WWVB Loopstick Antenna Project
I exploring the parts needed to construct this particular VLF Loop Stick
Antenna by Richard Q. Marris G2BZQ.
I have uploaded the article to my DropBox Account here:
https://www.dropbox.com/s/niv64xqmghu76z3/1_1201157_4_Ultima_loopstick_VLF_a
ntenna.pdf?dl=0
The project explains you should use 9.5mm (3/8") Diameter X 15cm (6") Length
Ferrite rods.
The closest I have been able to find are 10mm (0.393") Diameter X 160mm
(6.299) Length.
Will it make much of a difference?
Thank You
Don Resor
On 9/10/22 7:59 AM, D. Resor via time-nuts wrote:
I exploring the parts needed to construct this particular VLF Loop Stick
Antenna by Richard Q. Marris G2BZQ.
I have uploaded the article to my DropBox Account here:
https://www.dropbox.com/s/niv64xqmghu76z3/1_1201157_4_Ultima_loopstick_VLF_a
ntenna.pdf?dl=0
The project explains you should use 9.5mm (3/8") Diameter X 15cm (6") Length
Ferrite rods.
The closest I have been able to find are 10mm (0.393") Diameter X 160mm
(6.299) Length.
Will it make much of a difference?
Thank You
Don Resor
Not much difference.. the diameter 0.375 vs 0.393 isn't much. Length
doesn't much matter, as long as the windings fit.
A bigger issue might be the permeability of the rod.
The referred article by Richard Q. Marris is a good one but liekly mass
overkill for this application.
Seek a rod that is good at the 125kHz RFID frequency. Type material 78
comes to mind, but almost any Manganese Zinc Ferrite is going to work.
Although they'll probably be fairly small . All the higher frequency
rods will be fine on losses but have low perm and need lots of turns.
Something with an initial permeability of at least 2000 will be suitable.
greater Length/Diameter will increase mu-rod. 6" x 3/8" sounds good.
You might not need that much rod, I dont know what the field strengths
are (does anyone know) but something like this might be suitable :
https://www.fair-rite.com/product/antennarfid-rods-3078990901/
a ferrite rod is not necessary if you have space... if this is a fixed
application, many turns around a foot square will be just as
effective. No need for a ferrite rod.
Suggest electrostatic shield and balanced feed for the wire , coreless
loop.
For a small ferrite rod, put the rod length wise in a deep aluminium
channel section.
It's certainly easier to build a ES shielded small rod than a loop.
-glen
On 11/09/2022 12:38 pm, Lux, Jim via time-nuts wrote:
On 9/10/22 7:59 AM, D. Resor via time-nuts wrote:
I exploring the parts needed to construct this particular VLF Loop Stick
Antenna by Richard Q. Marris G2BZQ.
I have uploaded the article to my DropBox Account here:
https://www.dropbox.com/s/niv64xqmghu76z3/1_1201157_4_Ultima_loopstick_VLF_a
ntenna.pdf?dl=0
The project explains you should use 9.5mm (3/8") Diameter X 15cm (6")
Length
Ferrite rods.
The closest I have been able to find are 10mm (0.393") Diameter X 160mm
(6.299) Length.
Will it make much of a difference?
Thank You
Don Resor
Not much difference.. the diameter 0.375 vs 0.393 isn't much. Length
doesn't much matter, as long as the windings fit.
A bigger issue might be the permeability of the rod.
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@lists.febo.com
--
Glen English
RF Communications and Electronics Engineer
CORTEX RF
Pacific Media Technologies Pty Ltd trading as Cortex RF
ABN 40 075 532 008
PO Box 5231 Lyneham ACT 2602, Australia.
au mobile : +61 (0)418 975077
Seek a rod that is good at the 125kHz RFID frequency. Type material 78
comes to mind, but almost any Manganese Zinc Ferrite is going to work.
Although they'll probably be fairly small . All the higher frequency
rods will be fine on losses but have low perm and need lots of turns.
Something with an initial permeability of at least 2000 will be suitable.
I used a spare
https://fr.aliexpress.com/item/1005004383694303.html (actually
https://www.conrad.fr/p/platine-de-reception-dcf-641138-pour-serie-c-control-641138
but more expensive than the Chinese version) when assembling
http://jmfriedt.free.fr/agu_dcf77.pdf (see Fig 2 taken from
https://www.qsl.net/dl4yhf/dcf77_osc/index.html: 60 or 77.5 kHz
will not make much of a difference).
