Jim Kelley wrote:
It's ridiculous to assert that someone "thinks EM waves can't be
reflected" based on the fact that they might happen to take issue with
one or more of your speculations on the laundry list shown above.

You obviously have not been following the arguments.
--
73, Cecil http://www.w5dxp.com

Cecil Moore wrote:
Jim Kelley wrote:
It's ridiculous to assert that someone "thinks EM waves can't be
reflected" based on the fact that they might happen to take issue with
one or more of your speculations on the laundry list shown above.

You obviously have not been following the arguments.

Neither have you, Cecil.
73,
Tom Donaly, KA6RUH

Tom Donaly wrote:
Cecil Moore wrote:
You obviously have not been following the arguments.

Neither have you, Cecil.

Tom, please inquire about reflected energy just "sloshing"
around rather than traveling end to end at a VF(c) speed.
--
73, Cecil, w5dxp.com

On Jun 5, 11:40 am, Cecil Moore wrote:
On Jun 4, 5:39 pm, "Tom Donaly" wrote:

Maybe you'll tell me who you think thinks waves of any sort can't
be reflected. I haven't run into anyone who thinks EM waves can't be
reflected, refracted, etc. Maybe there's a misunderstanding somewhere.

I don't want to get personal but if you have followed the reflected
wave arguments, you know who they are. Some simple true/false
questions will highlight the argument.

1. Do reflected EM waves actually exist in reality?
2. Is the reflected EM wave a traveling wave?
3. Does a reflected EM wave obey the rules for traveling waves?
4. Do reflected EM waves contain ExB joules/second?
5. Do reflected EM waves have any effect on forward waves in a
constant Z0 environment?
6. Do standing EM waves superceed and obsolete the component traveling
waves?
7. Does reflected EM energy violate the laws of physics by standing
still within the standing wave?
8. Does reflected EM energy violate the laws of physics by just
"sloshing" around?
9. Does reflected EM energy travel in the reverse direction at VF(c)
until it encounters an impedance discontinuity?
10. Is it valid to consider the forward EM traveling wave and the
reflected EM traveling wave separately and then superpose the
resulting fields (voltages, currents)?
11. Are the decades-old EM wave intensity equations from the field of
optics valid for an RF EM wave analysis?
12. Can standing wave current be used to determine the delay through a
75m mobile loading coil?
13. Is the current "drop" through that loading coil just an illusion
caused by superposition of forward and reflected currents?
14. Would the delay be different if only a forward traveling wave was
used for measurement purposes?
--
73, Cecil, w5dxp.com

An excellent list of questions, but you left out a few:

15. Can superposition be used in the analysis of linear
time invariant circuits?
16. Does P equal E times I?
17. Can source (or output) impedance be used to compute the
reflection occuring at the generator?
18. Does a directional wattmeter MEASURE power?
19. Do reflections occur at places other than physical
impedance discontinuities?

....Keith

Owen Duffy wrote in
:

Owen Duffy wrote in
:

...
Search Jaycar's site for a LO1238. If that is what you have, you
could ask them for data.

I should have added that I think it is similar to the L8 material
described in their data sheets.

I have a vague recollection of measuring the inductance of a winding
on the material, and I think the ui was around 1500 which suggests it
is low loss up to a few hundred kHz, perhaps to 1MHz or so.

I am back at home and dug out my measurments for LO1238. I make ui around
1100 at 10kHz (Al ~145nH), so it is a little lower than the L8 material,
probably goes to slighly higher frequency before loss sets in.

Owen

On Saturday, June 2, 2007 at 1:54:28 AM UTC+10, wrote:
I came across two ferrite toroids with the measurements of 35mm
diameter, the hole in the middle is 21mm and it is 13mm thick. On the
packet it says that the ferrite material is L15. Does anybody know if
L15 is equivalent to 43 or 61 ferrite material? I have searched the
net but have been unable to find any information. Any information
would be appreciated. Cheers.

Owen was was right saying 259 can't measure inductors with impedance over j500, say j4788. With small VNA you get accurate scan over entire HF.
Roy seems to be using 259 for everything, including making pizzas.
I know only one way for 259 to be accurate with high impedance inductor. Add capacitor and 50 ohms in series with inductor, and 259 becomes very accurate around resonant frequency. I doubt there is another way to do it properly.
Tino VK3EGN

On Mon, 27 Apr 2020 23:59:13 -0700 (PDT), wrote:
On Saturday, June 2, 2007 at 1:54:28 AM UTC+10, wrote:
I came across two ferrite toroids with the measurements of 35mm
diameter, the hole in the middle is 21mm and it is 13mm thick. On the
packet it says that the ferrite material is L15. Does anybody know if
L15 is equivalent to 43 or 61 ferrite material? I have searched the
net but have been unable to find any information. Any information
would be appreciated. Cheers.

Owen was was right saying 259 can't measure inductors with impedance over j500, say j4788. With small VNA you get accurate scan over entire HF.
Roy seems to be using 259 for everything, including making pizzas.
I know only one way for 259 to be accurate with high impedance inductor. Add capacitor and 50 ohms in series with inductor, and 259 becomes very accurate around resonant frequency. I doubt there is another way to do it properly.
Tino VK3EGN

And, why do you think you could try to participate in a
13 YEAR OLD conversation? Oh, I see. A google grooper.

On 28/04/2020 07:59, wrote:
On Saturday, June 2, 2007 at 1:54:28 AM UTC+10, wrote:
I came across two ferrite toroids with the measurements of 35mm
diameter, the hole in the middle is 21mm and it is 13mm thick. On the
packet it says that the ferrite material is L15. Does anybody know if
L15 is equivalent to 43 or 61 ferrite material? I have searched the
net but have been unable to find any information. Any information
would be appreciated. Cheers.

Owen was was right saying 259 can't measure inductors with impedance over j500, say j4788. With small VNA you get accurate scan over entire HF.
Roy seems to be using 259 for everything, including making pizzas.
I know only one way for 259 to be accurate with high impedance inductor. Add capacitor and 50 ohms in series with inductor, and 259 becomes very accurate around resonant frequency. I doubt there is another way to do it properly.
Tino VK3EGN

========
To test any toroid with a spectrum analyser is of course ideal. However
testing a toroid as an rf transformer with a variable signal generator
and a RF millivolt meter can also provide much information about the
device usefulness.

Frank , EI7KS