30 septembrie 2013

Experience put to work


The time has come to change the hobby for a more professional way of doing things. Therefore, among with my buddy, Edi, YO3HCV, we started a little enterprise for professional projects dedicated for targeted high-end clients.
SynergyBYTE is the concept that describe our team.
It's an open team but don't call us, we will ask you to join us.

26 septembrie 2013

TRBONET IPSC for Radioamateur DMR YO Net

Today is a great day! I manage to connect two DR3000 repeaters into a IPSC network. Well, I tried before but something seemed to be wrong as I didn't manage to hear a QSO from one repeater's frequency to another! Only after I put both repeaters under a router I had the IPSC running! Maybe this is a clue for other experimenters like me!

08 septembrie 2013

Antena gonflabila pentru CUBESAT

Professor Sara Seager KB1WTW - Image credit MITO echipa de cercetatori de la MIT (Massachussets Institute for Technologies), condusa de  Alessandra Babuscia anunta dezvoltarea unui nou proiect de antena pentru microsateliti cunoscuti sub numele de CubeSat.
Datorita dimensiunilor mici, microsatelitii folosesc in prezent antene dipol sau monopol. Datorita dimensiunilor, aceste antene au castig relativ mic ceea ce restrictioneaza largimea de banda utilizabila pentru transmisia informatiilor catre statiile la sol; o antena cu castig mai mare ar permite cresterea acestei largimi de banda.
Professor Sara Seager KB1WTW – Image credit MIT

Echipa MIT, condusa de Alessandra Babuscia  este parte a unui grup de cercetare compus din radioamatori din care fac parte Profesorul Sara Seager KB1WTW, Mary Knapp KB1WUA, Benjamin Corbin, Mark Van de Loo - absolventi MIT,  si Rebecca Jensen-Clem de la California Institute of Technology.
Noul design conceput de echipa poate creste semnificativ distanta de comunicatie al acestor sateliti, permitandu-le chiar instalarea pe orbite mai inalte. Echipa a construit si testat antena care ocupa un spatiu restrans in satelit si se poate umfla odata ce acesta a ajuns pe orbita.
Echipa sustine ca distanta la care se poate comunica cu ajutorul acestei noi antene creste cu pana la 7 ori fata de distanta acoperita cu antenele CubeSat traditionale.
Alessandra Babuscia - Image Credit MIT
Alessandra Babuscia – Image Credit MIT
“Cu aceasta antena vor fi posibile comunicatii chiar de pe Luna”  sustine Alessandra Babuscia, care conduce acasta cercetare in cadrul studiilor postdoctorale la MIT. "Aceasta antena este cea mai ieftina si mai economica solutie la problema comunicatiilor" mai afirma cercetatoarea.

Pudra "magica"
O antena gonflabila nu este, de fapt, o idee noua. De fapt, experimente anterioare au demonstrat validitatea principiului pe sateliti mai mari. Sistemul insa necesita o serie de dispozitive specifice (valve de presiune, rezervoare de gaz) care ar ocupa un spatiu pretios in microsatelitii CubeSat. Babuscia ridica si o alta problema de ordin practic: un satelit cu dispozitive presurizate la bordul rachetei purtatoare poate pune probleme pentru securitatea incarcaturii, mai ales ca microsatelitii sunt, de regula, incarcatura secundara. Ei pot exploda, cu consecinte dezastruoase pentru echipaj si incarcatura principala.
Din acest motiv, s-a cautat o alta metoda pentru umflarea acestor antene.

Mary Knapp KB1WUA - Image credit Interplanetary Small Satellite Conference
Mary Knapp KB1WUA – Image credit Interplanetary Small Satellite Conference

Echipa de cercetare a gasit o alta metoda constand in sublimarea la presiune zero a unei pulberi . Aceasta inseamna ca o pulbere, expusa presiunii din spatiul cosmic se va transforma, din stare solida, direct in gaz.

