[hpsdr] JanOz-163 and SDR-1000 without INA163

[dx at guyatkins.com]

Excellent investigative work, Ahti! I very much look forward to the
SDR-1000 modification that will come from this. My soldering is idling at
the curb, ready to rumble... :^)

Guy Atkins  KE7MAV
Puyallup, WA


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Message: 1
Date: Wed, 30 May 2007 20:41:17 +0300
From: "Ahti Aintila" <oh2rz.sdr at gmail.com>
Subject: [hpsdr]  JanOz-163 and SDR-1000 without INA163
To: "Phil Harman" <pvharman at arach.net.au>,	"Sami Aintila"
	<oh2bfo at gmail.com>, HPSDR <hpsdr at hpsdr.org>

Phil,

Today I tried the balanced I/Q input to Janus taking the signals
directly from the sampling capacitors and without any amplifier. The
connecting cable was 1 meter long Cat 5e with 4 twisted pairs. The
unused pairs and the shield wire were connected to ground at both
ends.

The result are promising:
- testing frequency 3.7 kHz
- RFE included, no attenuator used
- noise floor -147 dBm/10,7Hz, Blackman-Harris window
- noise -132 dBm/500Hz
- no compression/clipping at -7dBm (max signal of my generator)

<SNIP>

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