Hi folks, new here.

I have been in need of a weather radio, but when shopping for one this
week it seemed such a waste to receive only 7 frequencies when I could
be receiving thousands. So I ended up with a scanner, just like that.

Wow! Instant hobby! Big mistake! I'm a serial compulsive, so now it's
time to start making antennas...

The scanner is one of those closeout RS Pro-2052s. With the stock
antenna I can receive the local police at around 39 and some
frequencies in the 100s, around 125 and 150, including civilian air.
Maybe more, but I'll concentrate on these for now.

Would like to build a simple half-wave dipole to start with. In my
garage I have a roll of 10ga solid copper, some solid aluminum wire
maybe twice as thick (don't know what it is, is left over from a
satellite TV system), and some galvanized 1-inch steel pipe.

Antenna would be mounted inside a detached garage so weather/weight
are not significant factors.

Reading the archives I can't tell whether to go with the copper
because it is a better conductor than the others, with the aluminum
because it is thicker than the copper, or with the galv pipe because
it is much thicker than the copper though somewhat lossy.

Any thoughts appreciated.

Thank you,
Paul

was of them all
if its inside make a dipole out of coax.

however.
i'd use the ally meself, you wont get a better sig with copper it would be
wasted and weather badly
CSA does not really play much of a role in RX only aerials

mike

"Paul Monaghan" wrote in message
...
Hi folks, new here.

I have been in need of a weather radio, but when shopping for one this
week it seemed such a waste to receive only 7 frequencies when I could
be receiving thousands. So I ended up with a scanner, just like that.

Wow! Instant hobby! Big mistake! I'm a serial compulsive, so now it's
time to start making antennas...

The scanner is one of those closeout RS Pro-2052s. With the stock
antenna I can receive the local police at around 39 and some
frequencies in the 100s, around 125 and 150, including civilian air.
Maybe more, but I'll concentrate on these for now.

Would like to build a simple half-wave dipole to start with. In my
garage I have a roll of 10ga solid copper, some solid aluminum wire
maybe twice as thick (don't know what it is, is left over from a
satellite TV system), and some galvanized 1-inch steel pipe.

Antenna would be mounted inside a detached garage so weather/weight
are not significant factors.

Reading the archives I can't tell whether to go with the copper
because it is a better conductor than the others, with the aluminum
because it is thicker than the copper, or with the galv pipe because
it is much thicker than the copper though somewhat lossy.

Any thoughts appreciated.

Thank you,
Paul

Make a Half - wave vertical with pipe. If the wall is dry wood, you can
simply clamp it in place on the wall. You figure out the length of this
antenna by the following formula

468 / freq (in MHZ)

Hook the center conductor of the coax to the antenna, and then simply run a
wire from the shield braid of the coax to a nearby ground. Presto. You now
have a half - wave vertical.

A l;ittle note on dipoles. the bands you want to listen to are primarily
vertical in nature. so if you made a diplole, you would want to mount the
thing vertically, not horizontally. The side of the diplole with the center
conductor connection would go at the top.

the sides of this antenna can be figured out by the following formula

234 / freq (in MHZ)

this gives you one side of the dipole. shield to one side, center conductor
to the other. I would use the copper wire for this.

Another antenna is the loop. the entire length of this antenna is figured
out by the following

1005 / freq (in MHZ)

this is a loop of wire, and is usually tacked onto the wall. the hookup is
made at the side of the loop for vertical polarization. Once again, the
copper wire is best suited for this antenna. the only trouble with this
antenna is that it is slightly directional, recieving best at a 90 degree
angle to the plane of the loop in both directions. The loop is usually
formed into a circle or a square on the wall. (square is the usual case).


all of the answers in these equations give the answer in feet and fractions
of a foot. simply multiply the fractional part by 12 to get inches. rounding
to the nearest inch is fine.

naturally, this mounting info is based on an indoor environment, outside
mountings need to be dealt with a bit differently. also, we are assumiong
that the building does not have metal siding, which will tend to block radio
waves. These do make excellent attic mounted antennas in the house, by the
way. Just mount the antenna on the end wall of the attic, straight up. If
you feel you must insulate the antenna, then electric fence insulators are a
quick and easy way to do this. simply tap the nails into a convenient stud
to mount the antenna. The half wave vertical can also be made from the
copper wire, by the way, and it will work well. The half wave does not
require radials , by the way. That is why we simply run a ground wire from
the braid to ground on this antenna.

for the coax connection points, a piece of thick plexiglass makes a good
terminal block. just drill a couple holes in the block, close together, and
put an extra washer and nut on the screws. walla ! you have a place to hook
the wires up. Screw spacing ? 1/2 inch or so works pretty well....



