# Link to SARL VHF, UHF & MICROWAVES DX TABLE Click here
In today’s tutorial we focus on Satellites. Four years after the launch of Sputnik 1 the first OSCAR was launched from the USA with a beacon transmitter on board. OSCAR is the acronym for Orbiting Satellite Carrying Amateur Radio
On 3 March 1969 AMSAT was established in the US. The first few OSCARS carried only beacons. AMSAT OSCAR 6 was the first amateur satellite that carried a transponder. This was the beginning of phase 2. Phase 3 are high altitude satellites such as OSCAR 10 and 13 and phase 4 will be geostationary amateur satellites. The first geostationary amateur satellite will be Es’hail – 2, to be launched later this year. It is sponsored by the Qatar Amateur Radio Club with the payload having been built by AMSAT DL. It will provide great coverage over Africa and Europe
The phase 2 satellites were very popular during their short lifespan, and were joined by several Russian RS satellites with downlinks on 29 MHz. As launches became expensive and free launches were difficult to secure, radio amateurs joined the Academic fraternity which developed the CubeSat concept, a small 10 x 10 x 10 cm satellite. The advances in electronics and miniaturisation of components has made it possible to pack almost as much capability in a CubeSat as in the earlier phase 2 amateur satellites.
To operate a CubeSat in FM mode during overhead passes all you need is a handheld transceiver for 435 MHz and 145 MHz, but if you wish to work other satellites then you will need an all mode rig, and a small beam such as 145 and 435 MHz Yagis on a portable boom, or an arrow type, to increase your range. The current record for amateur satellites is about 8000 km, and can only be achieved with higher gain Yagis and higher power.
South Africa has one CubeSat in orbit, TshipisoSat, developed and built by students at the Cape Peninsula University of Technology. Currently AMSATSA is developing and building a CubeSat for now called Kletskous. It will have a 70cm up, 2 metre downlink transponder as part of its payload. You can find more about Kletskous on www.amsatsa.org.za
Next week we will look at Moonbounce (EME)
VHF, UHF & MICROWAVE NEWS
THE RADIO SPECTRUM ABOVE IS WHERE THE FUTURE LIES FOR RADIO COMMUNICATIONS
Radio communications started off on long and medium wavelengths, first on Maritime Mobile spark transmissions, and later followed by AM Broadcasting. After radio amateurs discovered Shortwave DX communications the commercial world rushed down to Shortwaves too to make their worldwide transmissions. In time commercial stations realized that they need more bandwidth to operate their TV stations and also FM Broadcasting stations, which was then available on VHF.
With the advent of commercial satellite operation DSTV became possible on the Ku Microwave bands. But for a small group, most radio amateurs were reluctant to explore these higher frequencies except for repeater operation on VHF. Fortunately there were a number of overseas amateurs who ventured to experiment on the microwave bands even as high as the Terahertz spectrum. What has now become clear is that DX can be worked almost daily on EME when the Moon is visible, using small portable dishes, low power and digital on microwave frequencies, which could be a boon for townhouse EME operation.
REPORTS OF RECENT SARL VHF/UHF CONTEST – “I think the analogue leg went well – you always have the ones saying the opposite as they have no antenna or psu connected to the vhf and rigs above, Hi. I must really get skilled in CW – missed a lot of opportunities but I tried at least. Had a sort of success with Andrew ZS2PA but not for logbook logging – we both tried our hand at CW. We did test on voice too but then decided CW will be better for hearing something definite – it was done on 6m. Pieter V51PJ.”
Thanks to everyone that made contact with ZS1CRG in Piketberg this weekend for the SARL VHF/UHFAnalogue Contest. Just following up on the forum conversations, we mostly had FM contacts on both 2m and 70cm. It should be remembered that most new hams are keen to participate but lack equipment with SSB and often are using one or other cheap Chinese handheld to get into things. This should not hold them back from participating at all. We made contacts with quite a few hams in Cape Town over the weekend running 5-Watt handhelds or a questionable setup by their own admission and low power but still able to make a QSO at +/- 100 km distances on FM.
There is a lot said of these cheap Chinese radios but we can't ignore they open up the 70 cm band in particular for contacts that otherwise would not have existed for us despite being FM only. With a good external antenna or going to a high site, much can still be achieved for the new amateur using these. Just go out there and try! Unfortunately conditions just didn't work for us on SSB while pointed up north this weekend on 2m. We did note certain times of the day however seem to favoured 70 cm over 2m with the same distance covered and same power used. Thanks for a great contest again. 73 Dieter ZS1CRG.
“Was mobile along the Cape West Coast on Saturday afternoon and evening. Thank you ZS1CRG for giving me my longest distance 70 cm contact ever! Interesting that without changing equipment on both sides (just QSY from 145 MHz to 433 MHz) the audio is much better on 70 cm than on 2 metres. Dieter, the OM in Kleinzee (possibly Kobus ZS3JPY) has told me a few months back that he works two stations in the Piketberg area on 2m simplex fairly often, but has never been able to work via the 145,625 MHz repeater on top of the Piketberg mountain. Perhaps the Piketberg being "free-standing" on a fairly open countryside protrudes above the inversion layer? The same effects have been reported from Mont Aux Sources and Cathkin peak in ZS5. 73 Ean Retief, ZS1PR.”
