Author Archives: dave

WIRELESS SECTION REPORT. For NOVEMBER & DECEMBER 2005

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FRIENDS OF THE SAAF MUSEUM, SWARTKOP, 12th JANUARY 2006.
WIRELESS SECTION REPORT. For NOVEMBER & DECEMBER 2005.

Sincere apologies for the “non-arrival” of the November 2005 report which seems to have gone astray in the “bowels” of the e-mail system!

SATURDAY MORNINGS.
As usual ZS6MUS was activated on the 4 Saturday mornings of
November to join with the Southern African Antique Wireless Association.
Saturday 26th November was actually important milestone as 50% of the Wireless room did some work! They were helped by Peet ….(?) and Dave Pearson. A new nylon rope to hoist the antenna was installed in place of the old one which has given great service over the last 5 years. Nylon does not last very long when exposed to the sun for so long. Peet did the hardest part of the work. He opened the end of the old rope and fed the start of the new inside so that it could be pulled through the pulley. No mean task!!
Many Thanks!!!
As usual ZS6MUS was activated for the first time in 2006 on Saturday morning 07-01-2006 to join with the Southern African Antique Wireless Association net.
Ionospheric propagation never ceases to amaze us, especially, this Saturday morning, whilst the Natal stations are heard loud and clear at Swartkop those on the Reef, even Kemptom Park, are barely heard!!!
We all thank Frans van Nieuwekerk for cleaning out the Wireless Room during December 2005.

NEW EQUIPMENT.
A Collins transmitter and receiver (Naval types) plus a home-made power supply were donated to the museum by Dave Smith ZS6AZP of Irene. These new pieces have promise of being restored in the near future than other items.

AMERICAN WOMEN IN WW2 US INDUSTRY.

The most famous real-life “Rosie the Riveter” was Rose Will Monroe, who was a riveter at the Ford Willow Run Aircraft factory in Ypsilanti, Michigan, where bombers were built.
Monroe was the model for the famous poster, showing a woman wearing a polka-dot bandana on her head with her sleeves rolled up, flexing her muscles, and the caption, “We Can Do It!” Unlike most of the “Rosies”, Rose kept working after the war.
An even more famous lady worked in an aircraft factory in Bakersfield, California, during the war, Norma Jean Baker. She worked in the same factory as husband James Doherty. An army photographer spotted her and asked her to pose for posters for the troops. That led to a modeling career, and a whole new life and a new name: Marilyn Monroe.

HISTORIC DATES.

07/01/1935 AVRO 652 ANSON
08/01/1941 AVRO 683 LANCASTER
27/01/1945 Ausweits “”Liberated””
27/01/…….. Australia Day

RADIO SCOUTING APRIL-MAY 2004

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by Dave Gemmell ZS6AAW
and the Broomstick Warriors.

The 37th Springvale Cubs held a “sleep” over at Swartkop Air Force Base with the intention of badge passing.

(Please see Museum Column)

“REGISTRATION” OF JOTA/JOTI STATIONS.

(47th JOTA 16TH & 17TH OCTOBER 2004)

Remember that you don’t have to ask for permission to run a JOTA station, registration as educational stations with the SARL means that the non-licensed girls and boys can talk and use CW on the ham bands.

Secondly, you may be approached or decide to run a station just a few days before the JOTA week-end then go ahead and do it!

The registration of special event callsigns and stations is not done to annoy or inconvenience any one! Knowing what stations and therefore hams and addresses before hand is going to make my life a lot easier. Last year’s participation cards which arrived in SA only 10 days before JOTA which meant some guides and scouts only received them after the week end! Guessing which Groups and hams plus the number required didn’t make life easier!!

So this year if those of you interested in JOTA and/or JOTI please send me your name and address so that I can get the cards to you as soon as possible. Please include your e-mail address as well just to speed-up any “last minute” info (if any).

One big advantage would be after the week-end I could check with SARL HQ to see how many stations took part and which Guide or Scout Groups were involved.

JOTA 2004 CALENDAR.

