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Handwritten code made with Cute-HTML
| A collection of radio oriented diagrams, add-ons and designs |
Always busy all those years ............... |
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©CopyRight, modifications add-on design, drawings, photographs,
gal programming, and research by: W.A.J. Geeraert ( PE1ABR ) email
Click over HERE for some utilities
to work with old LAYO1 and ORCAD for DOS.
All the work you find over here has been made with it!
Almost all the drawings are made available in PDF format.
You MUST have Adobe Acrobat reader 
installed, see at the bottom of this page.
If problems: copy PDF files to harddisk first without double click, but with "copy to" option.
AERIAL SUPPLEMENT / THE LOOP PROJECT:
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This loop aerial uses the same principle as a small 10 sq. cm coaxial EMC pickup-loop coil. If we make that loop as hughe as possible (150 sq. meters !!! in my case) we could use it as a wideband receiving aerial, working already from very low frequencies. Much amplification was needed for a usable result. But it works great!
Here is the latest high dBm amplifier |
 An early version with 2 P8002 power FET's The old drawing for the above Amp |
 The latest version according the drawing with J310 and 2N3866 |
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A dutch text written by me about this loop and published by the Dutch amateur radio magazine Electron in februari 1999 in text only on the VERON site The same "coax-loop" piece from ELECTRON februari 1999 about my loop aerial now in original PDF print quality. The above is available in Dutch only, but the original article has been referred to in English in The above link brings you to an English PDF version of the Radcom articles (200 KBytes) A PRESELECTION TUNER SKETCH FOR THE LOOP: For a good receiver as the NRD-515 sufficient extra preselection with only this device. |
ACTIVE E-FIELD AERIAL PROJECT:
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The basic idea behind this project was to make a good active aerial with a very high intercept point, especially for those frequencies where a normal (too short) long wire was not good enough. Optimised for frequencies from about 10 - 50 kHz to about 10 - 25 MHz. So longwave, beacon, medium wave a.s.o. It is basically a symmetric (balanced) circuit that is used a-symmetric. By varying the class-A current and at the same time varying the balance too, a point can be found where the two FET curves are mirrors of each other. If tested with heavy overload, this point is the point with minimum cross-modulations, it cancels out!! I use a two tone test generator with 2 and 3 MHz, and cancel out 5 MHz. Because 5 MHz is NOT in the original signals. The generator I've created is crystal controlled so the signals are in phase, nice view on scope, up to 10Vpp linear HF on the primary of the transformer!! |
Circuit diagram of the early first public 1996 version (only in Dutch) Now abandonned due to unavailability of the VHF power-FET semiconductors. Circuit diagram outdoor active aerial unit and now / en nu: NL versie Layout component side CAD outdoor unit Layout solder side CAD outdoor unit Outdoor unit mount and now / en nu: NL versie Circuit diagram power supply unit and now / en nu: NL versie Layout component side CAD indoor unit Layout solder side CAD indoor unit PSU board mount and now / en nu: NL versie Layout mainsfilter Mount mainsfilter Front and back panels indoor unit Mounting overview all components power supply unit |
  Click for surprise! |
PHOTOGRAPHS: Nice new photographs active aerial system Some re-scanned EMC/ferrite related photographs |
  Only one unit is equal to none! With more you can add directivity with a phasing unit! |
| Now some Radio add-on hardware, aerial info, diagrams and photos |
GENERAL COVERAGE RECEIVER AERIAL T-PIECE (RF-SPLITTER)
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This is a modified copy of a Radio/TV splitter adapted for the frequency range of a general coverage receiver. Works with perfect separation from lower than 100 kHz to at least 15 MHz. (This is something else than signal pass-through, that works to 50 MHz.) With extra care and an extra compensation capacitor the separation specifications are valid up to 25 Mhz, but pass-through drops to 35 MHz. Mounted in a small tin-can previously used for purée of tomatoes! Intended to connect an aerial to two receivers with very low mutual influence. Signal drop about 4 dB, mutual suppression more than 25 dB. It can also be used to connect two aerials to one receiver, it will reduce QSB. But it can also cause cancellation on a rare single frequency, so be carefull! DC pass-through (2 active aerials...) is also possible with an extra capacitor in transformer ground. PDF is simple drawing. |
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Here is the UK splitter drawing in PDF. Or drawing in a Dutch PDF. |
Click to enlarge the picture |
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FOUR-PORT GENERAL COVERAGE RECEIVER SPLITTER
This is a splitter based on a different principle with only three cores in total, only one core is used to split in two. Based on a principle also (re-)published by John Bryant an Bill Bowers: Rolling your own splitter. With three toroid sets you first split in two with the first set, and afterwards you split both outputs another time in two. Result: a four output port unit with only three toroid sets. Keep in mind that this is the practical maximum without the need for additional amplification. A least you reduce the signal with -6 dB. For stretching the pass-through frequency curve it was handy to add a small capacitor in between both sets of toroids. A gradual decay in signal is equalised with the capacitor to above 30 MHz, above 40 MHz it now has a dip. I've choosen 2x 27 pF to obtain an equalised pass-through. The cores used for each duo-core-set are: ex-Philips 23 mm 4C65 (purple) AL = 82 and an old 23 mm core comparable with Philips 3H1 (red + yellow) AL = 1850. Due to the rather low high-AL core a good Q and lower losses during tests. A little more windings are needed for 50 ohms to reach about 100 kHz as the lowest frequency, if you compare it with orange 3E25 cores. (Or use 23 or 25 mm 3F3, 3C85 or 3C11, with an AL around 2000. FT114A-77 is also usable.) 50 ohm side turns: N = 12, split side: N = 2x 8 bifilar. Usable from under 100 kHz to above 30 MHz. This version is build in a fish tin as you can see....... It only smells if you connect a transmitter to it (HI). A drawing will be added later |
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A STANDARD PI-ATTENUATOR NETWORK BOX, plus.......
