China se ruimtestasie sal in 2017 terugval Aarde toe

sttationChina se eerste ruimtestasie, Tiangong-1, sal na verwagting in die tweede helfte van 2017 terugval Aarde toe, ná ongeveer ses jaar in die ruimte. Tiangong-1 is in September 2011 gelanseer en het in Maart vanjaar sy datadiens afgehandel toe hy “omvattend sy geskiedkundige sending vervul het”, het Wu Ping, adjunkdirekteur van die bemande ruimte-ingenieurskantoor gesê. Volgens Wu is die ruimtestasie nog heel en in ʼn wentelbaan met ʼn gemiddelde hoogte van 370 km. Die ruimtestasie was vier en ʼn half jaar lank bedrywig, twee en ʼn half jaar langer as waarvoor dit ontwerp is. Dit het by die Shenzhou-8, Shenzhou-9 en Shenzhou-10-ruimtetuie aangesluit en het ʼn reeks take afgehandel en belangrike bydraes gelewer tot China se bemande ruimtestasie-projek. “Gebaseer op ons berekeninge en analisa, sal meeste dele van die ruimtelaboratorium uitbrand wanneer dit na die aarde terugval,” het sy bygevoeg. “Dit is onwaarskynlik dat lugvaartbedrywighede hierdeur geraak

Source: China se ruimtestasie sal in 2017 terugval Aarde toe | Maroela Media

Sonuitbarstings veroorsaak amper Derde Wêreldoorlog

‘n Sonvlam in 2011 wat weg van die aarde gerig was

Die aarde is op 23 Mei 1967 byna in ’n Derde Wêreldoorlog gedompel, toe ’n sonvlam verskeie van die VSA se radarinstallasies buite werking gestel het. Die Amerikaners het geglo dit was die Russe se werk en dus ’n oorlogsdaad en Amerikaanse vliegtuie wat met kernwapens toegerus was, het gereed gemaak om op te styg. Gelukkig het die VSA toe ook al ’n ruk lank in sonnavorsing belê en navorsers kon betyds hul opwagting maak om die situasie te ontlont. Die sonfakkel wat op 23 Mei die radar uitgeskakel het, was so intens dat dit met die blote oog van die aarde gesien kon word. ’n Verslag oor die voorval het pas in die vakjoernaal, Space Weather, verskyn. Bronne: Space Weather, Christian Science Monitor

Source: Sonuitbarstings veroorsaak amper Derde Wêreldoorlog | Maroela Media

Story of a Lancaster radio operator

In the spring of 1943 I was called up and chose to join the RAF for training as aircrew. They said I could elect to be trained as a pilot and wait to join up for a year. Alternatively, they had vacancies for rear gunners – come next Monday. I was keen to get started but… ummm. There was a third choice, be a wireless operator and come in three months. That sounded like a reasonable compromise, and I took it. August Bank holiday 1943 found me reporting to the ACRC (Air Crew Reception Centre), at Lord’s cricket ground for induction and training.

I joined a squad of 30 likely lads, all destined to train as wireless operators, and we started initial training. Three weeks of inoculations and square bashing to commence. We lived in commandeered luxury flats along Prince Consort Road, marching to be fed in a similarly commandeered cafe at the zoo just across the road in Regents Park.

Training

Then to Bridgnorth to 19 ITW (Initial Training Wing), where we started the rudiments of wireless training and began to absorb Morse code.

November came and we moved to Number Two Radio School at Yatesbury in Wiltshire – a huge wooden-hutted camp in the middle of nowhere but with a small grass airfield next door, from which we would be flown to do our training for wireless operating in the air. The course we were embarked upon had been of two years duration before the war. Now it had been condensed into six months because of the enormous demand for aircrew in RAF Bomber Command. Enormous? Yes, the Bomber Command strength had built up to an ability to deliver 1,000-bomber raids over Germany on a nightly basis. Losses were significant, sometimes tragically large. They needed Aircrew.

We were all desperately keen and training classes went on from 8am to 6pm, six days a week – Sundays off. Phew! During this time I became friendly with another trainee in the group, Keith Gosling. We were very alike in character and background – Grammar school boys from stable homes, imbued with an ethic for hard work. Middle class, I suppose you would have had to call us. We had similar interests and abilities. Did I say ‘desperately keen’? It’s worth repeating. We, and most of the other lads around us, were entirely and selflessly committed to becoming the best wireless operators ever! Neither Keith nor I had the slightest difficulty with the theoretical side of the course, but both found it extremely difficult to conquer the required speed barriers in Morse. I came from suburban London; Keith came from Frizinghall, Bradford.

On standby
The course ended in the spring and we both passed with excellent marks. My mark on the theory side was 95%, and for operating in the air it was 85%. We proudly became sergeant wireless operators and stood by for posting to OTU (Operational Training Unit), the next stage towards operational flying.

