R
rickman
Guest
On 3/18/2017 9:34 PM, tabbypurr@gmail.com wrote:
Know any?
--
Rick C
Know any?
--
Rick C
R
rickman
Guest
On 3/18/2017 9:27 PM, Clifford Heath wrote:
Not sure what you are saying. 25:1 capacitance ratio is hard to get
with *any* means. I suppose you could literally switch caps in and out.
Why can't you do that with the varactors?
How did small varactors do any better? Were they switched in and out?
Actually, looking at the data sheets for some of these devices they spec
a capacitance range more than 15:1 over less than the full range.
I think you could either work with a wider voltage range (within the max
spec of course) or switch a single fixed cap in and out. Does the
tuning need to be continuous?
--
Rick C
Not sure what you are saying. 25:1 capacitance ratio is hard to get
with *any* means. I suppose you could literally switch caps in and out.
Why can't you do that with the varactors?
How did small varactors do any better? Were they switched in and out?
Actually, looking at the data sheets for some of these devices they spec
a capacitance range more than 15:1 over less than the full range.
I think you could either work with a wider voltage range (within the max
spec of course) or switch a single fixed cap in and out. Does the
tuning need to be continuous?
--
Rick C
A
amdx
Guest
On 3/16/2017 9:57 PM, John Larkin wrote:
EDIT; I reread the OPs post, he didn't say 6" dia he said 6" length,
so, my experiment was a bit of a waste and doesn't answer his question.
But here's the info from my experiment.
First, I don't know if the OP was tuning or not, I could not measure
any signal without tuning. So, I tuned.
Two 6.75" diameter coils using 660/46 litz, both approximately close
wound on a styrene pipe coupler.
Coils tuned with a high quality cap and a 20pf fine tune trim cap.
The air core coil has 33 turns and measures 236uh
The core with ferrite has 30 turns and 232uh. without the rod, the coil
measures 195uh. The rod is 3/8" diameter x 8" long. Not a large
inductance change to put a small ferrite rod in a large air core coil.
To center the rod in the coil, I cut two, 1/2' styrofoam circles to fit
the inside of the coupler and put a hole in the center for the rod.
To measure the signal I have high input impedance amp with a gain of 1.
I used the amp to drive a scope (ch 2) set at 50mV/div. I took the
channel 2 output from the back of the scope to drive a Boonton 92BD RF
millivolt meter. I used the scope to compare the visual to audio from a
portable radio to know where I was tuned.
I have three local stations 590kHz, 1290kHz, and 1430kHz.
I did two separate tests, but they were so close it didn't matter.
Modulation made the signal vary, but the Boonton has an analog meter to
help peak the signal.
I did try a second larger diameter poorer quality rod 1/2" diameter
x 7.25 long. It may have out did the air core on the low end with a
few more turns to bring the inductance up to match the others, but it
failed on the upper end.
Best Ferrite Poorer ferrite
236uh 232uh 216uh
33 turn 30 turn 30 turn
Air core coil Ferrite Coil Ferrite Coil
590kHz 59 mv 43 mv 59 mv
1290kHz 15.5 mv 6.7 mv 7.1 mv
1430kHz 10.5 mv 4.2mv 3.2 mv
Mikek
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OK, I did the experiment.On Thu, 16 Mar 2017 15:39:52 -0500, amdx <nojunk@knology.net> wrote:
On 3/16/2017 3:06 PM, John Larkin wrote:
On Thu, 16 Mar 2017 12:12:14 -0700 (PDT), Bill Beaty
billb@eskimo.com> wrote:
Which one would capture the most signal at the AM Broadcast frequencies
Is your real question , how do we optimize electrically-small 500KHz loop antennas?
Start by defining optimum.
He did, as did the op, (capture the most signal)
The most power? That implies a conjugate load, which will kill
selectivity.
EDIT; I reread the OPs post, he didn't say 6" dia he said 6" length,
so, my experiment was a bit of a waste and doesn't answer his question.
But here's the info from my experiment.
First, I don't know if the OP was tuning or not, I could not measure
any signal without tuning. So, I tuned.
Two 6.75" diameter coils using 660/46 litz, both approximately close
wound on a styrene pipe coupler.
Coils tuned with a high quality cap and a 20pf fine tune trim cap.
The air core coil has 33 turns and measures 236uh
The core with ferrite has 30 turns and 232uh. without the rod, the coil
measures 195uh. The rod is 3/8" diameter x 8" long. Not a large
inductance change to put a small ferrite rod in a large air core coil.
