Oude "DX News"-berichten
2011
27-12-2010
Ingediend door: ON4AVJ
Het nieuwe jaar is aangebroken, en in naam van de VHF commissie en mezelf wens ik iedere lezer en zijn familie het beste toe voor 2011. Ik wens jullie ook veel plezier toe met de hobby.
Traditioneel is dit de periode om even over de schouder te kijken naar het voorbije jaar. Het was het jaar van mijn eerste kennismaking met de werking van de C5 commissie binnen de IARU (VHF commissie). Dit jaar hebben we ook de eer gehad om de IARU R1 50MHz contest te organiseren. De volledige uitslag is te vinden op de VHF pagina’s van onze website. Maar ik wens alvast een dikke proficiat te wensen aan de ploeg van E7DX (multi-op) en aan TA2ZAF (single-op).
Het was ook het jaar dat we met een vernieuwde ploeg van start zijn gegaan. Het resultaat was zichtbaar in de VHF rubriek in CQ QSO die regelmatig gevuld werd met artikels.
Dit nieuwe jaar staat in het teken van het herbekijken van het RIO en het Vademecum om u nog beter van dienst te zijn. We zijn dan ook van plan op tijdens het UBA-Congres een “open VHF Commissie” te organiseren, maar daarover later meer.
ON4AVJ
VHF Manager
Dutch Amateur Contest (DAC)
16-10-2010
Ingediend door: ON4AVJ
I am very pleased to inform you that the VERON VHF commission has decided to approve my proposal to introduce the Dutch Amateur Contest (DAC).
The first contest will be Tuesday January 4 in line with the NAC and the UKAC. The bands and dates are exact copies of the NAC.
50 MHz in Oman
13-08-2010
Ingediend door: ON4AVJ
In a letter dated 4 August 2010, Brgd. Abdulrazak Alshahwarzi, A41JT, the Secretary General of the Royal Omani Amateur Radio Society, informs that the 6 metre band (50 – 52 MHz) has been allocated for the Amateur Radio and Amateur Radio usage by the Telecommunications Regulatory Authority in the Sultanate of Oman, on a secondary basis, effective June 2010.
Radio amateurs in the Sultanate of Oman hope to work you on the "Magic Band."
QRP moonbounce on 5.7 GHz
14-07-2010
Ingediend door: ON4AVJ
Hi all,
Good activity on 5,7 GHz EME was expected during the second week-end of july, thanks to the coordination of G3LTF.
I decided to have a try, using my 2,3 m offset dish and the system used normally for tropo and rain scatter.
This system consists of a transverter kit from DB6NT and a modified surplus 6 GHz amplifier, giving about 8 W output.
Noise figure of the system is around 1 dB.
The 5,7 GHz transverter has an output on 144 MHz and is followed by another transverter 144 to 28 MHz.
There are various 28 MHz outputs. One output goes to a yaesu FT840 HF transceiver.
Another output goes to an SDR, and another one to a calibrated 28 MHz receiver, allowing precise measure of sun noise and moon noise.
During operation, permanent reading of moon noise allows perfect aiming of the dish and confirms that the system is working alright.
Most EME stations use circular polarization, so a "septum feed" was built following a description by OK1DFC.
Dimensions were adapted in order to illuminate correctly the offset dish.
After optimizing carefully the position of the feed, I could measure 0,5 to 0,6 dB of moon noise versus cold sky. Sun noise was a good 10,5 dB, meaning that the receiving side was working correctly. The feed has some sidelobes and is far from perfect, but efficiency seems to be quite good.
Now the results: during the week-end, 13 stations from Europe, USA and Japan were heard.
To my great surprise, some of them were even able to decode my QRP signal and 3 good QSOs resulted !!!
Conclusion: this band offers very interesting possibilities for the experimenter.
Tropospheric propagation and rain-scatter allow surprisingly good distances even with very small set-ups.
The above results also shows that EME contacts are possible with very low power, thanks to the amazing receiving capability of some stations.
73
Eric
ON5TA
Good activity on 5,7 GHz EME was expected during the second week-end of july, thanks to the coordination of G3LTF.
I decided to have a try, using my 2,3 m offset dish and the system used normally for tropo and rain scatter.
This system consists of a transverter kit from DB6NT and a modified surplus 6 GHz amplifier, giving about 8 W output.
Noise figure of the system is around 1 dB.
The 5,7 GHz transverter has an output on 144 MHz and is followed by another transverter 144 to 28 MHz.
There are various 28 MHz outputs. One output goes to a yaesu FT840 HF transceiver.
Another output goes to an SDR, and another one to a calibrated 28 MHz receiver, allowing precise measure of sun noise and moon noise.
During operation, permanent reading of moon noise allows perfect aiming of the dish and confirms that the system is working alright.
Most EME stations use circular polarization, so a "septum feed" was built following a description by OK1DFC.
Dimensions were adapted in order to illuminate correctly the offset dish.
After optimizing carefully the position of the feed, I could measure 0,5 to 0,6 dB of moon noise versus cold sky. Sun noise was a good 10,5 dB, meaning that the receiving side was working correctly. The feed has some sidelobes and is far from perfect, but efficiency seems to be quite good.
Now the results: during the week-end, 13 stations from Europe, USA and Japan were heard.
To my great surprise, some of them were even able to decode my QRP signal and 3 good QSOs resulted !!!
Conclusion: this band offers very interesting possibilities for the experimenter.
Tropospheric propagation and rain-scatter allow surprisingly good distances even with very small set-ups.
The above results also shows that EME contacts are possible with very low power, thanks to the amazing receiving capability of some stations.
73
Eric
ON5TA
Een oplossing voor probleem simplex hotspots op dezelfde frequentie.