During this time, waiting to be posted, two unusual things happened. First we were both asked to go before a commissioning board with a view to becoming officers. We were not told the results and suspected that we were not selected. The second strangeness came one morning on parade when the NCO in charge called on all those who had learned German at school to step forward. After a moment’s hesitation, I did so. So did Keith with two others from the group.

Within a week we four were called in and told that the remainder of our training would be cut by some months – we would be posted to a familiarisation unit to get used to flying in heavy bombers. That we would probably be flying on operations within a month! The job we were to do would be to fly in Lancasters as an extra crew member with the specific task of operating special jamming equipment designed to prevent the Luftwaffe night-fighter pilots from hearing directions from their ground controllers.

Lancaster Finishing School

It was a very exciting time. We were sent to No.1 LFS (Lancaster Finishing School) at Hemswell, north of Lincoln, to fly for 10 hours as passengers in Lancasters, and familiarise ourselves with being carried in large four-engined bombers. lanc1This was quite necessary as our air experience previously had been in the stately Dehaviland Dominie and tiny Percival Proctors. The Lancaster was large, loud, fast, and fierce. While we were there, the second front opened with D-Day on 6 June 1944.

Very soon now we went on to No.101 Squadron at Ludford Magna on the Lincolnshire Wolds. 101 was a three-flight squadron, flying up to 24 Lancasters in the bomber stream, armed and loaded with bombs just like the other heavy bombers.

Jamming
Upon arrival the first thing was a few day’s introduction to the equipment we were to operate. It went under the codename ‘ABC’, which stood for Airborne Cigar; I have no idea why they named it that. It consisted of three enormous powerful transmitters covering the radio voice bands used by the Luftwaffe.

To help identify the place to jam there was a panoramic receiver covering the same bands. The receiver scanned up and down the bands at high speed and the result of its travel was shown on a timebase calibrated across a cathode ray tube in front of the operator. If there was any traffic on the band it showed as a blip at the appropriate frequency along the line of light that was the timebase. When a ‘blip’ appeared, one could immediately spot tune the receiver to it and listen to the transmission. If the language was German then it only took a moment to swing the first of the transmitters to the same frequency, press a switch and leave a powerful jamming warble there to prevent the underlying voice being heard. The other two transmitters could then be brought in on other ‘blips’. If 24 aircraft were flying, spread through the Bomber stream, then there were a potential 72 loud jamming transmissions blotting out the night fighters’ directions.

The Germans tried all manner of devices to overcome the jamming, including having their instructions sung by Wagnerian sopranos. This was to fool our operators into thinking it was just a civilian channel and not worth jamming. I think ABC probably did a useful job, but who can say what difference it made.

lanc2.jpegAnyway, it was an absorbing time for keen, fit, young men who thought only of the challenges and excitements of their task and little of the risks they were about to run.

Pilot Officers
Next step was to get “crewed up”. The normal seven-man crews for Lancasters had been made up and had been flying together for months before arrival at the Squadron. We Special Duty Operators now had to tag on to established crews and it was left largely to us to find out with which pilot we, in our ignorance, might wish to fly.
Just before this process started both Keith and I were called into the Squadron Adjutant’s office one morning and told that we had been commissioned as Pilot Officers. The Adjutant, a kindly, ageing Flight Lieutenant, advised us to go to Louth, the local town, see a tailor and order an officer’s uniform. We were to get the tailor to remove our Sergeant’s stripes and replace them with the narrow pilot officers shoulder bands on our battle-dresses. He should finally provide us with an officer’s hat! The adjutant gave us vouchers to hand to the tailor to assure him he would be paid! We were told to move our kit from the NCOs’ quarters to officers’ accommodation and the Adjutant would see us in the Officers’ Mess at 6pm to buy us each a beer.
I had imagined that becoming an officer would include some kind of OTU or training course to instruct us what sort of behaviour might be expected of us. Not so, not for newly commissioned aircrew on a Bomber station in Lincolnshire in the middle of 1944. What is described in the previous paragraph is all that happened.
Looking back I can see that all the things we were experiencing at this frenetic time were tremendous shocks to our systems. They left us ill equipped to take the apocalyptic decisions we were about to make and which, as it happened, would decide whether we lived or died.
Canadian pilots in the officers’ mess
Crewing up was to follow shortly, but on our first evening in the officers’ mess we had met two Canadian pilots, Messrs Meier and Hodgkinson, newly arrived on the squadron with their crews and eager to find their extra ABC wireless operators. Our decisions were made that night. I got on well with both of them, but perhaps had marginally more in common with Gordon Hodgkinson than Meier. Keith felt perhaps closer to Meier and so our choices were made, almost by the toss of a coin: me for Hodgkinson; Keith for Meier.
I started flying with Hodgkinson who, as it happened, did not find it easy to settle down to the conditions over a hostile Germany. Our first operational flight was on 30 June 1944. ‘Hodge’ managed seven operations, but remained unsettled and had turned back unwell on two occasions. He was finally taken off flying and went back to Canada. I was re-crewed with a succession of other crews and completed my tour of 30 operations on 6 January 1945.
lanc3Keith started flying with Meier about the same time as I started. Our other two sergeant colleagues from Yatesbury also joined crews of their choice. One of them, Englehardt, died I believe in a raid on Stettin in August and was buried where his aircraft crashed in Sweden on the way home. I am not too sure about the date here. The fourth of us, Auer, survived like me.