"Paul Monaghan" wrote in message
...
Hi folks, new here.

I have been in need of a weather radio, but when shopping for one this
week it seemed such a waste to receive only 7 frequencies when I could
be receiving thousands. So I ended up with a scanner, just like that.

Wow! Instant hobby! Big mistake! I'm a serial compulsive, so now it's
time to start making antennas...

The scanner is one of those closeout RS Pro-2052s. With the stock
antenna I can receive the local police at around 39 and some
frequencies in the 100s, around 125 and 150, including civilian air.
Maybe more, but I'll concentrate on these for now.

Would like to build a simple half-wave dipole to start with. In my
garage I have a roll of 10ga solid copper, some solid aluminum wire
maybe twice as thick (don't know what it is, is left over from a
satellite TV system), and some galvanized 1-inch steel pipe.

Antenna would be mounted inside a detached garage so weather/weight
are not significant factors.

Reading the archives I can't tell whether to go with the copper
because it is a better conductor than the others, with the aluminum
because it is thicker than the copper, or with the galv pipe because
it is much thicker than the copper though somewhat lossy.

Any thoughts appreciated.

Thank you,
Paul

"Zombie Wolf" wrote in message
...
Make a Half - wave vertical with pipe. If the wall is dry wood, you can
simply clamp it in place on the wall. You figure out the length of this
antenna by the following formula

468 / freq (in MHZ)

Hook the center conductor of the coax to the antenna, and then simply run
a wire from the shield braid of the coax to a nearby ground. Presto. You
now have a half - wave vertical.

The end impedance of a half wave antenna is in the neighborhood of
1000--5000 Ohms depending on the diameter of the conductor; fatter
conductors, lower Z.

Connecting a coaxial cable to the bottom end of a half wave element and the
shield to ground will then result in a V.S.W.R. of roughly 2500/50 or
500:1. You need to convert the feed Z to 5o Ohms either by:

1. A quarter wave stub as in the popular J antenna
2. A lumped element L or Pi network


Dale W4OP

"Dale Parfitt" wrote in message
news:rMHOg.91$W13.22@trnddc05...

"Zombie Wolf" wrote in message
...
Make a Half - wave vertical with pipe. If the wall is dry wood, you can
simply clamp it in place on the wall. You figure out the length of this
antenna by the following formula

468 / freq (in MHZ)

Hook the center conductor of the coax to the antenna, and then simply run
a wire from the shield braid of the coax to a nearby ground. Presto. You
now have a half - wave vertical.

The end impedance of a half wave antenna is in the neighborhood of
1000--5000 Ohms depending on the diameter of the conductor; fatter
conductors, lower Z
The END impedance is not where you are making your connection. The impedance
at the connection point on a half wave vertical is about 30 to 35 ohms. Not
a perfect match , but certainly not 500 to 1 !.

Connecting a coaxial cable to the bottom end of a half wave element and
the shield to ground will then result in a V.S.W.R. of roughly 2500/50 or
500:1. You need to convert the feed Z to 5o Ohms either by:

They didnt "convert" it when i ran a half wave whip on my car , and the
shield was grounded to the chassis. I ran this for 15 years and never had an
swr of over 1.5. My 40 meter vertical outside doesnt have an swr of 500,
either, and it has worked well over the last 20 years. No stub matching is
required in either case. Better tell this to the thousands of hams that have
been running these antennas for the last 50 years ! No antenna matcher is
needed, either (your lumped L or pi network). The formulas and the antenna
itself came right out of the arrl handbook.

1. A quarter wave stub as in the popular J antenna
2. A lumped element L or Pi network


Dale W4OP

"Zombie Wolf" wrote in message
...

