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YooFab RFLEGO, Assembly Instructions Manual

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YooFab RFLEGO Assembly Instructions Manual Download Page 9

YooFab Antenna Loop Differential pair amplifier

Notes On Simulation:

Please note that in the above animated simulation, there are two 10 MΩ resistors that 

go to ground. These are needed by the 

SPICE

 simulation and are not needed in reality. 

The real world and the simulated world are different. Simulation is very useful. However,

necessarily it presents an artificially 'perfect' world where components behave as 

idealists. In the real world no component is ideal, which results in differences in the 

performance when compared to the simulated world.

ASSEMBLY INSTRUCTIONS

RFLEGO Active Antenna Receiving Loop 

Copyright © 2018 - 2019 

www.yoofab.com

                                   G.D.COWNE - MØOOZ

page 9 of 66

Summary of Contents for RFLEGO

Page 1: ...bly instructions RFLEGO Active Antenna Receiving Loop Designed and produced by YOOFABTM ASSEMBLY INSTRUCTIONS RFLEGO Active Antenna Receiving Loop Copyright 2018 2019 www yoofab com G D COWNE MØOOZ page 1 of 66 ...

Page 2: ... 22 Step 2 22 Step 3 23 Step 4 24 Step 5 25 Capacitors C1 C2 C3 C4 C5 C6 C7 26 Step 6 26 Step 7 27 Transistors 29 Step 8 29 How to identify Base Emitter and Collector on 2N2222 TO 92 transistor 30 WINDING THE TOROIDAL TRANSFORMER 31 IMPORTANT 31 Toroid winding step 1 32 Toroid winding step 2 33 Toroid winding step 3 34 Toroid winding step 4 35 Toroid winding step 5 36 Toroid winding step 6 37 Toro...

Page 3: ... 23 54 Toroid winding step 24 55 Toroid winding step 25 56 Using the FT37 43 56 Step 9 57 Soldering the transformer to the PCB 57 Which wire Which winding 59 Remember 59 No excuses 59 So where are the leads soldered onto the PCB 60 HARDWARE 61 Step 10 61 Step 11 63 Step 12 64 Step 13 65 Congratulations 65 ASSEMBLY INSTRUCTIONS RFLEGO Active Antenna Receiving Loop Copyright 2018 2019 www yoofab com...

Page 4: ...er remember this This type of receiving antenna has a certain immunity to near field electrical QRM noise which is a distinct advantage for those that live in urban areas and particularly to those who live in blocks of flats This antenna permits stealth operation Many radio enthusiasts live in places which prohibit the installation of large antennas This antenna provides excellent results when use...

Page 5: ...for a half decent receiver This antenna should operate across all HF bands and is a form of Low Noise Amplifier LNA Its compact size makes possible a rapid setup You may then receive HF HAM radio signals with the much same ease as the use of a typical antenna fitted to a VHF consumer type radio This antenna is great for almost any type of HF receiver However it is especially useful for direct conv...

Page 6: ... hardware components such as bolts or connectors may vary Attention In the photo we see 3 transistors there are two used in the circuit ASSEMBLY INSTRUCTIONS RFLEGO Active Antenna Receiving Loop Copyright 2018 2019 www yoofab com G D COWNE MØOOZ page 6 of 66 ...

Page 7: ...0Ω 2 Resistor Printed Circuit Board 1 Vinyl protected copper 35 mm stand off 4 Black plastic M3 bolt 4 Black plastic washer 5 mm 2 Led finishing RCA connector Phono 1 Gold Plated Banana Connector 2 Power Connector 2 1 mm 1 Wire red and black 2 Galvanized wire 1 m length Decal 1 To be placed on top of the PCB Polystyrene piece 1 To organize your components while building ASSEMBLY INSTRUCTIONS RFLEG...

Page 8: ...ected signal appears on both inputs it should be rejected Below we can see the circuit simulation of a 5uV p p input signal from the wire loop This signal is amplified because it appears to the differential amplifier s inputs such that as one side becomes positive the other side becomes negative The 5uV p p signal appears on the left side of the loop coloured Green and on the right side coloured B...

Page 9: ...eality The real world and the simulated world are different Simulation is very useful However necessarily it presents an artificially perfect world where components behave as idealists In the real world no component is ideal which results in differences in the performance when compared to the simulated world ASSEMBLY INSTRUCTIONS RFLEGO Active Antenna Receiving Loop Copyright 2018 2019 www yoofab ...