Over the Ruhr
When we were flying on raids to the industrial Ruhr the route for the bomber stream was often from base to Reading; Reading to Beachy Head; Beachy Head to Le Treport; then East across France and into Germany. This was our route on the night of 21 July. After the raid, Meier’s Lancaster did not return and the crew were posted as missing. It was less than a year since Keith and I had joined up on August Bank Holiday in 1943 at Lords Cricket Ground.
Keith’s mother Florence knew that we had been friends and wrote to me. There was little I could do to help or advise her as to what had happened. For a while I hoped that we would hear that Keith had been taken prisoner but it was not to be. It was some months before I heard the story of the crew’s fate that night. Strangely enough it came from Florence. Meier’s Lancaster had been caught by a night fighter not long after crossing the French coast and was shot down. Apparently, the damage caused the aeroplane to lose a wing and break up. By the best of good fortune one member of the crew was flung clear and parachuted down into occupied France. A second member of the crew also managed to make a parachute descent to safety. The other six, including my pal Keith, did not escape. All this information was vouchsafed to Florence in a letter from one of the survivors who had felt obliged to write to the relatives of each member of the crew when he was released from a POW camp.
Although she was wrong Florence had thought that it was Meier the pilot who had survived and she could not understand how the captain of the aircraft could have survived when six of his crew had died. She quoted the naval tradition that a captain should be the last to leave his sinking ship.
Gentle correction
I had seen our bombers shot down in daylight raids, and knew that once an aircraft began to break up there was absolutely nothing that anyone could do except try to save himself. I tried as gently as I could to get this across to Florence. We continued to exchange letters but our correspondence petered out in mid 1945 when the German war was over and I was posted out to India to prepare for the attack on Japan. Of course the bomb in August made that un-necessary and I spent two years in various parts of the Far East, waiting to be demobilised.
When I came home again I never forgot my friendship with Keith, but I did not feel inclined to re-open an old wound for Florence by trying to get in touch again. Maybe I should have done so, but I didn’t.
Remembrance
As the years have gone by life has of course developed in many other directions but I have always been reminded of Keith when a place, or a song, or some other thing has sparked a memory of our close but brief comradeship. He is the one I think of and shed a tear for on Armistice Day. Secretly, over the intervening years, I have felt a need to find out where Keith was buried and to visit the grave to say a sombre and measured farewell.
The opportunity to follow that wish came on the 50th Anniversary of the War’s end approached. I made enquiries at the Ministry of Defence as to war graves and received a very speedy and helpful response. He was buried in a cemetery near Cambrai on the road that goes in the direction of Solesmes in grave B, row 31 – all very precisely military.
My wife and I crossed the channel to Calais early on the morning of 21 July 1994, the fiftieth anniversary of Keith’s death. We drove to Cambrai past some of the massive military cemeteries from World War One. Through the town we found the road to Solesmes and looked for our cemetery. The only one in sight was a German World War One cemetery, well tended and stark with granite crosses. We passed it by looking for the more familiar British headstones. On to Solesmes, still no other cemetery of any nation and we re-traced our steps towards Cambrai, thinking we must have missed it.
The German cemetery
The German cemetery was on the outskirts of Cambrai itself and in desperation we stopped there hoping to obtain directions. Inside a gardener was cutting hedges and I went to speak to him not knowing whether to try German or my more halting French. After my first words he replied to me in English. He was a Londoner, an employee of the British War Graves authorities. Apparently the gardeners did not always work in the cemeteries of their own nations.
Yes, he did know where World War Two RAF graves might be found. They were in a plot set aside in the civilian cemetery next door – only about 100 yards from where we were speaking. We were quickly there, and sure enough we found a group of some 40 RAF graves. The dates on the headstones told their own sad stories. There were sets of headstones, side by side with the same date – clearly each set from the same bomber crew.
The set for 21 July 1944 had four headstones, one of them Keith’s. I did not know the other names in that crew. There were two gaps in the line. I learned later that these probably represented the spots where bodies had been repatriated by relatives, probably to Canada. So that was it, two had survived, four were here, and two had moved on. The whole crew of eight were accounted for.
Still in uniform
In my mind’s eye, over the 50 years, I had imagined Keith as having been found, and his body, still in uniform, laid peacefully to rest. I looked at the headstone – carefully carved at the top was the RAF crest, and at the foot the words ‘Proud and treasured memories’. That must have been Florence’s wording. I read the other words, ‘Pilot Officer K. Gosling. Pilot. Royal Air Force. 21st July 1944. Age 19’.
Did I say that one should never go back to renew old acquaintances? Well, as you know Keith was a Wireless Operator like me. Why should it say Pilot on the headstone? How much had they found to bury? I was strangely upset.
Sam Brookes

DIE JAKKALS

Brian ZS6YZ

Op Saterdag 20 Augustus tydens die Klubvergadering het die lede van MRK ‘n inleiding tot jakkalsjag ervaar.

