On 11/1/2015 10:32 PM, Jeff Liebermann wrote:
On Sun, 1 Nov 2015 21:58:32 -0500, rickman wrote:

Ok, so if you can force it to shrink with springs or ropes or whatever,
then something will be needed to force it to expand again.

Yep. A bicycle pump, hand pump, crank pump, bellows pump, electric
pump, or pressure vessel will all inflate the antenna.

I'm having
trouble seeing how this will work without the antenna losing all shape.

Below some pressure level, it will probably flop over if mounted
vertically. That's why I mumbled that I wasn't sure if it should be
mounted vertically with a support pole, or horizontally on a flat
sheet of plywood. Both will work, but I'm not sure which is better.

Hang it upside down.

Mikek

On Mon, 2 Nov 2015 09:13:38 -0600, amdx wrote:

Below some pressure level, it will probably flop over if mounted
vertically. That's why I mumbled that I wasn't sure if it should be
mounted vertically with a support pole, or horizontally on a flat
sheet of plywood. Both will work, but I'm not sure which is better.

Hang it upside down.
Mikek

But, all the photons will fall out of the loop that way.

Actually, there's a problem. It doesn't work as well upside down.
The magnetic loop has a rather directional field and takeoff angle and
does NOT have a constant current around the loop:
http://www.nonstopsystems.com/radio/vids-ant/antenna-Mag-Loop-Demo1.wmv
https://www.youtube.com/watch?v=SUYI81dkEMA

I suspect that an inverted loop will send most of the RF into the
ground. I should probably test this.
http://www.nonstopsystems.com/radio/img-ant/antenna-magloop-rad-angle.gif

You might find this interesting on designing the 50 ohm matching
network to the loop, where the impedance varies by where it's fed:
http://www.g0cwt.co.uk/magloops/new_page_6.htm

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On Mon, 02 Nov 2015 16:39:09 -0800, Jeff Liebermann
wrote:

You might find this interesting on designing the 50 ohm matching
network to the loop, where the impedance varies by where it's fed:
http://www.g0cwt.co.uk/magloops/new_page_6.htm

Mo
https://www.youtube.com/watch?v=NdofH6R22Dg
Skip forward to 12:03 for an interesting comment:
"Commercial loops are usually radiating towards the ground and
a lot of the signal is warming the snails. I don't know how
so many people could have got it so wrong for so long".

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On 11/2/2015 6:39 PM, Jeff Liebermann wrote:
On Mon, 2 Nov 2015 09:13:38 -0600, amdx wrote:

Below some pressure level, it will probably flop over if mounted
vertically. That's why I mumbled that I wasn't sure if it should be
mounted vertically with a support pole, or horizontally on a flat
sheet of plywood. Both will work, but I'm not sure which is better.

Hang it upside down.
Mikek

But, all the photons will fall out of the loop that way.

Actually, there's a problem. It doesn't work as well upside down.
The magnetic loop has a rather directional field and takeoff angle and
does NOT have a constant current around the loop:
http://www.nonstopsystems.com/radio/vids-ant/antenna-Mag-Loop-Demo1.wmv
https://www.youtube.com/watch?v=SUYI81dkEMA

I suspect that an inverted loop will send most of the RF into the
ground. I should probably test this.
http://www.nonstopsystems.com/radio/img-ant/antenna-magloop-rad-angle.gif

You might find this interesting on designing the 50 ohm matching
network to the loop, where the impedance varies by where it's fed:
http://www.g0cwt.co.uk/magloops/new_page_6.htm



Sorry Jeff, When my post didn't show up, I noticed I sent it to you.
Here it is for the rest.



Just to add to the confusion,
Helically Loaded


You might glean info from here, or at the least

admire all the work put into the projects.



http://theradioboard.com/rb/viewtopic.php?f=10&t=4399

Copper doughnut with lots of solder connections
http://www.aa5tb.com/jl1boh_03.jpg

http://www.hlmagneticloopantennas.com/

Hmm, I read a few comments, maybe not the way to go.



Mikek

On 11/2/2015 7:39 PM, Jeff Liebermann wrote:
On Mon, 2 Nov 2015 09:13:38 -0600, amdx wrote:

Below some pressure level, it will probably flop over if mounted
vertically. That's why I mumbled that I wasn't sure if it should be
mounted vertically with a support pole, or horizontally on a flat
sheet of plywood. Both will work, but I'm not sure which is better.

Hang it upside down.
Mikek

But, all the photons will fall out of the loop that way.

