From: jl@glen--canyon.com
On Sun, 9 Nov 2025 18:13:52 +1100, Bill Sloman
wrote:
>On 9/11/2025 4:36 am, Edward Rawde wrote:
>> "Bill Sloman" wrote in message news:10
mofm$2cnh3$2@dont-email.me...
>>> On 8/11/2025 7:44 am, Liz Tuddenham wrote:
>>>> Bill Sloman wrote:
>>>>
>>>>> On 8/11/2025 1:46 am, Liz Tuddenham wrote:
>>>>>> Bill Sloman wrote:
>>>>>>
>>>>>>> On 7/11/2025 9:24 pm, Liz Tuddenham wrote:
>>>>>>>> Bill Sloman wrote:
>>>>>>>>
>>>>>>>>> On 7/11/2025 10:41 am, john larkin wrote:
>>>>>>>> [...]>
>>>>>>>>>> A real inductor is a nightmare. Especially a long solenoid. Every
turn
>>>>>>>>>> inductively couples to every other turn with all possible coupling
>>>>>>>>>> coefficients. Distributed capacitances will be similarly complex.
>>>>>>>>>
>>>>>>>>> This is ignorant nonsense.
>>>>>>>>
>>>>>>>> I suspect the ignorance is yours.
>>>>>>>>
>>>>>>>> I worked for a company that built its reputation on the R.F. inductors
>>>>>>>> it designed; these factors were among the many problems they tackled.
>>>>>>>
>>>>>>> Probably not very well.
>>>>>>
>>>>>> What makes you say that about a leading radio company that I haven't
>>>>>> even identified.
>>>>>
>>>>> I spent 22 years in England in the high tech end of the UK electronic
>>>>> business, and the understanding of the wound components they used was
>>>>> never impressive.
>>>>
>>>> Just because the company you worked for didn't understand inductors, it
>>>> doesn't exclude the possibility that other companies did understand
>>>> them.
>>>
>>> I spent three years at EMI Central Research. Some of their emplpoyees did
get stuff wrong, but they were very high level
>>> misunderstandings.
>>> I got the staff briefing on their nuclear magnetic resonance imaging
system, and asked them why they weren't using
>>> super-conducting magnets, and got told that that was a naive question.
>>>
>>>>>>> The English language text books I could find ...
>>>>>>
>>>>>> What is the relevance of that?
>>>>>
>>>>> It makes a point about the local culture. Kibble and Rayner's "Coaxial
>>>>> AC Bridges" had some great stuff about wound components, but
>>>>> interwinding capacitance was treated pretty superficially.
>>>>
>>>> How does that support your contention that an unnamed company, that
>>>> built its reputation on the excellence of its R.F. inductors, didn't
>>>> design them very well?
>>>
>>> John Larkin doesn't understand what he is doing all that well,but if you
keep experimenting and testing for long enough you can
>>> come up with pretty impressive products. Not as good as they could be -
but quite good enough.
>>
>> You don't seem to be interested in providing information which would lead
to better products Bill.
>> You seem to be much more interested in telling other people how stupid they
are
>> for only designing products which are "quite good enough".
>>
>> The circuit below is not good enough in my view but you didn't seem to be
able to handle any
>> criticism of it some time ago.
>
>Since it comes from the early part of a very long thread, and since I
>subsequently posted variations which performed a whole lot better, I
>seem to have been able to handle well-informed criticism pretty well.
>
>JM was a whole lot more helpful than you were.You did post a variation
>of one of his circuits which managed to use eight transistors in the
>adjustable gain section - which he promptly cut down to four, and I
>subsequently increased to five which got us up to 150db suppression of
>the higher harmonics
You can Spice -150 dB as a parlor game, but you'll never build
anything that good. Opamps won't do it. Thermals won't allow it. Not
even real capacitors or resistors.
And how would you demonstrate it?
John Larkin
Highland Tech Glen Canyon Design Center
Lunatic Fringe Electronics
--- SoupGate-Win32 v1.05
* Origin: you cannot sedate... all the things you hate (1:229/2)
|
