what I want. I never use them in
random situations.
73 Tom
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
like no matter how much people freely contribute to others in this
world, it is never enough for some. They demand even more free stuff.
73 Tom
___
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not even be radiating much if it is near a tower.
I changed the front tires to new economy six plies, fuel tank shock mounts,
changed a fuel filter, and repaired the fuel tank crack on my tractor, and
the new front tires let me mow twice as far on a tank of fuel.:-)
73 Tom
diodes that does not ruin a
system's dynamic range. This is because the diodes start to go non-linear
resistance below the hard-clamping voltage, which is already far too low.
73 Tom
___
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a few dB better. It's pretty hard to
quantify the TOI, because control settings and receiver impedance affects
it, but someone is far better off using a real amplifier if needed.
73 Tom
___
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://www.w8ji.com/counterpoise_systems.htm
73 Tom
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
and white.
73 Tom
___
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there are many
radials dividing the current. It all comes down to levels and phase at any
point.
73 Tom
___
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if we divide current between enough radials
each radial will not radiate much at any distance compared to the antenna.
We not only have cancellation at a distance, we have much less near each
radial.
Spreading things around is a good thing.
73 Tom
Hello Topbanders,
I noticed this come across another list and thought I would share it here.
Have any of you used this?
73 de Tom, K6VCR
http://users.otenet.gr/~jmsp/#dnld
This guy decided to take on the very dirty task of rewriting the 1980's
FORTRAN code that makes up the NEC2 engine
Tom
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
, no matter what color.
73 Tom
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
That doesn't work for me for some reason.
-Original Message-
From: topband-boun...@contesting.com
[mailto:topband-boun...@contesting.com]On Behalf Of Jerry Keller (K3BZ)
Sent: Friday, August 17, 2012 4:15 PM
To: (REFLECTOR) Topband
Subject: Topband: UA9YAB SK - PayPal Page
I
abandon the band until our seasonal alarm clocks ring in the late summer or
early fall. 160 is open all year, if we look on quiet days.
When no one tries, the band is closed.
73 Tom
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
or a spurious in the AM
transmitter.
73 Tom
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
the AM transmitter has a spurious
in some sort of mixing or frequency synthesis scheme, it is nearly certain
to be a receiver problem.
An attenuation test will only show nonlinearity in the receiver, and it does
not sound like that is the problem based on the image being on a 5.
73 Tom
it ,
and wax it. It will run better, and get better fuel mileage. (A popular Ham
author actually put that in an article on mobile installations!)
I think this is what Rick was driving at.
73 Tom
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
never give up, and should experiment with the best
they can do. Even if it doesn't work close to right, it can make people
happy.
73 Tom
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
the
day.
If any of us **really** had an antenna as sharp as a long Yagi, we'd need 16
or more antennas to cover useful directions.
That's pretty typical behavior for a properly installed Beverage no matter
what the location, unless you park it over saltwater.
73 Tom
If a radial runs along the ground and then up over a wall, what difference
would it make?
Good question.
The radial only goes up for 4 feet and back down for 4 feet.
That is exactly like adding a 4-foot shorted stub in series with the radial.
All that worry about induced current in a 4-foot
has the same current on each side if the coax is not
radiating.
Of course some people write entire articles about Kirchhoff not applying to
RF, but we know that isn't true if we understand displacement current (stray
capacitance).
:-)
73 Tom
___
UR
are
not flawless.
73 Tom
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UR RST IS ... ... ..9 QSB QSB - hw? BK
is like thinking Ohm's law applies to dc circuits only.
73 Tom
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
found the solder joint just as clean
as
it was when it was first done even after several years.
Same here.
73 Tom
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
laws cannot be satisfied in AC
circuits involving capacitances, either lumped as a component or distributed
along conductors.
73 Tom
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
applicable to open ended antennas and time-varying
charges.
We seriously handicap ourselves when we think Kirchhoff's laws are only
applicable to closed dc circuits.
73 Tom
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
size chokes in RF applications.
http://www.w8ji.com/rf_plate_choke.htm
73 Tom
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
Kirchhoff law is a joke), and
since field strength was never measured, the entire article is a puzzlement
to me.