Brian ZS6YZ het ‘n jakkals sender gebou en die sender is versteek in die parkie by die klubhuis.

Aanvanklik sou die sender ‘n klein sender gewees het wat bestaan uit ‘n DVR818V TRX module. Die idee vir die sender het bekom van die Junie uitgawe van die Radio ZS waar Kevin ZS6KMD ‘n 2m TRX beskryf het wat deur middel van ‘n Arduino beheer word. Die sender wat gebou is het baie goed gewerk. Die sender het sy eie ingeboude uP met geheue so dit sal kan werk sonder die Arduino en sal op die laaste stelling werk wat die vanaf die Arduino ontvang het. Die ideale jakkalsjag sender.

jak3.jpeg

ʼn Week voor die klubvergadering het die sender egter besluit om nie meer saam te werk nie en daar moes haastig aan ‘n plan B gedink wordjak4.

Plan B het toe bestaan uit ‘n Icom T70 Hand radio.

jak5 Die minimum uitset krag van die hand radio was egter 500mW. Die uitset krag sou te hoog gewees het vir die oefening in die parkie. Die sein moes verswak geword het. Aanvanklik is ‘n 60dB verswakker gebou maar toetse het gewys dat die maar so 16dB verswakking gee.

n 6dB koaksiale verswakker is gebruik in lyn met die 16dB om so 22dB verswakking te gee. Die is toe gekoppel aan ‘n kuns las. Metings met ‘n spektrum analiseerder so 0.5m vanaf die kunslas het gewys dat die sein teen -20 dBm nog te sterk was. Hoe nou gemaak!! ‘n Koffieblik is toe nader gesleep en daar is gevind dat wanneer die kunslas in die blik geplaas word, word die sein verswak tot -30dBm. Toe is altwee die verswakkers in die blik geplaas saam met die kunslas en die sein het verder verswak tot -40dBm.

Om te verseker dat die jakkals nie die heeltyd TX nie is ‘n ATtiny85 uP gebruik om die PTT van die hand radio te beheer. Die radio het vir 6 sekondes ‘n FM draaggolf uitgesaai en toe vir 10 sekondes gerus. Die uP het ook sy uitdagings gebied deur dat die uitset puls wat die relê deur die transistor beheer ‘n vierkantsgolf is en die veroorsaak steurings wat groot genoeg is om die radio se onderdrukker (squelch) te laat skakel en die radio het dus tydens ontvangs geraas. Deur gebruik te maak van 100nF kapasitors op die inset en uitset van die spanningsreguleerder is die geraas gedemp.jak6

Die uP is gekoppel aan ‘n 12V 7Ah alarm battery wat ook direk die hand radio kragvoorsien het om te sorg dat die radio se battery nie pap raak nie.

Die jakkals was nou reg om versteek te word.

Tydens die klub vergadering het Brian die beginsels van jakkalsjag bespreek en dat daar baie opsies is wanneer dit by ‘n jakkalsjag ontvanger kom. ‘ Lus antenna kan gebruik word, of selfs ‘n Yagi antenna maar die groot geheim is om die sein te kan verswak en vir ‘n minimum sein te soek eerder as om ‘n sterk sein te soek.

‘n Eenvoudige manier is om die sein wat ontvang word genoeg te verswak sodat die begrenser (limiter) van die hand radio wat as die ontvanger gebruik word nie aanskakel nie. Dit laat toe dat wanneer jy die radio voor jou teen jou lyf hou en stadig in die rondte draai, jou lyf die sein vanaf die sender teen so ‘n matte sal verswak dat die geruis sal klim en duidelik hoorbaar sal wees. Wanneer die geruis dan op sy hardste is sal die sender direk agter jou wees. Indien jy dan op die wyse ‘n driehoek meting sou kan doen kan jy bepaal waar die sender se posisie moontlik kan wees. Daar is natuurlik altyd die moontlikheid dat jy steurseine en weerkaatsings kan optel en dan moet jy maar effens rond beweeg weg van geboue af om die weerkaatsings te verminder.

jak7

Afhangende van watter been by die antenna van die hand radio ingedruk word, word die sein meer of minder verswak.

Wanneer jy so naby aan die sender is dat die weerstand netwerk nie meer die sein genoegsaam verswak nie dan gebruik jy eenvoudig die radio sonder ‘n antenna.

Die klublede het toe die parkie ingevaar om die jakkals te soek. Die wat die tegniek beter verstaan het, het naby die jakkals gekom, alhoewel hulle nie presies kon vasstel in watter voertuig die jakkals versteek is.