Best, Jean-Michel
Have you come across these fascinating YouTube videos by W1VLF? They may be
of interest to you.
WWVB Antenna Part 1 https://www.youtube.com/watch?v=ySWpaAXiJCQ
https://www.youtube.com/watch?v=ySWpaAXiJCQ
R/
Patrick Murphy (KG5YPQ)
On Sat, Sep 10, 2022 at 8:37 PM D. Resor via time-nuts <
time-nuts@lists.febo.com> wrote:
I exploring the parts needed to construct this particular VLF Loop Stick
Antenna by Richard Q. Marris G2BZQ.
I have uploaded the article to my DropBox Account here:
https://www.dropbox.com/s/niv64xqmghu76z3/1_1201157_4_Ultima_loopstick_VLF_a
ntenna.pdf?dl=0
https://www.dropbox.com/s/niv64xqmghu76z3/1_1201157_4_Ultima_loopstick_VLF_antenna.pdf?dl=0
The project explains you should use 9.5mm (3/8") Diameter X 15cm (6")
Length
Ferrite rods.
The closest I have been able to find are 10mm (0.393") Diameter X 160mm
(6.299) Length.
Will it make much of a difference?
Thank You
Don Resor
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@lists.febo.com
--
R/
Patrick Murphy (KG5YPQ)
The header seems to say the application. A wwvb antenna.
If you look in any of the simple cheap atomic clocks you will find a rod
about 2-3" long.
Typically a resonating cap right on the antenna for 60 KHz. These work well
enough to receive wwvb at night when the signals much stronger than during
the day.
As insight near Boston 60 uv day and last night 1500 uv on a 5' loop tuned
for 100 KHz not wwvb. The 10' square loop is something like 200/10,000 uv.
Honest. Not every night but many of them. I have used bundled rods for a
number of years but the square loops are better. More importantly no
ferrite was ever harmed in building them.... So that must mean the square
loops are more green. Right?
OK sorry went of topic.
all things are a tradeoff. Large loops are hard to install and then manage
over time. Especially when a large branch crashes through the loop after 5
years. Thats why at 100 KHz I went to a 5' loop. Less of a target.
Whats nice about the rods are they really are pretty small.
Regards
Paul
WB8TSL
On Sun, Sep 11, 2022 at 12:08 AM glen english LIST via time-nuts <
time-nuts@lists.febo.com> wrote:
The referred article by Richard Q. Marris is a good one but liekly mass
overkill for this application.
Seek a rod that is good at the 125kHz RFID frequency. Type material 78
comes to mind, but almost any Manganese Zinc Ferrite is going to work.
Although they'll probably be fairly small . All the higher frequency
rods will be fine on losses but have low perm and need lots of turns.
Something with an initial permeability of at least 2000 will be suitable.
greater Length/Diameter will increase mu-rod. 6" x 3/8" sounds good.
You might not need that much rod, I dont know what the field strengths
are (does anyone know) but something like this might be suitable :
https://www.fair-rite.com/product/antennarfid-rods-3078990901/
a ferrite rod is not necessary if you have space... if this is a fixed
application, many turns around a foot square will be just as
effective. No need for a ferrite rod.
Suggest electrostatic shield and balanced feed for the wire , coreless
loop.
For a small ferrite rod, put the rod length wise in a deep aluminium
channel section.
It's certainly easier to build a ES shielded small rod than a loop.
-glen
On 11/09/2022 12:38 pm, Lux, Jim via time-nuts wrote:
On 9/10/22 7:59 AM, D. Resor via time-nuts wrote:
I exploring the parts needed to construct this particular VLF Loop Stick
Antenna by Richard Q. Marris G2BZQ.
I have uploaded the article to my DropBox Account here:
ntenna.pdf?dl=0
The project explains you should use 9.5mm (3/8") Diameter X 15cm (6")
Length
Ferrite rods.
The closest I have been able to find are 10mm (0.393") Diameter X 160mm
(6.299) Length.
Will it make much of a difference?
Thank You
Don Resor
Not much difference.. the diameter 0.375 vs 0.393 isn't much. Length
doesn't much matter, as long as the windings fit.
A bigger issue might be the permeability of the rod.