Perhaps the following “calendar” could make the situation a little clearer.

January Pay the Special event call-sign license fee when you receive the “account”.
(Hopefully, the custodian is a person and not the Club!! )
April/May Check www.scout.org/jota and www.scout.org/joti as the World JOTA Report may be down loaded from this address.
June Register the special event callsign as an Ed. Station at SARL HQ.
October Preferably on the 1st day, check with SARL HQ that your callsign is still on the JOTA List.
October 16th & 17th/10/2004 (probably) THE GREAT WEEK-END!
November Please ensure that a short report of what ever activity took place has been sent to Dave ZS6AAW at:
davegemmell@bmknet.co.za
December Dave ZS6AAW compiles the National Report for SA and sends it to the World Scout HQ.

Please note the modes which can be used to contact me!!!
davegemmell@bmknet.co.za and P.O.BOX 77, IRENE, 0062 and TEL: and
FAX: 012 – 667 2153 (NB. Please ask for the FAX!)

THE QRP COLUMN APRIL-MAY 2004

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THE ------- COLUMN APRIL-MAY 2004.
    80 / 40

by Dave Gemmell ZS6AAW
and the Low Power Bunch!

1. (a)

(b) Low Power (SINGLE-OP LOW or SINGLE-OP [BAND] LOW): Same as 1(a) except that output power shall not exceed 100 watts. Stations in this category will compete only with other low power stations.

(c) QRP (SINGLE-OP ALL QRP or SINGLE-OP [BAND] QRP): Same as 1(a) except that output power shall not exceed 5 watts. Stations in this category will compete only with other QRP stations.

(d) Assisted/with Packet (SINGLE-OP-ASSISTED ALL HIGH or SINGLE-OP-ASSISTED ALL LOW): Same as 1(a) except the passive use (no self-spotting) of DX spotting nets or other forms of DX alerting is permitted. Stations in this category will compete only with other Assisted stations.

Wireless Institute of Australia’s Welcome to HF QSO Party. On New Year’s Day 2004 Australian radio amateurs will gain access to the High Frequency (HF) bands using licences that do not require the passing of Morse code telegraphy tests.

The International Amateur Radio Union has been campaigning for more than three years to have code tests removed as a licence requirement to operate on amateur bands below 30 MHz, and for Australia this will happen on the 1st of January 2004.

To celebrate the occasion, there will be a “WIA Welcome to HF QSO Party.” It is going to last 35 hours – starting with the early arrival of New Year’s Day down-under at 1300 hours UTC on 31 December and concluding at 2400 hours UTC on the 1st of January.

The QSO Party is an all mode activity – on all HF bands, with most of the
activity expected on 80, 40, 20, 15 and 10 metres. The event aims to welcome VK radio amateurs appearing on HF bands for the first time. These can be identified by three-letter VK call sign suffixes that begin with the letters H, T, U, X, Y and Z. WIA amateur stations will be on air to join the HF QSO Party, and these have two-letter call sign suffixes “WI” or three letter suffixes starting with “WI.”

Listen for the call “CQ WIA Welcome to HF QSO Party.”

8. SADX Club Looking For Old Members. Eddie Engelbrecht is looking for ex-members of the SADX Club (South African Short-wave Listeners Club).  A number of years ago we used to use the clubhouse of the Johannesburg Branch, SARL.  Since then the club has gone to pot for various reasons outside of our control, such as computers, etc.  I would be pleased if ex-members would contact me on my cell phone at 072-655-1895 or 011-837-5177 or on my e-mail address finetuner@absamail.co.za, for a re-union.

 

THE QRP COLUMN JANUARY-FEBRUARY 2004

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THE ------- COLUMN JANUARY-FEBRUARY 2004.
    80 / 40

by Dave Gemmell ZS6AAW
and the Low Power Bunch!

ZS6UT OBTAINS 160 m DXCC CERTIFICATE.