"Dale Parfitt" wrote in message
news:rMHOg.91$W13.22@trnddc05...

"Zombie Wolf" wrote in message
...
Make a Half - wave vertical with pipe. If the wall is dry wood, you can
simply clamp it in place on the wall. You figure out the length of this
antenna by the following formula

468 / freq (in MHZ)

Hook the center conductor of the coax to the antenna, and then simply
run a wire from the shield braid of the coax to a nearby ground. Presto.
You now have a half - wave vertical.

The end impedance of a half wave antenna is in the neighborhood of
1000--5000 Ohms depending on the diameter of the conductor; fatter
conductors, lower Z
The END impedance is not where you are making your connection. The
impedance at the connection point on a half wave vertical is about 30 to
35 ohms. Not a perfect match , but certainly not 500 to 1 !.

Connecting a coaxial cable to the bottom end of a half wave element and
the shield to ground will then result in a V.S.W.R. of roughly 2500/50
or 500:1. You need to convert the feed Z to 5o Ohms either by:

They didnt "convert" it when i ran a half wave whip on my car , and the
shield was grounded to the chassis. I ran this for 15 years and never had
an swr of over 1.5. My 40 meter vertical outside doesnt have an swr of
500, either, and it has worked well over the last 20 years. No stub
matching is required in either case. Better tell this to the thousands of
hams that have been running these antennas for the last 50 years ! No
antenna matcher is needed, either (your lumped L or pi network). The
formulas and the antenna itself came right out of the arrl handbook.

So, you're telling me you have a 66' tall 40M vertical that is fed directly
with coax?
I would appreciate a model of the antenna in EZNEC or ELNEC or AO. In
addition, the reference and year of the Handbook or any professional journal
where it describes end feeding a half wave antenna directly with coaxial
cable.

Dale W4OP

Yes, I do have a 66 foot vertical, that is suspended from about an 80 foot
tree out here, and i have been using it for a very long time. And the mobil
antenna is still on the old truck, also. Out here in the country, they dont
care what you put up for antennas. I also have a horizontal loop antenna out
there that is 150 feet on each side.

If you are so convinced that it doesnt work, then try it out. Its just that
simple. Put a three foot one up in the attic, as i described, and see if it
"fails to work".on the 155 mhz police band. Out here, we dont use EZNEC. We
just put 'em up, tune 'em, and use 'em. The antennas I dexcribed here are
well known to any novice operator (back when you had to know something about
it). The half - wave vertical is problably one of the oldest antennas on the
ham bands. It's not some "new idea" that i dreamed up..........

"Dale Parfitt" wrote in message
news:caJOg.123$GO2.84@trnddc01...

"Zombie Wolf" wrote in message
...

"Dale Parfitt" wrote in message
news:rMHOg.91$W13.22@trnddc05...

"Zombie Wolf" wrote in message
...
Make a Half - wave vertical with pipe. If the wall is dry wood, you can
simply clamp it in place on the wall. You figure out the length of this
antenna by the following formula

468 / freq (in MHZ)

Hook the center conductor of the coax to the antenna, and then simply
run a wire from the shield braid of the coax to a nearby ground.
Presto. You now have a half - wave vertical.

The end impedance of a half wave antenna is in the neighborhood of
1000--5000 Ohms depending on the diameter of the conductor; fatter
conductors, lower Z
The END impedance is not where you are making your connection. The
impedance at the connection point on a half wave vertical is about 30 to
35 ohms. Not a perfect match , but certainly not 500 to 1 !.

Connecting a coaxial cable to the bottom end of a half wave element and
the shield to ground will then result in a V.S.W.R. of roughly 2500/50
or 500:1. You need to convert the feed Z to 5o Ohms either by:

They didnt "convert" it when i ran a half wave whip on my car , and the
shield was grounded to the chassis. I ran this for 15 years and never had
an swr of over 1.5. My 40 meter vertical outside doesnt have an swr of
500, either, and it has worked well over the last 20 years. No stub
matching is required in either case. Better tell this to the thousands of
hams that have been running these antennas for the last 50 years ! No
antenna matcher is needed, either (your lumped L or pi network). The
formulas and the antenna itself came right out of the arrl handbook.

