Hello,

This email message is a notification to let you know that
a file has been uploaded to the Files area of the loopantennas
group.

File : /capcalc.exe
Uploaded by : qrpbear <qrpbear@...>
Description : KI6GD's Capacitance Calculator for making your own capacitors.

You can access this file at the URL



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Regards,

qrpbear <qrpbear@...>

Karl,

Glad to meetcha!

I just uploaded KI6GD's Capacitor Calculator program which you will
find in the Files section.

This program takes the plate area, spacing and number of plates then
calculates the capacitance and voltage rating. It does not take into
account any dielectric other than air (dielectric constant = 1) but
you can "fudge" that in if you know the constant for the material.
Just multiply the capacitance as given by the calculator by the
dielectric constant to get a ballpark figure. Other dielectrics will
also affect the voltage rating, of course.

It would be interesting to find a source for curves defining Straight
Line Capacitance, Straight Line Frequency and Straight Line
Wavelength plate areas. I have looked for them but have not been able
to find them. I used to have some of these years and years ago but
they have long since vanished.

73,

'Bear' NH7SR

--- In loopantennas@..., "Karl" <portlypaddler@y...>
wrote:

Hi All! New to the group, but not to radio. When I was a kid (very
long ago), we used to make our own variable capacitors. Basically,
we'd take a square of wood, varnish it well, and mount a square or
disc of aluminum in the center, and attach a lead to it. This

became

the stator. A piece of celluloid (later plastic) was glued over

this

stator plate, and a similar piece of aluminum with a lead attached
and a piece of phenolic rod glued in it's center, was placed on top
to become the rotor. Both leads were attached to the board by
fanstock clips. By manipulating (sliding) the rotor plate across

the

stator plate, you could go from full mesh to wide open. A friend of
mine and fellow Boy Scout even took india ink and marked the

receive

locations of his favorite stations on the celluloid, making
essentially, a rudimentary dial. Now, why am I bringing this all up
(other than to wallow in nostalgia)? It seems to me that variable
capacitors are becoming hard to find these days, and when you can
find them they're pricy, and usually have to be combined with other
items to make a "minimum purchase". Not good for a geezer like me,
living on a fixed income. Does anybody have any experience
homebrewing VCs? If so, maybe you could share some data or formulae
for scaling the plates. Well, talk with you all again soon, Karl

This has indeed become a very good day. No sooner did I ask for a cap
calculator, then one appears in the files section. Thank you very
much! So many great links, so many interesting posts...think I'm
gonna like it here. Thanks again, Karl

Michael, thank you very much indeed. I've already downloaded the
calculator and have been playing with it. I've got a table of
dialectric constants around here someplace, and should be happily
homebrewing soon. Thanks again, Karl--- In
loopantennas@..., "Michael Hebert" <qrpbear@y...> wrote:

Karl,

Glad to meetcha!

I just uploaded KI6GD's Capacitor Calculator program which you will
find in the Files section.

This program takes the plate area, spacing and number of plates

then

calculates the capacitance and voltage rating. It does not take

into

account any dielectric other than air (dielectric constant = 1) but
you can "fudge" that in if you know the constant for the material.
Just multiply the capacitance as given by the calculator by the
dielectric constant to get a ballpark figure. Other dielectrics

will

also affect the voltage rating, of course.

It would be interesting to find a source for curves defining

Straight

Line Capacitance, Straight Line Frequency and Straight Line
Wavelength plate areas. I have looked for them but have not been

able

to find them. I used to have some of these years and years ago but
they have long since vanished.

73,

'Bear' NH7SR

--- In loopantennas@..., "Karl" <portlypaddler@y...>
wrote:

Hi All! New to the group, but not to radio. When I was a kid

(very

long ago), we used to make our own variable capacitors.

Basically,

we'd take a square of wood, varnish it well, and mount a square

or

disc of aluminum in the center, and attach a lead to it. This

became

the stator. A piece of celluloid (later plastic) was glued over

this

stator plate, and a similar piece of aluminum with a lead

attached

and a piece of phenolic rod glued in it's center, was placed on

top

to become the rotor. Both leads were attached to the board by
fanstock clips. By manipulating (sliding) the rotor plate across

the

stator plate, you could go from full mesh to wide open. A friend

of

mine and fellow Boy Scout even took india ink and marked the

receive

locations of his favorite stations on the celluloid, making
essentially, a rudimentary dial. Now, why am I bringing this all

up

(other than to wallow in nostalgia)? It seems to me that variable
capacitors are becoming hard to find these days, and when you can
find them they're pricy, and usually have to be combined with

other

items to make a "minimum purchase". Not good for a geezer like

me,

living on a fixed income. Does anybody have any experience
homebrewing VCs? If so, maybe you could share some data or

formulae

for scaling the plates. Well, talk with you all again soon, Karl

Howdy, Gregg,

Welcome to the group and thanks for the links. The design of your
loop's support structure is especially interesting to me. I've been
kicking this around for a while without coming up with anything. The
drawings on your web page put a new perspective on it for me... looks
like it may be just what I'm looking for.