Since starting on his quest for DXCC on the Top Band in May 1995, it has taken Ed Willers, ZS6UT, 8 years to get the much sought after DXCC No. 1024 which was issued on 24th July 2003. Congratulations to Ed and well done!

QRP category. Rudi ZS6DX took the top spot in the world. Rudi made 1,440,318 points from 1,043 QSOs and 471 prefixes on all bands.

Single Operator. Two call signs are listed. Dave ZS6HO made 1,364 points with 22 QSOs and 22 prefixes as an All band high power station. Rae ZS6RAE took part as an All band low power station (100 watts and less) and made 48,236 points from 139 QSOs and 124 prefixes.

Multi-operator Single Transmitter. ZS0M with 3,730,510 points from 1,838 QSOs and 685 prefixes.

Well done to Rudi with his top QRP spot in the world. Also congratulations to Dave, Rae and ZS0M.

SARL KIDS’ DAY.

The 14th of February is an important day! No! Not because its Valentine’s Day but because it is SARL Kid’s Day! Don’t forget, if you would like to your children to speak on the air or to send messages using morse code on your equipment please remember to register your callsign with SARL HQ (if you did’nt do it in June 2003!!!) THEN fill in and FAX the Notification Form to SARL HQ at least SEVEN days before 14/2/2004.

This Column is a bit short this month due to a lack of input from you readers! Please help!!

davegemmell@bmknet.co.za and P.O.BOX 77, IRENE, 0062 and TEL: and FAX: 012 – 667 2153 (NB. Please ask for the FAX!)

RADIO SCOUTING JANUARY/FEBRUARY 2004

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by Dave Gemmell ZS6AAW
and the Broomstick Warriors.

46th JOTA/JOTI. {18 – 19/10/2003}

Well, the 46th JOTA/ 7th JOTI has come and gone, but certainly not forgotten!! Many thanks to the following Hams and stations who supported the Guiding and Scouting movements over this notable week-end!

ZS1CT/P, ZS1B BUDDY, Cape Town, – ZS3KBS, Kimberly,

ZS4BS DENNIS BLOEMFONTEIN – ZS4WRC/ZS4NS NICO – WELKOM

ZS6ABD RON – LADISMITH/NATAL, ZS6ARV JAN – JOHANNESBURG,

ZS5PMB/ZS5RK ROD – PIETERMARITZBURG/NATAL,

ZS5ZLB/ZS5WI WILLIE ESHOWE/ZULULAND, ZS6ARV JAN

ZS6BP/JOHN ZS6RNA / ZS6RN NIGEL – ARROW PARK/EAST RAND

ZS6SRC/ZS6AYC SID – SECUNDA/GAUTENG

ZS6WRS – WHITERIVER/MPUMALANGA

A extra special thanks goes to following people who sent in reports;

ZS1B BUDDY, JOHN ZS6RNA, Mercia ZR5MMG,

DC. Anthony Mac Gregor. – Northern Natal

Glynis Longhurst – Akela, 1st Eshowe Cubs

Dawn & Paul Smit, Bradley Davies – 1st Secunda Scout Group

Many thanks must also go to the Hams not mentioned here but whom, nevertheless, contributed to JOTA unfortunately the only …..?????

RADIO versus the “PLASTIC BRAIN”.

(Hopefully, the following paragraphs may simulate a bit of discussion!!!)

As I edit these reports I have noticed a few “things” as far as South Africa is concerned and would like your comments when comparing them to the rest of the World. Actually it was the following comment about JOTI by Buddy ZS1B which set me thinking!

“It was obvious that they found HF ham radio the most popular with echolink being a close second, while the JOTI activity seemed to be a poor 3rd, judging by the comments of the scouts. They are looking forward to next year’s event”.

 

The summary of the various modes used during JOTA/JOTI are as follows:

a) AMATEUR RADIO.

Cape Town ZS1CT/P controlled by Buddy ZS1B. More than 80 contacts were made with 40 countries, of which a total of 31 were JOTA stations.

b) ECHOLINK.