73 Tom
___
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Hi Bill,
Tom, it's worth adding to this that trying to make current measurements in
the ground using 60hz is pretty useless for another reason: induced
currents from the ac power system (especially in north america). 60hz will
be present on just about anything -- you'll even see
on that silly idea.
http://www.w8ji.com/radiation_resistance.htm
73 Tom
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
) varies significantly with frequency and some frequencies will
be pretty sour.
The nice thing is almost anything can work DX when conditions are good.
73 Tom
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
So gently getting back to the topic of the original post which was:
Getting thoughts on relatively simple and relatively inexpensive
portable 160 m antenna, potentially deployable by one person, that
allows for flexibility and somewhat predictable tuning for use on modest
Dxpeds or rare location
.
The only possible way to measure efficiency change is to measure field
strength.
People who measure feedpoint resistance changes while changing radials or
ground systems and think they know loss changes are just kidding themselves.
73 Tom
___
UR
) firsts handbooks.
Just be aware Orr had a consistent mistake in his articles on folded
antennas. He claimed folding reduced ground losses by significant amounts.
I'm not sure where that idea started, but using a folded element does not
change ground loss one bit.
73 Tom
.
Top loading with a hat not only gives *up to* four times the radiation
resistance (reducing ground losses), it increases bandwidth and makes base
voltages tolerable.
Or you can just do like the original design plan called for. Have so much
distributed loss voltages never get high.
73 Tom
during any one contest, and could not track the
rate with an instant antenna change, I'm sure our rate would go up year
after year. This is because scores overall have been going up year after
year.
I still think about trying another one. :-)
73 Tom
or better.
73 Tom
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
like this shows the difference between EM radiation, electric
induction, and magnetic induction fields.
73 Tom
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
Completely agree, but you didn't say how to get past the garden
committee. :) 73, Guy.
Thin wire or move.
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
Hi Guy,
This is a non-issue, Tom.
I think it is a critical issue, because it demonstrates the difference
between EM radiation and induction fields that only store and return energy
to the system.
It stems from what I meant when I said cancel fields.
Apparently some considerable number
a proper reference antenna?
73 Tom
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
Elegant analysis, Tom. Thanks. I looked at Guy's very well done piece
in the National Contest Journal (the one timed for reading on the
airplane going to Dayton) and wondered why a serious common mode choke
would not work.
Thanks, not really so elegant though.
Any common common mode choke
what we are really going to find is there are many ways to have
about the same field strength in the same area, provided we don't do
something wrong. It is more about not making mistakes, or fixing mistakes,
than any sort of magic.
73 Tom
___
UR RST
feet away, why would it not reach earth?
73 Tom
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
than the $200 commercial chokes I have. :-)
73 Tom
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
Has anyone looked at, or looked for, cheap electric fence gaps??
My system copper pipes near tower legs work great for me on rigid towers, I
can bend them so they spring away from the tower and then slide an inner
pipe in or out to set gap distance. I'm thinking of gaps for wire antennas.
- Original Message -
From: Mike Waters mikew...@gmail.com
To: topband topband@contesting.com
Sent: Friday, July 27, 2012 11:33 AM
Subject: Re: Topband: Spark gaps
I don't think carbon balls are suitable for lightning protection.
I agree. The last thing we want is high surface
Man, I don't know, Dave. How long have they been selling those carbon
balls
for that purpose?
I've never seen a carbon ball in a lightning gap application. I'd have to
see a few after being in action a long time before trusting them.
Broadcast stations use hard metallic balls, as do
wires and
cables without shorting out the tower to ground on 160, and it serves as a
trickle drain. You could use 1/4 wave of shorted coax as a grounding stub on
a 1/4 wave vertical.
73 Tom
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
Q would be in the
hundreds, so dissipation would be negligible.
73 Tom
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
inch form. You could use #12 wire Teflon
insulated, and have a Q of maybe 300 or so. Again less than 1 watt heat out
of 1500.
Personally, I'd use #12 or 14 Teflon on some old PVC pipe.
73 Tom
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
30 watts is correct for 1500 watts in a 50 ohm system and a coil Q of 226.
The power loss is 0.1 dB and the coil temp rise is around 20 deg C.
No, it isn't.
1500 watts is 273 volts into 50 ohms.
If Q is 226, and reactance 226 ohms, Rp is 51,077 ohms. 273 volts is 1.46
watts heat.