Nadat die jakkals uit sy skuiling gehaal is het Brian verduidelik hoe hy die jakkals aanmekaar gesit het en die uitdagings wat hy gehad het.

Die lede het almal die miniatuur jakkalsjag geniet en daar is besluit om in die toekoms weer ‘n jakkalsjag te hou of by Kleinfontein of by ‘n ander plaas in die Hartebeeshoek omgewing wat deur Johann ZS6PSS kan gereël word.

Brian ZS6YZ

Jakkals jag

Chris ZS6CVE

Die jakkals jag het daar in die park by die klubhuis plaas gevind.

Brian YZ het eers ‘n praatjie gelewer t.o.v. die bou van die sundertjie was as die jakkals gedien het en daarna is die oukêrels in groepies van drie gedeel en is almal toe buitentoe.

Die groepies het vanaf die vier hoeke van die park na die middel gewerk en sodoende die jakkals gesoek.

Dit was nogal ‘n hele bedrywigheid en die mense wat in die park rond gesit het , het die storie met groot oë gade geslaan.artjak1.jpeg

Met die tyd het die manne so op ‘n manier na die middel van die park gewerk maar daar was ‘n paar manne wat al om die karre gedraai het wat daar onder die groot bome geparkeer was.

Daar was nie spesifiek iemand wat die jakkals gekry het nie maar ‘n hele paar manne was baie warm op sy spoor en het al om Brian YZ se motor gedraai.

Om die jakkals jagters van hul ellende te verlos het Brian toe maar sy motor se kattebak oop gemaak en daar het die jakkals so ewe in ‘n koffie blik gelê.

Die gesoek het seker so om en by ‘n uur en ‘n half geduur.

Daarna is almal weer terug klubhuis toe en is nabetragting t.o.v. die jakkals jag gehou.

Baie interessant en leersaam. Ons kan gerus weer so maak.

jak2.jpeg

KLASIE EN OOM FANIE

Deur Pieter zs6bvt

Oom Fanie sit op die stoep en koffie drink terwyl hy oor die vlakte uitkyk voor hom. Hy kan voel dat die Somer aan die kom is, hy sien dat van die rose alreeds besig is om uit te loop, oom Fanie geniet die vars lug in die oggend wat hom sommer opgewonde maak vir die dag wat voorlê. Hy kan nie wag om ʼn paar groente en nog wat in die grond te sit nie.

Die gedreun van Klasie se motorfiets laat hom die rigting van die grootpad kyk en hy sien hoe Klasie by die plaas indraai vir sy Saterdag oggend kuiertjie. Klasie maak sy motorfiets staan en kom sit by oom Fanie op die stoep. Klasie is ook nie meer so dik aangetrek nie en trek sy dunnerige baadjie uit en hang dit oor die rugleuning van sy stoel.

Hoe gaan dit oom, vra Klasie met die wete dat hy nou eers ʼn ontleding van die nuutste nuus gaan kry voordat hulle lekker gaan gesels.

Dit gaan goed dankie Klasie sê oom Fanie, ek is net bly dat die verkiesing nou verby is. Jy weet Klasie die verkiesing het gewys dat die nommer een party nie meer so populêr is nie en dat hulle sal moet vinger trek om nommer een te bly. Die opposisie en die rooi oorpakke het gewys dat daar groot fout is met hulle en die mense keelvol is vir hul leuens en gestelery. Ek sien maar swarigheid vir hulle in die toekoms, die nuwe Leiers van die munisipaliteite moet nou net hul ding doen en bewys dat hulle beter is. Die volk het gepraat. Ek sien die Vaaldam is amper leeg, ek het hom nog nooit so leeg gesien nie, ons sal een van die dae ook vir die Vaaldam moet water stuur om hom nat te hou. Ek sien die grootbaas van SA rugby het bedank, ek wonder wat hy nou aangevang het om net so te staan en bedank, dit maak glad nie vir my sin dat die ou sommer so uit die bloute staan en bedank nie. Ons het nou VIR ʼn jaar nie beurt krag gehad nie, ek glo dit glad nie, dit het nou van beurt krag na kabeldiefstal verander, ons was nou al ʼn hele paar keer sonder elektrisiteit hier op die plaas. Ek sien die spul studente eis al weer gratis onderrig, hier kom alweer ʼn klomp optogte, dit is jammer dat die ouens die kampusse so ontwrig.

Jy weet Klasie, sê oom Fanie, Hierdie land kan so fantasties wees indien almal net vir mekaar die son oor almal se koppe gun en nie so jaag na rykdom en mag nie. Baie sal ongelukkig ʼn gedaante verwisseling moet ondergaan voordat dit gebeur.