Only Cape Town ZS1CT/P reported 15 QSOs were via echolink to 9 countries. Kevin ZR1KDG on 2 metres where he had fun working through a local repeater which was linked to ZR1EL, who effected the Echolink for most of the weekend.

c) IRLP.

No JOTA station in SA seems to have used this mode !!! As far as I know there are only two IRLP repeaters ZS5DBN in Durban and ZS6ERB east of Jo’burg.

d) INTERNET.

Only Cape Town ZS1CT/P and Secunda ZS6SRC reporded any JOTI activity but only ZS6SRC sent full details, an abbreviated “table” of which appear below.

 

SECUNDA JOTI CONTACTS

Australia = 9, Netherlands = 6,

United Kingdom and Johannesburg = 3 each

Gauteng, Germany, New Zealand and Mexico = 2 each

Botswana, Brazil, Nepal, Ireland, Norway, Peru, Phillipines, Singapore,

Slovenia, and Sweden = 1 each (total of 30)!

 

So that’s the sum total of what I know about bringing JOTA/JOTI up-to-date!!! Are these details accurate? Do they give a true reflection of the interest in JOTA and thus an interest in Ham Radio?

Personally, I don’t see Ham Radio, as we know it, to be threatened by computers in general. The only suggestion I can make is that more accent be placed on “homebrew” equipment and special events. In other words activities in which young and old can partake. Believe me many ham radio activities do not need much supervision only a little effort on the part of the beginner or the ham. JOTA provides a very good “testing ground” for my statement.

There are enough complaints/suggestions about how to Modernize/ Update ham radio using the computer but judging from the JOTA reports I received (6 in total) what has happened? Then there’s the report from Northern Ireland about GN4SIW being the one of the few JOTA stations in that country!

My opinion is that every hobby seems to be going through a “dip” but in difference is killing the hobby! Any suggestions of how we can overcome this apathy before it does any real damage? At least, as far as Ham Radio is concerned.

 

“THE ADVANTAGE OF SARL MEMBERSHIP.

I received the following message from David GI4FUM from Northern Ireland!

“I got your email details from the SARL bulletin. I’m a SARL member. Just to let you know that GN4SIW will be one of the very few JOTA stations QRV from Northern Ireland. It is being run by Antrim and District Amateur Radio Society from the scout hall in the town of Randalstown which is about 25 miles North West of Belfast. I am chairman of the club and also the district commissioner.”

 

Once again! My plea for more info. from you chaps! This column of yours needs some livening up! Please send contributions (even in rough form) to:-

davegemmell@bmknet.co.za and P.O.BOX 77, IRENE, 0062 and TEL: and FAX: 012 – 667 2153 (NB. Please ask for the FAX!) MNI TNX.

THE MUSEUM COLUMN. OCTOBER 2001.

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by a Staff Reporter

Well! It’s a bit difficult to write something for a Column like this if you haven’t got anything to write about! Here I sit, in the land of museums (UK) and I can’t think of anything to write about either. I should be careful about complaining but there are several museums in South Africa with attendant and interested Hams who could supply info. for this Column.
Please forgive me for saying “They do like this in the UK …….. etc.” It’s annoying but to me what’s even more annoying is that the people of South Africa, especially we radio amateurs, could just as well! The lack of funds shouldn’t hold us back either! Many museums have surplus equipment, not suitable or appropriate for any particular display (or having much cash value attached to it!) which may be used for demonstration. Just about all the museums I’ve seen have a children’s section which is geared up for the young to fiddle with bit and pieces and learn something about certain physical properties. One such display caught my fancy, a section of an aircraft was clearly marked “Touch Here” . Another was a number of tubes of the type used for cleaning pools, all knotted with their beginnings and ends marked! The idea was to show the tube allows one to talk to some in another position without causing interference to some other conversation. The section was appropriately named, “Explorers’ World – Interactive and Science Centre”!
Another point, a very big point, that was very evident was the availability of pamphlets and brochures which were available at various points where the interested could see them clearly, railway stations, bus stations, tourist bureaux, etc. Even the individual museums had brochures of others in same area!
The standard thought seems to be …. “If its old keep it, preserve it and make it interesting to look at” . Above all, a small charge to see it won’t chase anyone away.
Judging by the attendance most of these places of interest are doing fairly well especially in the shops where novelties relating to the museum are sold.