Actually, there's a problem. It doesn't work as well upside down.
The magnetic loop has a rather directional field and takeoff angle and
does NOT have a constant current around the loop:
http://www.nonstopsystems.com/radio/vids-ant/antenna-Mag-Loop-Demo1.wmv

I don't get this video. I can't really hear what he is saying so when
he says at the end, "this is not what you would expect" I don't get it.


https://www.youtube.com/watch?v=SUYI81dkEMA

This video is about the voltage and current around a loop, but he says
it is a 1/10 wave loop, but I can't tell that. He has another video
showing the directionality of a 1/4 wave delta antenna. I'm wondering
if this is also a 1/4 wave antenna.


I suspect that an inverted loop will send most of the RF into the
ground. I should probably test this.
http://www.nonstopsystems.com/radio/img-ant/antenna-magloop-rad-angle.gif

Which type of loop antenna are you talking about, 1/4 wave, or 1/10
wave (small, magnetic)? I can't tell anything about this antenna and it
seems to contradict the other video.


You might find this interesting on designing the 50 ohm matching
network to the loop, where the impedance varies by where it's fed:
http://www.g0cwt.co.uk/magloops/new_page_6.htm

--

Rick

In message , rickman
writes



https://www.youtube.com/watch?v=SUYI81dkEMA

When he's measuring towards the capacitor, won't the presence of his
hand be causing the loop to de-tune - hence less current?


--
Ian

On 11/4/2015 6:49 AM, Ian Jackson wrote:
In message , rickman writes



https://www.youtube.com/watch?v=SUYI81dkEMA

When he's measuring towards the capacitor, won't the presence of his
hand be causing the loop to de-tune - hence less current?



Yes. But, is it measurable?

In message , John S
writes
On 11/4/2015 6:49 AM, Ian Jackson wrote:
In message , rickman writes



https://www.youtube.com/watch?v=SUYI81dkEMA

When he's measuring towards the capacitor, won't the presence of his
hand be causing the loop to de-tune - hence less current?



Yes. But, is it measurable?

Being a high-Q circuit, I would think that a small amount of additional
C would cause considerable de-tuning.
--
Ian

On 11/4/2015 8:52 AM, Ian Jackson wrote:
In message , John S
writes
On 11/4/2015 6:49 AM, Ian Jackson wrote:
In message , rickman
writes



https://www.youtube.com/watch?v=SUYI81dkEMA

When he's measuring towards the capacitor, won't the presence of his
hand be causing the loop to de-tune - hence less current?



Yes. But, is it measurable?

Being a high-Q circuit, I would think that a small amount of additional
C would cause considerable de-tuning.

Wouldn't that also give less voltage? That didn't seem to go down any.

--

Rick

On Wed, 4 Nov 2015 00:17:11 -0500, rickman wrote:

On 11/2/2015 7:39 PM, Jeff Liebermann wrote:
On Mon, 2 Nov 2015 09:13:38 -0600, amdx wrote:

Below some pressure level, it will probably flop over if mounted
vertically. That's why I mumbled that I wasn't sure if it should be
mounted vertically with a support pole, or horizontally on a flat
sheet of plywood. Both will work, but I'm not sure which is better.

Hang it upside down.
Mikek

But, all the photons will fall out of the loop that way.

Actually, there's a problem. It doesn't work as well upside down.
The magnetic loop has a rather directional field and takeoff angle and
does NOT have a constant current around the loop:
http://www.nonstopsystems.com/radio/vids-ant/antenna-Mag-Loop-Demo1.wmv

I don't get this video. I can't really hear what he is saying so when
he says at the end, "this is not what you would expect" I don't get it.

I had the same problem. I would guess(tm) that what he's mumbling is
that one would expect the current to be constant around all parts of
the loop, yet it displays obvious maxima and minima.

https://www.youtube.com/watch?v=SUYI81dkEMA

This video is about the voltage and current around a loop, but he says
it is a 1/10 wave loop, but I can't tell that. He has another video
showing the directionality of a 1/4 wave delta antenna. I'm wondering
if this is also a 1/4 wave antenna.

At 6:30 in the above video, he proclaims that it's a 1/4 wave loop.
At 6:42, the MFJ-259B shows 29.555 MHz on the display. I couldn't
find where he said it was a 1/10 wave loop. 1/10 wave is the
defacto definition of a "small" loop.

I suspect that an inverted loop will send most of the RF into the
ground. I should probably test this.
http://www.nonstopsystems.com/radio/img-ant/antenna-magloop-rad-angle.gif

Which type of loop antenna are you talking about, 1/4 wave, or 1/10
wave (small, magnetic)? I can't tell anything about this antenna and it
seems to contradict the other video.

I'm not saying anything about the drawing except that it shows that
the loop might be somewhat directional, which might be a problem.
Where's the contradiction?
http://www.nonstopsystems.com/radio/frank_radio_antenna_magloop.htm

Gone...(again).
--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558