ZARS Newsletter Volume 1 , Issue 2 October 1999

Once again a news letter.!! Or are we getting too carried away with ourselves.

new editor Fred Wilkinson

In accordance with the decision by the branch committee we are sharing the job of editing the

newsletter, and it is now my tum. Having to follow the

excellent copy started by Wynard I will have to pull out

;orne stops to meet the high standard he set, so here

goes.

I have tried to give a bit of cover to various topics with the emphasis on what are we doing at a branch level. A

lot of activity is underway at present but like all good

well run organizations a few are doing a lot, So a

challenge for the closet types, join in the fun and make

ham radio fun and interesting.

You will find a few of the articles have a slant in

activities I have decided to work with and as I am the

editor for this issue I will do it my way and then have to

face the mail bag from those who do not like it.

Anyway enough of the editors drivel lets get the show on the road .

NSIDE THIS ISSUE

1 Once again a news letter.

1 Z21 PES new call sign

1

2

3

4

6

7

8

9

Calendar of Events

Autobiography: Nigel R Tucker- Z21 KI/R G7URW

OPERATING PRACTICES

Abnormal Propagation

QSL Bureau

TECH corner

HF Beacons

Y2K (it even gets in here)

9 What's on at PE radio club

ZARS Newsletter

Z21 PES new call sign Z2 l PES. The society has now registered a radio station for the hilleL f- d\\ trd '->d ool r d11 ub with the call sign Z21PES. This cal sign was inaugurated over the weekend of 9/1 Oth October 1999 by taking part in the South African radio league field day competition. The objective of the field day station was to set-up a station on a green field site with no infrastructure starting from 9:00 on Saturday and have the station on air by 12:00. The station was then to be operational untill2:00 on Sunday. Together with the boys from the club and the help of Rocky we started setting up camp at 9:00 but due to salt mine activities I arrived on site at 12:00 with the technical part of the station. About one hour later we were on air with an HF and 2m station. The station consisted of an 12 metre high guyed mast lifting an HF open wire dipole which can have its length changed to operate on any band. On top of the pole was mounted a slim Jim antenna for the 2m band. The whole operation was run from a 200 watt Honda generator which chuntered away during the whole period without missing a beat. In all we made a few contacts over the 24 hour period which included Marion island, Uganda, Botswana, and various stations in RSA with some great signal reports relating to the quality of our audio. Of the stations in RSA some of the more note worthy included a contact with the special event station ZS l 00 celebrating the centenary of the Boer war, a house boat in a field of grass. The Branch bulletin was also broadcast from this site on Sunday. Three of the boys stayed on overnight and in all a great introduction to some of the daft things Radio amateurs get up to as part of the hobby. On their own they set up an HF receiver, and in all we had a great time. Thanks to KL and HA for helping out in the running of the station and making all the efforts legal.