So, you're telling me you have a 66' tall 40M vertical that is fed
directly with coax?
I would appreciate a model of the antenna in EZNEC or ELNEC or AO. In
addition, the reference and year of the Handbook or any professional
journal where it describes end feeding a half wave antenna directly with
coaxial cable.

Dale W4OP

On Thu, 14 Sep 2006 20:41:53 GMT, Paul Monaghan
wrote:

Reading the archives I can't tell whether to go with the copper
because it is a better conductor than the others, with the aluminum
because it is thicker than the copper, or with the galv pipe because
it is much thicker than the copper though somewhat lossy.

It's a mechanical decision, mostly. The antenna has to be 1/2
wavelength long (and vertical) for best reception, so consider that
when you decide what to use.

My personal decision would be a ground plane, not a dipole. Radials
(the horizontal elements) about 75" each (for the 39 MHz signals) and
a few vertical elements - one 75" long, one about 26" long for the
aircraft band and another about 19" long for the 150-160 MHz range.
(You can add as many as you like - the only constraint is mechanical -
how do you do it?)

"Make a half wave vertical and simply run a wire to the nearest ground
and presto", you have a very high impedance antenna that will not match
to 50 ohms and is very bad advice. Make it a quarter wavelength vertical
radiator and ground the coax to something substantial, that would be
better advice. On the half wave dipole, it doesn’t matter if the element
connected to the center of the coax points up or down, the antenna
doesn’t know any different and it works the same.
Bob



Zombie Wolf wrote:
Make a Half - wave vertical with pipe. If the wall is dry wood, you can
simply clamp it in place on the wall. You figure out the length of this
antenna by the following formula

468 / freq (in MHZ)

Hook the center conductor of the coax to the antenna, and then simply
run a wire from the shield braid of the coax to a nearby ground. Presto.
You now have a half - wave vertical.

A l;ittle note on dipoles. the bands you want to listen to are primarily
vertical in nature. so if you made a diplole, you would want to mount
the thing vertically, not horizontally. The side of the diplole with the
center conductor connection would go at the top.

the sides of this antenna can be figured out by the following formula

234 / freq (in MHZ)

this gives you one side of the dipole. shield to one side, center
conductor to the other. I would use the copper wire for this.

Another antenna is the loop. the entire length of this antenna is
figured out by the following

1005 / freq (in MHZ)

this is a loop of wire, and is usually tacked onto the wall. the hookup
is made at the side of the loop for vertical polarization. Once again,
the copper wire is best suited for this antenna. the only trouble with
this antenna is that it is slightly directional, recieving best at a 90
degree angle to the plane of the loop in both directions. The loop is
usually formed into a circle or a square on the wall. (square is the
usual case).


all of the answers in these equations give the answer in feet and
fractions of a foot. simply multiply the fractional part by 12 to get
inches. rounding to the nearest inch is fine.

naturally, this mounting info is based on an indoor environment, outside
mountings need to be dealt with a bit differently. also, we are
assumiong that the building does not have metal siding, which will tend
to block radio waves. These do make excellent attic mounted antennas in
the house, by the way. Just mount the antenna on the end wall of the
attic, straight up. If you feel you must insulate the antenna, then
electric fence insulators are a quick and easy way to do this. simply
tap the nails into a convenient stud to mount the antenna. The half wave
vertical can also be made from the copper wire, by the way, and it will
work well. The half wave does not require radials , by the way. That is
why we simply run a ground wire from the braid to ground on this antenna.

for the coax connection points, a piece of thick plexiglass makes a good
terminal block. just drill a couple holes in the block, close together,
and put an extra washer and nut on the screws. walla ! you have a place
to hook the wires up. Screw spacing ? 1/2 inch or so works pretty well....



"Paul Monaghan" wrote in message
...
Hi folks, new here.

I have been in need of a weather radio, but when shopping for one this
week it seemed such a waste to receive only 7 frequencies when I could
be receiving thousands. So I ended up with a scanner, just like that.

Wow! Instant hobby! Big mistake! I'm a serial compulsive, so now it's
time to start making antennas...

