Sunday, 24 June 2018

CTARC Report on June Meeting - 24 Jun '18

The CTARC met on Saturday 23 June at 14h00 for the monthly meeting. Rainy winter weather didn’t discourage our members’ enthusiasm - by 13h50 seating space was already getting difficult to find as more people packed into the venue, which is great news. Danny ZS1BL was kept busy at the entrance taking in subscriptions and Morningstar payments as members dug hands into pockets to find the necessary. Thanks to all who have paid timeously. For those who intend to renew their CTARC membership, annual subs are due at the end of June...

Chairman Rob ZS1SA opened the meeting with a welcome, and gave a report back on the recent committee meeting. He reminded us of the club’s AGM next month, and the August meeting which will be the International Lighthouse/Lightship Weekend held at Green Point Light on the weekend of 18/19 July 2018. Rob announced that John ZS1EQ is going to assist increasingly with managing our club’s ILLW involvement (a big task that Rob has carried with Spartan fortitude for the past eight years). Also, we have two new bulletin readers joining our team in the persons of John ZS1EQ and Chris ZS1CDG.

Next, we were given the opportunity to see a very interesting piece of gear before the main talk. It was a Special Operations Executive spy transceiver of the type issued to SOE agents inserted into Axis-occupied France, Belgium, the Netherlands and the Balkans in the dark days of the Second World War. This compact W/T transceiver fits into a small leather suitcase. It was the smallest transceiver used in anger by the Allied forces at the time. It was manufactured by Marconi in 1943, and is referred to as a Type 21 Mark iii, or Type "A" Mk iii, or simply "A3" suitcase radio).

Solidly assembled and using just five valves – a 7Q7, three 7H7’s and a 7C5, this compact set was a vast improvement on its predecessor, the Mark ii (also called the "B2"), which had occupied three bulky boxes and would have been difficult for an agent (trying to avoid the enemy search teams) to transport discreetly. The Mark iii fits into a little suitcase just 13 x 9 x 4 inches in size. It is a CW transceiver (which can also receive A3 telephony), capable of operating between 3.2 and 9.55 MHz (sorry - Megacycles!), the transmitter frequency being controlled by a crystal and the receive frequency operating in split mode (for better security and to avoid jamming). Typically,. three crystals were issued per set – one for the daytime frequency, a night time one and one for emergencies. The receiver is a reaction-tuned super-regenerative type with an Intermediate Frequency of 1200 kc/s.

The rig pushes out just 5 watts, which is not that much considering the antenna and counterpoise were often set up just inside a single room to avoid visual detection. However, the home stations back on British soil would be copying the fugitive signal via a rhombic antenna connected to an HRO or AR88 communications receiver. Under ionospheric conditions at the time, ranges of 500 miles were possible. Also, this was surely one situation where “less is more” on account of a very diligent enemy with direction-finding equipment, highly motivated to find the clandestine transmitter soon after it came alive.

There is a vast amount of information on the Internet about the Special Operations Executive, their agents' training, missions, successes and failures through the war years. In addition to the European mainland operations, SOE was also active in the Balkans, the Middle East and the Far East as well. It makes for riveting reading.

An interesting feature of this set is a switch with a ring-pull attachment. This switches the set instantly from mains to 6V battery power (it can be powered by both). This was because it was common practise for the hunters to first DF the approximate location of the transmitter, then to switch off the mains power area by area, block by block. Should the transmitter suddenly drop out as mains power was cut, that indicated the approximate block, street or building of its location, which would then be cordoned off and searched. The ring pull switch enabled the transmitter to keep on going – not so much as to complete the message (which could always be completed on a fall-back frequency and schedule) , but to try to fool the hunters as to its location.

Then it was time for the main talk of the afternoon, “Keeping Track”. Rob introduced the speaker, Peter ZS1PGC. The project, intended primarily for documenting the club’s assets, also has great relevance for individual radio amateurs to apply to their own ham shacks. (Your humble reporter, having embarked on a similar mission, is given pause to wonder if he is not going into too much detail when he tallied Asset no. #8732 - not quite taking it down to individual component level, but close…)

Peter has ably taken on the enormous task of documenting all the physical assets in our club. There are a number of reasons for doing this; not just to list everything so we know what we have, but also to know where to find it, to keep records of service, maintenance and performance (very useful in terms of recording antenna SWR, for example), to know the purchase and replacement values for insurance purposes, and to have easy access to the essential manuals and documentation.

After initial technical gremlins, Peter started his presentation with a brief description of component nomenclatures through the history of electronics, looking at that for valves, semiconductor (with Mullard, Toshiba and JEDEC protocols), and even geographic location systems. The point being made that standardisation is very helpful and in the vast complexity of electronic systems and protocols, the absence of a consistent system leads to chaos.

Very practically, Peter considered the following sensible design considerations for an asset-recording system:
•    It should not be dependent on a specialist IT person;
•    It should not be internet based;
•    It should not be dependent on one person (who may not be available forever) to maintain it;
•    It should not be a database package;
•    It should be free if possible;
•    It should not be limited to a particular operating system;
•    It should require no programming skills;
•    It should use no macros;
•    It should be easy to use;
•    It should be easy to maintain by someone with basic computer skills;
•    It should be expandable.

Peter has, in fact, already set up a very effective parallel system on his iPad, complete with photos of each item. But that breaks the “particular operating system” proscription, because not all of us have iPads! So instead he decided to implement the record system using Libre Office. This freeware set of applications, which includes Word Processing, Spreadsheet, Database, Presentation, Draw and Project Management capabilities, can also read and write Microsoft Office files, which is very useful.

Then Peter discussed the core Information elements required. These are:
•    Description;
•    Serial Number;
•    Asset Tag;
•    Location.

He showed us the above info, applied to a simple spreadsheet, which appears to work just fine.

A further advantage is that hyperlinks can be added to individual spreadsheet cells, which can provide links to - well, anything else required. In this context, those local hyperlinks point to a picture of the item, and to the manual for that piece of equipment (where applicable). But when you think of it, you could, in the fullness of time, link to all sorts of relevant information. Should internet access become available, the range could be extended even further.

Then it was time for a little wizardry. Peter showed us what he is doing with QR codes. These square “bar code” images can be generated on easily obtainable freeware such as Zint Barcode Studio (currently version 2v4). The QR code format can accommodate quite a lot of text information per item. Astonishment was expressed when people at the back of the venue discovered their smartphones could pick up and read QR codes held up (in low light) at the front of the room. So the idea is to incorporate the basic information for each item and affix a QR code for same on each item.

Peter concluded the talk by answering several questions from the audience. Then Noel closed the meeting formally (Rob had to depart shortly after introducing Peter) and we started stacking chairs and perusing the swops on display. Paul ZS1S had generously provided boxes of Stuff for folk to take as needed, and several happy hams walked off with some free earthing leads and mains power cables. Post-meeting ragchews continued for a bit before we closed up shop and headed home. A most interesting afternoon indeed.

Our following meeting will be the CTARC AGM on Saturday, 28 July 2018. We encourage all CTARC members to:
•    Attend that very important meeting;
•    Listen to the Sunday morning bulletins for further info;
•    Pay their subs and Morningstar fees (where applicable) if they have not done so already;
•    Take part in our weekly Monday evening natter at 20h00 on the 145.750 MHz repeater.

We do look forward to seeing you all at our next meeting in July.