Re: LF: RE: Todmorden receiver

[JACK ASKEW <va7jx@shaw.ca>]

Paul

You are still very young in comparison to me :-)   I agree

I tend to spend more time going into depth learning about new

technology these days. EbNaut is one good example, very 

complex system to learn for me but I find fascinating. 

I hope some day someone writes a basic book on how to get

started with using it. Maybe it will encourage more to get on

VLF using this method.

I'm caught between building hardware or using software with

a sound card etc. If I go with hardware I'm unclear how you

could record the data and view several hours of it later.

It comes back to using something like SL with its QRSS

capabilities. I wish I had a good file that worked at 8720kHz

for QRSS600 as an example. This would be a good start if nothing else.

Jack Askew

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From: "Paul Nicholson" <vlf0403@abelian.org>
To: "rsgb lf group" <rsgb_lf_group@blacksheep.org>
Sent: Friday, January 5, 2018 11:33:51 PM
Subject: Re: LF: RE: Todmorden receiver

Receivers will be off at various times today to install that
power supply upgrade and replace some random cabling with
something a bit more robust.

  http://abelian.org/vlf/tmp/180106a.jpg

The box on the left terminates the cat5 cables coming in from
the E and H rx sites.  It's a junction box with isolating
transformers and on/off switches for each rx.  It has three
balanced VLF outputs and a three-channel 137kHz output.

The other box is a dual 55V PSU.  Nominally 48V but adjusted
up to the max. I didn't want to have both rx share the same
supply, hence two of everything.  Decided to use a bit of
extra ripple smoothing and RF filtering to make the DC bus
really clean.

Each rx will have to come in for replacement DC-DC converter.
Then everything needs recalibrating which takes only about 2
hours now for both rx.   I just hope the weather holds good.

All my radio equipment and the computers that go with it, lives
outside the house in a small shed.  One plug isolates the shed
during thunderstorms.  As well as protecting the house from
fires and lightning, it seems much easier to manage and limit
noise and interference that way and there is much less cabling.

Jack wrote:

 > But when you get to be 75 years old ones ability to absorb
 > technical complex issues gets more problematic ;-)

I hope not - I'm catching you up fast.  Only yesterday I was
in my 30s, and a couple of days before that, my 20s!

No, I don't believe that Jack.  I think that when you're older
it seems to take longer, perhaps because you go into things in
more depth with more understanding.  The youngsters just
learn which buttons to push.

Andy reminds us that there are other ways to receive coherent
signals...  my knowledge is limited to sound cards and PC
software.  I envy those that can build things out of PICs and
DSP chips.

--
Paul Nicholson
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