CALENDAR OF EVENTS

NEXT BRANCH MEETING

gTH NOVEMBER

No meetmg for December

ZARS BULLETIN

14TH NOVEMBER

121H DECEMBER

PE RADIO CLUB MEETING

EVERY WEDNESDAY 4 TO 6 PM DURING SCHOOL TERM

page 1

Autobiography: Nigel R Tucker- Z21KI/R G7URW When did my interest in communications start? having been born and educated in Devon that is the UK equivalent of the Orange Free State! there is not that much to do unless you are crazy about cows and sheep. As I am not Australian, the only logical thing to do was join the Air Training Corps during my college days. The A TC was good fun but the only thing related to communications was (to me) the most boring thing on earth, Morse. Despite being very bored with dots and dashes I managed to get to the shattering speed of 5 WPM As a natural progression from the ATC, the Royal Air Force seemed to be the way to escape from Devon. After joining up in 1960 and going through the joys of 'square bashing.' and polishing everything that moved and painting things that were fixed, it was time to attend trade training at RAF Melksham as an Instrument Mechanic (later during the years with the RAF one became dual trade fitters ie Instrument and Electrical). Following many months of being trained on things like autopilots, gyros and things called 'valves 'etc etc, it was time for posting to a real unit with real aircraft. The posting came and off I went to the Central Flying School at Little Rissington. Besides having lots of aircraft that had real VHF radios (without valves) and the big stuff such as 1154 and 1155 HF units, this station was the highest operational airfield in UK and had every sort of weather possible. What was one of the most enjoyable aspects of this station was the fact that there were more WRAF,s (uniformed ladies) than men which led to a very enjoyable 'social life'. In 1962 I was selected for the Red Pelicans which was The aerobatic display team in the RAF at that time (which in 1964 led to the fonnation of what we now know as the Red Arrows). The 62 season was tremendous in all respects with displays all over UK and Europe and one particular display at Cambrai in France nearly required the whole team to attend a "de-tox" course on return to CFS. The reason for this was that we were the first 'boys in blue'- that the people of the town had seen since the liberation in 1945. They poured every sort of wine and beer down our throats in vast quantities. Denmark was also a very happy time (from what I remember through the 'haze'). As is the case today, the fmal display of the season is at ­Farnborough which is great. You are present during the private days without the crowds that attend on public days which allows access to displays and stands that the public never see. Most ex RAF people have very clipped or abrupt RT procedure due to the volume of traffic. We were even more clipped, as at times it was difficult to talk due to 'medical reasons'!!! The RAF decided that they had enough of the ring leaders of the 'crazy gang' at Lit1le Rissington and we were all posted to various parts of the world (one of the gang was the son of an Air Vice Marshal which made daddy rather upset to say the least!). My posting was to Nicosia, Cyprus which was fine until 8pm on Christmas Eve 1963 when the civil war started in earnest Not much can be said about this phase of my life due to the 30 year Official Secrets Act but after 1999 look out for a book which will be called "913 Days-The Cyprus Issue". During this period some very 'hairy' trips were made in Hastings of No 70 Squadron and in such areas as Libya and other countries that can be classed as ' iffy', the faithful 1154 and 1155 equipment provided the only method of keeping in touch with the outside world; the reliability of this equipment was to say the least fantastic. After this unpleasant segment of my life it was time to return to the "real world" and was allowed to select a station in UK but what the RAFIMOD forgot was the Crazy Gang had maintained contact during the years so we all selected RAF St Mawgan in stmny/wet Cornwall and during the summer of 65 we re-assembled at this Coastal Command station to work and play hard. As flying buffs will know, Coastal Command was flying Avro Shackleton aircraft. These aircraft were lovely aircraft to fly and were fitted with every form of radio and radar equipment available at the time. Despite the fact they had four Griffm engines (a development of the Merlin used in Spitftres etc) they had problems getting ali the radio equipment, depth charges, rescue equipment plus 14 crew off the deck, therefore two Viper 203 turbojets each producing 2000lbs thrust were implanted at the rear of No' s 1 and 4 engines. Now at least we could get off the ground and stay in the air for 14 hours plus (many trips were flown at an altitude of 200' for 10 hours above sea level). In those days there was no SELCAL so the ears took a bashing both from the intercom system and also from VHF and HF traffic! but that was flying and even if you had no wings or a half wing, depending on the captain, you had your turn at the 'pole' trying to keep the 6 engine bird straight and level (going to South America, we nearly lost one, but again, that is another tale). During this period I met my first wife who was an air-traffic controller (Z21EK remembers her from his days with DCA at Salisbury Airport) but despite all the hours with earphones glued to my head with 42 Squadron, amateur radio was still a long way off!! My wife and I decided after spending a year working as civilians in UK to immigrate to Australia but at the last moment I decided that South Africa would be a better choice (having subsequently spent periods working "down under", I still regret not going to that wonderful land even though I don't fmd sheep pretty!!). So off we went to RSA to take up a position as a civilian aircraft inspector attached to the SAAF. ll months of living in Pretoria was enough so we moved to Salisbury in 1970. Due to my aircraft work I met quite a few "valve heads" as they were called in the trade including Z21 GH Des, Z24S George and many others but still no thoughts of becoming a "Ham" despite my dormant interest in VHF communications (as the old Airways Club took up a lot of spare time). In 1978 I met my present wife Ursula, who in the mid 80,s introduced me to Z21HA Mark who discovered my interest in VHF therefore he kept suggesting that I attend the meetings at the QV Having bad memories of banging a key during the ATC days left me with no thoughts oftaking any form of examination that involved CW. One evening I did attend a meeting at a local hotel as the subject was Satellite Weather Systems which was presented by the "Guru" of everytlting electronic, Z21EK the President of ZARS at that time and friend to everyone who has problems more complex than Ohms Law!. This meeting came at the time that I was flogging to and from Washington DC on a regular basis.

continued on page 4

ZARS Newsletter page 2

OPERATING PRACTICES Followmg on the top1c Introduced last 1ssue lets take up

another subJect. This has been extracted from the RRU

manual.

General Operating Procedures in an emergency

After having established the severity of the emergency you will need to establish yourselves or another station as a communication control station. When operating via a repeater, check you are not in a "dead" spot, and that you are being received by the listening station.

It must be remembered at all times that an operator transmitting messages under emergency conditions must maintain the highest standards of efficiency in order to pass messages clearly, with complete accuracy and in a calm manner.

In transmitting, make sure that you are on the correct frequency and that the frequency is clear of other traffic. You should call "Z2 ....... (Your callsign) with traffic" or in the case of a dire emergency, "Z2 ....... (Your callsign) with priority traffic."

When your call has been answered, TALK ACROSS THE FACE OF THE MICROPHONE that will ensure that sibilants, breath sounds, the "popping" of P's and similar sounds are eliminated. By using this technique your communications will be clear and readily understood by the receiving station.

