From: bill.sloman@ieee.org
On 16/11/2025 10:40 pm, Jan Panteltje wrote:
>> Bill Sloman wrote:
>>> On 16/11/2025 7:23 am, john larkin wrote:
>>> On Sat, 15 Nov 2025 19:04:45 +0000, liz@poppyrecords.invalid.invalid
>>> (Liz Tuddenham) wrote:
>>>
>>>> Bill Sloman wrote:
>>>>
>>>>> On 15/11/2025 8:23 pm, Liz Tuddenham wrote:
>>>>>> Bill Sloman wrote:
>>>>>>
>>>>>>> On 15/11/2025 4:46 am, Liz Tuddenham wrote:
>>>>>>
>>>>>>
>>>>>> [...]
>>>>>>>>
>>>>>>>> The Johnson noise of a 50-ohm resistor at 20 C with 5 Kc/s bandwidth
is
>>>>>>>> -130 dBm. If we take the rail-to-rail output voltage of an op-amp to
be
>>>>>>>> about +20 dBm, that gives 150 dB difference. Claims that a device is
>>>>>>>> capable of achieving this sort of figure in any practical situation is
>>>>>>>> stretching the limits of credibility.
>>>>>>>>
>>>>>>>> If the signal is lower than +20 dBm, you either have to start cooling
>>>>>>>> the device or reducing the measurement bandwidth, otherwise 150 dB S/N
>>>>>>>> ratio is impossible to achieve.
>>>>>>>
>>>>>>> Johnson noise is broadband. The harmonic of interest in evaluating a
low
>>>>>>> distortion sine wave oscillator are rather narrow band.
>>>>>>
>>>>>> When you get down to signals as low as -150 dBm there will be Johnson
>>>>>> noise and intermodulation products contributed by the components within
>>>>>> the oscillator. Selecting individual harmonics with a narrow-band
>>>>>> filter will give an unrealistic number that doesn't represent the total
>>>>>> unwanted output.
>>>>>>
>>>>>>> You are comparing apples and pears as your "5 Kc.s bandwidth" makes
>>>>>>> clear. if you have been cribbing from a more modern source it would
have
>>>>>>> been a 5kHz bandwidth.
>>>>>>
>>>>>> You have no idea what I did, so stop posting offensive nonsense.
>>>> [...]
>>>>>> I have written a calculator based on a spreadsheet which gives the RMS
>>>>>> noise as a voltage and as dBm from user inputs of resistance, bandwidth
>>>>>> and temperature. I chose 5 Kc/s as a tolerably low figure for audio
>>>>>> work; it would be a suitable measurement bandwidth for a 1 Kc/s signal
>>>>>> if you wanted to include the third harmonic. I chose 50 ohms as it is
>>>>>> the lowest output impedance in common use - for audio work 600 ohms
>>>>>> might have been more appropriate but the figures would have been even
>>>>>> worse.
>>>>>>
>>>>> I'm pretty confident that you don't have much of an idea what you did
>>>>> either.
>>>>
>>>> You will notice that I have moved your comment by one paragraph so that
>>>> it now comes after my explanation of exactly what I did. Your post
>>>> appears to have been done purely to be offensive and obfscate the facts.
>>>>
>>>> Please stop behaving like a troll, you are in danger of driving useful
>>>> contributors away from this group.
>>>
>>> He's been doing that for years.
>>
>> As has John Larkin. It hasn't worked.
>> Jim Thompson claimed to have denounced me to the FBI as "dangerously
>> anti-American" which would have ruined his credibility with them - at
>> one stage I was cleared to "most secret" which was enough to get me into
>> US Army ECOM when it was a Fort Monmouth, New Jersey.
>
> Do not worry, John Lu^Harking^H likes to play boss or something
> He has the highest level of off topic posts here AFAIK.
This time it was Liz Tuddenham who was trying to exert her authority.
John Larkin does try do it more often.
> He flips if I give links to sciencedaily.org, then immediately
> babbles about shirts... clear sign of a minority complex obfuscation
> No wonder, designing for some idiots that do 'fusion power' research is
something I would not do!
> ..
> 'Chain reaction' can be seen as a couple of compressed mechanical springs
each hold by a thin fragile wire.
> Hit one and the spring releases and if other similar ones are around you get
a chain-reaction until all those similar things have expanded.
> Fusion however is trying to press the strings back and keep them locked ,,
> You will, by definition, never get more power out (by releasing them again)
than you put in there compressing them.
> So, it is 'merrica all over again, startups try it again and again with no
usable result.
> Fusion.. Fusor, was done long ago, magnitudes below break even.
Jan Panteltje hasn't notice that we've got a fusion reactor hanging in
the sky - we call it the sun - which gets loads of energy out of fusing
protons together to make helium. As you look at successively heavier
atomic nuclei up to about iron they get heavier each time you add in a
proton or neutron, but not quite as much heavier as you'd expect from
the weight of an isolated proton or neutron. It's called the mass defect
and was known about even before Einstein published his mass to energy
equation.
https://en.wikipedia.org/wiki/National_Ignition_Facility
that John did some work for is more about creating the conditions that
exist inside a nuclear explosion than fusing hydrogen nuclei - they can
do it, and have done it, but it is incidental to it's main job.
> He is sitting there getting kids to build stuff
> complaining about 1 cent price differences in things that he maybe! sells 3
or 4 pieces of, makes no sense either,
> the electricity needed for posting here is more expensive.
> Telling us what we should do and say is a silly ego trip, this is NOT a
moderated group,
Expressing opinions about what has been said may not always be a silly
ego trip
> Maybe it is the SF LSDs after effect, or the insane Tramp precedent, that
lowers the IQ of 'merricans.
> I can hardly wait for that King Kong in that Warhouse to disappear.
> Now it King K. is war mongering with Venezuela.
> Do you think I would cry if US got nuked into oblivion?
> Dirty war machine.
> Acting as war criminals in Gaza, many places, ...
>
> * People of the US = stand up against your King Kong monster leader = ,
may be you last chance. *
They last did it in 1776. We now have less violent ways of getting rid
of a foolish leader. With any luck the Americans will be able to fake up
some evidence that "proves" that Donald Trump was in on Jeffrey
Epstein's child prostitution racket. Much cheaper than a revolution.
Couldn't happen to a nicer pussy-grabber. Getting rid of J.D. Vance
might be harder, but maybe he will have enough sense to behave well
enough not to put his job at risk. Of course, if he had that much sense
he probably wouldn't have lined up with Donald Trump.
--
Bill Sloman, Sydney
--- SoupGate-Win32 v1.05
* Origin: you cannot sedate... all the things you hate (1:229/2)
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