Urban Ministry Live And Unplugged: Atmospherics Monitor [1]

Wednesday, September 9, 2009

Atmospherics Monitor [1]

When it comes to electronics, I consider that there’s only one thing as interesting as a radio circuit. That is an atmospheric charge monitor. Here is a simple design I did (on the right -- taken from one of my books), which uses an analog or digital multimeter to display atmospheric charge. Once one gets a feel for the changing multimeter display, one can confidently predict lightning strikes, cold fronts, and much more. It is fascinating to place the meter on one's desk and observe atmospheric activity. Comparator IC1 is the "engine room" of the circuit, and includes an antenna and an earth to measure potential difference between atmosphere and earth -- see Atmospherics Monitor [2] for instructions on the antenna. IC1 has an extremely high input impedance, which reduces the "thin" atmospheric charge at 2½ metres' (2½ yards’) height to an estimated 1V at its non-inverting input. VR1 adjusts the inverting input at pin 2 to roughly match the potential at the antenna. This must be a multi-turn preset potentiometer. Other potentiometers do not have the required precision. R1 slightly mutes the responsiveness of the circuit. The Atmospheric Monitor is ideally powered off a DC plug-pack power supply, for the sake of stability. Attach a multimeter to the circuit as shown, and switch it to its 5V range. Turn VR1 across its entire range until a point is reached where the output voltage swings wildly. At this point, continue with very careful adjustment, until the output voltage stands at about 2.5V. Do not make this adjustment when the ground is wet, as this will likely skew the readings. OBSERVATION: You will notice daily variations of charge -- mostly gradual. If the multimeter readout tends to drift too high or too low, carefully readjust VR1. When a thunderstorm approaches, there should be a very obvious increase in output voltage, and ultimately sharp fluctuations with lightning strikes. If the voltage goes off scale, use VR1 to bring it back within range. You may click on the diagram to enlarge. To follow the electronics trail on this blog, click on the "Electronics" category top left.

NOTE: You may re-publish this design, on condition that you acknowledge the designer (Thomas Scarborough) and this blog (http://thomasscarborough.blogspot.com).

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About This Blog

I have spent ten years in suburban ministry, twenty-two years (total) in urban ministry, and seven years in country ministry. My involvements in ministry continue, now reduced.

There are a few reasons for this blog: 1. To help people form a picture of what ministry is about -- in particular urban ministry -- not least seminary students who may be destined for urban ministry. I have found that the image and the reality may be far apart in academia. 2. My experience in ministry may be (and, in fact, often has been) an encouragement to other ministers -- alternatively, a cautionary tale, as the case may be! Many notes of thanks have been recorded on this blog. And 3. Friends have simply told me how interesting reports of ministry are.

This is not a "parochial" blog. Only a tenth or so of readers are local (in South Africa). Outside of my home country, this blog is most read in Europe and North America. Russia is no. 4 on the list, and there is some interest in Muslim nations. At one point, this was the most authoritative Religion blog in Southern Africa (I now do not know how it is ranked).

With all of the above in mind, the purpose of this blog is simply to record urban ministry "live and unplugged", in the form of accounts. This blog is not a "church blog", but a "ministry blog". For the most part, I don't intend to share my views. The emphasis is the experience of ministry and the various events that surround it.

A definition of “live” is “actually being performed at the time of viewing”. A definition of “unplugged” is “without amplification or modification”. However, see my Posting Policy below.

Posting Policy

This blog may be unique with regard to its degree of transparency about urban ministry. Many people have written to me to say how they cherish the help they have received through this. However, this means that special attention needs to be given to confidentiality in particular. I use the following guidelines for posting on this blog:

I apply the following questions to posts: Are they posted in good faith? Are they balanced? Are they compassionate? Are they informative about ministry? Do they help one better understand a problem or issue?

I consider a post to be unproblematic if a person's identity is unknowable in the post, if the facts are public knowledge, or if a change of particulars (name, place, date, and so on) will truly protect privacy. If I consider that anyone who was not involved in an incident would recognise those who were, then I do not post. If a post could compromise the safety of those I blog about, then I make a post safe, or I do not post.

I believe that these measures should enable me to continue to be "open" about urban ministry while not compromising privacy.

In 2013, ninety percent of the posts on this blog were removed. I then put the question of the freedom of the blog to the South African Human Rights Commission. The position is this: if a post is legal, it is legal. Essentially, all of my posts were OK. There is freedom of expression in South Africa.

Having said this, if any post should even cause discomfort, it will be removed from this blog immediately. This has always been the position. One does need to contact me for that, best through an e-mail or a blog comment, and I prefer to see a name on it. The post will be put back up only if there would seem to be compelling reason for it. It is hoped that there will be the assumption that I wish to address any discomfort satisfactorily, compassionately, and efficiently.