Do not use the word BREAK unless you cannot gain access to a net. The word" BREAK" IS NEVER USED UNLESS THERE IS A TRUE EMERGENCY

Speak slowly, distinctly, clearly and do not let your voice trail off at the end of words or sentences.

Begin speech only after you have operated the push to talk (PTT) button of your transmitter for at least a second and so avoid clipping the first words of any transmission. This will also allow a slow receive squelch system to operate before any transmissions are made.

Know what you are going to say before you push the microphone button. Do not clutter the air with "Net control, uh, this is Z2, uh, six uh, xyz, uh I have a message uh ...... " It is very easy to confuse the whole transmission if the operator does not have the facts right on the tip of the tongue and ready to deliver the message in a crisp and orderly fashion.

Avoid doubling with another transmission . Listen before transmitting - the pause in general transmissions is often non-existent and this makes it difficult to break into an existing net.

In a net, the control station will leave a pause at the end or beginning of a transmission as there may be other stations that are trying to call in with messages.

ZARS Newslette r

Make it a rule to leave a pause before you transmit any message and to check that you are not doubling. The time you may think you are wasting is in fact well spent if errors are eliminated in this way.

Eating food or chewing gum when transmitting must be avoided at all times. Such actions only make transmissions muffled and indistinct.

When using a hand-held transmitter, make sure that you do not move about whilst transmitting as this can and often does result in your signal being lost.

When operating via a repeater, make sure that you are being received by the listening station. You may hear the repeater well but may not be able to reach the repeater from your location. Remember the repeater has much more power than your hand-held!.

Under stress, many operators have the habit of talking very quickly. Even if you are in the midst of the action, remember to talk slowly and clearly to get the message across. ACCURACY FI RST, SPEED SECOND.

Avoid angry comments on the air at all costs. Obscene statements are unnecessary and only serve to reflect on your own character whilst also reflecting on the amateur radio fraternity as well . Remember that there are many listeners out there, some not licensed amateurs but interested people who may have your operating techniques under observation at all times.

If you are relaying a message for another person, be sure you repeat the message exactly and word-for-word, as it is given to you. Make sure that the message makes sense to you or first get an explanation before you put it on the air. Refer the message back to the originator for clarification if necessary. Whenever possible use the RRU message form to provide a written record of the incident in case of future inquiries.

Sound alert. Nothing destroys confidence as much as a bored or tired sounding radio operator. If you are tired , get a relief operator to take your place at the radio.

Forget humour on the air. There is enough confusion during an emergency without wisecracks and jokes. Amateur radio is a hobby to enjoy, but the function of RRU is a serious business and must be treated as such at all times. There is a time and place for everything.

Be careful when using certain words. Words such as "can" sounds like "cant" when conditions are poor. Words such as "unable" are a better choice.

Use "affirmative" for yes, "negative" for no etc. Roger is a good word. It means message received and understood.

The use of the "Q" codes on voice transmissions must be avoided. They are too easily misunderstood, rarely save time and often result in errors.

continued on page 4

page .J

Continued from page 2

During one visit to Washington, I purchased a hand held scanner (along with lots of other toys) and tuned to one of the local repeaters which was slightly different to our Harare Romeo 2. The repeater antenna was mounted on top of a 600' mast and the output was 650 Watts! , with tone burst and all the "bells and whistles" that one finds in a country where you buy anything at a third of the cost in UK. I was aware that the Mash branch guys wanted to up-grade Romeo 2 therefore on one of the shopping trips to a major ham store at Woodbridge, l happened to mention this to the manager of the store (as we had developed a good relationship) old man Curtis WB4KZL so he said "come and have a look as we still have lots of ex government cavity filters going cheap". So I thought this would be great to present 6 cavities to the guys who know what the are doing (un-like me!) back in Harare. What a shock when the cavities were pulled out, they were for mid band but each one was about 7' tall and 1.5' wide and could handle more watts than all the 2 metre equipment in Zimbabwe combined!! so ended the shopping trip for cavities. As time progressed "the guru" kept pushing me to take a /R licence so in the end I did and to my complete amazement managed to pass, so to get on air I needed a 2 metre rig that would also be stable enough for A TP satellite signal reception. This was purchased in Australia (for financial reasons) and so started the continual expenditure on cables, plugs, PSUs amplifiers etc. etc. but what a pleasure to be able to have QSOs with a good bunch of guys (and ladies, sorry Molly) and all the help and advise that has been provided , many thanks to you all. Subsequently I have operated 2M in many European countries under my CEPT licence and in Australia, but for me the real ' cream' was operating in ZL as the New Zealand ' Hams' have a set up second to none with solar powered and mains powered repeaters all over North and South Island .. To really understand what they have achieved, have a look at the ZL Call Book. The next phase was to get on to Packet so that I could communicate further than line of sight!! . For me Packet is a great mode ~ of communication and recently Z21EK both scrapped TPK and installed WinPack V6.2 which is Windows based . There is not much Packet activity in Harare (only about 6 or 7 regular users) which is a great pity, but the 'boys in the bush' i.e. Bulawayo use it a lot (or did !). Currently the SYSOP in Harare is Phil, Z21DC who does a fantastic job operating the BBS 24 hours per day. This is supported by Dick, ZS6RO who is the link man into the Harare BBS, Z21JHE As a natural progression, 6M became the nex1 ' toy ' to play . Obviously yet another antenna had to be built with the help of my dear wife who is so very understanding with regards to the nwnber of antennas that keep 'breeding' and the ever increasing runs of RG213 that have to enter the house. For an /R its very nice to have contacts into Europe (with the exception of one country that I wont mention for ethical reasons, but it is long and sticks out into the Med !). The latest add on is the 70' (21m) tilt over mast that will be planted in the garden so that most of the ' antenna farm' can be positioned in one place. It is a pity that Zimbabwe does not follow the US system with 6 types of licence so that people such as myself that live in the 20th century could use HF on a restricted basis without having to learn to bang a key. The ARRL are quite amazed at the increased number of licences issued since the licence system has been revised . There is light at the end of the tunnel as our members are aware i.e. the WW trend to visit the requirements for CW to operate certain HF bands so possibly before my toes point in a vertical axis, I may be able to have QSO's with VK6. The Radio Reaction Unit is slowly getting into shape with the manual about to be released shortly, and it is hoped that when the application forms are sent out with the news sheet, the RRU will be in a position to give support to the community along with more publicity for ZARS. Well that's it, and I hope this has not been too boring, but the Editor is unable to compile a news sheet without input from members!. 73 de Nigel ,....

