[Lf] Greetings! I have a modest proposal...

[Bob Bruhns]

This is an interesting idea.  If we get a few transmitting stations
runnng, we can also try phase-synchronized transmitters beaming in a
particular direction.

Are you the Brodsky who published some soundcard interface
information a few years back?

  Bob, WA3WDR

----- Original Message -----
From: "Jake Brodsky" <frussle at erols.com>
To: <lf at amrad.org>
Sent: Friday, November 16, 2001 2:47 PM
Subject: [Lf] Greetings! I have a modest proposal...


>
> I haven't seen any activity in a couple weeks since I signed up,
so I
> figure I'll introduce myself and hopefully you guys won't laugh
too
> hard...
>
> Some of you may remember me.  My call is AB3A.
>
> Tony McConnell (N3JLI) and I were intrigued by K0BRA's antenna
> article.  We're building four of these things.  Bear with me for a
> minute, I have an idea and I'm wondering if anyone has considered
> anything of this sort.
>
> I'm curious if any of you have discussed the possibility of large
> scale synchronous reception on LF.
>
> The plan would be to use a set I and Q inputs from a quadrature
> receiver, such as described by KK7B.  We would use two or more
> receivers, spaced at least several wavelengths apart.  Suppose for
a
> minute that we manage to build an LO which we discipline to some
> common reference, such as WWVB or GPS.
>
> Knowing the precise position of each active antenna (using DGPS),
one
> might be able to construct a long base-line array if all the
receivers
> were tuned to the same frequency.
>
> My initial thought was to have a local station (which both
receivers
> could hear) transmit an in-band signal with some sort of time mark
on
> it so that we could integrate the recordings from each site.
>
> A carrier with a +/-90 degree phase shift each second would do
nicely.
> Using this time mark, one could take the recordings from each of
the
> two stations and sum them together making a long baseline phased
> array.
>
> I was thinking that if the station we were trying to receive were
> maybe 1 kHz or so away from our reference transmitter, we ought to
be
> able to record the I and Q channels. Then, using a packages such
as
> Cool-Edit Pro, we ought to be able to sum them together with the
> appropriate phases and time delays.
>
> Has anyone considered this?  Is anyone interested in trying it?
>
> 73,
>
> Jake Brodsky, mailto:frussle at erols.com
> PP ASEL IA, Cessna Cardinal N30946, Based @ FME
> Amateur Radio Station AB3A
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