VK5SRP 2014 projects and some finished off in 2015
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A 400 Watt HF Power and SWR meter
I have got my HF beam operating and it is not connected through any antenna tuner as it SWR is excellent on the band segments I wish to operate it. I also have a 400 Watt linear Amplifier I wish to use with it and my ATU's cannot handle much more than 200 Watt.
Here are the project files for this item:
RadCom project from December 2014
A 'jpg file for the meter scale, right click and save.
This project started when a friend brought me some electronic equipment to recycle. One of these items was a "Permascope" by Helmut Fisher GMBH+CO and I must admit I did nor even do a web search to find out what is was, withing a day of it arriving on my bench the case housed the meter you see here.
A simple 40 dB pad for transmitter testing
When you wish to look at the RF output from a typical 100 Watt Ham Rig DO NOT connect an Oscilloscope or a frequency counter accross the antenna output terminals, the chances are you will "fry" the input to modern instruments. The two PL259 connectors are the input and the output and the test instrument connects to the BNC connector. The attenuator network consists of a 2.4K series resistor and a 50 Ohm resistor terminating the BNC connector. I used three 820 Ohm resistors in series for the 2.4K and two 100 Ohm resistors in parallel for the 50 Ohm termination.
100 Watt of RF power into 50 Ohm has an RMS voltage of 71 Volt but remember the P-P voltage will be three times this figure and that is what may do the damage to an instrument.
Simple Crystal tester
While building and experimenting with QRP rigs I soon discovered the crystals in the crystal ladder networks needed to be matched quite closely. Rockby Electronics often have bags of 50 or 100 suitable crystals so this would give me plenty to choose from. This crystal tester I made about five years ago but it was just a circuit board lying on the bench and so I decided it needed to go in a box. notice my adaptor for the smaller crystals made from a bit of high quality IC socket. The circuit consists of a Colpits Oscillator followed by a buffer stage and then a diode detector and a transistor, to drive a LED to show the crystal is oscillating. The buffer also supplies a signal to a BNC socket for connection to a frequency counter. If you do not have a frequency counter you can use a communications receiver or an HF Rig to measure the frequency. A frequency counter is required if you wish to match crystals for a filter.
A PCB design for this project can be down loaded from my web site at: http://www.philipstorr.id.au/download/
The files with a .lay6 (the PCB file) and .lmk (the macro file) extensions are PCB files for Sprint Layout version 6 and the files with the .sch extension are for EESchema, the circuit diagram drawing part of the KiCad.
Simple portable frequency counter made from a KD1JV Digital Dial kit
I bought two of these kits to build into BoatAnchor rigs but I soon realised I would need quite a few of them if I were to modify several of the old radios I have. I built one into a box to use with my Heatkit DX-60 AM transmitter and the second one was put away for "a rainy day". That day came when I wanted to align the FRG-7 communications receiver and I realised I needed to know the exact frequency comming from one of my RF Signal Generators. I looked at adding high level output to the excellent old Philips GM 2883 but when I opened it up I decided such a modification would compromise the excellent RF shielding and the generator would then leak RF and its output calibration would no longer be valid when measuring receiver sensitivity. After repairing the dial drive mechanism I settled for the Lodestar SG-4160B and added a simple FET buffer and a high level output socket to drive the frequency counter.
Silicon Chip RF Level and Power Meter
This was a project first published in Silicon Chip is 2008 but I did not find it until it was published in the English magazine Everyday Practical Electronics in December 2010. I was glancing at the magazines in a local news agent and this project looked interesting. I bought the magazine and ordered the PCB's from the UK. When the boards arrived I assembled them and put the project away in an un prepared jiffy box hoping to get back to it one day soon. That day came about four years later, early in 2015, when I needed to measure the output level from the Philips GM 2883 RF Signal Generator to check the sensitivity of several of my older communication receivers.
My version of VK3YE's SDR 40, simple SDR 40 Metre receiver
This project was published in the March 2014 edition of Amateur Radio, the WIA journal. The first picture below is of my Mk3 version with a front end tuned circuit and a FET RF amplifier. The second picture is of this board mounted in a jiffy box and the last picture is of the eight frequency DDS I am constructing to replace the plug in crystal so the receiver can cover the entire 40M band. The DDS is based on a project on VK5TM's web site and uses an AD9850 module and a PIC processor. In this picture I have not as yet connected the diode matrix to the DDS board.
This little project deserves a PDF document to explain it in full.
Other projects started in 2014 include a BitX40, more development of my version of the Beach40 by by Peter Parker and a BlekokQPR Micro40 by YD1KKK. Each of these projects deserve their own web pages when they are finished.
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Written by and Copyright, Phil. Storr © Last updated 3rd November 2016