Z21Kl/R - G7URW •

j "Nice one Nig ho" about some more history from the other members!!!'' Editor

Abnormal Propagation Various types of wave propagation in the atmosphere occur, depending on variations in the atmosphere itself. In travelling from a more dense into a less dense medium, a radio wave or light wave is refracted so that it bends away from the normal, but this is only part of the picture. The paths of many radio signals are curved since they move through the atmosphere with different velocities. Their actual velocity depends on a number of factors, including temperature, atmospheric pressure, and the amount of water vapour in the air.

Curve A in Fig. 3-10 shows that the velocity increases as the temperature decreases, moving from left to right This same curve applies to atmospheric pressure where, as the atmospheric pressure decreases going from left to right, the velocity of the signal again increases.

Curve B shows the water vapour increasing from left to right. As the water vapour increases, the velocity of the radio signal decreases.

Thus for each of these variable (change in temperature, pressure, or water vapour), the velocity of the radio wave changes. continued on page 9

ZARS Newsletter page 4

Continued from page 3

Identification of a station is essential and required by the Postmaster General. However, during an emergency net it is permissible for the control station to allocate abbreviated call signs to stations e.g. Alpha 1 -ambulance station 1 -etc., and the control station can give a complete ID at least once every 5 minutes to comply with the regulations.

Always identify your station at the beginning of every transmission . The control station needs to know who is calling because voice identification may at times be difficult.

Do only what you are asked to do by the control station. Do not act as a relay station without net control instructions. Do not speak unless you have a message to transmit or are called by the control station.

When transmitting numbers (house or street or telephone etc.) you must always transmit such numbers as a series of individual numbers. Never say numbers in combination . Avoid "43 12th Street". Say" the address is NUMBERS 4 3 TWELFTH STREET".

When spelling any word , place name or proper name use the International Phonetic Alphabet. Learn it and use it. DO NOT invent your own. This will only result in confusion.

Always acknowledge calls and instructions. This can be done by merely giving your unit identification or callsign . Nothing disrupts the smooth flow of a message than to be greeted by dead silence in response to a message. If you cannot copy or respond to a call immediately, then tell the caller to repeat or stand by, otherwise acknowledge every call immediately. Do not use the term "QRX 1" for "stand by"!

Never acknowledge unless you understand the call or instruction. If you do not understand, ask the station to repeat the message and then make sure you have the instruction or message copied correctly before acknowledging. If you need a message repeated , then transmit "say again " or "say again all after???" do not use the word repeat as this can be heard as received when conditions are poor.

When calling the net control station and not being answered immediately, be patient. The control station has many tasks to perform and may be busy at the time. If no reply is received, call again in a minute or two. If your message is urgent, call again until a response is received . Check that you are not in a "dead spot" and cannot be heard.

Transmit only facts. If your message is a question, deduction or educated guess, identify it as such. Do not transmit non-essential information. Be factual and remember that any transmission can be and often is monitored by other persons. Be careful what you say on the air, a rumour started in error or as a joke can often have very serious results.

ZARS Newsletter

Always know where you are located. If you are mobile moving around always keep a lookout for a landmark or location identification. Net control and many other stations may have to know exactly where you are physically located, so keep a sharp eye on surroundings. This is of the utmost importance if a search team or other mobile units need to locate you.