Testarea ideei
Babuscia si colegii sai au construit doua astfel de antene, folosind Mylar: una in forma conica si a doua in forma cilindrica. Au determinat configuratia optima la pliere si au reusit sa inghesui aceasta antena intr-un spatiu de 10cmc.
Au testat apoi modul in care antena se umfla, intr-o camera vidata iar testul a avut rezultate pozitive.
Rebecca Jensen-Clem - Image credit Interplanetary Small Satellite Conference
Rebecca Jensen-Clem – Image credit Interplanetary Small Satellite Conference
Echipa a testat apoi caracteristicile  electromagnetice ale acestei antene. In simularile celor doua geometrii, s-a constatat ca antena de forma cilindrica se comporta mai bine decat cea conica.
Desi, cu potential major, antena din Mylar subtire poate fi vulnerabila la fragmentele meteoritice sau chiar la deseurile care pot fi intalnite pe orbitele joase; una din solutiile pentru a compensa micile perforatii ar fi o rezerva suplimentara de pulbere care sa compenseze pierderile de presiune din antena.

MIT student with a CubeSat - Image credit MIT
MIT student with a CubeSat – Image credit MIT

Kar-Ming Cheung, inginer la Laboratorul de Propulsie Reactiva de la NASA (JPL), specializat in comunicatiile spatiale a afirmat ca o antena directionala a fost, pana acum, in afara discutiei referitoare microsateliti si ca "aceasta idee este foarte promitatoare".

Students build a 3U CubeSat - Image Credit NASA
Students build a 3U CubeSat – Image Credit NASA

Traducere si adaptare, Adrian, YO3HJV. 
Articolul original: http://amsat-uk.org/2013/09/07/inflatable-antenna-could-give-cubesats-greater-reach/

Hamradio contesting - a menace to hamspirit

Well, some will say that i am wrong only by reading the title...
As a foreword, it is not my intention to blame contesters.
I am in my early 40 and have a busy job, some other particular projects and can operate my radio in weekends.
I do not have, yet, established a "big-gun" station; only 100 W from a FT2k, a vertical and a Inverted V antenna on the rooftop of my building.
I also have some familly obligations here so I cannot stand in front of my radio to make QSOs in weekdays.
The only time I have for chatting is in the weekends, even in holydays BUT...
Yeah, you already know!
Try to search a weekend WITHOUT a contest!
As a practical observation, not a single weekend for old fashion hamradio QSO in this summer! Everytime I powered up the radio, there was a contest. thousand of Watts, QRM from "Russian QRP" and all you can hear are contest exchanges and the ubiquitous "599".
Is this hamradio? I think is not!
The regulations - at least in YO - ask for operators to send a REAL REPORT in the QSO's. I don't know how, but in the contests I NEVER heard a REAL REPORT based on Strenght, Rediability and Tone!
We, the OM, teach the younger how to sent a receiving report in a QSO. The contest means that the contesters are tested about the capacity to copy signals, to wrote the (correct) informations in a LOG and to sent back some (correct) informations AND to make a certain number of QSO's in the contest time..
Instead, the contest become more and more a speed run.
I am bored of local QSO's about weather and cristal sets; I want to discuss with other hams about Emergency comms, about how their local clubs manage to keep the team, about new technology.
Well, it is almost impossible to do so in weekends on shortwave!
Try this on a contest!
The progress in hamradio, at least in the last years, means big antennas and QRO mainly for the contest activity.
It is almost impossible to chat with a fellow ham about new receving techniques, about new modulations or something like that!
The ham bands was established also for experimenting but, at least on IARU bands, you hardly find a non-contesting segment to do some tests with a faint signal station... Spletters and QRM.
So, more and more, the experimenting activity moved to internet discussion groups which, in my opinion means death to real hamspirit! The contesting is only a fraction of that!

73 de YO3HJV.

The picture is courtesy of http://k5go.com/

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