Michael,

I must say that is one very impressive loop!!! You can be sure I'll
be consulting your drawings and pictures the next time I build an HF
loop.

This is definitely one to point people to and say, "This is how you
do it when you do it right!"

73,

'Bear' NH7SR

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

Thanks Steve, that is most kind of you and much appreciated! Glad

you liked it and hope others will gain some ideas for their own loop
or just to copy mine.

Best regards!

Michael.
----- Original Message -----
From: Steve
To: loopantennas@...
Sent: Friday, August 27, 2004 12:14 AM
Subject: [loopantennas] Re: Loop Details


Very nice!

I created a folder called "Remote_Tuned_Loop" and moved them all

into

it. It will make it much easier to follow for people looking into

the

files in the future.

Steve Greenfield

--- In loopantennas@..., "Michael Stevenson"
<portstevos@t...> wrote:
> Hello everyone,
> Full construction details, diagrams and photos have now been
uploaded to this group's web site in the Files section under the
titles of:
...



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Does anyone has a schematics for a VHF/UHF multiband fractal antenna.
I'm very interesting to build one. Thank's.

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开云体育

Very nice!

I created a folder called "Remote_Tuned_Loop" and moved them all into
it. It will make it much easier to follow for people looking into the
files in the future.

Steve Greenfield

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

Hello everyone,
Full construction details, diagrams and photos have now been

uploaded to this group's web site in the Files section under the
titles of:
...

Michael, very nice job on the antenna. I especially like the motor
control for the variable cap. This allows you to tune the antenna yet
have it away from all local noise sources.

On the files, I recommend that you create a folder in the files
section and put all your files into it. That way it does not splatter
the main files section so much.

Overall, a great job.

Al KA5JGV
San Antonio, Tx.


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

Hello everyone,
Full construction details, diagrams and photos have now been

uploaded to this group's web site in the Files section under the
titles of:

Michael Stevenson,
Australia.

开云体育

Garth,

For a _tuned_ loop increasing the number of turns moves the tuning
range lower in frequency. For any given frequency, the single-turn
tuned loop will have a larger diameter (and thus greater capture
area) than a multi-turn tuned loop. This translates to greater
sensitivity with a single-turn tuned loop. The sensitivity of the
loop is directly related to its "Q" or effective bandwidth. The
higher the Q, the narrower the bandwidth, the greater the sensitivity
and the lower the noise.

Thumb's Rule states that for best Q the multi-turn loop should have
its turns spaced at least 1 conductor diameter.

Depth of nulls will be affected by proximity to other objects in the
near field of the loop on the horizontal plane. As the angle of
signal arrival increases above the horizontal plane the depth of null
will decrease. For signal arrival angles above 30 degrees the loop is
essentially omnidirectional.

The 1.0" hardline should make a very good loop. The only problem with
it may be in the connections to the tuning capacitor. You will need
to make them as mechanically and electrically sound as possible...
and thoroughly weatherproofed to retard oxidation at the joints.

73,

'Bear' NH7SR

--- In loopantennas@..., "Garth M.Conover" <ewrtsa@m...>
wrote:

I am looking for info as to a 3 or 5 turm Magnetic loop.(using 1.0"
hardline for outdoor stabilty) along with the usual tuning cap.

Will

it produce any better results when campared to the same diameter

mag

loop but just 1 turn. Will I get deeper nulls/improved directivity?
This is meant to be a rcv. loop only. I want to use large dia.
hardline due to its built in solid outer metal conductor. I figure

It

will be easier to stabilize the turns. Which brings me to another
question. I realize turn counts Vs spacing is a consideration with
wire loops. But what are the implications with a multi turn coax
loop. Should the hardline turns be basiclly intimate with the black
plastic outer conductor touching or should the turns be seperated
by "X" I would think that there should be some sort of spacing. Any
guidance for those who have this info or links to find same would

be

greatly appreciated.

I am looking for info as to a 3 or 5 turm Magnetic loop.(using 1.0"
hardline for outdoor stabilty) along with the usual tuning cap. Will
it produce any better results when campared to the same diameter mag
loop but just 1 turn. Will I get deeper nulls/improved directivity?
This is meant to be a rcv. loop only. I want to use large dia.
hardline due to its built in solid outer metal conductor. I figure It
will be easier to stabilize the turns. Which brings me to another
question. I realize turn counts Vs spacing is a consideration with
wire loops. But what are the implications with a multi turn coax
loop. Should the hardline turns be basiclly intimate with the black
plastic outer conductor touching or should the turns be seperated
by "X" I would think that there should be some sort of spacing. Any
guidance for those who have this info or links to find same would be
greatly appreciated.