Klasie vra vir Oom Fanie hoe dit met die radio amateur stokperdjie gaan om die onderwerp te verander. Dit gaan goed sê oom Fanie, die voortplanting sukkel so ʼn bietjie maar wanneer daar openings is, gesels ons lekker. Jy weet Klasie ons het maar in die oorlog ook gesukkel wanneer die bande toe was, al wat ons toe kon doen was om oor te skakel na gelykgolf toe want met die mode kon ons altyd ʼn boodskap deurkry.

Jy weet Klasie ons het met alles en nog wat in die weermag geëksperimenteer om te kyk of ons nie van die toerusting en stelsels kon verbeter nie. art201Ek dink byvoorbeeld die keer toe ons met antennas gespeel het om te sien of ons nie ons radio kommunikasie kon verbeter nie. Ons het die antennas na alle moontlike vorms verander om die antennas se doeltreffendheid te verbeter.Ons het gou agtergekom dat die antenna een honderd persent aan die radio aangepas is en so hoog moontlik moet wees om goeie resultate te kry. art202Ons kon egter nie gerigte antennas bou nie aangesien ons maar lae frekwensies gebruik en die soort antennas baie groot sou wees.

Ons was weer een dag besig met die antennas toe ons deur die Duitse lugmag aangeval word. Die Stukas het oudergewoonte baie laag ingekom en alles wat in hul pad was stukkend geskiet. Die vliegtuie draai om sodra hulle die kamp gevlieg het en kom dan weer laag in vir nog ʼn sarsie. Die Stuka was bewapen met ʼn 20mm kanon wat alles in sy pad vol gate skiet, ons kon nie veel uitrig teen die vliegtuig nie, hy het laag en baie vinnig gevlieg. Toe die Duitsers uiteindelik padgee was daar chaos in die kamp. Die hele kamp is vol rook wat van die brandende voertuie veroorsaak word, die parade grond lê vol gewonde en dooie soldate waar die mediese ouens hul begin behandel, Die antenna wat ons wou optrek het ook deurgeloop. Ek besluit net daar en dan dat ek die vliegtuie volgende keer ʼn les gaan leer, ons is nou is gewoond om elke Woensdag aangeval te word.

art203Dit is Woensdag 12uur in die kamp, almal hou die horison dop om te sien of die Duitsers ons oudergewoonte weer gaan aanval. Net toe ons dink dat ons hierdie Woensdag uitgespaar is hoor ons die gedreun van die Stukas. Almal wag in spanning vir die aanval om te begin, skielik sien ons hulle, daar is 5 van hulle, net toe hulle so 500 meter van ons af is begin ons die grootste net optrek wat nog ooit van draad gemaak is. Al 5 die vliegtuie vlieg in die net vas en ons vang hulle soos voëltjies. art204Dit is net stof en stukke vliegtuie wat die hele wêreld vol vlieg, die vlieëniers word baie gou gevang voordat hulle die hasepad kon kies.

Om ʼn lang storie kort te maak word ek deur Jannie Smuts met medaljes en range toegegooi, ek het nie geweet ʼn mens kry so baie soorte medaljes nie, ek kon die medaljes nie gelyk op my bors tentoonstel nie. Klasie kan sy lag nie hou nie, hy groet vir oom Fanie, spring op sy motorfiets en ry die plaaspad af huis toe terwyl oom Fanie hom met ʼn groot glimlag op sy gesig agternakyk.

Pieter zs6bvt

Outomatiese beheerstelsel vir Magnetiese Lus Antennas – Tienie ZS1HO

In my soeke na ‘n goeie geskikte beheerstelsel vir ‘n Magnetiese Lus Antenna het ek op die webtuiste van ‘n OK genaamd Loftur (TF3LJ/VE2LJx), in Kanada afgekom, en presies dit, en nog meer gevind as waarvan ek ooit kon droom.
Ek glo elke leser wat vertroud is met die alombekende en beproefde Magnetiese Lus Antenna met sy hoë Q-faktor/nou bandwydte, sal saamstem dat dit nog al ‘n pyn in die patat kan wees elke keer as daar van frekwensie verwissel word, selfs net ‘n paar kHz op of af, en nog meer so as daar op en af deur die bande gesoek word vir moontlike band aktiwiteite.
Lees gerus onderstaande uittreksels geneem uit die OK se artikel (met sy mede wete en toestemming) ten einde ‘n eerstehandse blik te kry waar toe ‘n goed deurdagte beheerstelsel in staat is. magloopDit dien ook gemeld te word dat die gratis sagteware daarvoor op ‘n gereëlde basis deur hom bywerk en op dateer word, soos nuwe radiotoerusting wat daar deur ondersteun word by kom. Daar is selfs ‘n “PC Bord” teen $20 elk beskikbaar vir die doel.
Besoek gerus sy webwerf hierna vermeld, vir ‘n stroombaan diagram plus ‘n detail beskrywing met foto’s, sagteware en ander verwante inligting.
https://sites.google.com/site/lofturj/sites.google.com/site/lofturj/
(to-automatically-tune-)
Die enigste probleem wat ek ondervind het met my stelsel in wording; is dat ‘n paar van die items wat nie plaaslik (op die plateland) beskikbaar is/was nie, vanaf die buiteland ingevoer moes word. Onderdele van daar is relatief goedkoop, maar posgeld (shiping charges) is giftig (a.g.v. ons swak Rand/$ wisselkoers). My voorstel (as klublede of ander belangstellendes ‘n hand hieraan wil waag) is om as ‘n groep saam te werk, en nie beskikbare onderdele as ‘n enkel besending die land in te bring ten einde op “shipping charges” te bespaar.