Page 10: ...ifference and so nothing is amplified YooFab Differential amplifier for loop antenna No amplified signal Remember This When Testing We must remember the differential nature of this amplifier when testing If we forget this and connect a signal generator to both sides of the differential amplifier then at best nothing will appear at the output In practice the amplifier is not completely immune to co...

Page 11: ...arge dynamic range The Output The output is taken from the transformer which is used to convert the balanced output to an unbalanced output suitable for feeding along 50Ω coaxial cable Here we must note that there is a DC path to ground through the output winding of the transformer No capacitor coupling is used as it is assumed that the input of our receiver will have a capacitor We may choose to ...

Page 12: ...b RFLEGO However you may need to use an adaptor or make your own cable if you need to connect this to BNC or UHF type connectors 3 Wire Loop A and B Two Banana sockets allow the connection of a 1 1 5 meter length of wire Your kit includes a length of galvanized wire which may be fashioned into a loop This is thin wire yet has enough rigidity to maintain a form Note that the form does not have to b...

Page 13: ...s the steps necessary to completely build the kit How to build your kit 1 Read the instructions twice even if you have much experience with electronics 2 Verify the contents of the kit use the piece of polystyrene supplied to place the components prior to building 3 Prepare your work area keep it clean and organized 4 Follow all instructions in the prescribed sequence 5 Visually check the finished...

Page 14: ...solder you can apply a few layers of lacquer hairspray on top of the copper surface Apply each coat of lacquer about 25 cm away from the board and let dry for about 10 minutes Apply the second coat following the same procedure And a third This lacquer will protect the copper from fingerprint stains during the construction process and it will also protect it from future oxidation This lacquer will ...

Page 15: ...using a knife in the indicated locations For ease of assembly cut all excess pieces as shown below with a side cutter Carefully affix the decal to the non copper side of the PCB Take care to align the drilled holes with those of the decal sticker Proceed to place the connectors and other through hole elements through both the board and decal and finally proceed with the assembly ASSEMBLY INSTRUCTI...

Page 16: ...rom trusted suppliers All components are mounted on a single sided predrilled printed circuit board The board is supplied with a vinyl protection no legend solder resist or other markings 5 The PCB style used is popular among RF design engineers 6 RFLEGO is a term used to convey the modular and connective nature of an educational and functional system that is the intellectual property of YooFab 7 ...

Page 17: ... this is a Printed Circuit Board with ample ground plane and wide tracks 6 The layout of this PCB permits assembly of a great looking finished circuit with a high build quality where the guess work is removed and which is durable 7 When compared to a through hole board with vias and tented thermals soldering is somewhat easier as nothing is hidden However we need to be aware that components will o...

Page 18: ... there is enough heat to heat an area within the large copper tracks or ground plane while also liquefying the solder rapidly We do not want to apply heat to the component lead for more than 3 seconds So we do want to heat up the copper track and component lead rapidly and then apply the solder to the point in the track where we want the joint 13 A temperature setting between 260 C and 350 C is op...

Page 19: ...onents are mounted only on the copper side of the board and the excess component lead will get in the way of working on the board On this board only the connectors pass through drilled holes to the other side 16 Inspect soldered joints and cables Make sure that component leads or wires do not touch the board in any place other than the designated positions marked in the illustrations ASSEMBLY INST...

Page 20: ...s front panel is the non copper side of the board Where possible an illustration and a photograph are shown The photographs show a prototype board with the same design In most cases the photographs in the instructions below show soldering by a novice at the YooFab Lab Despite this the modules worked perfectly first time ASSEMBLY INSTRUCTIONS RFLEGO Active Antenna Receiving Loop Copyright 2018 2019...

Page 21: ...that the illustration shows a difference between the tracks dark grey and the ground plane light grey In reality there should be no difference in the appearance of the copper tracks and that of the ground plane ASSEMBLY INSTRUCTIONS RFLEGO Active Antenna Receiving Loop Copyright 2018 2019 www yoofab com G D COWNE MØOOZ page 21 of 66 ...

Page 22: ...der R1 and R2 into position These are both 120Ω resistors Photograph of Step 2 showing both 120Ω resistors ASSEMBLY INSTRUCTIONS RFLEGO Active Antenna Receiving Loop Copyright 2018 2019 www yoofab com G D COWNE MØOOZ page 22 of 66 ...

Page 23: ...d R7 into position These are both 270Ω resistors Photograph of Step 3 showing both 270Ω resistors ASSEMBLY INSTRUCTIONS RFLEGO Active Antenna Receiving Loop Copyright 2018 2019 www yoofab com G D COWNE MØOOZ page 23 of 66 ...