It is also imperative that on a highway at a motor accident you give an accurate location fiX. You must give the municipal area and the nearest intersections or interchanges if your information is to be of value. In the case of highways use the kilometre pegs.

The direction of travel is also important otherwise the emergency units can well arrive on the incorrect side of the highway!

Try to give a location as follows "Motor accident. Multiple vehicle collision . Injuries serious with numbers Seven, I Say Again Seven patients. Location is Bulawayo Road , at the intersection of High Glen Road . Require traffic officers, ambulances and rescue vehicles to free trapped and injured occupants of numbers Two, I Say Again Two vehicles. Fuel spillage on road presents fire hazard and necessary equipment to deal with situation required . Also require tow vehicles to clear vehicles from roadway blocking all lanes."

This description will find your location and tell the emergency services the type of units required , injuries sustained and the need to send ambulances that have to transport patients to various hospital locations.

Remember you must stay at the scene in the event that further information is required from you. You must also advise the control station when the emergency services arrive at the scene. In this instance the control station will be a base station answering your call and will require the registration numbers of the emergency vehicles to complete its records.

Should you have to leave your radio unattended for any reason, then leave a person to monitor the frequency. This person can be a passer-by or any other person who can alert you should a call be put out for your station. Remember that the regulations allow you to talk to any other station in an emergency and that another person may operate your radio if life is at stake.

Always advise the control station if you are leaving your station and again when you return. The control station must be aware of your location at all times.

Stay off the air unless you are sure you can be of assistance. The offering of advice or other comments that can add nothing to the situation must be avoided. It is better to remain silent and be thought a fool than to open your mouth and remove all doubt!

Continued on page 6

page 5

continued from page 5

So to summarise the important facts when emergency communications are being transmitted:

Speak slowly and clearly, talk across the microphone.

Keep calm.

Check your frequency and that you are operating simplex or on duplex as needed.

Check that you are not doubling and that the frequency is open for your use.

Call by saying "Z2 .... .. . with traffic" or "Z2 ...... . with priority traffic", in extreme emergencies and when you cannot break into a net call "break for traffic -Z2 ....... ".

Press the PTT, pause for a second then talk.

Know what you are going to say before transmitting.

Keep a proper written record of your messages and replies.

Maintain pauses between transmissions .

Do not eat when transmitting .

Stay at your location, do not move about.

When relaying a message repeat it verbatim, do not add your comments or change the context.

Sound and stay alert or have another operator relieve you.

Do not joke or be humorous when operating your station.

Use words such as" affirmative, negative, roger, say again, numbers" etc to avoid any confusion.

Do not use abbreviations or the "Q code" with voice transmissions.

Use proper station identification at all times.

Use only the International Phonetic Alphabet when spelling words .

Acknowledge calls promptly or ask the calling station to stand by - do not ignore any call to your station.

Call the control station and wait to be called in.

Transmit factual information only.

Give your location clearly and precisely.

Keep quiet unless you are called or have something useful to report.

Pause during long messages and request verification from the other station by saying "roger so far over'' wait for the station to acknowledge then proceed with your message.

In conclusion , nothing in all the above disagrees or contravenes the spirit and real world of amateur radio. The "rules" we have set out are there to help you become a better operator whether you are a RRU member or other operator.

Above all, analyse your present operating methods and try to perfect each element so that you can set an example when operating under emergency conditions or at any other time.

Net control may have the final authority, but good clean operating methods and procedures almost makes a net operate by itself.

Lastly, ignore any criticism you will hear on the air when using proper procedures. These comments usually come from the few operators who know no better and may one-day have their lives depend on you when the chips are down.

QSL Bureau News, October 1999. In a moment of weakness, I said I would contribute something about the QSL Bureau, but now that it comes to the point, I wonder just where to start.

I used to keep statistics of the number of cards that came in and from where and those that went out and to where they were destined. but no one seemed very interested so I gave that up. Now I only have a record of outgoing packets and their destination. However I will in future try to keep members informed through this medium of the movements of packets through the Bureau and other bits of relevant information.

Of all our members only a handful QSL via the Bureau and half of those give me perhaps 80% of the outgoing cards. I suppose that is why most of the incoming cards are likewise for but a handful of our members. Considering that Z2 is a desired country, I am rather surprised that there is not more movement.

For the information of members, I will be doing a fairly extensive clearance during November 1999 and cards that reach me before say 20th will be included in that mailing. After that there will be a complete clearance in March 2000.

I hope this slot will become a regular feature and that I will be able to provide members with information on the current goings-on in the QSL Bureau as well as other bits of , hopefully, useful information .

73, de Maarten, (Z21GY) ZARS QSL Manager.