The Magnetic Loop Controller tunes the antenna in real time, tracking every movement of the Transceiver VFO. In other words, unlike other magnetic transmitting loop antenna controllers, there is no need to transmit and re-tune for minimum SWR every time the frequency has been changed.

The controller receives frequency information from the Transceiver and calcu-lates an appropriate Capacitor position accordingly. Initial programming of the Controller is an easy Tune and Store operation, one position per 50 or 100 kHz. 200 memory pre-sets can be stored, but in practice much fewer are needed. The Controller tunes in a linear fashion between the stored pre-sets.

The Controller can communicate with the following Radios:

  • Elecraft K3 / KX3art101
  • ICOM CI-V (all relatively recent ICOM HF transceivers)
  • Kenwood TS-480, TS-590, TS-2000
  • Yaesu FT-100, FT-100D
  • Yaesu FT-747GX (not tested yet)
  • Yaesu FT-817, FT-847, FT-857, FT-897
  • Yaesu FT-990 (not tested yet)
  • Yaesu FT-1000MP (not tested yet)
  • Yaesu FT-1000MP MkV (not tested yet)
  • Yaesu FT-450, FT-950, FTdx1200, FT-2000, FT-2000D, FTdx3000, FTdx5000…
  • TenTec Argo V, Argo VI, Eagle, Omni VII… (these have not been tested yet)
  • Pseudo VFO (used with non-serial enabled radios)

Daar word gebruik gemaak van ‘n tipiese stepper motortjie vir die kapasitor verstelling, Let gerus op na die akuraatheid waartoe dit instaat is.

A typical Stepper Motor gives a resolution of 1.8 degrees per step. Each step can be divided into 8 micro steps; hence a 1.8 deg/step motor will give 1600 distinct positions per each full revolution. In other words, the Controller can keep track of a frequency/position pair with an accuracy of 1600th of a revolu-tion, over a range of hundreds of revolutions. This is more than sufficient reso-lution to tune a multi turn vacuum variable capacitor. If you are using a butter-fly or similar air variable capacitor, then you will probably need at least 5 to 1 gear reduction for to get sufficient resolution of the capacitor positioning.

Option: Automatic tuning for best SWR

Other similar controller projects have focused on SWR based auto tuning. This requires “Transmit to Tune” every time the frequency is changed. This Controller, by reading the frequency information from the Transceiver – and by having the antenna characteristics stored in memory – will retune the an-tenna automatically without any need to Transmit.

In other words – not really any need for SWR based auto-tuning.

Having said that : the latest version of the Controller can now also do SWR based auto-tuning. This simplifies the initial calibration/store of frequency + position memories and is useful for one-click recalibration. It also facilitates using this controller with Transceivers that cannot provide frequency infor-mation. This Option also implements a dual-bar graph Power / SWR meter, similar to the one described here (normally not implementing the AD8307 log amp circuitry, however this option is also supported in the firmware).

Actually it is quite amazing to see the SWR auto tune in action; it is blazing fast, takes a couple of seconds or less.

Firmware for the Magnetic Loop Controller

The firmware for the Controller is written in more or less straight C using the Arduino Environment, with Teensy Extensions available here: https://www.pjrc.com/teensy/td_download.html

The firmware is free software, released under the GNU General Public Li-cense.

The complete source code and 3 pre-compiled HEX files are available at the bottom of this webpage, see ML_vXXX.zip.

Note that certain firmware features can be tailored through modification of parameters in the ML.h file included in the source code for the firmware.

The firmware source code is commented throughout and should hopefully be relatively easy to understand/modify/expand/adapt by those who wish to contribute to this project.

Firmware functionality and features

The controller can be described as a manager of memorized capacitor positions, using frequency information from the Radio Transceiver to calculate an appropriate position between any two memorized frequency/positions.

Each memory contains a frequency/position pair, the frequency is stored with a resolution of 1Hz, the position is stored with a resolution of 1600 po-sitions per full revolution, within a range of up to thousands of revolutions (just in case you happen to be in possession of a 1000 turn capacitor 🙂

200 frequency/position pairs can be memorized, but you won’t need to store more than 10 – 15.

art102The controller uses a serial connection to the Radio (TTL or RS232 levels) to enquire once every second which frequency the Radio is tuned to.