The scanner is one of those closeout RS Pro-2052s. With the stock
antenna I can receive the local police at around 39 and some
frequencies in the 100s, around 125 and 150, including civilian air.
Maybe more, but I'll concentrate on these for now.

Would like to build a simple half-wave dipole to start with. In my
garage I have a roll of 10ga solid copper, some solid aluminum wire
maybe twice as thick (don't know what it is, is left over from a
satellite TV system), and some galvanized 1-inch steel pipe.

Antenna would be mounted inside a detached garage so weather/weight
are not significant factors.

Reading the archives I can't tell whether to go with the copper
because it is a better conductor than the others, with the aluminum
because it is thicker than the copper, or with the galv pipe because
it is much thicker than the copper though somewhat lossy.

Any thoughts appreciated.

Thank you,
Paul

Ladies and gentlemen, here is a perfect example of CB mentality that has
plagued the radio hobby from the beginning. Someone here obviously
doesn’t understand the fundamental nature of antennas but preaches bogus
information as it was gospel. Maybe the half wavelength mobile antenna
with the perfect match he refers to is his fiberglass loaded CB antenna,
which is advertised in half, full, one and a half, and every combination
of silly lengths to please CBrs as the dealers take their money. They do
match ok, but are not the full length, end fed, very high impedance half
wave antenna that he originally described in this thread. If you
actually read the ARRL handbook you will see Mr. Wolf’s grievous mistakes.
Bob


Zombie Wolf wrote:
Yes, I do have a 66 foot vertical, that is suspended from about an 80
foot tree out here, and i have been using it for a very long time. And
the mobil antenna is still on the old truck, also. Out here in the
country, they dont care what you put up for antennas. I also have a
horizontal loop antenna out there that is 150 feet on each side.

If you are so convinced that it doesnt work, then try it out. Its just
that simple. Put a three foot one up in the attic, as i described, and
see if it "fails to work".on the 155 mhz police band. Out here, we dont
use EZNEC. We just put 'em up, tune 'em, and use 'em. The antennas I
dexcribed here are well known to any novice operator (back when you had
to know something about it). The half - wave vertical is problably one
of the oldest antennas on the ham bands. It's not some "new idea" that i
dreamed up..........

"Dale Parfitt" wrote in message
news:caJOg.123$GO2.84@trnddc01...

"Zombie Wolf" wrote in message
...

"Dale Parfitt" wrote in message
news:rMHOg.91$W13.22@trnddc05...

"Zombie Wolf" wrote in message
...
Make a Half - wave vertical with pipe. If the wall is dry wood, you
can simply clamp it in place on the wall. You figure out the length
of this antenna by the following formula

468 / freq (in MHZ)

Hook the center conductor of the coax to the antenna, and then
simply run a wire from the shield braid of the coax to a nearby
ground. Presto. You now have a half - wave vertical.

The end impedance of a half wave antenna is in the neighborhood of
1000--5000 Ohms depending on the diameter of the conductor; fatter
conductors, lower Z
The END impedance is not where you are making your connection. The
impedance at the connection point on a half wave vertical is about 30
to 35 ohms. Not a perfect match , but certainly not 500 to 1 !.

Connecting a coaxial cable to the bottom end of a half wave element
and the shield to ground will then result in a V.S.W.R. of roughly
2500/50 or 500:1. You need to convert the feed Z to 5o Ohms either by:

They didnt "convert" it when i ran a half wave whip on my car , and
the shield was grounded to the chassis. I ran this for 15 years and
never had an swr of over 1.5. My 40 meter vertical outside doesnt
have an swr of 500, either, and it has worked well over the last 20
years. No stub matching is required in either case. Better tell this
to the thousands of hams that have been running these antennas for
the last 50 years ! No antenna matcher is needed, either (your lumped
L or pi network). The formulas and the antenna itself came right out
of the arrl handbook.

So, you're telling me you have a 66' tall 40M vertical that is fed
directly with coax?
I would appreciate a model of the antenna in EZNEC or ELNEC or AO. In
addition, the reference and year of the Handbook or any professional
journal where it describes end feeding a half wave antenna directly
with coaxial cable.

Dale W4OP