-'An., n ... ~ ......... , page u

Tech corner. SUBJECT: Wire antennas - part one and two Dollar for dollar. the wire antenna is an Amateur Radio Operators (AROs) best bet when it comes to inexpensive antennas. In the lower bands, 160, 80, and 40m, the wire antenna is nearly the only means for most AROs to work those bands. Wire antennas perform from great to poor depending on many factors even when the antenna is cut for the frequency desired. I'll discuss some of my findings with wire ante.nnas in this ten part series. Since most of the wire antennas are published in numerous antenna books, the specifics of most wire antennas will be left to the reader to investigate for the band they wish to operate in. Instead, I will discuss some helpful hints, fmdings, and misgivings about wire antennas that the ARO can use in overcoming the difficulties encountered with their fJ.rst wire antennas and some that the old pros may fmd useful. I will be discussing the advantages and disadvantages of wire antennas on different bands, wire diameter, ground height, matching, multi-band wire antennas, and a few other odds nd ends. irst, let's look at the capture area of a wire antenna cut as a

dipole. We can examine this at lOrn for ease of calculations and understanding. Many hams use a #12 or #10 wire when constructing their wire antennas. It's cheap and easy to obtain. Some wire antennas come as kits and use stranded wire verses the solid conductor many hams use in their home construction. Looking at the diameter of the wire, whether strained or not, it can be easily seen that a dipole made from aluminium tubing has a greater capture area, without picking up a calculator to fmd out the difference. Larger diameter elements produce greater bandwidths, thus a wire dipole on lOrn would have a limited bandwidth compared to it's aluminium tubing counterpart. How does one overcome this? Through trial and error, and a tight budget when I first got into Ham radio, I found that cutting the wire antenna slightly shorter that the designed frequency and adding some tubing to the end of the dipole, I was able to expand the bandwidth of the wire antenna up to three times the original value. t doesn't take much tubing or a large diameter to accomplish

this. I used two of these units (of course, one on each end). There are two parts to the extension. Use a 12-in x 1/2-in diameter tube with an 8-in x 3/8-in tube telescoping inside the former. By placing a vertical cut into the 12-in section, a clamp can be used to lock the two tubes together. Now you have tuneable end pieces. Run the support rope through the tubing and attach to the wire then secure the wire to the 1/2-in end of the tubing. A good electrical contact is a must. The rope will support the tuneable end piece. The end pieces are also much greater in diameter than the wire, adding to the capture area. Also they provide a tuneable method for zeroing the dipole to the frequency desired or changing the frequency of the dipole later. At lOrn, I would recommend an aluminium tubing dipole and save this technique for the 30m and below antennas. For the lower frequency wire dipoles and inverted vees, the tubing can be made much longer for better results. There is a fine line between weight and performance that needs to looked into ws

ZARS Newsletter

when using this method and it's a function of the antenna support and support lines. I stumbled across this technique while putting around with a 40m inverted vee. I just could not get the bandwidth and SWR right. It was either too high for the resonate frequency or too low no matter what the calculator thought. The SWR was 2:1 and I wanted an antenna that did not require a tuner for my solid state radio. I grew tired of soldering and cutting wire and decided to add the tubing extenders. Not only did I get the Inverted Vee on target, 7.15 MHz, but I covered the entire 40m band and the MARS frequency I was required to attend on. The SWR was below 1.5:1 across the entire band also! :-) In this posting, we'll look at long wires and random wire misconceptions. Placing an undetermined length of wire out to a tree or support mast is *not* a long wire antenna. This is a random wire antenna which most of the amateur community calls a 'long wire' antenna. This misconception leads to many discouraging ideas about long wires. A long wire antenna is an antenna that is at least five wave lengths at the lowest frequency. After five wave lengths, the SWR becomes insignificant to the xcvr for a properly tuned long wire. Five wave lengths you say. Yes, five wave lengths. So, at 3. 7 5 MHz the length of a minimum long wire would be (984/fMHz) X 5 or 1312-ft. Not an antenna you can slap in most back yards unless you are a rancher. When it comes to VHF and above, the long wire antenna can be easily outclassed by numerous other designs, but at low HF frequencies the other designs become too cumbersome to use and the long wire fills the niche. Let's take a look at the random wire antenna used by so many of us hams. A tuner is a must for any work with a random wire antenna. These antennas usually consist for a wire stretched between here and there. Disappointed hams soon fmd that the easy way out isn't the answer. That 75-ft wire is not going to get them the performance they envisioned. Random wires are good for SWLing provided a tuner is used with the antenna. They're cheap to construct and cheap to buy. But a 75-ft wire in a standard size lot is not much of an antenna for amateur radio use. Granted it maybe all you can afford or be able to set-up at your QTH, but a ham can do better for transceiving. Long wires can provide nearly 3dB of gain over a dipole at 4 wave lengths provided the antenna is sufficiently placed above the ground and the wave angle of the antenna is correct. Five wave lengths is minimal for best results. The formula for long wire length is: Length in ft= 984(N-0.0250)/fMHz where N is the number of wavelengths. The long wire is a fixed antenna, so care should be taken where the antenna is to be placed. Your favourite RF stomping grounds such as Europe or the Far East, etc should be kept in mind. Next posting will have some additional information on long wires and other wire antennas for standard size lots.

