SDR Cube Transceiver Online Assembly Guide Detailed construction notes for building and testing each of the SDR Cube kit modules
Home  Bill of Materials    I/O Board    Controls Board    DSP Board      Softrock SR-Base     Softrock TX/PA   RXAMP    X-LPF    Internal Cable Set    External Cable Set      Main Enclosure     Accessory Enclosure    Digital Subassembly Test    Final Assembly    RF Functional Test

What Is It?

 

The External Cable Set is used when an external RF deck is going to be used with the Cube, instead the internal Softrock RF deck.

 

The External Cable set is comprised of the 40-wire flat cable that connect the DSP and I/O boards ("Cable 1"), and the 5 smaller ribbon cables that interconnect the DSP board with the 15-pin D-style "External Softrock" connector that gets mounted on the rear panel of the Enclosure.

 

CONSTRUCTION STEPS

[____]  STEP 1: Inventory the supplied parts

 

Check to make sure you received the CABLE-Kit-Ext bag and all the components that are pictured below.  (Click on any photo to see a larger image.)

 

 

 

 

Cable-1 (wire)	1	DSP-to-I/O Cable
J101, J102	2	CONN 40POS IDC SOCKET 10GOLD
J103	1	Receptacle, 2x4, 0.1", cut from 20P 2ROW STRT SOCKET
J105	1	Receptacle, 2x4, 0.1", cut from 20P 2ROW STRT SOCKET
J107	1	Receptacle, 2x4, 0.1", cut from 20P 2ROW STRT SOCKET
J109	1	Receptacle, 2x4, 0.1", cut from 20P 2ROW STRT SOCKET
J111	1	Receptacle, 1x2, 0.1", cut from 36P 1ROW STRT SOCKET
J115	1	D-style, 15p, female, panel mount
P117	1	D-style, 15p, male, cable mount
	1	D-style backshell, 15p

 

STEP 2:  First build Cable1, the 40-position flat cable that connects the DSP and I/O boards ...

 

	This is the goal ... create a 40-wire flat ribbon cable that is 2.5" long, with IDC connectors on either end, pointing in opposite directions
	Hold the pieces in place ... Start by holding the two connector halves (connector and the thinner clamp) in place with the ribbon cable in between.  The ribbon cable should come right to the end of the outside of the connector (i.e., don't go too much past the end such that it sticks out the other side of the IDC.)  The connector sides have little ridges that tend to center the ribbon cable in the right position when you press the connector halves together with your fingers. (Hence the name of this IDC connector: Insulation Displacement Connector.)
	Pressing Method #1 ... Using wide hand clamp (e.g., from Harbor Freight) ... Making sure the ribbon cable stays in position, press the two halves together with the hand vise until the connector pins "bite" through the wires and the ends of the thinner plastic clamp snap onto the end knobs of the connector.
	Pressing Method #2 ... Using a bench vise (preferred method) ... Making sure the ribbon cable stays in position, press the two halves together with the bench vise until the connector pins "bite" through the wires and the ends of the thinner plastic clamp snap onto the end knobs of the connector. (Harbor Freight ... http://www.harborfreight.com/4-inch-jaw-capacity-drill-press-vise-30999.html) (harbor Freight ... http://www.harborfreight.com/2-1-2-half-inch-drill-press-vise-5927.html)
The completed Cable #1	The completed Cable #1 - side view

 

    

 

NEXT ... The Internal Cable Set Construction! ...

 

NOTE:  Before you start, be aware that Cable 6 (SR Power) really needs to be about 6" long, not 3" as supplied with the initial run of kits.  We're now shipping a 6" cable, and we're sending a 6" replacement ribbon cable in the Service Pack ... But if you want to make progress right now, just grab two 6" lengths of hookup wire or ribbon cable and use it instead of the 3" ribbon cable provided.  The cable just supplies 12V power (~300ma) to the SR-base - no special precautions are necessary.

 

STEP 3:  Separate the wires at each end of each cable such that about 1" of each wire in the ribbon cable is free and separate.

 

STEP 4:  Strip off about 1/8" of the insulation for each wire on each end of the cables, and tin the exposed wire

 

STEP 5:  Organize the supplied ribbon cables according to the diagram above for the right length of cable, the right connector for each end, and the red and blue shrink tubing.

5a) One way of organizing things is to get a piece of paper and put down 5 lengths of double-sticky tape.  This will hold the cables in position.

 

5b) Label each one so you know which cable is which: Cable 2 through Cable 6.   Go in the order of the diagram above - it will be a big help!

 

5c) Press each cable down along its respective "row of tape" on the paper.

 

5d) Cut the length of RED heat shrink tubing into 5 pieces.  Each one should be no longer than 1/4" .. actually a tad less than this will make it easier for you.  The purpose of the red shrink is to denote "pin 1" on each connector, and to protect the bare wire connection you will make to those pins.

 

5e)  Cut the length of BLUE heat shrink tubing into 11 pieces.  Each one should be no longer than 1/4" .. actually a tad less than this will make it easier for you.  The purpose of the blue shrink is to denote "the other pins" on each connector, and to protect the bare wire connection you will make to those pins.

 

 

STEP 6:  Installing the External Cable Set

 

Now that the External cable set is created, you just need to install it into your Cube enclosure ...

6a) Insert the ends of the cables through the hole in the rear of the chassis such that the 15-pin D-style connector is on the outside of the chassis.  Attach the D-style connector using the #4-40 screws and nuts provided in the External Cable bag. 

 

6b) With the subchassis (and I/O board attached to it) completely loose (not yet attached to the chassis), attach cable #3 to the DSP board pinheader P9, and cable #5 to the DSP board pinheader P8, as illustrated in the Board Interconnect diagram.  Take care to orient pin 1 of each connector properly, as indicated the in the Interconnect diagram.

 

6c) Attach Cable #6 to P10 on the lower portion of the I/O board on the subschassis.  Be absolutely certain of correct orientation - pin 1 (pin with red shrink should go on the side of P10 closest to the large electrolytic on the I/O board.) 

 

6d) Carefully lower the subchassis assembly down over top of the three cables (#3, #5 and #6), ensuring that these ribbon cables are going through the slots in the lower edge of the subchassis, and thus are not pinched when the subchassis is tightened down.  Study the photos below for suggested routing of these three cables.  [NOTE: If you have one of the earlier subchassis, you will need to make an extra small slot for Cable #5 to pass through at the bottom edge directly beneath the I/O board.  You can do this with a nibbling tool or a file.  Be sure to not create any sharp edges.]

 

6e) Attach the subchassis assembly to the chassis using the #4 hardware provided (two #4-40 screws & nuts on the rear panel, and two black #4 self-tapping screws on the chassis bottom.)  Again, ensure that the three cables are freely going through the slots at the bottom edge of the subchassis.

 

6f) Attach the remaining three cables to the DSP board: cable #2 to P12 and cable #4 to P10.  As before, ensure proper orientation of the connectors as illustrated in the Board Interconnect diagram.  Also be sure to route these cables through the slots at the top edge of the subchassis such that they do not get pinched when the Cube's cover is installed.

 

6g) Using your index finger, push the connector on the loose end of the 40-wire Cable #1 firmly onto its mating pinheader of the I/O board.

 

6h)  Click on any of the photos below to see detail of the cable connections ...