73,

'Bear' NH7SR

--- In loopantennas@..., Gregg <dxlover2003@y...> wrote:

I own four loops, the first two were the Radio Shack loops, which

is/are a fine product. *BUT* - I wanted more because I knew I could
get more out of a loop antenna.

My second passion (very close) to SW listening is BCB dxing. I have

what I feel two great BCB dx setups. They both include the GE P-780,
if you aren't familiar with this 'just BCB' dx radio here is the
link, follow the other links with this to read all about it.

It 'truly' is an amazing BCB radio and they are built like a

battleship and I own a lot of radios and I finally found the perfect
setup for me. This radio (which is key) is that it is both sensitive
and selective. I've sat my first radio ( I own two of these beauties)
on my lazy susan turntable and on the back of that table is what I
call my 'Black Beauty.'

It is a 30x30 (painted black) PVC loop

it is a Diamond Loop or some call a 'pancake Loop' with a variable

cap that is a six section-830pF that tunes from 530-1830. It is
literally mounted to the back of my table and has a very big what I
call 'capture zone.' This loop, because it is PVC, can be tilted
forward (which is great) leaned backwards turned to either side, I
can even spin it around upside down if I wanted. It is really an
excellent setup for DXing and blows away when I had 500ft. of wire
hooked to it.

I had so many signals coming from everywhere at one time, it was

too much. This loop has totally eliminated that problem and I can't
be happier, I wished I could take a pic and post it but I don't have
a camera and I wouldn't know how to send it. But my table I wouldn't
sell for a grand, this setup has added MANY qsl's.

I highly recommend both the radio and that loop, if you can make it

bigger- even better.

In my living room, I have a real nice old varnished/stained sewing

machine stand, of course minus the sewing machine. It look just like
a table till you open up the top and the lid entends out, it is on
rollers On that I have another GE P-780 along with another loop,
this one costs me some money, it was made out of wood and stained and
has spokes and beautiful red litz wire was used. It was originally
tuned from like 670 but I let Dave know I use the entire BCB and he
added a small toggle switch and badda bing I have the entire BCB.
Here is the link, scroll down to the 'Penta-Loop'.....the pic just
doesn't do it justice. It truly is a piece of work............

Dave takes

pride in his radios and his loops and it shows, both in looks and in
how it works.

So that is my story and my loops, I love the 'Black Beauty' though,

isn't that crazy, the PVC over the wooden/stained.... but both work
great, it's just I spend more time in this room.

Thanks,
Gregg


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Hello,

This email message is a notification to let you know that
a file has been uploaded to the Files area of the loopantennas
group.

File : /The Bear Cave/An Introduction to the Mysteries of Ground Radio.txt
Uploaded by : qrpbear <qrpbear@...>
Description : Do Geomantic antennas exist? Do they work? This article documents some of the discoveries made by early telegraph/telephone pioneers.

You can access this file at the URL



To learn more about file sharing for your group, please visit



Regards,

qrpbear <qrpbear@...>

No... they ain't loops but they do offer some interesting potential
that seems worthy of exploration. Especially for ground dwelling folk
like me that have limited area for antenna farming. They are stealth
antennas by nature.

I have uploaded two text files regarding them to the "Bear Cave" in
the Files area.

73,

'Bear' NH7SR (Now where's my pick'n'shovel? Got a bit of "gardening"
to do <G>)

Since the subject of Geomantic Antennae can get rather far afield and
lead into some other rather peculiar areas (dowsing, radionics, Ley
lines, etc) I have created a new group at...

<>

Y'all is welcome, now, y'hear!?

73,

'Bear' NH7SR (Polishing up his dowsing rods)

--- In loopantennas@..., "Michael Hebert" <qrpbear@y...>
wrote:

No... they ain't loops but they do offer some interesting potential
that seems worthy of exploration. Especially for ground dwelling

folk

like me that have limited area for antenna farming. They are

stealth

antennas by nature.

