Ensemble RX II (HF/LF) Local Oscillator and Control
Band: HF

Install these resistors first, so as to protet against solder splashover at pins 4 and 8 off the Si570 (see below)

Do not install C33, per this advice from FiveDash.com:  ATTENTION:  An SMT capacitor (C33) on pin 1 of the Si570 needs to be removed to comply with the NO CONNECT for this pin for the Si570 supplied with the various kits. Having this capacitor mounted on the circuit board degrades the performance of the RXTX transceiver, especially the higher frequency builds of this kit.

Watch out when installing C35 to avoid solder splashover into the adjacent holes for the T1 primary windings.

Note the orientation photo for the Si570 and install with correct orientation.

Pay close attention to the pins 4 , 7, and 8, as their footprint is quite small relative to the other pads. The very tight space around those pins and the multiple contacts in close proximity can easily lead to frustrating solder bridges.  (See helpful video below from Alan, W2AEW):

Inductor Information

Common Techniques:

• Wire Gauge: remember the higher the number, the thinner the wire. E.g., #30 wire is thinner than #26 wire.
• One turn:
  • For toroids, one turn is a single pass through the center hole.
  • For binocular cores, one turn is a pass in which the wire goes in the bottom, comes out the top, goes back in the other hole at the top, and comes out the other hole at the bottom.
• Bi (tri) filar means 2(3) equal lengths of wire. You get the bi(tri)filar strand by taking the length of wire specified for the primary winding, folding it into half(thirds), twisting it to 3~ twists per inch, and winding it over the primary winding. One end of such a strand will have two(three) leads; the other end will have a "hairpin" bend (and a single lead in the case of tri-filar).
• Multi-filar windings are usually done AFTER the uni-filar winding is done.
• Windings shoud be evenly spaced and ideally made such that the winding covers ~345 degrees of the toroid
• Inductance values given are for the single (uni-filar) winding. They are provided to help verify turn counts and core material selected. It's often reported inductances are higher using the theoretical number of turns as calculated by the manufacturer's windings calculator tool, e.g. http://toroids.info/. Normally though these are not too critical, especially with the LF bands antenna noise will still be seen.
• Toroid nomenclature provides the outside diameter of the toroid (in hundredths of an inch - the "30" in "T30-2"), and material code (the "2" in "T30-2"). Color codes used in these kits are:
  • 2=Red
  • 3=Gray
  • 6=Yellow
  • 7=White
  • 10=Black
  • 12=Green (with White on opposite side)

Inductors In This Step

XFRMR: 5.76uH: 2T(bi)T #30(5 (2x2.5)in) on BN43-2402
Primary/Secondary using a total of approximately 5 inches of #30 wire, wind 2 turns , bifilar, on a BN-43-2402 ferrite.Inductance of the single winding (usually the primary) is 5.76 uH.

After two turns with the twisted pair you have a transformer with two windings (each winding corresponding to one of the two twisted single wires).
Each winding (primary and secondary) is two turns. Since the windings are identical in length and number of turns, you can arbitratily pick either one as the primary, with the remaining winding serving as the secondary winding.
(Hont: use an ohmmeter (or other continuity checker) to identify which wire-ends go together to make the ends of a winding.

Alert!!!! Examination of the Ensemble receiver PCBs  shows the grounding point of the two windings of the LO isolating transformer, T1, are diagonally apart, not adjacent.  The ground connection of the primary winding is on the right; the ground for the secondary winding is on the left.  If the local oscillator isolation transformer is not connected properly some of the Si570 fundamental and harmonics will be radiated from the USB and other cables.   The principle is that the grounded side of the isolation transformers should go to the same end of the primary and secondary. The two wires that come from the same hole in the binocular core.must be switched (for one of the windings, primary or secondary - your choice). See the article by Alan G4ZFQ for IMPORTANT details.

Double check the orientation on the two optoisolators. They should be oriented so that their "dimple" is in the upper left-hand corner.

Careful installing the resistors and diodes clustered near the USB connector area. Builders have been known to insert these into the wrong holes. Review the board layout and the orientation column below to double check the orientation.

The body of each zener is to be located above the silkscreen circles for D1 and D2 on the board with the diodes mounted standing perpendicular to the board in a hairpin fashion. The banded end of each diode is then at the lead of the diode that loops back to the circuit board.

