Soft Rock - V6 Production Board

Soft Rock 6 Production Board

This data is from my Soft Rock V6 production board built using the MAX op amp.

MDS was measured as -111/-109 dbm (80/40 meters) with a Delta 44 sound card. For the Extigy the MDS came in at -112/-111 dbm for 80/40 meters. Not quite sure why the Extigy appears to be outperforming the Delta 44, as the Delta 44 is the better sound card. Did see a bit of gunk 0-5khz above DC on 80 meters on both the Extigy and Delta 44 setups that can be seen in the Panadapter screen shots below. Other than the hump a bit above DC on 80 meters it the spectrum pics looked very clean.

Phase and balance of the IQ outputs looked excellent on the scope and only took minor corrections in the PowerSDR IQ calibration dialog.

Some other measurements:

Input current: 30 ma (80 meters) and 35 ma (40 meters) with @ 13.8 V supply and -19 dbm input signal.
Max input signal without distortion on IQ output: -18 dbm for a 7.065 MHz input, -19 dbm for a 3.540 Mhz input
I/Q output for max distortion free signal: 4.5 Vpp.
Oscillator Frequency: 28.223 MHz
Resistance from output of 7805 to ground: 1.05k

Panadapter view, --60 dbm @ 3.510 MHz - Extigy

Panadapter view, --60 dbm @ 3.510 MHz - Delta 44

Panadapter view, -60 dbm @ 7.065 MHz - Delta 44

Some pictures of the board

Top Side

Bottom Side

Some Waveform Pics from the Scope

All of these waveforms were captured with a 7.065 MHz -18 dbm input signal applied to the antenna input and the JP1 jumpered for 40 meter operation.

IQ output (connection to sound card)

Pin 1 of JP1 (oscillator output)

Pin 3 of JP1 (output of 80 meter divider, Pin 9 of U2)

Pin 9 of U3

Pins 5 and 9 of U3, S1 and S0 inputs to U4 - quadrature clocking

The 500mV reading for channel 2 on the scope is erroneous, it's 5V/div on both channels - scope did not know probe on ch 2 was 10x,

Comments to: Bill Tracey (

Last Updated 11 April 2006

Copyright © Bill Tracey 2006