REMINISCENCES OF SOME BYGONE VHF DAYS BY PIETER V51PJ –
“I also tried 2m with the guys on Piketberg Mountain – that made me think of the ZS2BWB incident. They were testing a 70 cm antenna – a rubber duck style at Piketberg Mountain while assembling the Yagis. Ken Tremeer, ZS2BWB, responded on their call and gave them a report. Of course they thought it was someone pulling a stunt on them. I also asked them to please respond to Ken’s call as it is a new UHF record to start and a once in a lifetime happening. To say the least Ken was not pleased at all with them. When they realized that it was indeed a ZS2 opening on 70 cm between Piketberg and Port Elizabeth it was far too late – no more good conditions at all.
“Same happened with me one year – I was still ZR1AEE then – new in the VHF arena and a 4-stack 10-element 2m Yagi array pointing to ZS6. I heard people call – called them back and the ZS6 field station I think it was West Rand then - they still went to a mountain or hilltop then for field day events and for contests. Ettienne ZS6Y still gave me their cell phone number and I called them to say that this is a real call. Well we also did SSTV and PSK31 then on 2m – a once in a lifetime happening. I booked the analogue and the digitals on the logs then for the competition – to me as a newcomer it was thought that it is normal to work ZS6 from ZS1 on 2m as it was my first competition then – I can’t remember if it was PEARS or SARL competition then. Today I know better – it is a once in a lifetime happening!
“The days when we had no 4m yet – only commercial 4m – me and my dad built 4m handhelds then from modifying Uniden VHF portables – all passed sabs tests. We were busy in the workshop in Bellville when we heard Italians talking on the one 4m repeater based in Cape Town then. We – me and Shawn ZR1EV realized that the 4m band is open to Europe from ZS1 – now these portables were rated 7 Watts then – we connected it to the 4 stack dipole array and had QSO’s on simplex 4m commercial frequencies to taxi drivers etc in Italy – yes the English was an issue added the dialect too, This happened for 2 weeks continuous – we had to actually switch all local repeaters off as the Italian repeaters were coming in sometimes stronger than the local repeaters on 4m
“But again the point I want to make is to be there and to be aware that the bands are open – we just don’t know to where – take WSPR on HF as well as FT8 on HF as an example – activity shows where the bands are open although every day we hear – HF is dead. The sunspot is so low that they can’t even issue a number to it but the contacts are still there. If we can get activity in Africa south of the equator it will definitely bring a big change in VHF to light. What the African States can do in the meantime is to monitor our FM Broadcasting stations between 87,5 to 108 MHz near our northern border for openings on Tropo Ducting and Sporadic-E, which should inspire them.”
TWO-WAY SIGNALLING POSSIBLE WITH A SINGLE QUANTUM PARTICLE –
Classically, information travels in one direction only, from sender to receiver. In a new paper, however, physicists Flavio Del Santo at the University of Vienna and Borivoje Dakić at the Austrian Academy of Sciences have shown that, in the quantum world, information can travel in both directions simultaneously—a feature that is forbidden by the laws of classical physics. In classical communication, such as email, text message, or phone call, a message is embedded in an information carrier, such as a particle or signal that travels in only one direction at a time. In order to communicate in the other direction using the same information carrier, it is necessary to wait until the particle arrives at the receiver and then send the particle back to the sender. In other words, it is classically impossible to perform two-way communication by using the single exchange of a single particle.
However, this is exactly what Del Santo and Dakić theoretically show. To do this, they use a quantum particle that has been put in a superposition of two different locations. As the physicists explain, being in a quantum superposition means that the quantum particle is "simultaneously present" at each partner's location. Therefore, both partners are able to encode their messages into a single quantum particle simultaneously, a task that is essentially impossible using classical physics. ‘Consider the simplest scenario, where two players, Alice and Bob, want to exchange a simple bit of information, i.e., either 0 or 1," Dakić explained. "They encode their respective bits (messages) at the same time, directly into the superposition state of a quantum particle. Once the information is encoded, the partners send their 'parts of quantum particle' towards each other. Positioned halfway in between Alice and Bob is a unitary device, which may be experimentally implemented by, for example, a beam splitter.
"Conditioned on the messages that the particle carries, when the particle hits the unitary device, it bounces back either to Alice or Bob deterministically," Dakić said. "More precisely, the unitary device guides the particle a 'smart way,' such that, at the end both Alice and Bob get the bit (message) that has been sent to them. For example, if the particle ends up with Alice, she would know that the Bob's bit was just opposite from her bit, and vice versa."
So in the end, both players send and receive a message—all within the same amount of time it would take to send a one-way message using a classical particle. These theoretical results have already been verified by a new experiment using single photons, reported by Del Santo, Dakić, and their co-authors. The experimental results further strengthen the new concept by showing that the communication is secure and anonymous. In particular, the direction of communication is hidden—an eavesdropper cannot tell who the sender is and who the receiver is. Consequently, the results may lead to improvements in quantum communication that has advantages in terms of both speed and security.