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This is a standard attenuator network like everyone builds them. Nothing special. But please keep in mind that the resistor wires should be as short as possible. After a few -10 dB networks leakage becomes a problem. So screen the sections from each other. See pictures, works up to 200 MHz. If you want to do it much better, you should make it in SMD, and with much more screening. That's special!! It will work perfectly over 500 MHz!! Although it is a hell of a job to make it..... More than 5 sections ( = -50 dB !! ) is still unwise due to leakage, use more units then if you need it. |
 Top of the PI-sections. Click to enlarge the picture |
 Inside of the PI-sections. Click to enlarge the picture |
 And in SMD! Click to go to a special sub-page about this device |
A TUBE RADIO RF-GENERATOR CORRECTION NETWORK
(ARTIFICIAL AERIAL NETWORK)
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This is a dual "impedance correction network" to be connected between a RF-generator with low impedance and a common (old) tube radio with higher-Z "wire aerial" input. One branch is a simple 1 to 10 impedance transfer. The other branch is an artificial wire aerial simulation circuit for a common home wire aerial. It is needed during RF circuit alignment. The PDF is a simple drawing. |
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UK drawing in PDF Dutch PDF The curve is NOT taken when connected to a radio set, but when loaded with a 500 - 600 Ohm test resistor. |
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RF SNIFFER PROBES AND CLAMPS
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Over here some info how to build RF-sniffer probes and RF current measuring clamps. This part is not finished yet. Wait for more to come!! Because the resulting Z of a sniffer wound on ferrite is frequency dependant (I expect a 1 to 10 freq. range as practical), you need more than one sniffer for a large frequency range. To test it I made two small versions, one on half a pignose with airgap and 10 windings, the other on half a 4A11 14 mm toroid with only 5 windings. Both are "terminated" with 10 ohms, and series connected with 39 ohm to connect it to 50 ohm coax. Ferrite cutting is done with a miniature grinding wheel. Further some current clamps, one version with more signal output, it has 10 windings directly to a 50 ohms terminator, but it has a smaller frequency range. And a second version with 6 single windings in parallel, terminated with 5 ohms and series 47 ohm to coax. Lower output, buth higher frequency range. And some bigger pickup-sniffers. One version is simply a wound coax loop, terminated with 51 ohms in series on the short-circuit point. This one has a hughe frequency and pickup range, large signal is picked up within 1 - 2 meters range, also from cables in the ground. Wound on 70 mm wastewater pipe with RG174 - after glueing the pipe is removed. It has 16 windings, it is made in such a way (for relative voltage measurements...) that the total square is 1/16 sq. meter ( 25 x 25 cm square equivalent). Because it is a coax loop it is better screened to electrical fields than a "normal" pickup coil. For more precise cable identification on very low frequencies ( from 10 - 20 kHz and up) a second "big" sniffer is made on half a clamp. The inductance with 30 windings was OK to comply at the design commands. It is about 80 - 90 uH and terminated with 10 ohms, connected to 50 ohms with a 39 ohm series R. Step along and click the pictures to have an idea how I made them |
 Here it starts with, a modified pignose and a 14 mm toroid. Half a pignose and with an air-gap, the toroid is simply cut in halves. |
 Damped with 10 ohm, and a 39 ohm series R to 50 ohm coax. Fixed in place on a piece of PCB. |
 And here it is stabilised with 2-comp. resin, and an old felttip pen. The ex-pen forms a luxury handgrip! |
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| some drawings to come... |
 The high outputvoltage current clamp and high frequency version (right). All the green windings are in parallel. |
more drawings to come.... |
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 The big coax-loop sniffer mounted on a 16 mm PVC pipe. |
 Example of a wound clamp halve with 30 windings. |
 And here the big sniffer clamp on a PCB board with terminating R's on a 16 mm PVC pipe, isolated and protected with self-vulcanizing tape. |
SIMPLE WIDEBAND EMC CONVERTER