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@lists.febo.com
--
Glen English
RF Communications and Electronics Engineer
CORTEX RF
Pacific Media Technologies Pty Ltd trading as Cortex RF
ABN 40 075 532 008
PO Box 5231 Lyneham ACT 2602, Australia.
au mobile : +61 (0)418 975077
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@lists.febo.com
Good stuff Paul
What needs to be determined is the required Signal to Noise for the
application, since its about using the signal for analytical purposes.
That will drive the design and requirements. Higher SNR for indoor
antennas will certainly be got with electrostatic (ES) shields -
But the trap is that you cannot just use a very low efficiency antenna
in a high noise environment- with very low efficiency antennas this
leaves very small signal values which can easily get drowned out by any
common mode noise getting on the cable, which means you have to work
VERY hard on common mode rejection / suppression and balance, and also
garbage getting onto the cable in the shack, if the coax is not choked
where it leaves the shack, will take noise to the near field of the
antenna !
So, careful thought is required- balanced input preamp on the antenna
terminals is recommended- not because there is a lack of signal, but to
give it a boost above everything else. Either that or tale great care,
perhaps twincoax balanced feed and resonant common mode chokes to get
Zcm > 10,000.
Well I am getting off topic, there are a thousand ways to skin this cat.
A 5' loop with ES shield in the attic can work well, as long as you
dont have LED lightning wires criss-crossing under your antenna.
I'd suggest a smaller loop with more turns FURTHER away from the house.
Why? because noise will dominate close to the house. The near field
pickup region will be smaller for a smaller antenna.
Perhaps a 2' loop up on a piece of pipe, or a rod.. You can likely
dispense with the ES shield if it is a mile away from any noise source
and structure.
On 12/09/2022 1:13 am, paul swed wrote:
The header seems to say the application. A wwvb antenna.
If you look in any of the simple cheap atomic clocks you will find a
rod about 2-3" long.
Typically a resonating cap right on the antenna for 60 KHz. These work
well enough to receive wwvb at night when the signals much stronger
than during the day.
As insight near Boston 60 uv day and last night 1500 uv on a 5' loop
tuned for 100 KHz not wwvb. The 10' square loop is something like
200/10,000 uv. Honest. Not every night but many of them. I have used
bundled rods for a number of years but the square loops are better.
More importantly no ferrite was ever harmed in building them.... So
that must mean the square loops are more green. Right?
OK sorry went of topic.
all things are a tradeoff. Large loops are hard to install and then
manage over time. Especially when a large branch crashes through the
loop after 5 years. Thats why at 100 KHz I went to a 5' loop. Less of
a target.
Whats nice about the rods are they really are pretty small.
Regards
Paul
WB8TSL
On Sun, Sep 11, 2022 at 12:08 AM glen english LIST via time-nuts
time-nuts@lists.febo.com wrote:
The referred article by Richard Q. Marris is a good one but liekly
mass
overkill for this application.
Seek a rod that is good at the 125kHz RFID frequency. Type
material 78
comes to mind, but almost any Manganese Zinc Ferrite is going to
work.
Although they'll probably be fairly small . All the higher frequency
rods will be fine on losses but have low perm and need lots of turns.
Something with an initial permeability of at least 2000 will be
suitable.
greater Length/Diameter will increase mu-rod. 6" x 3/8" sounds good.
You might not need that much rod, I dont know what the field
strengths
are (does anyone know) but something like this might be suitable :
https://www.fair-rite.com/product/antennarfid-rods-3078990901/
a ferrite rod is not necessary if you have space... if this is a
fixed
application, many turns around a foot square will be just as
effective. No need for a ferrite rod.
Suggest electrostatic shield and balanced feed for the wire ,
coreless
loop.
For a small ferrite rod, put the rod length wise in a deep aluminium
channel section.
It's certainly easier to build a ES shielded small rod than a loop.
-glen
On 11/09/2022 12:38 pm, Lux, Jim via time-nuts wrote:
> On 9/10/22 7:59 AM, D. Resor via time-nuts wrote:
>> I exploring the parts needed to construct this particular VLF
Loop Stick
>> Antenna by Richard Q. Marris G2BZQ.