From a packet mail by ZR2ABT

page 7

HF BEACONS FOR PROPAGATION PREDICTIONS

There are a number of HF beacons distributed around the world which can be used to assess the propagation conditions from your station to the beacon area.

A feature of these beacons is that after its identification (call sign) has been transmitted in Morse code there is a series of dashes when power usually drops in four distinct steps from 1 00 watts to 1 watt . The transmission repeats every 3 minutes. Each beacon station actually transmits on the lowest frequency then after 10 seconds shifts to the next higher frequency as can be seen in Table B. Even if you are not familiar with Morse code, but provided you have a watch or clock which is accurate to within say 5 seconds, you can determine which beacon you were able to hear, although always subject to possible QRM. It is surprising how often you will be able to hear the 1 Watt signal!

The following method and Tables A and B will let you determine the identification of the beacon either from its call-sign or by knowing accurately the time that the beacon starts to transmit.

Method--Identification by accurate timing

1. Set your watch or clock to the correct time and to within 2 or 3 seconds by using standard frequency transmission station WNV or BBC time signals (last pip) .

2. Tune your receiver to the frequency of interest in the CW mode. Listen for about 4 or 5 minutes to see if you can hear any beacons.

3. The cycle of beacon transmissions start on the hour then repeat every 3 minutes. Determine from Table A which cycle would have started then add the minutes of Table A to the times in Table B which are given in minutes and seconds. The time that a beacon starts to transmit will enable you to identify it.

4. An example will illustrate the method. Suppose you want to see if you can hear or identify the ZS6 DN beacon on 14.100 MHz.-- Wait for, or prepare for, the next cycle start time from Table A and add 1 min. 40 sec. (see slot 11 of Table B for 14.100 MHz.), then the beacon will be heard at a Table A time (minutes) plus 1 min. 40 sec. repeating every 3 minutes.

TABLE A TABLE B Time that a cycle Beacons and slot time allotted starts in (minutes) (mins:sec.) 0 15 30 45 SLOT CALL 14.100 18.110 21.150 24.930 28.200

3 18 33 48 1 4U1UN * 00:00 00:10 00:20 00:30 00:40

6 21 36 51 2 VE8AT 00:10 00:20 00:30 00:40 00:50

9 24 39 54 3 W6WX 00:20 00:30 00:40 00:50 01:00

12 27 42 57 4 KH6WO 00:30 00:40 00:50 01 :00 01:10 5 ZL6B 00:40 00:50 01 :00 01:10 01 :20 6 VK6RBP 00:50 01 :00 01:10 01 :20 01 :30 7 JA21GY 01 :00 01 :10 01 :20 01 :30 0 1:40

8 UA ?? 01:10 01 :20 01 :30 01 :40 01 :50 9 BY ?? 01 :20 01 :30 01:40 01 :50 02:00

10 4S7B 01 :30 01 :40 01 :50 02:00 02:10 11 ZS6DN 01 :40 01 :50 02:00 02:10 02:20 12 5Z4B 01 :50 02:00 02:10 02:20 02:30 13 4X6TU 02:00 02:10 02:20 02:30 02:40 14 OH2B 02:10 02:20 02:30 02:40 02:50 15 C53B 02:20 02:30 02:40 02:50 00:00 16 LU4AA 02:30 02:40 02:50 00:00 00:10 17 OA4B 02:40 02:50 00:00 00;10 00:20 18 YV5B 02:50 00:00 00:10 00:20 00:30

* 4U1UN at New York (United Nations)

The basic beacon information was obtained from a 1998 PW article . - Eric Christer, Z21 FO

IMPORTANT NOTICE UNLESS INDICATED OTHERWISE, THE CONTENTS IN THIS NEWSLETTER IS THE WORK OF AND OPINION OF THE AUTHORS. THE ZIMBABWE AMATEUR RADIO SOCIETY (ZARS) OR ANY OTHER OFFICIAL BODY DO NOT NECESSARILY SANCTION ANY CONTENTS AS EXPRESSED BY THE VARIOUS AUTHORS. WHERE REFERENCE IS MADE TO PREVIOUS PUBLISHED WORK, CREDIT TO THE SOURCE HAVE TO BE GIVEN. CARE IS TAKEN TO PROVIDE ACCURATE CONTENT BUT IN THE SPIRIT OF THE NEWSLETTER ALL PUBLISHING IS DONE IN GOOD FAITH.

,..

Fig. 3-10

Alrrospheric pressure decreasing

Temperature decreasif1!1

W>l.er vapor lllCreasong

standard, or normal, or altitude above sea level.