To center the rod in the coil, I cut two, 1/2' styrofoam circles to fit
the inside of the coupler and put a hole in the center for the rod.
To measure the signal I have high input impedance amp with a gain of 1.
I used the amp to drive a scope (ch 2) set at 50mV/div. I took the
channel 2 output from the back of the scope to drive a Boonton 92BD RF
millivolt meter. I used the scope to compare the visual to audio from a
portable radio to know where I was tuned.
I have three local stations 590kHz, 1290kHz, and 1430kHz.
I did two separate tests, but they were so close it didn't matter.
Modulation made the signal vary, but the Boonton has an analog meter to
help peak the signal.
I did try a second larger diameter poorer quality rod 1/2" diameter
x 7.25 long. It may have out did the air core on the low end with a
few more turns to bring the inductance up to match the others, but it
failed on the upper end.
Best Ferrite Poorer ferrite
236uh 232uh 216uh
33 turn 30 turn 30 turn
Air core coil Ferrite Coil Ferrite Coil
590kHz 59 mv 43 mv 59 mv
1290kHz 15.5 mv 6.7 mv 7.1 mv
1430kHz 10.5 mv 4.2mv 3.2 mv
Mikek
---
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C
Clifford Heath
Guest
On 19/03/17 13:11, pcdhobbs@gmail.com wrote:
Thank you. I didn't realize they used series Schottky strings.
Could the need be somewhat averted with back bias instead?
Thank you. I didn't realize they used series Schottky strings.
Could the need be somewhat averted with back bias instead?
K
Kevin Aylward
Guest
"Kevin Aylward" wrote in message
news:kfudnRgqWLyQIlDFnZ2dnUU7-XvNnZ2d@giganews.com...
I don't see that there can be much more of a cold-bloodied, calculated
murder, than having 12 people calmly sit on seats debating the merits of
killing someone over several days, with a state sponsored judge exposing
all sorts of "rational" arguments as to how it is ethically justifiable to
execute said person being debated. Said person is then dragged to a room
with gawking onlookers watching the deliberate injection of chemicals to
terminate said life. This is no less barbaric than at a Roman gladiator ring
where the emperor points his thump up or down.
What is even more grotesque, is that large numbers of those barbarians
supporting state sponsored murder are alleged Christians, despite their role
model, Jesus, emphatically instructing them that "thou shall not kill".
More, stunningly the xtians claim that it is they that there the morally
righteous ones.
-- Kevin Aylward
http://www.anasoft.co.uk - SuperSpice
http://www.kevinaylward.co.uk/ee/index.html
news:kfudnRgqWLyQIlDFnZ2dnUU7-XvNnZ2d@giganews.com...
I don't see that there can be much more of a cold-bloodied, calculated
murder, than having 12 people calmly sit on seats debating the merits of
killing someone over several days, with a state sponsored judge exposing
all sorts of "rational" arguments as to how it is ethically justifiable to
execute said person being debated. Said person is then dragged to a room
with gawking onlookers watching the deliberate injection of chemicals to
terminate said life. This is no less barbaric than at a Roman gladiator ring
where the emperor points his thump up or down.
What is even more grotesque, is that large numbers of those barbarians
supporting state sponsored murder are alleged Christians, despite their role
model, Jesus, emphatically instructing them that "thou shall not kill".
More, stunningly the xtians claim that it is they that there the morally
righteous ones.
-- Kevin Aylward
http://www.anasoft.co.uk - SuperSpice
http://www.kevinaylward.co.uk/ee/index.html
C
Chris
Guest
On Sat, 18 Mar 2017 16:04:00 +0000, Cursitor Doom wrote:
Now *that's* what I call a "procedure" LOL., I hope Jim's is far less
dramatic! :-D
Now *that's* what I call a "procedure" LOL., I hope Jim's is far less
dramatic! :-D
C
Cursitor Doom
Guest
On Sat, 18 Mar 2017 16:15:05 -0700, tabbypurr wrote:
culpability of the defendant are beyond any doubt at all, the death
penalty should at least be available.
Can't agree. In cases of the very worst crimes, where the identity and
culpability of the defendant are beyond any doubt at all, the death
penalty should at least be available.
C
Cursitor Doom
Guest
On Sat, 18 Mar 2017 20:03:50 -0400, krw wrote:
> That's impossible, which is the whole "reasonable" thing.