>>
>> I have uploaded the article to my DropBox Account here:
>>
>>
https://www.dropbox.com/s/niv64xqmghu76z3/1_1201157_4_Ultima_loopstick_VLF_a
>>
>> ntenna.pdf?dl=0
>>
>> The project explains you should use 9.5mm (3/8") Diameter X
15cm (6")
>> Length
>> Ferrite rods.
>>
>> The closest I have been able to find are 10mm (0.393") Diameter
X 160mm
>> (6.299) Length.
>>
>> Will it make much of a difference?
>>
>> Thank You
>>
>> Don Resor
>
>
> Not much difference.. the diameter 0.375 vs 0.393 isn't much.
Length
> doesn't much matter, as long as the windings fit.
>
> A bigger issue might be the permeability of the rod.
>
> _______________________________________________
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe send an email to time-nuts-leave@lists.febo.com
--
Glen English
RF Communications and Electronics Engineer
CORTEX RF
Pacific Media Technologies Pty Ltd trading as Cortex RF
ABN 40 075 532 008
PO Box 5231 Lyneham ACT 2602, Australia.
au mobile : +61 (0)418 975077
_______________________________________________
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@lists.febo.com
Well Glen as you say tradeoffs. Always. Thats why the Loops are 162' away
from the house with some woods around. The 10' loop is shielded and the 5'
not. They are directive. Which helps reduce local noise. Boy does it exist.
My noise floor today on the 5' loop is 20 uv. I do hear lots of crud/noise.
I remember when the only thing you needed to worry about was a leaking
power line insulator. Power company got tired of fixing them so they
invented CFL, LED lights, and switching power supplies. Now they never get
calls.......
The 5' loop is actually tuned for 100 KHz not 60 KHz.
Anyhow go big or go home. Chuckle.
Regards
Paul
WB8TSL
On Sun, Sep 11, 2022 at 4:06 PM glenlist glenlist@cortexrf.com.au wrote:
Good stuff Paul
What needs to be determined is the required Signal to Noise for the
application, since its about using the signal for analytical purposes. That
will drive the design and requirements. Higher SNR for indoor antennas will
certainly be got with electrostatic (ES) shields -
But the trap is that you cannot just use a very low efficiency antenna in
a high noise environment- with very low efficiency antennas this leaves
very small signal values which can easily get drowned out by any common
mode noise getting on the cable, which means you have to work VERY hard on
common mode rejection / suppression and balance, and also garbage getting
onto the cable in the shack, if the coax is not choked where it leaves the
shack, will take noise to the near field of the antenna !
So, careful thought is required- balanced input preamp on the antenna
terminals is recommended- not because there is a lack of signal, but to
give it a boost above everything else. Either that or tale great care,
perhaps twincoax balanced feed and resonant common mode chokes to get Zcm >
10,000.
Well I am getting off topic, there are a thousand ways to skin this cat.
A 5' loop with ES shield in the attic can work well, as long as you dont
have LED lightning wires criss-crossing under your antenna.
I'd suggest a smaller loop with more turns FURTHER away from the house.
Why? because noise will dominate close to the house. The near field pickup
region will be smaller for a smaller antenna.
Perhaps a 2' loop up on a piece of pipe, or a rod.. You can likely
dispense with the ES shield if it is a mile away from any noise source and
structure.
On 12/09/2022 1:13 am, paul swed wrote:
The header seems to say the application. A wwvb antenna.
If you look in any of the simple cheap atomic clocks you will find a rod
about 2-3" long.
Typically a resonating cap right on the antenna for 60 KHz. These work
well enough to receive wwvb at night when the signals much stronger than
during the day.
As insight near Boston 60 uv day and last night 1500 uv on a 5' loop tuned
for 100 KHz not wwvb. The 10' square loop is something like 200/10,000 uv.
Honest. Not every night but many of them. I have used bundled rods for a
number of years but the square loops are better. More importantly no
ferrite was ever harmed in building them.... So that must mean the square
loops are more green. Right?
OK sorry went of topic.
all things are a tradeoff. Large loops are hard to install and then manage
over time. Especially when a large branch crashes through the loop after 5
years. Thats why at 100 KHz I went to a 5' loop. Less of a target.
Whats nice about the rods are they really are pretty small.
Regards
Paul
WB8TSL
On Sun, Sep 11, 2022 at 12:08 AM glen english LIST via time-nuts <
time-nuts@lists.febo.com> wrote:
The referred article by Richard Q. Marris is a good one but liekly mass
overkill for this application.