I have just been watching a short TV documentary about nations who were invaded and conquered by barbarians. Occasionally the “take-over” was, in a way, a good thing and brought a new and better way of life. Other times it was a total “take-over” with the older and probably better ways being absolutely replaced by something quite foreign. The main reason for the defeats seems to be the lack of co-operation between the defenders! Perhaps we, as hams, should take note of these ancient battles, invasions, etc., etc., etc. because to me that’s what seems to be in our SA Ham circles is that we are running around in circles and not standing together to defend and protect what we’ve got! A pretty good amateur radio system! Yes! There are a few dents and blemishes, here and there, to clean up but we do have a very good working system!

 

If you think this Column is too Euro-centric you’re probably correct! Then whose fault is that??? For a more South African oriented feature please send your contributions to P.O.Box 77, Irene, 0062, or Fax/phone 012-667 2153 or be really un-museumlike use the ultra-modern e-mail to davegemmell@BMKNET.co.za

THE QRP COLUMN OCTOBER 2001

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THE ———- COLUMN OCTOBER 2001
80/40
by DAVE GEMMELL and
the Low Power Bunch

Well! Here I am typing your Column in Surrey, merry England! Yet I have a tale of woe! As I’ve no correspondence from you chaps I have to resort to I have to resort to
Ye Olde Thumbe Suck to fill this, your Column with goodes fit to be read! Nevertheless here goes! Hey Nonny Nonny!

Well, I got a homebrew QRP rig together and put it in a padded envelope which was then put into the pocket of my anorak which I wore on the flight to the aforesaid merry England. It took me a few days to get the necessary wire for the antenna and other items together before I could “get-on-the-air”.
The main problem was actually the 12 volt power source for the home brew QRP transceiver followed by a means of checking whether the main power transistor was going it’s job or not!

Fortunately the scullery was close enough to the back door and the garage so that
the 12 volt car battery could be used as the main power source. The problem of a safe connection between battery and equipment was solved by using the cord from an old power supply, the type that is plugged directly into a wall socket.

The antenna was made from “twin-flex” which is normally used for bedside lamps, etc. I wanted to operate on 40 metres which means the actual dipole section had to have a length of 20,2 metres, ie. A half-wavelength at 7.05MHz less 5%. We must get it clear in our minds that dipole and feeder line are formed from one length of cable!
This type of cord has a figure-of-eight cross section, the insulation forms the “8” bit with the two conductors the centres of the loops! Now to “make” a dipole for
7.05 MHz you take the one end of the “twin-lead” split the conductors apart for a length of 10,1 metres, ie. Quarter-wave length at the “design frequency” and you have an dipole of insulated wire, 20,2 metres from tip-to-tip with the feeder connected in the middle! That’s the reason for original piece of cable being one quarter wavelength plus the required feeder length! So be careful when choosing your operating position and where your antenna is to be erected.

The antenna section, when erected in a “straight line” and high enough always has a terminal impedance of 72 ohms. In the set up I used the two legs of the dipole were at about 90 degrees to each other so bang goes to 72 ohms especially at a height of around two metres.

Another point, still to be investigated, is that of the characteristic impedance (Zo) of the “twin-flex”. The calculations I made to find Zo gave a result of about 83 ohms which wouldn’t be a bad match at all but I would like to try it out on someone’s
MFJ-259 VSWR analyser, just to check.

It’s nice to know that the SWR is more a less within limits! This is not serious for receiving but can be very important even when transmitting one watt. Certain transistors, such as my ancient 2N1711, can give up the ghost quite easily and completely!

