QRP
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.

      QRP
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!)

QRP
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

      QRP
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.