Nothing whatsoever impossible about it!
> That's impossible, which is the whole "reasonable" thing.
Nothing whatsoever impossible about it!
C
Cursitor Doom
Guest
On Sat, 18 Mar 2017 23:13:15 +0000, Kevin Aylward wrote:
No it isn't, Kev. And where it *is* possible, and the identity and
culpability of the defendant is beyond question, the death penalty should
be available for the most heinous crimes.
No it isn't, Kev. And where it *is* possible, and the identity and
culpability of the defendant is beyond question, the death penalty should
be available for the most heinous crimes.
Guest
On Sunday, 19 March 2017 14:21:57 UTC, Cursitor Doom wrote:
People make a mockery of reason too often. Maybe you should spend some time watching groups of people making such decisions.
NT
People make a mockery of reason too often. Maybe you should spend some time watching groups of people making such decisions.
NT
Guest
On Sunday, 19 March 2017 15:52:04 UTC, Kevin Aylward wrote:
Naivete about the mechanics of 'justice' is not unusual.
Naivete about the mechanics of 'justice' is not unusual.
J
John Devereux
Guest
"Kevin Aylward" <kevinRemovAT@kevinaylward.co.uk> writes:
World leaders: China, Iran, Pakistan, Saudi Arabia, USA.
Look at that map:
<https://en.wikipedia.org/wiki/Capital_punishment_by_country#/media/File:Capital_punishment_in_the_world.svg>
Says it all really...
--
John Devereux
World leaders: China, Iran, Pakistan, Saudi Arabia, USA.
Look at that map:
<https://en.wikipedia.org/wiki/Capital_punishment_by_country#/media/File:Capital_punishment_in_the_world.svg>
Says it all really...
--
John Devereux
A
amdx
Guest
On 3/14/2017 11:18 PM, billbowden wrote:
I'll run the experiment.
Do you want it tuned?
If not, I have no way to measure the signals of my local stations.
I need the resonance peaking to see the signal.
What diameter PVC?
I have 1/2" OD polystyrene that will allow a little closer coupling
between the ferrite and the wire. 400 turns #28 = 203uh air core.
I have 1/2" CPVC. actual OD. 0.615"
290 turns #28 = 200uh air core
I have 1/2 PVC, actual OD. 0.832. 175 turns #28 = 205uh air core.
Pick one.
I'll also wind one with less turns and use my best Q rod that is 8" long
x 0.375" diameter.
I will check three frequencies, 590Khz, 1290kHz and 1430Khz.
I made a post last night of the wrong experiment (6"dia not 6" long)
It has not shown up this morning, so I'll repeat my measurement method.
To measure the signal I have a very high input impedance amp with a
gain of 1.
I use the amp to drive a scope (ch 2) set at 50mV/div. I took the
channel 2 output from the back of the scope to drive a Boonton 92BD RF
millivolt meter. I use the scope to compare the visual to audio from a
portable radio to know where I am tuned.
Modulation causes a bit of amplitude bounce, but I do a visual average.
Let me know what you want.
Mikek
---
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I'll run the experiment.
Do you want it tuned?
If not, I have no way to measure the signals of my local stations.
I need the resonance peaking to see the signal.
What diameter PVC?
I have 1/2" OD polystyrene that will allow a little closer coupling
between the ferrite and the wire. 400 turns #28 = 203uh air core.
I have 1/2" CPVC. actual OD. 0.615"
290 turns #28 = 200uh air core
I have 1/2 PVC, actual OD. 0.832. 175 turns #28 = 205uh air core.
Pick one.
I'll also wind one with less turns and use my best Q rod that is 8" long
x 0.375" diameter.
I will check three frequencies, 590Khz, 1290kHz and 1430Khz.
I made a post last night of the wrong experiment (6"dia not 6" long)
It has not shown up this morning, so I'll repeat my measurement method.
To measure the signal I have a very high input impedance amp with a
gain of 1.
I use the amp to drive a scope (ch 2) set at 50mV/div. I took the
channel 2 output from the back of the scope to drive a Boonton 92BD RF
millivolt meter. I use the scope to compare the visual to audio from a
portable radio to know where I am tuned.
Modulation causes a bit of amplitude bounce, but I do a visual average.
Let me know what you want.
Mikek
---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus
C
Cursitor Doom
Guest
On Sun, 19 Mar 2017 09:07:05 -0700, tabbypurr wrote:
I don't agree with you and probably never will, but - in what must be a
Usenet first - I can at least see where you're coming from here.