I have uploaded two text files regarding them to the "Bear Cave" in
the Files area.

73,

'Bear' NH7SR (Now where's my pick'n'shovel? Got a bit

of "gardening"

to do <G>)

There's another compact antenna with its own new group here on Yahoo
at...

<>

There isn't much there yet but a few pictures and a link to the
owner's home page. The antenna he describes is a form of ground
independent coaxial monopole helically wound on a plastic flowerpot.
It is tuneable by adding a variable capacitor across the far end of
the antenna. There is a photo illustrating it.

Throw an arrangement of plastic flowers in the pot and you have a
nice attractive and very stealthy antenna. Now who could possibly
object to something like that on 12th floor veranda in a condo?

73,

'Bear' NH7SR

I am thinking about getting some wood , and build a 4 foot
loop, cause my broadband loop has got the winding less than 10
turns. Are there any other projects that I should try out to
dramatically improve my AM and LW reception? I will take notes.

Adam Ebel Thanks.

Steve,

Ninty messages in the first week! You have one hot group here!

Regards,

Steven

--- In loopantennas@..., "Steve" <alienrelics@y...>
wrote:

We're up to 55 members! And lots of activity.

Remember, if you have not posted yet, all new members are

moderated.

So don't be alarmed if your first message takes a few hours or a

day

to appear. I get on fairly often to check, subject to Real Life

(tm).

Once you've posted, I'll set you unmoderated. Just my way of

quietly

blocking spammers.

Steve Greenfield,
moderator of the new loopantennas

Gents...

I have built my first geomantic (ground-coupled) antenna which I am
calling the Geomantic Spiral. It's nothing more than 30' of RG58 coax
rolled into a tight, flat spiral and placed on the ground under some
bricks on my lanai (patio to you Mainland folk).

Performance is _very_ good!!!

I have posted a more detailed description and preliminary listening
results in my new group at...

<>

Drop in and check it out. Everyone is welcome.

'Bear' NH7SR (Doing happy Snoopy dance)

开云体育

Michael,

Thanks for joining. I have set you to unmoderated so you can post at
will. I don't have a camera at present so there won't be any photos
for the time being. I'll see if I can whip together some kind of
drawing. I haven't done any kind of analysis yet as to the why and
how the Geomantic Spiral works. Looks like a promising area for
experimentation and learning.

I'll still be hanging around here, of course. Got lots of loop ideas
I want to play with also.

BTW, if the signal I'm receiving on 3.925 MHz from NHK Tokyo right
now is any indication this hy'ar animule may turn out to be a very
good Tropical Band antenna.

73,

'Bear' NH7SR

--- In loopantennas@..., "Michael Stevenson"
<portstevos@t...> wrote:

Hi Bear,
Just joined the group and checked out your early results of the new

geomantic Spiral antenna, very interesting stuff. When you are ready
you will have to give a photo and more detailed construction notes,
could be a nice antenna to play with (after I finish the 14 foot loop
of course!)

Nice new group Bear and hope it does well for you!
Best regards!

Michael Stevenson,
Australia.
----- Original Message -----
From: Michael Hebert
To: loopantennas@...
Sent: Wednesday, June 16, 2004 5:21 PM
Subject: [loopantennas] The Geomantic Spiral


Gents...

I have built my first geomantic (ground-coupled) antenna which I

am

calling the Geomantic Spiral. It's nothing more than 30' of RG58

coax

rolled into a tight, flat spiral and placed on the ground under

some

bricks on my lanai (patio to you Mainland folk).

Performance is _very_ good!!!

I have posted a more detailed description and preliminary

listening

results in my new group at...

<>

Drop in and check it out. Everyone is welcome.

'Bear' NH7SR (Doing happy Snoopy dance)


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a.. To visit your group on the web, go to:


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Service.

开云体育

Michael,

My QTH is a typical(?) urban environment. I live on the ground floor
of a 3-story apartment building. My apartment is in the roughly NE
corner. The ground elevation here is about 10' above sea level (I'm
in a tidal wave inundation area). There is a large 25 story building
only 50' to the North of me and several other tall buildings
surrounding me within a 1/4 mile radius. I am also surrounded on all
sides by elevated electrical, telephone and cable TV lines within a
radius of 100 to 200'. There is a small park next to my building on
the East and Southeast side. Perhaps 1 acre or a little less in area.
There are a couple of very large, old Ficus trees growing there as
well as some other smaller trees. My lanai area is only about 8' wide
by 20' long. There is a Mock Orange hedge some 8' tall between me and
the park.

