[hpsdr] PureSignal and ANAN-10

[John Ackermann N8UR]

I've been playing with PureSignal and it definitely works!  Using an 
external spectrum analyzer, I'm seeing a 10dB 3rd order IMD improvement 
at 100W PEP.  But I'm not sure if I've optimized the system.

I'm using a TAPR Hermes mounted in an ANAN-10 enclosure/amplifier.  The 
10W output drives a TenTec 418 amplifier to 100W.  However, I'm seeing a 
crosstalk issue similar to that reported for the ANAN-100.  I'm 
wondering whether anyone else has experimented with the ANAN-10 
configuration and seen this.

I measured the signal present at the "RX IN" SMA connector with the 
ANT-1 BNC connected to a dummy load.  The signal ranges from -37dBm at 
160M to -8dBm at 6M.  (As usual, I've done a bunch of measurements and 
screenshots, and written up what I've learned so far at 
http://www.febo.com/pages/hpsdr/puresignal.)

This makes sense when you consider that the amp/lpf board is mounted 
parallel to Hermes and only an inch or so away.  But it means that the 
sampled signal needs to be pretty strong to overcome the crosstalk.

I have three questions today:

1.  Has anyone else done similar work with their ANAN-10?

2.  How much stronger (in dB) should the sampled signal be than the 
crosstalk, in order to make sure that PureSignal is correcting the whole 
RF chain rather than just the ANAN-10 amplifier?

3.  Given the ANAN-10 antenna configuration, it appears that feeding the 
sample into the SMA "RX IN" connector is the only way.  Am I missing 
something?

73,
John