Two More for the Shack
Geoff Theasby G8BMI has an Electronic Calculator and a Better Transistor Tester.
This first kit, by KKMoon, is available from many suppliers (including Amazon – Google ‘KKMoon calculator’), and is very easy to build. Electronically speaking, it takes about two hours to build, using only eight components, including a 20pin chip, although I had two resistors left over. Assembling the case and marrying the two took far longer, about four hours, as no instructions are included. Preparing the key tops with the correct legend is easy, but repetitive. Once the housing has the correct orientation established, by matching the screw holes and tabs, it can be screwed together, which is easy to say... The LCD display is easier to make up, just four black screws hold the bezel on. The 16-way pin header should be bent to match the angle of the display in the case, which is a little tricky. Just do not damage any item by forcing it.
Powering it up, it worked first time, although the display was almost unreadable due to lack of contrast. It is a common two-line 1602 display, so checking the datasheet online revealed that pin 2 is the one to use. As originally instructed, a potential divider formed of 10kΩ and 1kΩ resistors, tapped at their junction and taken to pin 3 controls the contrast.
If desired, a miniature 20kΩ PCB potentiometer could be fitted, but I tried a 47kΩ pot between pins 2 & 3, to get best contrast without dismantling, and the effective resistance measured. This was about 3kΩ, so 3.3kΩ was permanently added between the pins on the pin header. Pin 1 is on the right-hand end, looking in the back of the case, Fig. 1. Complete dismantling is required to change the batteries (CR2032 coin cells x 2) but if you do not completely separate the M2.5 screws and nuts holding the display on, it becomes easier, and you will not lose the nut in ‘the works’.
The device is a basic four-function machine, which is available in many forms for about £1 or £2 ready built. 40 years ago, these machines were very expensive, so it was worthwhile to save money by building a kit. Why now build your own? Because, you can say “I built it myself”. Of course, readers need not reveal that it is a very simple kit to make..., Fig. 2.
A Better Transistor Tester
In PW April 2019 I discussed a small transistor tester, which has since been in constant use here chez Theasby. It is invaluable when assembling kits.
However, the boffins have been busy, and there is now released the GM328, a ‘better mousetrap’ if you will, Fig. 3. Again, available from Amazon and others (Google ‘GM328’). Using a pre-programmed AT Mega 328P microcontroller, it performs a much more detailed analysis of many semiconductors, which was outside the scope of the previous version. It is also a square-wave frequency generator, using 20 fixed frequencies twixt 1Hz and 2MHz, although the waveform is most certainly not ‘square’, and it is best kept below 500kHz.
In addition, a frequency meter function, useful from a few Hertz to over 1MHz, and an adjustable PWM generator. Mine could be varied from 10% to 81% as seen on my Hameg HM307 ‘scope. Other facilities include a self-test routine, and all results shown on a 1.8in LCD colour display. The original design was by Markus Frejek, see:
A 64-page manual updated by KarlHeinz Kubbeler is available online at:
www.mikrocontroller.net/ attachment/164956/ttester_eng104k.pdf
Assembly was fairly easy, although components were a little tightly packed in places. Upon connecting a PP3 battery, nothing happened. Investigation found a couple of poor solder joints so I tried applying power once more, with the same results. Voltage tests revealed a solder bridge under a 9012 transistor. After rectifying this, it worked perfectly. No instructions are provided, but see the Bangood entry for this device on eBay. On test it was within 1Hz of my other audio frequency meter, and within 0.1V of my digitally metered power supply.
As for my own shack, I have long been the owner of the Davis Vantage Vue model, which sits on the roof and transmits to an indoor console (on 868.0-868.6MHz [US: 902-928MHz])), as it turns out, Fig. 1).
Moreover, the weather here in Blighty is often the subject of radio programmes, podcasts and TV documentaries. Naturally, both Practical Wireless (PW) and
RadioUser (RU) regularly publish articles about weather, mostly in connection with propagation (most recently, From Isobars to Millibars, in RU 2019/20).
In a more recent contribution on Time, Frequency and Propagation, I found that certain time signals also carry coded weather information, for instance, the VLF station DCF77 (77.5kHz).
Furthermore, weather often plays a part in our regular columns, especially when there are specific weather events to report on, such as the Spring 2020 floods. Tim Kirby GW4VXE wrote about this recently
(Signals from Space, RU May 2020).
New technologies are often catalysts for weather-related content in some of our columns. One recent example of this was Robert Connolly’s 2018 RU contribution on DRM Data-Casting in Maritime Matters.
The RadioWeatherWatchers
There are multiple reasons why we all keep an eye out for the weather. If you are a radio fan concerned about climate change, you may have studied the International Telecommunications Union’s Use of Radio Spectrum for Meteorology, or similar papers by other pertinent organisations, such as the World Meteorological Organisation (WMO).
Perhaps closer to home, you might have large antennas, masts or towers in the garden to keep an eye on.
Moreover, whether we are radio amateurs or DXers, skippers or flyers, we all need reliable weather information to assess signal paths and propagation conditions.
However, I feel that many of us are simply fascinated by the changing weather in itself and like to monitor conditions, locally, regionally, or on a wider scale.
Therefore, in the remainder of this article, I am aiming to pick out a handful of ways (ten, in fact), through which you can monitor weather with your radio(s), in
I am going to include something on all of those methods in what follows, my own modest and limited knowledge of the technology allowing. For this article, I am looking at ‘weather-information’ in a slightly wider sense, thus also including signals that you might prefer to see as ‘atmospheric’, ‘ionospheric’ or general ‘propagation’ data.
Therefore – since ‘weather’, in its most general sense, can be defined as the state of the atmosphere above and around your (or another) location – I thought it permissible to also include some ‘spaceweather’ and solar observation by radio, and other marginal topics.