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This design is an EMC up-converter for use with the above probes (and a lot more Rx huntingloop-devices) and a portable Sony allwave receiver. The converter is comparable with other wideband converter designs, but with a few differences. The input is ONLY usable if it is 50 ohms and wideband. And NO High-Z input!! And it should be usable from about 10 kHz. The upper input-limit is just below the medium wave band, lets say 500 kHz. Lots of interference is to be expected on medium wave if it is passed through without filtering, so this MW is suppressed. Also because most portable radio's are perfectly usable on MW as a detector! So the Rx-range becomes 10 kHz to 500 kHz. There is no interference or cross modulation from longwave megawatt transmitters (and small Rx-pickup devices or tuned hunting loops.......) The output frequency is chosen as high as practical for a standard Sony receiver. The 50 ohm load in combination with the tuned output frequency should be such that no additional manual tuning is needed. Some drop is allowed. Chosen is an available 24 MHz mixing crystal, so the output becomes 24010 to 24500 kHz. If you connect 12V directly to in- or output, they are "smoked out". |
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Here is the original DUTCH version PDF. Now a translated English version is also available. |
 Click to enlarge the picture |
AUDIO BOOSTER FOR RACAL RA-17
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This design is an add-on audio amplifier for use inside a Racal RA-17. Gives much higher audio volume. A few watts real audio output. Works without extra power supply transformer, uses doubled heater voltage. PDF set is drawing, CAD layout and assembly files. |
Here is the complete RACAL amplifier PDF set
GALVANIC SEPARATION AUDIO BUFFER
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Connects all your computer / decoding and interface hardware without a ground loop to your receiving system. Each individual output has its own modem transformer, bufferamp and volume control. |
Here is the complete PDF set (5 sheets)
SPECIAL RTTY DECODER FOR NAVTEX
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Special RTTY op-amp decoder adapted for NAVTEX DX purposes only. Extraordinairy good decoding performance. Signals in noise - between S0 and S1 - almost error free decoding is possible. Can be used as an external FSK decoder in HAMCOM and CODE3. This op-amp decoder uses an EMC free negative voltage converter, so ideal for mobile (car or boat) use!! |
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Remark: These are my original drawings: comments are still in Dutch Here is the first PDF drawing, the modified telex decoder Here is the second PDF drawing, the voltage converter Here are the PDF PCB-CAD files Some DX results (From Canada to Egypt), Rx in The Netherlands!! |
 Click to enlarge the Navtex decoder |
RS232 OPTICAL INTERFACE
| This is a black box with 2x 25pins Canon-D sockets. It fits in a standard RS232 cable. It is used with the RS232 on my Tektronix 2232 oscilloscope to avoid ground loops and to prevent a blown up device if a ground loop occurs during measurements in mains connected switch supply units (yes I know I must use a separation transformer). The device can do much more: data rate 150 kHz, handshake rate 75 kHz, withstands 230V AC between in and out!!
The opto coupler and PSU boards layout files in PDF |
 Click to enlarge the RS232 interface |
CAI BUFFER AMP
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A NON-standard CAI buffer amplifier with an amplification that is the reverse of the frequency dependant attenuation in a common home.
Some frequency dependant amplification correction has already been build-in, no further alignment needed. So after this buffer and many meters of cable before or after it the highest and lowest frequencies are equal in level!!!
Here is the latest high dBm amplifier |
A ROBUST 12V POWER SUPPLY
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This is a robust "extendable" 12V power cannon. Meant to feed a standard transmitter that needs about 15 Amps. It is of the old dissipative analog type. The more power you want, the more power Transistors you add with current divider resistors. Start with at least 4x 2N3772. It is based on a SGS L200 application with good overcurrent/foldback limitation. But it is extended and more thorough tested on the edge of currentlimit and attempts to let it oscillate. Every attempt caused counter actions during the design stage!! Also an extra diode brigde for high power is added ON THE OUTPUT to make it almost idiot proof by too heavy experiments. Try to understand the special way of wiring, keep to it to make it stable and also try to keep it EMC proof. The plus and minus "bar" are low impedance points on heavy output terminals, possibly enlarged with some heavy copper lugs. EMC capacitors from those points with very short wiring to ground = metal frame.