I don't agree with you and probably never will, but - in what must be a
Usenet first - I can at least see where you're coming from here.
C
Cursitor Doom
Guest
On Sun, 19 Mar 2017 15:51:55 +0000, Kevin Aylward wrote:
No I didn't, Kev. How the hell is the whim of one emperor comparable to
the evidentially-based reasoning of 12 impartial individuals under the
guidance of a senior judge well-versed in dealing with murder cases??
No I didn't, Kev. How the hell is the whim of one emperor comparable to
the evidentially-based reasoning of 12 impartial individuals under the
guidance of a senior judge well-versed in dealing with murder cases??
C
Cursitor Doom
Guest
On Sun, 19 Mar 2017 09:08:54 -0700, tabbypurr wrote:
> Naivete about the mechanics of 'justice' is not unusual.
You won't find such in me, Tabitha. And I'm the keenest observer of human
nature you will ever encounter.
> Naivete about the mechanics of 'justice' is not unusual.
You won't find such in me, Tabitha. And I'm the keenest observer of human
nature you will ever encounter.
T
Tim Williams
Guest
"Clifford Heath" <no.spam@please.net> wrote in message
news:58cddea6$0$42047$c3e8da3$3a1a2348@news.astraweb.com...
My monitor does both. It has switched capacitors (S-correction, the amount
of "S" required depending on sweep rate), and Litz in the deflection coil,
so there.
(Obviously, the "large signal" (100V?) regime makes it quite effective to
use individual power MOSFETs to switch capacitors into the circuit. It's
still an okay method in the small signal < 0.3V range too, but in that
inbetweeny range, err... )
Tim
--
Seven Transistor Labs, LLC
Electrical Engineering Consultation and Contract Design
Website: http://seventransistorlabs.com
news:58cddea6$0$42047$c3e8da3$3a1a2348@news.astraweb.com...
My monitor does both. It has switched capacitors (S-correction, the amount
of "S" required depending on sweep rate), and Litz in the deflection coil,
so there.
(Obviously, the "large signal" (100V?) regime makes it quite effective to
use individual power MOSFETs to switch capacitors into the circuit. It's
still an okay method in the small signal < 0.3V range too, but in that
inbetweeny range, err...
)Tim
--
Seven Transistor Labs, LLC
Electrical Engineering Consultation and Contract Design
Website: http://seventransistorlabs.com
T
Tauno Voipio
Guest
On 19.3.17 04:11, pcdhobbs@gmail.com wrote:
Maybe the best mixers can be built with CMOS analog switches.
Google for 'Tayloe mixer'.
--
-TV
Maybe the best mixers can be built with CMOS analog switches.
Google for 'Tayloe mixer'.
--
-TV
T
Tim Williams
Guest
"Clifford Heath" <no.spam@please.net> wrote in message
news:58cddfce$0$39518$b1db1813$7968482@news.astraweb.com...
Wait, "dynamic impedance" == mechanical resonance? Oh...
In other words, he made an ear. Or, a log periodic, or...
Tim
--
Seven Transistor Labs, LLC
Electrical Engineering Consultation and Contract Design
Website: http://seventransistorlabs.com
news:58cddfce$0$39518$b1db1813$7968482@news.astraweb.com...
Wait, "dynamic impedance" == mechanical resonance? Oh...
In other words, he made an ear.
Or, a log periodic, or...Tim
--
Seven Transistor Labs, LLC
Electrical Engineering Consultation and Contract Design
Website: http://seventransistorlabs.com
K
Kevin Aylward
Guest
I guess you missed the other bits about being on a par to the thumbs
up/thump down at the roman gladiator meet, or cold blood murder is the only
rational way to analyse the calculated way the jury, judge and executioner
carry out their daily business.
State sponsored murder is wrong on so many levels, its pretty stunning
anyone can attempt to justify it by going, hey, yes it _IS_ 100% possible to
determine guilt, in an ideal case, if its not raining on a Tuesday.
Murder is murder. Under the guise of the "law", doesn't change a thing.
I guess you are not familiar with the problems of state sponsored executions
in general. In Iran, after the revolution, it was something like 100,000.
I guess we just have different moral compasses.
Kevin Aylward
http://www.anasoft.co.uk - SuperSpice
http://www.kevinaylward.co.uk/ee/index.html