[Lf] "long" baseline LF reception

[Jake Brodsky]

Here are some ideas for mitigating some of the problems:

First, let's address linearity: I was hoping that KK7B's R2 Pro design
would be out and available by now, but I haven't seen anything to that
effect yet.  If anyone knows KK7B, and can find out what the new
design is like, I'd be happy to build one of those critters.  

The reason I want the R2 Pro is because it's supposed to have
*IN-BAND* 3rd Order IMD of around 85 dB.  That's nothing less than
awesome.  The original R2 receiver had about 55 dB of 3rd order
rejection in band (which was nothing to sneeze at).  

Secondly, I think it's helpful to have frequency locked LOs from more
than one site but phase relationships from site to site may vary and I
think compensating for this would be difficult.  Instead I think it
would be easier to expect just frequency locking, and sum up I+Q and
I-Q from each site, and THEN apply hilbert transforms to kill one
sideband.  

This way, we could work with just time delays between various sites
for weak signal recovery.  

Again, these are just lunchtime musings that Tony (N3JLI) and I have
been having.  Some of us have resources the others don't have.  If you
already have a clean WWVB lock at your site, you may think that's the
best thing to use.  Tony has a Rubidium standard reference he uses in
his shop.  I think GPS might be a good source too.  So, in the end, we
have lots of frequency references, but I don't want to tell anyone
which ones to use to slave their LO to...

73,

Jake Brodsky, mailto:frussle at erols.com
PP ASEL IA, Cessna Cardinal N30946, Based @ FME
Amateur Radio Station AB3A