John,

That makes sense. At MW especially the additional capacitance could
be problematical. At lower frequencies it might actually prove
beneficial to some degree.

73,

'Bear' NH7SR

--- In loopantennas@..., john nelson <jnelson123_us@y...>
wrote:

I was treating the telephone wire as if it was one
cable. Since I was establishing the correct length of
wire by trial and error it was easier that way. I
also theorized that the four wires were so close
together that there would be a stray capacitance
problem if I actually used them as separate windings.

John N.
--- Michael Hebert <qrpbear@y...> wrote:

John,

Very impressive looking antenna. One question...

Why did you connect the 4-conductor cable wires in
parallel? I assume
to resonate the loop.

I am thinking of something similar but series
connected and untuned.

73,

'Bear' NH7SR

I was treating the telephone wire as if it was one
cable. Since I was establishing the correct length of
wire by trial and error it was easier that way. I
also theorized that the four wires were so close
together that there would be a stray capacitance
problem if I actually used them as separate windings.

John N.
--- Michael Hebert <qrpbear@...> wrote:

John,

Very impressive looking antenna. One question...

Why did you connect the 4-conductor cable wires in
parallel? I assume
to resonate the loop.

I am thinking of something similar but series
connected and untuned.

73,

'Bear' NH7SR

--- In loopantennas@..., "John Nelson"
<jnelson123_us@y...> wrote:

I just posted a picture of my long wave and middle

wave loop in the

pictures section. The actual antenna was made

entirely of salvaged

materials for the exception of the brass bolts and

nuts in the
center

section. The outer loop is made of 4 wire flat

telephone cable
with

all sections paralleled. This section is a spiral

loop on just one

side of the support sections. The next section is

the MW loop and
is

made of 14 ga. conduit wire and is wound in a

basket fashion so as
to

hold down capacitance. The coupling loop is on

the inside and is
two

turns of two conductors in parallel. I thought

originally that I

could use the same loop for both bands using taps

but the
capacitance

of the wire made tuing up high enough for MW

impossible. Using

Varicap diodes in series it is possible to tune

_nearly_ all the

bands but not all. I finally put in a switch to

switch one pair of

diodes in and out and can easily cover more than

half of each band

with the high or low setting. The metal box

contains a FET

preamplifier, in/out switches, and the voltage for

the diodes. It

certainly is easier to tune the diodes remotely

than to bend over
and

adjust a variable cap. BTW the support section is

not near strong

enough-that wire in the LW section is really

heavy. On the 175-525

KHZ band, I have yet to detect anything but

non-directional beacons

but I'm still looking.

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开云体育

Michael,

Hey! It's finished! I am really looking forward to seeing the
pictures. Did you use the remote volume control motor for tuning?

73,

'Bear' NH7SR

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

My new magnetic loop antenna for shortwave is now fully finished

and in use. It's performance is extremely impressive and out performs
my 15 and 17 metre longwires. This is an active loop with a pre-amp
and tunes from below 2.3 MHz all the way up to 17.9 MHz, all with
full remote control.

I will be posting full details and photos to this group in the next

few days with a review of it's performance.

Best regards!

Michael Stevenson,
Australia.

John,

Very impressive looking antenna. One question...

Why did you connect the 4-conductor cable wires in parallel? I assume
to resonate the loop.

I am thinking of something similar but series connected and untuned.

73,

'Bear' NH7SR

--- In loopantennas@..., "John Nelson"
<jnelson123_us@y...> wrote:

I just posted a picture of my long wave and middle wave loop in the
pictures section. The actual antenna was made entirely of salvaged
materials for the exception of the brass bolts and nuts in the

center

section. The outer loop is made of 4 wire flat telephone cable

with

all sections paralleled. This section is a spiral loop on just one
side of the support sections. The next section is the MW loop and

is

made of 14 ga. conduit wire and is wound in a basket fashion so as

to

hold down capacitance. The coupling loop is on the inside and is

two

turns of two conductors in parallel. I thought originally that I
could use the same loop for both bands using taps but the

capacitance

of the wire made tuing up high enough for MW impossible. Using
Varicap diodes in series it is possible to tune _nearly_ all the
bands but not all. I finally put in a switch to switch one pair of
diodes in and out and can easily cover more than half of each band
with the high or low setting. The metal box contains a FET
preamplifier, in/out switches, and the voltage for the diodes. It
certainly is easier to tune the diodes remotely than to bend over

and

adjust a variable cap. BTW the support section is not near strong
enough-that wire in the LW section is really heavy. On the 175-525
KHZ band, I have yet to detect anything but non-directional beacons
but I'm still looking.