Page 24: ... position These are both 4 7K 4K7 resistors Photograph of Step 4 showing R5 and R8 soldered into position ASSEMBLY INSTRUCTIONS RFLEGO Active Antenna Receiving Loop Copyright 2018 2019 www yoofab com G D COWNE MØOOZ page 24 of 66 ...

Page 25: ...d R9 into position These are all 1K resistors Photograph showing R3 R4 and R9 soldered into position ASSEMBLY INSTRUCTIONS RFLEGO Active Antenna Receiving Loop Copyright 2018 2019 www yoofab com G D COWNE MØOOZ page 25 of 66 ...

Page 26: ...on These are all 100nF ceramic capacitors The component leads should be bent away from the capacitor body until an L shape is made with respect to the component body ASSEMBLY INSTRUCTIONS RFLEGO Active Antenna Receiving Loop Copyright 2018 2019 www yoofab com G D COWNE MØOOZ page 26 of 66 ...

Page 27: ...0uF or greater that is rated at 25 volts Be careful to allow room for the other components and hardware in this area of the printed circuit board ASSEMBLY INSTRUCTIONS RFLEGO Active Antenna Receiving Loop Copyright 2018 2019 www yoofab com G D COWNE MØOOZ page 27 of 66 ...

Page 28: ...Photograph showing C1 C2 C3 C4 C5 C6 C7 and C8 soldered into position ASSEMBLY INSTRUCTIONS RFLEGO Active Antenna Receiving Loop Copyright 2018 2019 www yoofab com G D COWNE MØOOZ page 28 of 66 ...

Page 29: ...rection Therefore it is best to bend and then solder each transistor one at a time The leads on the transistors may be bent directly at the body Be careful to do this ONCE Repeated bending of the leads will result in breaking the component lead from the body of the transistor ASSEMBLY INSTRUCTIONS RFLEGO Active Antenna Receiving Loop Copyright 2018 2019 www yoofab com G D COWNE MØOOZ page 29 of 66...

Page 30: ...sistors soldered into place How to identify Base Emitter and Collector on 2N2222 TO 92 transistor ASSEMBLY INSTRUCTIONS RFLEGO Active Antenna Receiving Loop Copyright 2018 2019 www yoofab com G D COWNE MØOOZ page 30 of 66 ...

Page 31: ...ing is a sequence of pictures that illustrate how to wind a ten turn bifilar transformer However instead of the black FT37 43 toroid which must be used in this circuit a large green toroid is used Additionally the sequence of pictures shows red wire and white wire The use of different colours and a bigger sized toroid should make it easier to see what is happening during this procedure Note YooFab...

Page 32: ...e enamelled wire you do not need to cut the wire into two pieces Instead you may simply fold the length supplied into two strands Clamp both strands of wire Here a vice is used However if you do not have one of these you can improvise Anything that will hold both wires while they are twisted together will suffice ASSEMBLY INSTRUCTIONS RFLEGO Active Antenna Receiving Loop Copyright 2018 2019 www yo...

Page 33: ...etween 2 5 and 3 CM of wire at the end These are referred to as pig tails which will be soldered to the PCB ASSEMBLY INSTRUCTIONS RFLEGO Active Antenna Receiving Loop Copyright 2018 2019 www yoofab com G D COWNE MØOOZ page 33 of 66 ...

Page 34: ...g step 3 The pig tails at this end are clamped such that these will not be twisted together ASSEMBLY INSTRUCTIONS RFLEGO Active Antenna Receiving Loop Copyright 2018 2019 www yoofab com G D COWNE MØOOZ page 34 of 66 ...

Page 35: ...step 4 Similarly we place the other ends of the two strands inside the chuck of a hand drill ASSEMBLY INSTRUCTIONS RFLEGO Active Antenna Receiving Loop Copyright 2018 2019 www yoofab com G D COWNE MØOOZ page 35 of 66 ...

Page 36: ...ing the wires together using the hand drill Note that in this case a battery powered electric hand drill was used ASSEMBLY INSTRUCTIONS RFLEGO Active Antenna Receiving Loop Copyright 2018 2019 www yoofab com G D COWNE MØOOZ page 36 of 66 ...

Page 37: ...Toroid winding step 6 Continue twisting the wire with the hand drill ASSEMBLY INSTRUCTIONS RFLEGO Active Antenna Receiving Loop Copyright 2018 2019 www yoofab com G D COWNE MØOOZ page 37 of 66 ...