The USB port enumerates as a second, virtual Serial port. If set up for seri-al<==>USB pass-through mode this port can be used for Computer control of the Radio. If not in pass-through mode then several USB commands are available. See list of USB commands further down on the page.

A rotary encoder (acts like a VFO knob) and Up/Down switches can be used to initially tune the capacitor when storing the pre-sets or when doing any after the fact adjustments. The rotary encoder/push switch combo is al-so used to navigate a menu of functions, such as storing/managing/deleting memory positions and Setup options; such as the selection of Radio serial protocol and levels, backlash/slop compensation on/off, number of micro steps, etc…

At compile time, End Stop functionality can be set up in three ways, see configuration in file ML.h:

1. Soft End Stops. Vacuum variable, no end-stop switches. In this case one has to take care that the stepper motor is just powerful enough to turn the capacitor but not excessively more so. The Up/Down switches will not work beyond the lowest/highest stored frequency/position and the Radio cannot tune the capacitor beyond the lowest/highest stored position. To go beyond an already “proven” range, one needs to turn the capacitor by turning the Encoder, and store new frequency/positions to extend the range. The downside of this method is that it only works if there is Frequency input available from the radio (“smart” mode).

Hard End Stops. Vacuum variable, end-stop switches. All as 1) except no software “intelligence” to inhibit use of Up/Down buttons or tuning beyond an already “proven range”. Can be used in “smart” mode with frequency input from radio, or “dumb” mode with no frequency input.

2. No End Stops. Butterfly capacitor. Otherwise same as 2).

In all my own loop builds so far, I use method 1, soft end stops.

Power/SWR Meter + SWR Auto tune can be enabled by setting #define PSWR_AUTOTUNE as 1 in ML.h. In case you will be implementing this op-tion, you may also need to tailor other #define[s] to the VSWR bridge that you are using. See #define[s] BRIDGE_COUPLING and VALUE_R15, VAL-UE_R17.

Vir die gene wat meer te wete wil kom of net weer die geheue wil verfris rondom Magnetiese Lus Antennas kan ook gerus die volgende webwerf besoek: http://www.nonstopsystems.com/radio/frank_radio_antenna_magl… (80 -20m Magnetic Loop Antenna by Frank N4SPP).
Lekker lees, en laat gerus weet wat u van so ‘n beheerstelsel dink.
73

art103

 

Huldeblyk vir Pieter ZS6LC / Marten du Preez ZS6ZY

Dit is met groot hartseer dat ons Pieter Scholtz ZS6LC groet wat Sondag 14 Augustus net 5 dae voor sy 91ste verjaarsdag oorlede is na lang stryd teen Alzheimers en ook later longontsteking. Hy was ‘n jare lange mede-amateur en vriend wat ons ontval het en sal hom baie mis.

Pieter het as jongman in die posafdeling van die Poskantoor in diens getree en het oral in die destydse Transvaal afloswerk gedoen. Hy was baie bedrewe in die vroeë jare met die gebruik van morsekode nog met klik-klak metode. Sedert 1950 was hy in Pretoria as administratiewe beampte werksaam.

Hy is op ‘n jeugdige ouderdom deur wyle oom Hennie van der Merwe van Lichtenburg aan amateurradio bekendgestel en sy lisensie in 1947 verwerf. Hy was deurgaans ‘n baie lojale ondersteuner van die SARL en TNT en later Magalies amateur klub. Hy was ‘n radioamateur in murg en been en baie getrou aan die stokperdjie deur ook verskeie proefnemings te doen

‘n Besondere baken op sy pad as amateur is dat hy vir ‘n aantal jare voorsitter van TNT was en ook op die komitee gedien het. As redakteur van Teenspanning het hy eiehandig die blaadjie saamgestel, gedruk en gebind om dit betyds aan ons lede beskikbaar te kan stel. Hy was vir 18 jaar die redakteur van teenspanning.

Daarom is hy beloon vir hierdie uitstaande onbaatsugtige werk met die 2 gesogte toekennings van die SARL nl. Jack Twine en later die hoogste toekenning van lewenslange erelid van die SARL. Hy was ‘n waardige ontvanger van hierdie toekennings. Ons bring hulde aan hom en sê baie dankie Pieter.

Ons sê ook baie dankie vir sy LV Louise dat sy Pieter heelhartig onder steun het en ons Pieter se vriendskap met haar kon deel. Vandag weet ons dat Pieter se stem nie meer op die radiogolwe na al die ver hoeke gedra sal word nie en sy vriendelike stem het stil geword en sal nie meer oor ons luidsprekers gehoor word nie. maar die blywende herinneringe aan hom sal voortleef. .

Saam met Paulus kan ons ook sê: Hy het die goeie stryd gestry, hy het die wedloop voleinding en die geloof behou. Ons gebede is dat Hy wat die hartseer van mense kan verander in dankbare en liefdevolle herinneringe vir Louise en sy kinders Anita, Rene, Frikkie en familie vertroosting en berusting sal bied.