To get 30
My Mistake:
To get 30 watts of heat with 226 ohms reactance, Q would have down near
unity. No one makes a coil that bad.
I misplaced a decimal. Q would have to be near ten in the coil with 226 ohms
reactance and 1500 watts to make 30W heat, not near 1.
The other numbers are correct. A Q of
not
help as an antenna becomes longer. As it becomes longer, the arriving wave
would be increasingly out-of-phase with current in the wire. But the primary
velocity factor and loss effects are going to be in differential mode, where
the field is most concentrated between conductors.
73 Tom
doesn't matter much in antenna mode. It
matters far more in transmission line mode.
73 Tom
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
. The horizontal spatial conductor length serves as a phasing and
transmission line connecting the vertical conductor lengths that serve as
antennas.
73 Tom
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
an inevitable extension of the antenna. Yet most early articles
suggested un-un's.
73 Tom
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
Wayne is using a DX Engineering bi-directional system. Unless DXE changed
to ununs without telling anyone, he has little to worry about there. ;-)
Yes. Cable grounds are isolated from signal grounds. That unit uses
primary-secondary isolation transformers.
I do have an old page up about this:
http://www.w8ji.com/k9ay_flag_pennant_ewe.htm
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
Has anyone ever made any attempt to characterize the line at HF?
A simple process like that would eliminate all speculation about RF
performance, and make rational cost vs. performance decisions.
Surely someone somewhere has made some reasonable attempt at characterizing
the line.
73 Tom
bigger as a radial,
just like folding wires in an antenna does not make it couple to space
better.
73 Tom
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
I think the characteristics of so-called WD-1 surplus phone line varies.
FWIW, the two short samples of WD-1 that I have here are as follows:
115 ohms impedance, calculated from the following: .033 diameter
(averaged), .0685 spacing. The dielectric constant of the insulation
(polyethylene) is
, antenna tuner, and transmitter, as
well as an antenna analyzer, could probably measure loss and impedance as
well as any VNA.
73 Tom
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
changed to ferrite core transformers with 73 mix beads as cores, and never
looked back. While they worked grounded on one wire, it was a day and
night difference in F/B ratio at the low end.
73 Tom
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
I am replacing the coax in my Beverage system and have a dumb
question. When using flooded cable and compression F connectors, is
it necessary to clean the goo off the stripped cable prior to
installing the connector? If so, how?
You normally won't need to clean it, just cut to size, fold the
or it will damage
coating and promote rust.
I only get 4-6 years maximum out of steel electric fence wire, some batches
less.
73 Tom
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
and drop cables,
turning copper black. We had to replace many connectors that had Noalox
contacting the copper. I think it was some sort of zinc-copper reaction, but
that was years ago.
73 Tom
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
Bingo. Any difference in the GE stuff and the silicon grease found in
auto
stores?
None that I can see. I use the stuff available from auto parts stores
without any issue. I use it on every outdoor electrical connection.
___
UR RST IS ... ...
to splice when it breaks either?
The solid wire stuff is, IMO, much easier to splice. Stranded has the same
problem you describe. It has to be watwerproofed, and heat removes the thin
copper whatever on each strand.
73 Tom
___
UR RST IS ... ... ..9 QSB QSB
A time domain reflectometer (TDR) allows you to check all major components
(feedline, transformer antenna and termination) of your Beverage antenna
from the comfort of your hamshack.
73
Frank
W3LPL
I do that with my MFJ-259. :-)
Sweep a wide range and look at peaks and nulls, or use
of time tossing iron or
regular filters at the problem. The key is good modem, like a 2wire modem,
and if that doesn't work, a really sharp roll-off filter.
Tossing iron at the CAT5 cables is OK, but it is not often useful on the
Telco side.
73 Tom
- Original Message -
From: Herb
on all the lines in and out.
With the old D-Link router the internet connection would drop when running 50W
on 160 or 80 even though my antennas are some 3 or 400 feet away from the house
and 'phone line.
Some of the newer modems are plainly more RFI proof.
73
Tom G3OLB
Hi Peter,
Hal said:
On Behalf Of Hal Kennedy
Common mode chokes DO NOT belong between boxes on your desk. As Tom and
others have said. The objective is to get them all at the same RF
potential, not isolate them from one another so they can seek their own
independent RF potential
, important basics are completely
overlooked or misunderstood.