Page 38: ...More Twist the wire until we arrive at between 7 8 twists per inch OR about 3 twists per centimetre ASSEMBLY INSTRUCTIONS RFLEGO Active Antenna Receiving Loop Copyright 2018 2019 www yoofab com G D COWNE MØOOZ page 38 of 66 ...

Page 39: ...Toroid winding step 8 Keep on twisting ASSEMBLY INSTRUCTIONS RFLEGO Active Antenna Receiving Loop Copyright 2018 2019 www yoofab com G D COWNE MØOOZ page 39 of 66 ...

Page 40: ...nding step 9 Finally we may detach the twisted wires from the clamp and the hand drill ASSEMBLY INSTRUCTIONS RFLEGO Active Antenna Receiving Loop Copyright 2018 2019 www yoofab com G D COWNE MØOOZ page 40 of 66 ...

Page 41: ...ee twists per CM Note This number of twists per CM shown above may also be used for the 33 SWG solderable enamelled wire that is supplied with this kit ASSEMBLY INSTRUCTIONS RFLEGO Active Antenna Receiving Loop Copyright 2018 2019 www yoofab com G D COWNE MØOOZ page 41 of 66 ...

Page 42: ...Toroid winding step 11 Hold one end of twisted pair in your left hand ASSEMBLY INSTRUCTIONS RFLEGO Active Antenna Receiving Loop Copyright 2018 2019 www yoofab com G D COWNE MØOOZ page 42 of 66 ...

Page 43: ... step 12 Oh Wait Using your right hand now push that end UP through the toroid Pay attention ASSEMBLY INSTRUCTIONS RFLEGO Active Antenna Receiving Loop Copyright 2018 2019 www yoofab com G D COWNE MØOOZ page 43 of 66 ...

Page 44: ...Toroid winding step 13 A more focussed picture of the same action ASSEMBLY INSTRUCTIONS RFLEGO Active Antenna Receiving Loop Copyright 2018 2019 www yoofab com G D COWNE MØOOZ page 44 of 66 ...

Page 45: ...Toroid winding step 14 Right up through the toroid ASSEMBLY INSTRUCTIONS RFLEGO Active Antenna Receiving Loop Copyright 2018 2019 www yoofab com G D COWNE MØOOZ page 45 of 66 ...

Page 46: ...o the point hold the pig tail and a bit more Hold this pair of wires against the toroid using your left hand thumb and finger ASSEMBLY INSTRUCTIONS RFLEGO Active Antenna Receiving Loop Copyright 2018 2019 www yoofab com G D COWNE MØOOZ page 46 of 66 ...

Page 47: ...Toroid winding step 16 The free end must now be passed DOWN through the toroid ASSEMBLY INSTRUCTIONS RFLEGO Active Antenna Receiving Loop Copyright 2018 2019 www yoofab com G D COWNE MØOOZ page 47 of 66 ...

Page 48: ...winding step 17 Down We pass the free end of the twisted pair DOWN through the toroid ASSEMBLY INSTRUCTIONS RFLEGO Active Antenna Receiving Loop Copyright 2018 2019 www yoofab com G D COWNE MØOOZ page 48 of 66 ...

Page 49: ...Toroid winding step 18 This counts as 2 two turns We must continue winding ASSEMBLY INSTRUCTIONS RFLEGO Active Antenna Receiving Loop Copyright 2018 2019 www yoofab com G D COWNE MØOOZ page 49 of 66 ...

Page 50: ...Toroid winding step 19 This counts as three 3 windings ASSEMBLY INSTRUCTIONS RFLEGO Active Antenna Receiving Loop Copyright 2018 2019 www yoofab com G D COWNE MØOOZ page 50 of 66 ...

Page 51: ...Toroid winding step 20 Keep winding ASSEMBLY INSTRUCTIONS RFLEGO Active Antenna Receiving Loop Copyright 2018 2019 www yoofab com G D COWNE MØOOZ page 51 of 66 ...

Page 52: ...Toroid winding step 21 FINISHED We now have 10 windings ASSEMBLY INSTRUCTIONS RFLEGO Active Antenna Receiving Loop Copyright 2018 2019 www yoofab com G D COWNE MØOOZ page 52 of 66 ...

