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Softrock_40_R External Connections
Band: 20m

Introduction

This stage involves connecting the stereo cable to the outputs of the opamps and connecting the short coax wires to the ANT/RET terminals. The software activities will be developed soon. In the meantime, refer to the similar procedures on the SR Lite II documentation for external connections and Rocky Software Installation

General Info About the Stage

Theory of Operation

This receiver makes certain assumptions about the external environment to which it is connected:

• 50 ohm Antenna: The antenna connected to this RX must be close to 50 ohms impedance for the bandpass filters to act effectively. A serious mismatch can cause very poor reception.
• Stereo Sound Card Inputs: For the PC to be able to operate independently on the I and Q outputs of this receiver, the sound card to which these must be input MUST have a STEREO input. The most common complaint about these I/Q RX kits is from the builder who runs the inputs into the "MIC" input of his laptop, assuming the "MIC" input is stereo when, in fact, it is mono. The common symptom of this is the appearance of two exaclt identical signals on either side of the "center-frequency" in the spectrum display of the SDR software.

Stage Schematic

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Board Layouts

Board Top

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Board Bottom

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External Connections Bill of Materials
( 20m band option)

(details for installation of each component are provided in the step instructions, further down the page)

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Detailed Build Steps

Install Cables

The audio cable provided (at least the author;s version) is two conductor with ground wire wrapped around the 2 conductors. The "TIP" conductor is a red wire; the "RING" conductor is a white wire.

Prepare the audio cable, stripping and tinning the red and white wires and soldering the common (shield) sheaf to a short length of hookup wire. This hookup wire, provided in the cable bag, will be wrapped arounf the cable at the point of connection to the board and then soldered into the "common" hole (between the "TIP" and "RING" holes, so as to have the hookup wire take the strain/stress from the cable.

Similarly, connect the coax cable's center conductor to the "ANT" hole and the braid to the "ANT-RET" hole. (The author used a bit of hookup wire soldered to the braid to make the actual connection to the ANT-RET hole).

Check	Designation	Component	top/Bottom	Marking	Image	Band
☐	strain_relief	misc hookup wire (top)				any
☐	cbl-audio	Stereo Audio Shld Cable, single 1/8" plug (top)				any
☐	cbl_ant	antenna COAX (top)				any	Yada not furnished with kit

Install Software

TBD: This step will describe the installation and use of the new SDR program "SDR Sharp" (or "SDR#").

See also the writeup by Alan G4ZFQ on installing SDR# (and Rocky)

In the meantime, the process of installing and using Rocky v3.7 (as described in the SR-LITE II kit builders notes may be used

Check	Designation	Component	top/Bottom	Marking	Image	Band

Connect Radio

Once the cables are installed and the Software installed and tested, the only thing remaining is to connect the radio to the PC and to the Antenna.

1. Connect the antenna cable to a 50 ohm antenna
2. plug the audio plug at the end of the audio calble into the "Line-In" jack of your PC's sound card. (Note: MUST BE STEREO")
3. Plug the Softrock 40-R's USB plug into a convenient USB jack on your PC
4. Start up the SDR software: Configure the software so it recognizes the center frequency for the Softrock 40-R (e.g., 20m is 14.047MHz)
5. Enjoy!

Check	Designation	Component	top/Bottom	Marking	Image	Band

Completed Photos

View of Completed Topside

View of Completed Underside

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Testing

Overview

Name of Test

Test Procedure

Potential issues:

Test Table

Seq	Test Point	Units	Nominal Value	Author's Value	Your Value
1 ☐	"A" on	unit	nom	authtbd	___________
2 ☐	"B" on	unit	nom	authtbd	___________

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