Perhaps, in some future issue of RADIO-ZS, a kind contributor to this Column will
send in a design of a light weight combined voltmeter /dummy load/power -/ SWR meter suitable for taking on holiday, etc. Dare say, the SWR part could similar to those found in certain CB rigs which operate an indicator on the front panel when there is a poor connection to the antenna or even an antenna problem.

This type works on the principle where an iron dust toroid is fitted over the lead to the antenna socket, most times on the PC board itself at the last point. This acts as the primary winding of the transformer. Another winding around the toroid is the secondary and is connected to the diode network which actual distinguishes between the forward and reflected voltages! A relatively simple circuit but the component count will be significant compared to the average QRP rig. We do like to keep these sets of ours fairly simple and that’s why I suggest an “add-on” that’s part of a multimeter type instrument.
I’m ashamed to say I didn’t make any contacts but I did call CQ CQ DE M/ZS6AAW
a few times, with little success, on two Saturday mornings, 8th and 15th September 2001. Very pleasant hearing other call signs like GM4OEC, G4PYW and a chap from Brussels ON4LBL.
So, at least the receiver section works quite well but I had to remove the PC board from it’s temporary box. This action seemed to cut out a lot of AF feed back with which this design is plagued. It’s my favourite design with transmitter, receiver and AF section all on one PCB so it looks like I’ll have to have another look at this layout, possibly putting each section on a separate PCB.

Before I close this Column and word about licencing! (Again!!) I did contact ICASA about the required HAREC certificate for me to operate in the UK. I left the arrangements a bit late but Elna, the lady at ICASA was very helpful and FAXed a copy of the necessary two pages to me very promptly. On my arrival I phoned the Radioauthority (RA) and the Radio Society of GB to be polite. Another lady at the RA helped me and it seems that for a short stay of up to about one month the HAREC Certificate is sufficient, anything longer than three months you have to apply for a temporary licence and pay £15-00. The HAREC Certificate is merely confirmation that you have successfully completed the RAE IN South Africa which equivalent to the corresponding UK one.
Please be patient those of you who have sent me e-mails and have not received any reply! Hopefully on my return I will get to grips with all facets of the e-mail system and send replies.
Well that’s it again. The bottom of the Column! Please send all contributions of your Low Power activity to the usual address: P.O.Box 77, Irene, 0062 , FAX or Phone 012 – 6672153 or e-mail …. davegemmell@MBKNET.co.za

RADIO SCOUTING. OCTOBER 2001.

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By Dave Gemmell and
the Broomstick Warriors.

PLEASE NOTE THAT ALL JOTA/JOTI IN FORMATION IS TO BE FOUND ON THE WEB. PLEASE CONSULT LAST MONTHS ISSUE OF RADIO-ZS FOR THE CORRECT WEB ADDRESS.

Well, it’s the October issue and it’s being written in the middle of September!
Hopefully, when you read this column most of the Guides and Scouts will either be busy on the JOTA week-end or busy with their final preparations. I hope all those stations taking part have registered as educational station so that the girls and boys can talk on the air or send messages using morse code.
Now here’s a thought!!! I suppose all JOTA stations which have packet radio, RTTY, SSTV, and so on., must also register as educational stations before the non-licenced will be allowed to use these modes? Your comments please, ladies and gentlemen!!!

Before I left on holiday I did submit the form to advise the SARL that JOTA would be taking place on 20th – 21st October 2001 and wanted to assume that one of these forms would be sufficient but as it required a callsign . Now I’m not so sure.
So please, chaps, fill in and send both forms.

I haven’t been around in SA to hear what’s going on radio-wise on the Scouting scene neither is there much news here in the UK mainly as I’ve yet to meet some Hams and scouting types.
Perhaps I will come across something or other in the next week or two.
At the bottom of this Column again with the major yearly plea for reports of the goings-on and happenings at your JOTA and JOTI stations. Hams, don’t wait for the scouts and girls and girls and boys don’t wait for the Hams to send in the report.
If individual hams, guides or scouts would like to send in separate reports please do so! These all help for the National JOTA Report which must be sent to World Scout HQ in Geneva. Please include attendance figures even “guestimates” will do. I would like to have these before 30th November 2001 as the completed report must get to HQ by 31st December 2001.