Page 53: ...ep 22 These windings should be distributed around the toroid so it looks like the picture above ASSEMBLY INSTRUCTIONS RFLEGO Active Antenna Receiving Loop Copyright 2018 2019 www yoofab com G D COWNE MØOOZ page 53 of 66 ...

Page 54: ...dings using an LC meter Note that this toroid will show different results than our black FT37 43 which is wound with 33SWG solderable enamelled copper wire ASSEMBLY INSTRUCTIONS RFLEGO Active Antenna Receiving Loop Copyright 2018 2019 www yoofab com G D COWNE MØOOZ page 54 of 66 ...

Page 55: ...Toroid winding step 24 Let s separate the wires here and measure again ASSEMBLY INSTRUCTIONS RFLEGO Active Antenna Receiving Loop Copyright 2018 2019 www yoofab com G D COWNE MØOOZ page 55 of 66 ...

Page 56: ...roduce 35 uH 3 5 MHz corresponds to an impedance of about 770Ω 7 MHz corresponds to an impedance Z of about 1 5KΩ 30 MHz corresponds to an impedance of about 6 5KΩ The above is sufficient for our transformer to work well over the entire HF spectrum ASSEMBLY INSTRUCTIONS RFLEGO Active Antenna Receiving Loop Copyright 2018 2019 www yoofab com G D COWNE MØOOZ page 56 of 66 ...

Page 57: ...nd the other end of this grounded winding is fed directly to the output Note that the diagram shows two dots above the transformer These dots tell us the polarity or magnetic sense of our transformer and this is important as this affects the phase of signals passing through our transformer ASSEMBLY INSTRUCTIONS RFLEGO Active Antenna Receiving Loop Copyright 2018 2019 www yoofab com G D COWNE MØOOZ...

Page 58: ...e toroid Conversely the left hand side of the windings will always have a pair of windings arching over from outside through the middle of the toroid and these then rest under the lower side of the toroid Above you will see the correspondence of the schematic circuit diagram to the physical windings on a toroid Again we must remember that our FT37 43 is much smaller AND that it is wound using copp...

Page 59: ...onnected directly to the output Whereas the WHITE bottom wire left hand side of the windings must be soldered to ground Remember Remember that we will not be winding a big easy to see toroid with two different coloured wires Instead we will be winding 10 twisted bifilar turns of 33 SWG enamelled copper wire onto a black FT37 43 Winding these toroids is easy when you stay totally focused on the job...

Page 60: ...is the other side of these dotted wires You can test this with a continuity meter 3 The two wires that go to C4 and C5 are one winding 4 The two other wires are the other winding or pair One side of which is soldered to ground and the other to the output track ASSEMBLY INSTRUCTIONS RFLEGO Active Antenna Receiving Loop Copyright 2018 2019 www yoofab com G D COWNE MØOOZ page 60 of 66 ...

Page 61: ...e printed circuit board with the ground side of the socket s thread facing the copper ground plane A ground solder tag is supplied which should be placed against the ground plane The nut is then tightened up against the copper side of the board Hold the RCA socket on the DECAL side using pliers Be careful not to damage the RCA socket using too much force Fit The 2 1mm Power Jack socket Note This i...

Page 62: ...ASSEMBLY INSTRUCTIONS RFLEGO Active Antenna Receiving Loop Copyright 2018 2019 www yoofab com G D COWNE MØOOZ page 62 of 66 ...

Page 63: ...ASSEMBLY INSTRUCTIONS RFLEGO Active Antenna Receiving Loop Copyright 2018 2019 www yoofab com G D COWNE MØOOZ page 63 of 66 ...

Page 64: ...low As mentioned above the BANANA posts may be soldered to the tracks directly using the tags or wire may be used instead ASSEMBLY INSTRUCTIONS RFLEGO Active Antenna Receiving Loop Copyright 2018 2019 www yoofab com G D COWNE MØOOZ page 64 of 66 ...

Page 65: ...longer lead goes to ground and the Anode goes to the track shown in the illustration The LED should not require anything other than solder to keep it in position ASSEMBLY INSTRUCTIONS RFLEGO Active Antenna Receiving Loop Copyright 2018 2019 www yoofab com G D COWNE MØOOZ page 65 of 66 ...

Page 66: ...astic screws are fitted to the DECAL side of the board Tighten the screws but do not over tighten them as this will damage the thread on the screw Congratulations Congratulations you have now completed the kit ASSEMBLY INSTRUCTIONS RFLEGO Active Antenna Receiving Loop Copyright 2018 2019 www yoofab com G D COWNE MØOOZ page 66 of 66 ...

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