst stuff you
can use. Well remember a 60' mast bent across my neighbours roof as a result
of using polyprop guys which had degraded in UV. You get splinters of the
stuff in your hands as well!
I use polyester (Terylene, D
It's the reference to termination resistors in the SPX data sheet that
bothers me.
Tom G3OLB
You mean this part of the SPX data sheet that screams "dummy load"? :-)
"Tower guys are made of tough
polypropylene rope. The resistive terminations are
mounted in pr
It's the reference to termination resistors in the SPX data sheet that bothers
me.
Tom G3OLB
K1FZ wrote:
http://www.spx.com/en/tci/pd-613t-and-f-broadband-dipole-antennas/>
_
Topband Reflector
f the wire
contributes much to DX response.
73 Tom
_
Topband Reflector
quot;giant array"
or used a really long Beverage antenna.
73 Tom
_
Topband Reflector
from
each element into the separate switch matrices?
Frank or Tom - are you already doing this? >>>>
You could split at every element, but unused splitter ports would require
termination in case that element was used for another phasing hub. This
could all be done at the array center
eiver designers miss or do not
understand.
The K3 is less than ideal, but much closer to ideal than anything else.
73 Tom
_
Topband Reflector
er perfect
earth.
73 Tom
_
Topband Reflector
l delta. It could have just as well been verticals with no loss of
pattern.
73 Tom
_
Topband Reflector
pace
many wavelengths from earth.
:-)
You have a local problem with a local noise generator, or a problem in the
radio or feedline.
73 Tom
_
Topband Reflector
to break things spaced that wide into cells
that I run in stereo.
73 Tom
_
Topband Reflector
proper installation. I've seen
expensive "professionals" actually leave O-rings out of outdoor connectors!!
73 Tom
_
Topband Reflector
eparated antennas is
good for maybe 3-6 dB in perception of signals in noise if the operator is
trained to use stereo.
Missing callers, unless the operator scans and the caller is persistent, is
inevitable.
73 Tom
_
Topband Reflector
The "Wullenwever" antenna was never a low-noise high performance antenna. It
was simply a system designed to find direction over a very wide frequency
range. The multitude of elements increased bandwidth, but the physical width
in wavelengths is the primary determinant of directivity.
If we ha
uldn't have a problem with "phase inversion" of time varying analog or
digital waveforms, and would instantly know exactly what they meant.
73 Tom
_
Topband Reflector
ertainty is 1/2 wave broadside and 180-s phase is almost never
optimum for anything, including transmitting.
For receiving, I would plan the phasing or spacing of directive cells so
each complementary cell forced the largest possible area null where other
cells had significan
e best
choice. Even my 45 degree spaced elements are not delayed 135 degrees, but
rather some larger delay amount. This actually increases null depth and the
statistical likelihood something unwanted is in a deep null.
73 Tom
_
Topband Reflector
signals clean, and not having one does not
make all signals dirty. It is the entire system that matters, and there is
certainly more than one clean radio in the world.
73 Tom
_
Topband Reflector
magine not using it, unless it is an AWA contest and I'm using a BC348.
73 Tom
_
Topband Reflector
And I DID contact each of the guys whose calls I cited during the contest.
In fact, I contacted about this issue two years ago when he was making a
mess in the JA window during the winter Stew, and two years later his
signal is still trashy.
That happens sometimes. There was an east coast sta
eone with an S8 background noise (and wide bandwidth that
lets in a lot of noise power) is probably not going to notice what would be
terrible with S1 background.
73 Tom
_
Topband Reflector
Would that EVERY such case be treated in the same manner, Tom, exactly as
you describe & as I acted upon---but sadly, it does not. And it leaves
so-called "transgressors" feeling hurt, angry, dis-enfranchised, and no
closer to any sort of resolution than before.
Whither the &qu
ys direct communications unless
something prevents that. That should go without saying.
73 Tom
_
Topband Reflector
or mica or air insulated caps.
73 Tom
_
Topband Reflector
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