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RE: LF: RE: Todmorden receiver

To: <[email protected]>
Subject: RE: LF: RE: Todmorden receiver
From: <[email protected]>
Date: Wed, 29 Nov 2017 14:25:58 -0500
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Hello Paul,

By noise from light do you mean shot noise from the average solar flux? I tried 
a quick calculation yielding < 1 nV/rt-Hz, and I guessed that your noise 
voltage density is more than 10x that. Did I calculate incorrectly or are you 
perhaps thinking of a different transduction mechanism? Very interesting in any 
case. I wouldn't have thought of noise from light and it's intriguing to think 
about how active nature is at your receiver's equivalent noise field strength.  


Jim AA5BW  

-----Original Message-----
From: [email protected] 
[mailto:[email protected]] On Behalf Of Paul Nicholson
Sent: Wednesday, November 29, 2017 12:12 PM
To: [email protected]
Subject: Re: LF: RE: Todmorden receiver

The re-built E-field rx was put outside this afternoon for a on-air trial.

Pre-amp inside the antenna tube

I'm a bit worried about noise from light getting into the tube - the plastic 
lets a bit of light through.  I'll probably have to fit an opaque liner.

Here's the power supply, filter and line driver

I just got finished at dusk

The antenna looks remote but there's still 140mV RMS of 50Hz on it.  This 
doesn't come from the house, or even the overhead power lines to the house, but 
from further away.

I'm using a metal support pole and guys - hopefully that means the calibration 
won't change so much between wet and dry conditions.

Here's the spectrum

It seems to be working well, no intermod.  The gain is a little too high, 
overall x30 voltage gain from antenna to soundcard input.  I'll have to drop 
that to about x15 tomorrow.  It really doesn't need much gain with a 2m antenna 
tube 2m off the ground.

Paul Nicholson

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