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Guys:
I can really help you get optimal SNR from your devices,
but I'm not a mag builder. Someday I'll have the time to
actually BUILD one, but for now I'm happy as hell to just
offer suggestions on my specialty: low noise, audio-band
electronics.
I don't have that Huggard article from 1970, and would appreciate
an e-mail that would show Huggard's original idea. From that,
I can give device suggestions and circuit modifications to
deliver the lowest noise that ambient temperature will allow.
Low noise devices are so plentiful and cheap, I can pull a bag
of 'em out of my stockroom and send them anywhere gratis, but
I'd like to know that they're being put to good use in a
fundamentally solid design.
First, I need whatever circuit you think is attractive, as I
have no experience switching from charge to listen mode, and
the best preamp design will have much to do with voltage
transients and the supression of same. Get me your rough idea,
and I'll deliver the details to optimize performance. Include
coil dimensions so I can calculate inductance and any resonating
component values so I can calculate source impedance values.
From the banter I've been ocasionally monitoring, I'll bet
we can improve SNR by some 6 to 10dB.... maybe. That's
a substantially longer noise free listening time!
By the way, for you guys going portable, remember that a 6dB
improvement in listening noise will reduce your charge power by
a factor of 4!!!
That's my offer, any takers?
Keith Barr
-----Original Message-----
From: [email protected] [mailto:[email protected]]
Sent: Friday, December 01, 2000 1:30 PM
To: The Proton Mag Forum
Subject: Re: Transistors used in Huggard Proton Magnetometer??
The Proton Mag Forum
Hello Henrik,
I found following Info in my Library about the Transistors:
2N5088, NPN-Silicon, VCEOm: 30Vdc, Icm: 50mA, Pd: 625mW, fT: 50MHz,
hfe: 350~1400 -> Motorola Type (pdf-avail.)
For these ones I got only short Descriptions
[Material,Type/App,(VCEm,Icm,Pdm),equivalents):
2N2712, NPN-Silicon, B>75 equiv: 2N2711,BC168,BC183,BC238,BC548...
2N2613, PNP-Germanium, LF-Type, 30V, 0,05A, 0,12W equiv:
AC125..126,AC151,2SB54,2SB56
2N2643, NPN-Silicon, Dual-Type ! ,45V,0,03A,0,5W, ft>40MHz equiv:
BFY81,2N2913..20
2N404, sorry no Info available (perhaps obsolete)
Greetings
Oliver - Germany
Valentin Mortensen wrote:
> The Proton Mag ForumAfter looking at several different suggestions
how
> to build a differential proton mag. it looks to me that the simple
way
> is the "Huggard" way (the articel from 1970). But since I am not a
> electronical expert, I have some problems to get the transistors.
> Anyone have an idee how to the
> transistors?2N50882N27122N26132N26432N404or transistors that
> correspond to the one used in the construction.Henrik - Denmark
>
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I can really help you get optimal SNR from your devices,
but I'm not a mag builder. Someday I'll have the time to
actually BUILD one, but for now I'm happy as hell to just
offer suggestions on my specialty: low noise, audio-band
electronics.
I don't have that Huggard article from 1970, and would appreciate
an e-mail that would show Huggard's original idea. From that,
I can give device suggestions and circuit modifications to
deliver the lowest noise that ambient temperature will allow.
Low noise devices are so plentiful and cheap, I can pull a bag
of 'em out of my stockroom and send them anywhere gratis, but
I'd like to know that they're being put to good use in a
fundamentally solid design.
First, I need whatever circuit you think is attractive, as I
have no experience switching from charge to listen mode, and
the best preamp design will have much to do with voltage
transients and the supression of same. Get me your rough idea,
and I'll deliver the details to optimize performance. Include
coil dimensions so I can calculate inductance and any resonating
component values so I can calculate source impedance values.
From the banter I've been ocasionally monitoring, I'll bet
we can improve SNR by some 6 to 10dB.... maybe. That's
a substantially longer noise free listening time!
By the way, for you guys going portable, remember that a 6dB
improvement in listening noise will reduce your charge power by
a factor of 4!!!
That's my offer, any takers?
Keith Barr
-----Original Message-----
From: [email protected] [mailto:[email protected]]
Sent: Friday, December 01, 2000 1:30 PM
To: The Proton Mag Forum
Subject: Re: Transistors used in Huggard Proton Magnetometer??
The Proton Mag Forum
Hello Henrik,
I found following Info in my Library about the Transistors:
2N5088, NPN-Silicon, VCEOm: 30Vdc, Icm: 50mA, Pd: 625mW, fT: 50MHz,
hfe: 350~1400 -> Motorola Type (pdf-avail.)
For these ones I got only short Descriptions
[Material,Type/App,(VCEm,Icm,Pdm),equivalents):
2N2712, NPN-Silicon, B>75 equiv: 2N2711,BC168,BC183,BC238,BC548...
2N2613, PNP-Germanium, LF-Type, 30V, 0,05A, 0,12W equiv:
AC125..126,AC151,2SB54,2SB56
2N2643, NPN-Silicon, Dual-Type ! ,45V,0,03A,0,5W, ft>40MHz equiv:
BFY81,2N2913..20
2N404, sorry no Info available (perhaps obsolete)
Greetings
Oliver - Germany
Valentin Mortensen wrote:
> The Proton Mag ForumAfter looking at several different suggestions
how
> to build a differential proton mag. it looks to me that the simple
way
> is the "Huggard" way (the articel from 1970). But since I am not a
> electronical expert, I have some problems to get the transistors.
> Anyone have an idee how to the
> transistors?2N50882N27122N26132N26432N404or transistors that
> correspond to the one used in the construction.Henrik - Denmark
>
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