Here is a schematics "sketch" set |
Mains Master-Slave ON/OFF unit:
| Here you find a homebrew mains master-slave unit, copied from a Dutch Elektor magazine from 1996. Switch ON/OFF together with the master-device all the other equipment, like adapters and other complimentary equipment. Usable for a computer or radio-set as master and lots of adapters for small equipment on the slave. BE CAREFULL, EVERYTHING IS MAINS CONNECTED!!! |
Complete set with plug and connectors |
Here is the complete story and circuit, copied from an old Dutch Elektuur (Elektor). Here is my circuit version with some changes and improvements, meanwhile a thermo fuse is added in the supply of the relay, you can see it on the picture right. Here is my latest CAD layout, the "ON" LED has its place on the board now. There is a peculiar point to mention. There is resonance effect with the toroid inductance and the capacitors in parallel to it. And: the main "ON" current lowers the inductance. The point with maximum effect = some resonance (is also a higher gate control voltage), should be at the high ON current and NOT at the "zero" current. Otherwise it won't switch off!! You have to add MORE capacitance to shift F-res to a lower inductance if it hardly switch-on and hangs for switch off. If you "plug" a test-C (1 - 3.3 uF) to lower the "zero" gate voltage KEEP IN MIND this is a HOT circuit! I've used the biggest toroid with at the same time the highest AL value ( 7000 - 10.000). You have to make some sort of fishermans knot tying lever tool to wind this type of toroid. You make it out of PCB clad, 1 cm wide and 25 to 40 cm long, use it as a wire holder during winding. See picture on the right. |
Circuit board pulled out of the box 
The winding tool A fishermans friend |
Homebrew counter for an Analog Rx
| An add-on counter system for an analog broadcast Rx. An example of a non-standard universal counter system (Digital readout) with cheap standard components for an old but perfect working analog receiver. In my case build-in in a Sony Rx. Fast six digit readout on FM, 3 to 5 digit on long-, medium- and shortwave, all with 1 kHz resolution, 64 msec refresh. So fast readout that follows the tuning!! Pre-load for IF substraction, two different IF's possible, with two substraction schemes ( FM / AM ). Something else than 455 kHz ( 468 f.i.) no problem. Ripple blanking on 3 MSB bits. Circuit tricks to buffer and amplify existing local oscillators and feed them with RG174 to the counter. NO SCANNING display readout, that's asking for trouble ( beeps and whistles). Sandwich construction with three tiny boards ( wire wrap experiment cards - NO CAD layout) Total enclosed in PCB-clad, size 1,5 times a 10/ 1.44 floppybox . EVERY LED display bit has its own feed-through capacitor (placed even after the current limiting-R). Brightness setting with diode voltage drops. NO expensive divide by-10 pre-scale, whole counter system works with 1/64th principle. NO expensive all-in-one chip with scanning ( beeps and whistles) readout (and with only 4 digits)
The set with all the sketch drawings in one PDF |
 Click to enlarge the Rx front  Click to enlarge the Rx front |
Homebrew counter for a Sweeper
| Another add-on counter system for an analog 0 - 200 MHz Sweeper System. Here is another special purpose counter.... For this version the whole control system is made in SMD to make it as small as possible, as small as a tiny matchbox, for build-in in a small metal mixer box in a 0 - 200 MHz sweeper system. Overthere in the box available were input frequency as well as a marker oscillator, who now also functions as a clock oscillator. Design problem: the whole range from zero to 200, standard components don't reach 200 MHz, prescalers don't go under 50 MHz to zero. So two input circuits in parallel are needed with the same divide ratio. Somewhere (halfway) the varicap control voltage range a switchover is made from the 0 - 40/60 MHz to the 40/60 - 200 MHz input circuits that work in parallel. You don't even notice the switch-over during tuning!! Again, all because 0 to about 50 MHz is impossible for a standard ECL prescaler. More than 50 MHz from zero is possible by the use of very fast 74HC74 SMD dividers ( NO HCT !!) with a transistor buffer in front, I got the fast HC74 from scrap from defective motherboards. Timing principle is comparable with the above "Sony" counter, also with 64 msec refresh. Layout boards available in SMD for control and standard layout for divider and display latch. Again with ripple blanking!
The set with all the sketch drawings in one PDF |
 Click to see a part of the front (Not finished yet)  Click to enlarge a standard driver board  Click to enlarge the tiny control system. ECL part is on the back |
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Copyright© 2001 - 2011 Walter Geeraert - All Rights Reserved
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radio.htm
by Walter - PE1ABR - 2011-10-21