Seek a rod that is good at the 125kHz RFID frequency. Type material 78
comes to mind, but almost any Manganese Zinc Ferrite is going to work.
Although they'll probably be fairly small . All the higher frequency
rods will be fine on losses but have low perm and need lots of turns.
Something with an initial permeability of at least 2000 will be suitable.
greater Length/Diameter will increase mu-rod. 6" x 3/8" sounds good.
You might not need that much rod, I dont know what the field strengths
are (does anyone know) but something like this might be suitable :
https://www.fair-rite.com/product/antennarfid-rods-3078990901/
a ferrite rod is not necessary if you have space... if this is a fixed
application, many turns around a foot square will be just as
effective. No need for a ferrite rod.
Suggest electrostatic shield and balanced feed for the wire , coreless
loop.
For a small ferrite rod, put the rod length wise in a deep aluminium
channel section.
It's certainly easier to build a ES shielded small rod than a loop.
-glen
On 11/09/2022 12:38 pm, Lux, Jim via time-nuts wrote:
On 9/10/22 7:59 AM, D. Resor via time-nuts wrote:
I exploring the parts needed to construct this particular VLF Loop
Stick
Antenna by Richard Q. Marris G2BZQ.
I have uploaded the article to my DropBox Account here:
ntenna.pdf?dl=0
The project explains you should use 9.5mm (3/8") Diameter X 15cm (6")
Length
Ferrite rods.
The closest I have been able to find are 10mm (0.393") Diameter X 160mm
(6.299) Length.
Will it make much of a difference?
Thank You
Don Resor
Not much difference.. the diameter 0.375 vs 0.393 isn't much. Length
doesn't much matter, as long as the windings fit.
A bigger issue might be the permeability of the rod.
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@lists.febo.com
--
Glen English
RF Communications and Electronics Engineer
CORTEX RF
Pacific Media Technologies Pty Ltd trading as Cortex RF
ABN 40 075 532 008
PO Box 5231 Lyneham ACT 2602, Australia.
au mobile : +61 (0)418 975077
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@lists.febo.com
Hi Paul
FB. Interference is a bit different now. With power line insulators
etc these tended to be very fast rise time spikes, and any sort of
bandwidth reduction as you know just squashes out the pulse.
Unfortunately with a resonant antenna like is used at LF, bandwidth
reduction is part of the course ! So very difficult to escape . Now we
have different interfering signals with very different statistics and
character. The quasi stationary interfering signals are a good
candidate for blind signal separation techniques.
I also do consulting work for underground magnetic coupled collision
avoidance systems (60-120 kHz), apart from 160m.....
If users are specifically interesting in building antennas for this you
can contact Paul or myself directly.
cheers Glen VK1XX, AI6UM
On 12/09/2022 6:40 am, paul swed wrote:
Well Glen as you say tradeoffs. Always. Thats why the Loops are 162'
away from the house with some woods around. The 10' loop is shielded
and the 5' not. They are directive. Which helps reduce local noise.
Boy does it exist. My noise floor today on the 5' loop is 20 uv. I do
hear lots of crud/noise.
I remember when the only thing you needed to worry about was a leaking
power line insulator. Power company got tired of fixing them so they
invented CFL, LED lights, and switching power supplies. Now they never
get calls.......
The 5' loop is actually tuned for 100 KHz not 60 KHz.
Anyhow go big or go home. Chuckle.
Regards
Paul
WB8TSLom mailto:time-nuts-leave@lists.febo.com
On 9/11/22 1:06 PM, glenlist via time-nuts wrote:
Good stuff Paul
What needs to be determined is the required Signal to Noise for the
application, since its about using the signal for analytical purposes.
That will drive the design and requirements. Higher SNR for indoor
antennas will certainly be got with electrostatic (ES) shields -
But the trap is that you cannot just use a very low efficiency
antenna in a high noise environment- with very low efficiency
antennas this leaves very small signal values which can easily get
drowned out by any common mode noise getting on the cable, which means
you have to work VERY hard on common mode rejection / suppression and
balance, and also garbage getting onto the cable in the shack, if
the coax is not choked where it leaves the shack, will take noise to
the near field of the antenna !
This is one reason tuned loop/loopsticks are popular - the reasonably
high Q resonance suppresses out of band signals.