Continued from page 4 Considering all of these factors, it is clear that the velocity of radio waves will also vary with altitude, since temperature, pressure, and water vapour all change with altitude. Under normal atmospheric conditions this variation or change is quite small. However, there is an increase in the velocity of radio waves as the altitude increases. This causes a small curvature in the downward direction of a radio wave travelling over the surface of the earth. The temperature and water vapour in the atmosphere undergo constant change; usually this change is such that the index of refraction will vary with the altitude, as shown in Fig. 3-11A. This is the

There are conditions, however, where the change in the refraction index is not normal, bringing about abnormal or anomalous propagation. A duct or a region of special characteristics is formed under these conditions, and the duct will carry the radio waves in a manner similar to a wave guide.

A B c

Normally, as the altitude is increased, the temperature will decrease. Also, as the altitude increases, the amount of water vapour decreases. There are special circumstances, however, where the temperature first decreases as the altitude is increased and then suddenly the temperature will increase again. This is an abnormal condition known as temperature inversion. It is also possible, under particular circumstances , for the water vapour content of the atmosphere to increase at a certain point above the surface of the earth. When these things happen, the unusual conditions form a duct; Fig. 3-11 B shows that the index of refraction

Index ct retracton changes in an unusual way as the Fig. 3-llA altitude in increased, and then the

change becomes normal for a further increase in altitude. In some cases, as in C, the duct occurs between two specific levels of altitude. In any case, the formation of the duct is unusual, and it affects radio waves in an unusual manner.

Duct

F1g 3-12 Increase m transmission range due to duct effect.

communications by many times.

ZARS Newsletter

Fig. 3-12 shows radio waves starting out at transmitter Tx directed toward receiver Rx. Under normal conditions, radio waves would travel in about a straight line, as shown at A. However, because of the duct effect, the radio wave is bent in its travel in path B; hence, energy from the transmitter reaches receivers at a greater distance in this abnormal fashion . Duct transmission may increase the transmission range of certain types of radio

continued on page 10

page 9

Y2K (it even gets in here) Worried about Y2K and radio equipment, see the article in the April issue of QST. Most of the amateur radio suppliers have given an assurance that there is no problem expected with our radios and the progranuning equipment. This obviously relates to the newer computer controlled rigs. AJso relating to the Y2K problem hams all over the world have been asked to be prepared to respond if required and the nonnal services fail due to the Y2K problems. I know that the hams down south have been officially put on alert by the authorities. On the good side we should be able to take part in some special events over the millennium for instance :-The RSGB have announced that a special event station M2000A will be opened by Lord Rix G2DQU on the 31st December which will operate until the end of February 2000. This station will be housed at the Rangers House, Blackheath which has one corner on the meridian line. The station will have two 70 foot towers carrying the HF antennas and a 40 foot tower carrying the VHF antennas. Visit internet site www.qsl.neUm2000a for more information or contact yours truly.

continued from page 9

What's on at PE radio club. Having had a term of bashing theory for the RAE. (we are still waiting for the results) we are now spending time on construction. This term we are constructing an HF QRP receiver, (yes I know RX is not QRP) which is based on two IC's and the cost of components is about Z$400 plus a few bit for case and board etc. Who said ham radio was e>.'Pensive. At present we have 12 sets in construction with the boys drawing the PCB layout and etching being done by myself. We have managed to purchase all but one IC from a local vendor so the parts are available. Four of the boys are now soldering in the components and we should have a few kits on air shortly. While all this construction is under way we are also tackling the Morse code. Once the lads have passed the Morse the ne>-1 project is a QRP transmitter which will match the RX and get them on air with a working transceiver. Who said construction was dead. these lads will carry on the tradition of 'when I started we had to build our own equipment and that was real ham radio '. We are also working on the next generation to carry on ne>.'t term and I will be looking to start a second club at a girls school so any volunteers to join in would be MOST welcome and would spread the load.. 1

Other types of transmission effects that are not abnormal but are unusual include reflections from things other than the ionosphere. For example, passive satellites are being used for communications where energy is sent from the transmitter, bounced off the satellite, and returned to the earth. Tropospheric scatter propagation is another means of extending the range of certain types of radio transmission. Most of the energy at very high frequencies is sent for short distances only. This is because energy at high frequencies is sent for short distances only. This is because energy at high frequencies will pass through the ionosphere with out being refracted and will effectively be lost for any communications use.

Although most of this energy is lost in outer space , a very small but useful amount is deflected by troposphere, and this scatters the energy beyond the horizon. Thus it is possible to use frequencies for communications beyond the normal radio horizon that normally would not be used for long-range transmissions. Tropospheric scatter propagation is not the same as reflection from ionosphere, because Tropospheric scatter depends on certain atmospheric

FR OM : . . '

f v NEWSt EITER MASHbNALANDBRANCH P.OBQX 2377

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Send to I. Rocky Campbell

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