开云体育

I just posted a picture of my long wave and middle wave loop in the
pictures section. The actual antenna was made entirely of salvaged
materials for the exception of the brass bolts and nuts in the center
section. The outer loop is made of 4 wire flat telephone cable with
all sections paralleled. This section is a spiral loop on just one
side of the support sections. The next section is the MW loop and is
made of 14 ga. conduit wire and is wound in a basket fashion so as to
hold down capacitance. The coupling loop is on the inside and is two
turns of two conductors in parallel. I thought originally that I
could use the same loop for both bands using taps but the capacitance
of the wire made tuing up high enough for MW impossible. Using
Varicap diodes in series it is possible to tune _nearly_ all the
bands but not all. I finally put in a switch to switch one pair of
diodes in and out and can easily cover more than half of each band
with the high or low setting. The metal box contains a FET
preamplifier, in/out switches, and the voltage for the diodes. It
certainly is easier to tune the diodes remotely than to bend over and
adjust a variable cap. BTW the support section is not near strong
enough-that wire in the LW section is really heavy. On the 175-525
KHZ band, I have yet to detect anything but non-directional beacons
but I'm still looking.

At 11:59 PM 8/10/04 -0700, you wrote:

Installation of DSL has caused terrible overnight
buzzing from the 500's to about 1000kHz.

Phone company made adjustments at street and
house.

Buzzing on portable radios re-radiated in vicinity?????????????

Hi:

I'm sorry I am no help re your problem... but I will be reading the mail as I am curious about your EMI situation and the DSL installation.? Does your phone line come to your house via buried cable or is an overhead line from the pole?? I have a DSL installation at this location .... in fact the outlet for the DSL modem and the modem itself are located about 1 1/2 ft from my operating position ..... I experience no noise from it what so ever .... however, I will check a little more closely on the frequencies you mention.? By the way the phone line here comes in via a buried cable (6 pairs) the local telephone company installed about 3 or 4 years ago.

Now I did have some noise problem from the telephone installation about 2 years ago.? The distribution within the house comes from the power panel.? That is they terminate the lines from outside and distribute lines within the house from that location.? At one point I had 4 lines terminated from outside and 5 cables going off to different locations within the house.? Over the years it became a rats nest of connections and wires.? Even when the phone company installed the new underground cable from the lane the rats nest remained.? Finally I couldn't stand it any more and I found a couple of 24 place barrier strips in the junk box and I mounted them on the wood backing of the power panel.? I then methodically terminated the incoming lines and the internal lines to the barrier strips.? I then drew up a schematic with the termination numbers.? I then cross connected the terminals to effect the desired distribution.? I used a 'LED' test tool to make sure the polarity of every line showed 'green' at every telephone jack.? Magically the noise stopped and the terminations really looked professional.? When they came to install the DSL service the installer was amazed at the setup .... 'this can't be our work' , he said!

Jim Dunstan
Thunder Bay, ON

Installation of DSL has caused terrible overnight
buzzing from the 500's to about 1000kHz.

Phone company made adjustments at street and
house.

Buzzing on portable radios re-radiated in
vicinity
of the four phones in the house.

On the outdoor phone line, portable radio reveals
that buzzing is propagated parallel to phone
line, not perpendicular.

Buzzing the loudest near our strongest overnight
signal at this location, 710kHz (710 KIRO/Seattle
50kW U2).

Why the buzzing only occurs overnight I haven't
figured out.

During the day = a hissing or whining sign on
weaker 1kW frequencies, even higher up the dial
(e.g. 1400kHz).

The old radio shack terk clone does not even help
that much at night.

Any info on what to tell phone company to do
would be very much appreciated, thanks...tom:

=====
Tom, webmaster, indigotalkradio
www.geocities.com/indigotalkradio



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It probably means the loop is not really tuned to null; instead it
is tuned -near- null, and is putting out just enough at 180 out of
phase with the internal ferrite to cancel out the signal being
received by it directly.

Steve Greenfield

--- realrussian <realrussian@...> wrote:

At 07:28 PM 8/10/04 +0000, you wrote:

Thanks, but what about my question regarding "auto disconnect" of the
internal ferrite bar?? When I turn the loop to null a strong, local
station (I don't hear ANYTHING)doesn't that suggest that the internal
antenna has been defeated in some way?

I am sure there is no 'auto disconnect' .... most receivers with the ferrite antenna that have external antenna connections will operate both at the same time.? There are a few exceptions .... for example the Sony 7600GR will disconnect the AM antenna when an external antenna jack is plugged in.? The disconnect is mechanical however.? A similar Grundig radio ... the YB400 with the same type antenna jack only disconnects the whip on SW .... but leaves the internal AM antenna.?

However that does not explain the strange behaviour you are experiencing.

Jim Dunstan
Thunder Bay, ON