Ensemble RX II (HF/LF) Auto Band Pass Filters
Band: HF

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: 23.04uH: 4T(bi)T #30(8 (2x4)in) on BN43-2402
Primary/Secondary using a total of approximately 8 inches of #30 wire, wind 4 turns , bifilar, on a BN-43-2402 ferrite.Inductance of the single winding (usually the primary) is 23.04 uH.

XFRMR: 23.04uH: 4T/2T(bi)T #30(9(4/2x2.5)in) on BN43-2402
Primary: Using approximately 4 inches of #30 wire, wind 4 turns on a BN-43-2402 ferrite.
Secondary: Using a total of 5 inches of #30 wire, wind 2 turns , bifilar, on the ferrite in the same direction as the primary winding. Inductance of the single winding (usually the primary) is 23.04 uH.

Includes winding and installing the two binocular transformers, T2 and T3.

T2 has a single primary and a single secondary windings; T3 one primary and two secondary windings.

ALERT! Original Ensemble RXII PCB layouts have an error in the placement of the leads for T2, the Antenna isolation transformer. If the antenna isolation transformer is not connected properly then the outer of the antenna coax will be prone to common mode currents causing noise pickup on receive. 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 orsecondary - your choice). See the article by Alan G4ZFQ for IMPORTANT details.

The T3 secondary windings are connected by a trace on the board such that the secondary winding ends not connected together are 180 degrees phase different. Only one secondary winding is connected through the QSD switches of U10 at any instant of time resulting in signal integration on capacitors C20 and C21. T3 also provides a 4:1 Z transformation from the BPF to the QSD circuit.

Once the transformers are wound and installed, you should turn the board over and run continuity tests on the primary and secondary windings, per the above diagram

In this step and the two steps following it, you will build the bandpass filter for the band 0 passband.

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

COIL: 5.5uH: 35T #30(20in) on T30-2(red)
Using approximately 20 inches of #30 wire, wind 35 turns on a 0.30 inch od T30-2 (red) ferrite. Inductance = 5.50 uH.

COIL: 2.6uH: 24T #30(15in) on T30-2(red)
Using approximately 15 inches of #30 wire, wind 24 turns on a 0.30 inch od T30-2 (red) ferrite. Inductance = 2.60 uH.

COIL: 5.5uH: 35T #30(20in) on T30-2(red)
Using approximately 20 inches of #30 wire, wind 35 turns on a 0.30 inch od T30-2 (red) ferrite. Inductance = 5.50 uH.

First, you want to wind and install the coils and then continuity test them. The continuity test checks for continuity between the points labeled "1" and then tests the continuity between the points labeled "2". Wherever possible, the test points have been assigned to vias removed from but electrically connected to the coils' vias, so as to give a good test of the soldering.

Once you have successfully verified continuity, you can proceed to install the remaining parts for the passband.

In this step and the two steps following it, you will build the bandpass filter for the band 1 passband.

First, you want to wind and install the coils and then continuity test them. The continuity test checks for continuity between the points labeled "1" and then tests the continuity between the points labeled "2". Wherever possible, the test points have been assigned to vias removed from but electrically connected to the coils' vias, so as to give a good test of the soldering.

Once you have successfully verified continuity, you can proceed to install the remaining parts for the passband.

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

COIL: 2uH: 21T #30(13in) on T30-2(red)
Using approximately 14 inches of #30 wire, wind 21 turns on a 0.30 inch od T30-2 (red) ferrite. Inductance = 2.00 uH.

COIL: 0.46uH: 10T #30(8in) on T30-2(red)
Using approximately 8 inches of #30 wire, wind 10 turns on a 0.30 inch od T30-2 (red) ferrite. Inductance = 0.46 uH.

COIL: 2uH: 21T #30(13in) on T30-2(red)
Using approximately 14 inches of #30 wire, wind 21 turns on a 0.30 inch od T30-2 (red) ferrite. Inductance = 2.00 uH.

First, you want to wind and install the coils and then continuity test them. The continuity test checks for continuity between the points labeled "1" and then tests the continuity between the points labeled "2". Wherever possible, the test points have been assigned to vias removed from but electrically connected to the coils' vias, so as to give a good test of the soldering.

Once you have successfully verified continuity, you can proceed to install the remaining parts for the passband.

In this step and the two steps following it, you will build the bandpass filter for the band 2 passband.

First, you want to wind and install the coils and then continuity test them. The continuity test checks for continuity between the points labeled "1" and then tests the continuity between the points labeled "2". Wherever possible, the test points have been assigned to vias removed from but electrically connected to the coils' vias, so as to give a good test of the soldering.

Once you have successfully verified continuity, you can proceed to install the remaining parts for the passband.

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

COIL: 1uH: 19T #30(9in) on T25-6(yel)
Using approximately 10 inches of #30 wire, wind 19 turns on a 0.25 inch od T25-6 (yellow) ferrite. Inductance = 1.00 uH.

COIL: 0.27uH: 10T #30 on T25-6 c(yellow)
Using approximately 7 inches of #30 wire, wind 10 turns on a 0.25 inch od T25-6 (yellow) ferrite. Inductance = 27.00 uH.

COIL: 1uH: 19T #30(9in) on T25-6(yel)
Using approximately 10 inches of #30 wire, wind 19 turns on a 0.25 inch od T25-6 (yellow) ferrite. Inductance = 1.00 uH.

First, you want to wind and install the coils and then continuity test them. The continuity test checks for continuity between the points labeled "1" and then tests the continuity between the points labeled "2". Wherever possible, the test points have been assigned to vias removed from but electrically connected to the coils' vias, so as to give a good test of the soldering.

Once you have successfully verified continuity, you can proceed to install the remaining parts for the passband.

In this step and the two steps following it, you will build the bandpass filter for the band 3 passband.

First, you want to wind and install the coils and then continuity test them. The continuity test checks for continuity between the points labeled "1" and then tests the continuity between the points labeled "2". Wherever possible, the test points have been assigned to vias removed from but electrically connected to the coils' vias, so as to give a good test of the soldering.

Once you have successfully verified continuity, you can proceed to install the remaining parts for the passband.

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

COIL: 0.46uH: 13T #30 on T25-6 core
Using approximately 8 inches of #30 wire, wind 13 turns on a 0.25 inch od T25-6 (yellow) ferrite. Inductance = 0.46 uH.

COIL: 0.13uH: 7T #30 on T25-6 core
Using approximately 6 inches of #30 wire, wind 7 turns on a 0.25 inch od T25-6 (yellow) ferrite. Inductance = 0.13 uH.

COIL: 0.46uH: 13T #30 on T25-6 core
Using approximately 8 inches of #30 wire, wind 13 turns on a 0.25 inch od T25-6 (yellow) ferrite. Inductance = 0.46 uH.

First, you want to wind and install the coils and then continuity test them. The continuity test checks for continuity between the points labeled "1" and then tests the continuity between the points labeled "2". Wherever possible, the test points have been assigned to vias removed from but electrically connected to the coils' vias, so as to give a good test of the soldering.

Once you have successfully verified continuity, you can proceed to install the remaining parts for the passband.

Note that there is an optional grounding via for the return side of the antenna connection. Normally, you would NOT want to ground this to regular circuit ground. However, there is some further discussion of this issue in this message thread in the Softrock40 reflector. One message suggested substituting a 4.7k ohm resistor for the grounding jumper to eliminate 60 Hz hum in the rx.