My 23' vertical antenna is located at the NE corner of the building
and is only 2' from the side of the building. The lower section of it
is 18" away from a 6' high chain-link fence. There are 3 elevated 24'
radials connected to it as well as 1 24' buried radial. My loop
antenna is on the roof of the apartment house and connected through a
100' RG-58 cable run. Currently the loop is acting intermittently. I
think I have a loose connection up there that I will need to fix.

The Geomantic Spiral is under the bricks in the barbeque area of the
lanai about 3' from the side of the building.

This is obviously not a "dream" DX location!! Despite that I have
been able to make some pretty decent contacts with QRP operation on
the 30 and 20 meter ham bands around the Pacific and into South
America while running only 2 watts output. The plus side to this
location is that it provides me the opportunity to play with and
develop various types of antennas that will be effective in a "less
than ideal" kind of environment.

73,

'Bear' NH7SR

--- In loopantennas@..., "Michael Stevenson"
<portstevos@t...> wrote:

Sound's great and will certainly have to give it a go after my loop

is upon it's final mounting. What is your QTH area like Bear?

Is it flat or are you in a valley or hollow or are you on top of a

hill or on the side of a hill?

Any trees or buildings around close by?
Thanks for the reply and best regards!

Michael.
----- Original Message -----
From: Michael Hebert
To: loopantennas@...
Sent: Wednesday, June 16, 2004 7:56 PM
Subject: [loopantennas] Re: The Geomantic Spiral


Michael,

Thanks for joining. I have set you to unmoderated so you can post

at

will. I don't have a camera at present so there won't be any

photos

for the time being. I'll see if I can whip together some kind of
drawing. I haven't done any kind of analysis yet as to the why

and

how the Geomantic Spiral works. Looks like a promising area for
experimentation and learning.

I'll still be hanging around here, of course. Got lots of loop

ideas

I want to play with also.

BTW, if the signal I'm receiving on 3.925 MHz from NHK Tokyo

right

now is any indication this hy'ar animule may turn out to be a

very

good Tropical Band antenna.

73,

'Bear' NH7SR

--- In loopantennas@..., "Michael Stevenson"
<portstevos@t...> wrote:
> Hi Bear,
> Just joined the group and checked out your early results of the

new

geomantic Spiral antenna, very interesting stuff. When you are

ready

you will have to give a photo and more detailed construction

notes,

could be a nice antenna to play with (after I finish the 14 foot

loop

of course!)
> Nice new group Bear and hope it does well for you!
> Best regards!
>
> Michael Stevenson,
> Australia.
> ----- Original Message -----
> From: Michael Hebert
> To: loopantennas@...
> Sent: Wednesday, June 16, 2004 5:21 PM
> Subject: [loopantennas] The Geomantic Spiral
>
>
> Gents...
>
> I have built my first geomantic (ground-coupled) antenna

which I

am
> calling the Geomantic Spiral. It's nothing more than 30' of

RG58

coax
> rolled into a tight, flat spiral and placed on the ground

under

some
> bricks on my lanai (patio to you Mainland folk).
>
> Performance is _very_ good!!!
>
> I have posted a more detailed description and preliminary
listening
> results in my new group at...
>
> <>
>
> Drop in and check it out. Everyone is welcome.
>
> 'Bear' NH7SR (Doing happy Snoopy dance)
>
>
> Yahoo! Groups Sponsor
> ADVERTISEMENT
>
>
>
>
>
> ----------------------------------------------------------------

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----------
> Yahoo! Groups Links
>
> a.. To visit your group on the web, go to:
>
>
> b.. To unsubscribe from this group, send an email to:
> loopantennas-unsubscribe@...
>
> c.. Your use of Yahoo! Groups is subject to the Yahoo!

Terms of

Service.


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ADVERTISEMENT





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----------

Yahoo! Groups Links

a.. To visit your group on the web, go to:


b.. To unsubscribe from this group, send an email to:
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c.. Your use of Yahoo! Groups is subject to the Yahoo! Terms of

Service.

开云体育

I bought this kit, also available assembled:



Very nice, from 1nH to 150mH, and .01pF to 1.5uF. Has an internal
reference that it calibrates itself from each time you turn it on.

Steve

Hello all,

I uploaded some pics of my 18" loop that had sagging wires.
It took a while at 46k bps !

Dave