73 Tom
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
are not physically long.
Thanks for posting that, it is an interesting concept.
73 Tom
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
Hi Carl,
Youre welcome to your opinion based upon your experience Tom.
It is much more than experience. Good science can be proven or illustrated
through experiments and measurements. Opinions are just opinions, and have
the same value as the effort that went into confirming them
.
73 Tom
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
unwanted signals to earth. Earthing is
for low frequency and AC safety, unless you run a longwire from the desk
tuner.
73 Tom
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
style for receiving, use a type-F
cable. Stay away from BNC's and other spring pressure connectors. Not only
is cable prep fast, and cable readily available, everything is dumbed down
to suit Larry-the-cable-guy.
73 Tom
___
UR RST IS ... ... ..9 QSB
mains. Some
even bring so much RF out the front on knobs, they can pull the VFO off
frequency! Things definitely are better.
73 Tom
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
problems more easily than decreasing problems.
73 Tom
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
them.
I can't think of a bigger waste of time and ferrite materials.
73 Tom
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
: Re: Topband: Cable shields
Very good, Tom.
I still wonder what the answer is to my earlier question (in late June)
about a flooded quad-shield coax with a corroded inner shield.
I suspect with a bonded foil inner shield, not much would change.
73, Mike
www.w0btu.com
Tom, I don't doubt that you performed the cable TI measurement correctly
but I have seen folks take data that is actually the TI of the test
fixture
and not the cables under test.
What TI impedance did you measure?
I can't actually measure it Dave. I have a spare port on my test fixture
any pieces of it.
Since the 1960's or 70's, this is the very first time I've seen this happen.
Are thunderstorms more violent now, or is wire cheaper? :-)
I'm not fixing my antennas until October or November.
73 Tom
___
UR RST IS ... ... ..9 QSB
the long term baggage of any other similar device, as ALL of
those links also seem to agree with.
At 600 watts it will be pretty clean. At 800 watts about at the lower limit
of what cheap tube amps can do. All of this requiring getting the heat out,
and shutting it off if SWR goes high.
73 Tom
worse.
73 Tom
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
it is anything special for HF or linear service, or going
to catch on fast.
73 Tom
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
, or be reliable at 200 watts CW
without SWR and thermal protection.
Apples and oranges.
When the device price comes down a bit, or if they make a smaller device
that allows spreading the heat around, you'll probably see the Freescale
device in Ham gear.
73 Tom
power devices in data sheets are just pure fiction, except in very
special cases that have nothing to do with real amplifiers we use.
73 Tom
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
.
Tom
K6VCR
-Original Message-
From: topband-boun...@contesting.com [mailto:topband-boun...@contesting.com]
On Behalf Of ZR
Sent: Wednesday, July 04, 2012 9:59 AM
To: Wes Attaway (N5WA); j...@audiosystemsgroup.com; topband@contesting.com
Subject: Re: Topband: Progress with ugly computer noise
of low-Q
beads. Cleaned it up so much the computer could not be heard right in the
same room.
I did the same with a Direct TV recorder next door. It drove the mains in
differential mode with significant energy.
73 Tom
___
UR RST IS ... ... ..9 QSB QSB
a crook or less-than.
73 Tom
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
For higher power applications and to avoid heat, especially with unknown
load situations, we want a core that has low loss tangent or high Q.
For good suppression, especially with unknown load situations, we want high
loss tangent and Q.
Should actually be:
For higher power applications and to
sitting around insulting
other people.
73 Tom
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
that keep the
meter well up the scale if accuracy is important.
73 Tom
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
.
To know the usefulness in various applications we have to know the real and
imaginary parts or something that lets us know the real and imaginary parts
of impedance.
73 Tom
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
of?
73 Tom
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
is no different, all we have to do is keep in mind how things
really work and wire accordingly. :-)
73 Tom
___
UR RST IS ... ... ..9 QSB QSB - hw? BK
Greg,
What is the brand and model of the SSD that you are having problems with?
-Original Message-
From: topband-boun...@contesting.com [mailto:topband-boun...@contesting.com]
On Behalf Of Greg Chartrand
Sent: Tuesday, June 26, 2012 3:37 AM
To: topband@contesting.com
Subject: Re:
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