All of the latest versions of essential firmware configuration programs, USB driver and their associated documentation can be obtained from Fred PE0FKO's website:

• Amateur Radio Certificate Authority
• USB driver: (search for "Download Firmware source and .hex files")
• CFGSR program: (search for "Download")
• Documentation

In order to test (and later, operate) your rig, you must download and install required software (SDR programs and Dynamic Link Libraries, along with hardware drivers. The actual steps and programs may vary, depending upon your computer's windows operating system version (XP, Vista, Windows 7, 8, or 10) and architecture CPU/memory (32 bit or 64 bit). Generally, the process involves the following:

1. Install the libraries and drivers (PE0FKO'a "All-In_One" Installer
2. Test installation using CFGSR
3. When ready to operate, install desired SDR program (e.g., HDSDR, SDR#, Rocky, PowerSDR, etc)

The following links are provided and, as of 1/22/2012, are current. Links highlighted in an Aqua-colored background apply only to those Softrock kits that use the SI570 programmable oscillator:

Install Driver

To be extra safe, it is highly recommended that you install the drivers with no other USB devices connected directly to your PC during the install. If your mouse and/or keyboard are USB, reconnect them through a USB hub. This seems to help avoid the dreaded "Unknown Device" Problem.

If you do not use the All_in_One Installer from PE0FKO, the correct procedure is to download the driver and put it in a suitable folder, then plug in the USB lead, Windows should detect new hardware has been found and you need to manually point it to the folder containing the drive. It should then install correctly. Certainly does on Win2000 and XP. On Vista or Windows 7, there used to be some issues with driver signing. There have been messages on the forum describing methods of working around these issues. One such solution is addressed in the author's MOBO4.3 builders notes.

LibUSB - "Unknown Device" Error

Others have experienced the dreaded "Unknown Device" problem upon plugging in the USB cable after having installed the LibUsb driver. This "unknown device" problem (and a remedy for those who are using Logitech cordless mouse and/or various wireless internet connection adaptors) are discussed in message #45071 and Message #47755 on the Yahoo Softrock40 Group

Another valueable resource for troubleshooting the "unknown device" error is Alan's webpage Installing the ATTiny45/85_USB Controller

Install/Run CFGSR ("ConFiGureSoftRock") (automatically installed in All-In_One Installer)

Once the driver is installed, if you run 'CFGSR' that will either automatically 'open' the firmware, or if not, you need to go to the 'USB' tab and select it from the list displayed in the bottom box. Which way depends on if you have 'CFGSR' set up to auto connect on program start or not.

Following configuration with CFGSR, it is adviseable to use one of the simpler SDR programs for initial testing of RX (and/or TX) functionality, even though you may want to have a more robust piece of software as your ultimate radio.

For further discussions of the software side of SDR and soundcard issues, see Alan G4ZFQ's pages.

Test Local Oscillator Using CFGSDRr

You can use 'CFGSR' to exercise the Si570 using the 'Tune' tab that makes it into a 'VFO'. Just a case of setting the frequency, and the Si570 should output a signal at 4 times the frequency displayed on the main display on the screen. Tuning can be done either by typing in the frequency or by using the mouse wheel to change the frequency by increments ranging from 1kHz to 10 MHz.

The 'Test' tab can also be used to look at all the various Si570 registers etc, but probably unnecessary as if you can hear or measure the Si570 output frequency, you know it is working.

Optionally, Install SD Program

You may, if you wish, install the SDR program of your choice here (e.g., HDSDR, Rocky, SDR#, etc.). However it is not necessary until the final stage of the build project, when you test out the receiver.

usbsoftrock" [Linux]:There is also a usb driver for Linux platforms. it's no longer available from the Google Code repository, but is still available in various Linux distros and in Alex Lee's github repo at https://github.com/alexlee188/usbsoftrock-alex

For the LF version, it will be essential to change the firmware configuration to successfully operate that version. Tthe default values are only suitable for the 'normal' HF version.

Changes needed are (using CFGSR.exe):

• Si570 tab

  set the minimum device frequency to 3MHz (default 6MHz). Although the Si570 will not run below 3.5MHz, the box only accepts integer values

• LO tab

  need to change the 'LO:Total' multiply for bands 0 - 3 from the default x4 to x16

• ABPF tab

  need to change the filter cross over points to 0.4, 0.8 and 1.6MHz

(TX to Bob G8VOI for the instructions on how to configure the Ensemble RX II Local Oscilklator for LF operation.)