JAMBOREE-ON-THE-AIR and JAMBOREE-ON-THE-INTERNET. 21st/22nd OCTOBER 2000

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RADIO SCOUTING
by Dave Gemmell and the Broomstick Warriors

JAMBOREE-ON-THE-AIR and JAMBOREE-ON-THE-INTERNET.
21st/22nd OCTOBER 2000
Hopefully most of you, Dear Readers, will read this Column before the first JOTA of this new millenium. If you are helping a the Guides or Scouts to run a station please remember that this an event when the young should be doing most of the communicating so please set up each contact as soon as possible. Then get as many boys and girls to “talk on the air” as possible. I have said this before but it’s a bit irritating when you’ve listened to some station you want to contact going on for about 5 or 10 minutes about something or other only to have him repeat the same thing when you eventually do get hold of him. Be very careful as both JOTA and JOTI are important Public Relation events for both Hams and the Guiding and Scouting Movements.
Having said this please remember the age and ability of those with whom you will be dealing. The children are at the stage when they want to try everything for themselves so it is a good time to introduce them to morse. Now before you “scream blue murder” let me add that CW is simple and is an ideal way to introduce an interested person to modulation. When keying a transmitter you are actually moving from 0% to 100% modulation. Secondly anyone can try this for themselves using a whistle or a flash light. So you may have a situation where the learner moves from being slightly to very interested in Ham Radio. This would be a good time to get if the Scout Group you are helping to enter the JOTA Low Power Contest. Perhaps you could build a few QRP transmitters of the single transistor.
Answer any question or query regarding CW positively. Please don’t “condemn” or ridicule morse as this may, strangely enough, only have a negative effect and cause the “inquirer” to take his/her interest else where. You should, however, mention that CW is used to send short messages and is ideal for use in emergencies.
Everything I’ve said about the use of CW can also be applied to construction. Children seem to be interested in everything so show how easy it is to build a simple oscillator. Then have them determine the greatest distance that can be achieved between them and your commercial rig.
If I have repeated myself for the millionth time in this column I still make no apology as these days it seems that despite modern technology there many people, Hams, Guides and Scouts who still do not know the basic principles of their own movements and how to achieve maximum benefit from them.
Please send in your JOTA reports to your local Scout Area Commissioner or JOTA Co-ordinator before the end of November 2000 as the National Report for South Africa must be sent to Geneva before the end of the year. If you aren’t sure who these people are please send them to me at the address below.

If you can, I’m sure Ray Webber ZS6RSW won’t mind you using his e-mail address to send me your contributions to this Column or JOTA/JOTI reports.
My postal address is, as usual, P.O.BOX 77, IRENE 0062. Many Thanks.

THE QRP COLUMN OCTOBER 2000

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THE ------- COLUMN OCTOBER 2000
     80/40

by Dave Gemmell and
the Low Power Bunch
This Column is being typed /compiled on a my daughter-in-law’s computer and e-mailed to our illustrious Editor Wolfy. Yes, occasionally I do make use of home labour-saving devices but what makes this task more pleasurable is that merely turning my head I can see a nice rural setting (horses and cows grazing the grass in Surrey) from the window of my son’ s computer room.
When planning this holiday some months ago I decided to “design/build” a QRP transceiver to take along. Now that SA is a member of CEPT I reckoned that it would be a “chinch” to get on the air! I built the transceiver but didn’t take it, mainly because it was built into a plastic sandwich box and might have looked, to those uneducated in matters electronic, like a bomb or what have you! It did occur to me that my XYL and I would be passing though at least four custom check points and trying to explain the joys of low power operation didn’t really appeal to me. Especially after spending an almost sleepless night with some 350 or so happy fellow travellers!
Now let’s look on the bright side!!! The next time I’m going to build a QRP rig to fit in the top pocket of my jacket!
There was quite a lot to be learnt from this exercise! Getting the parts together, building this rig and getting it to work, was fun in itself. The circuit I used is an old favourite of mine. Who knows, maybe I will be able to publish the circuit diagram in the next issue of RADIO-ZS! You should be able to draw your own circuit from the following description.
Choice of RF “power” transistor 2N1711 type as well which one operated the best. In fact, I used a socket for the “PA” power transistor this made it easier to select the best transistor for the job. It was amazing to find out the variation in the value of the power delivered by the thirty or so 2N1711’s in my “junk box”. Don’t forget to use a heatsink or you might burn out your entire stock of your transistors! A lot of similar transistors seem to be able to with-stand over heating for a short time but not so the 2N1711!
A 2N2222 was used for the oscillator to drive the power amplifier as well as the receiver’s diode mixer. The receiver RF amplifier was built around a BF115 which was followed by a double diode mixer the output of which is connected to a two stage directly coupled AF amplifier which gives enough gain and power to drive high impedance earphones. I tried to use the common collector circuit mentioned in a previous column be have no time to iron out some silly problem which cropped up.
Deciding what antenna to use was not without it’s “points of interest”. For the same customs and excise reasons plus the luggage weight limit set by the airline conpany, I wasn’t going to take a wire dipole and coax along so I was going to buy suitably priced copper wire at the nearest hardware shop and use ordinary table lamp “rip-cord” for the feeder line. I had been led to believe that this “rip-cord” had a characteristic impedance, Zo of 75 ohm but I thought I’d calculate it just the same using the formula Zo = 276 logD/d. After a few measurements and calculations, I ended up with the figure 230 ohms. Then I tried measuring the “rip-cord’s” Zo and obtained 120 ohms ???? If this type of cord was used irrespective of the value of Zo the output impedance of the transmitter could be adjusted to suit by varying the values of the capacitors in the Pi-coupler. The main problem is coupling to the antenna. I though of the windom fed with 300 ohm tape. So why not connect the feeder at a point where the impedance matched that of the “rip-cord”. This idea will definitely be investigated at the earliest opportunity.
Deciding what other accessories to take or not to take along was a very interesting exercise. The power requirements are 12 volt , receive cut about 30 mA and transmit current about 500 mA depending on the RF power transistor used. Normally a rechargable 12 volt battery, could be dry cells but these turned out to be a very expensive alternative if bought in the UK. Using a mains power supply seems to be the logical answer but its going to take a bit of experimenting to get something light in weight. Anyway I have a year or three to do something about this.
I have since learnt that if a South African Ham is staying in the UK for less than 3 months he/she may operate on the amateur bands without special permission or any payment. This situation changes when the stay is longer than 3 months when the SA Ham must apply in writing for a special licence which will be granted on payment of £15-00. (About R155-00 at the present current rate of exchange.)
How to call on the ham bands is laid out concisely in booklet BR 68, page 14, section 10(2):-
CEPT Amateurs shall transmit their home callsign after;
a)the United Kingdom callsign prefix “M”;
b)followed by the appropriate Regional Secondary Locator (if any); and
c)followed by the symbol “I”.
So if yours truly was operating from Scotland I would have to use MMI/ZS6AAW but from Wales it would be MWI/ZS6AAW or Northern Ireland MII/ZS6AAW. The regulations when operating anywhere in the UK seem to be almost the same as in SA but check first the Licence Requirements BR 68 which can be obtained from the UK Radio Communications Agency. It may be a good idea to check for any subtle changes before you start operating there. Secondly check with the relevant authorities about correct procedure to getting your equipment, home brew or commercial, through customs at each end of the route.

Here’s hoping the usual contributions from the QRP Bunch, the Radio Scouts (and Guides !) plus the Museum News have survived their trip down the digital tubes of
e-mail! But, seriously chaps, this Column (and others!) seriously need news and contributions from you the Reader. Please, please send in any item of low power news. It doesn’t matter how small. Even a sentence or two on the back of a post card can be a BIG help! The address is as usual – P.O.Box 77, Irene, 0062.