30-05-2010
Ingediend door: ON4AVJ
Simplex hotspots , die dezelfde ontvangst en zendfrequentie hebben, kunnen mekaar storen. Bijvoorbeeld omdat ze zich dicht bij mekaar bevinden of wanneer er goede propagatie is. Wanneer hotspot 1 data uitzend die het via de gateway aangevoerd krijgt, dan zal hotspot 2 dit ontvangen. Deze ontvangen data zal de hotspot op haar beurt weer via de gateway sturen. Zo ontstaat er een lus die het systeem in war brengt. Om dit probleem op te lossen kan je 2 dingen doen: ofwel kies je de frequenties zorgvuldig zoals dat met repeaeters bebeurt. Ofwel zorg je dat de DVAR software van de hotspot ingrijpt. Omdat de uitgezonden data-stream voorzien is van het callsign van de zender, kan je via de software bepalen of de ontvangen stream al dan niet via de gateway ‘mag’ doorgegeven naar het systeem. Door de callsigns van alle hotspots die op de zelfde frequentie op een ‘blacklist’ te zetten, zijn de gevlogen opgelost op sofware-niveau. Op RF-niveau (het zenden en ontvangen via de ether) blijven de storingen bestaan. Die kan je echter niet horen maar ze zijn er wel: zwakke signalen zullen niet ontvangen worden door de hotspot omdat die een andere hotspot ontvangt. Hier kan alleen maar beperking van het uitgezonden vermogen en een degelijke frequentie keuze op basis van de plaats een oplossing bieden. Meer over dit toch wel erg knap bedacht systeem hier en hier.
Croatian 50/70 MHz Contest
13-05-2010
Ingediend door: ON4AVJ
Croatian Amateur Radio Association invites you to participate in the third Croatian 50/70MHz contest on Saturday, May 15th 2010 from 12.00-17.00 UTC.
Contest rules can be found at: http://www.hrvhf.net/upload/croatian_50_70mhz_rules.pdf
Prizes: The first three stations in each category PLAQUES
Logs you can put by yourself on our VHF contest robot www.hrvhf.net Contest tab > upload EDI.
It's very simple.
73
Mate 9A4M
Croatian VHF/UHF/mw manager
ON0VHF and propagation....
11-05-2010
Ingediend door: ON4AVJ
DL7AFB wrote tu us about ON4VHF....
Dear OM's,
Dear OM's,
during last VHF contest I made a record of your beacon ON0VHF, which is always audible from my fieldday location in JO62JA, 588km away. Conditions were moderate, but the beacon was readable anyway.
Please listen to the sound sample on YouTube: http://www.youtube.com/watch?v=neVnSNYYmNE
best regards
Bodo, DL7AFB
D-Star Linking v 2.0 beta is er !
28-02-2010
Ingediend door: ON4AVJ
Het is al weer meer dan een jaar geleden dat D-Starlinking v1.0 gepubliceerd werd. Sindsdien is de PDF ervan het net rondgegaan en dat was de bedoeling . Ondertussen zijn we wat verder en er is heel wat gebeurd op dat jaar: zelfbouw repeaters staken de kop op. D-plus werd verfijnd, X-trust stak de kop op, GMSK kan zonder een chip en via PC. De DV-Dongle werd de basis voor een zelfbouw transceiver . Meer en meer gebruikers haalden een D-Star transceiver in huis of bouwden een DV adapter. De Hotspots en zelfbouw repeaters schoten als paddenstoelen uit de grond. Veel verandering en dus meer vragen waar op moet geantwoord worden . Dat willen we vooral met dit boekje, want dat is het ondertussen geworden. Vragen beantwoorden en iedere amateur of geïnteresseerde zicht geven op wat D-Star is, hoe het werkt en hoe het te gebruiken. Op – en aanmerkingen zijn steeds welkom !
Klik op foto voor download.
Nog meer downloads hier.
First contact JA-ON on 3cm
28-02-2010
Ingediend door: ON4AVJ
Yesterday Eric, ON5TA had a first QSO with JA on the 3cm Band EME.
Congratulations....
The QSOs needed quite a lot of preparation work, because japanese hams are only allowed to transmit on 10.450 MHz, not on 10.368 MHZ.
So a new receiving system had to be build here in order to be able to make "crossband" contacts.
We also needed a common window and the best possible moon conditions. These conditions were met yesterday, but wind could have been a problem.
The japanese hams used big 5 to 6m dishes, very sharp on 3 cm, which make aiming to the moon very difficult with the slightest wind.
As you know, we had wind here yesterday evening, but it was manageable during the QSOs
This why JA4BLC is talking about "a miracle" in his mail. HI !
A little piece of the mail of JA6CZD
Hi Eric,
Yes, QSO by ON5TA-JA6CZD is the first ever between ON-JA on 3cm EME, GREAT!
Me too very much pleased to work you. You are MY #3 on 3cm EME and good signal as well as G4KGC I worked 30minutes before.
It was miracle no wind happened during our QSO.
Iceland on 70MHz
22-02-2010
Ingediend door: ON4AVJ
On February 19, 2010 The Post and Telecom Administration in Iceland granted a temporary experimental access to the 4 meter band in Iceland. The permit is valid until December 31, 2010.
Frequency span: 70.000-70.200 MHz. Access is granted on secondary basis. Maximum bandwidth is 16 kHz and power limit is 100 W.
Licensees need to apply to the PTA for a special license. The experimental license is open to both “N” and “G” license classes.
Frequency span: 70.000-70.200 MHz. Access is granted on secondary basis. Maximum bandwidth is 16 kHz and power limit is 100 W.
Licensees need to apply to the PTA for a special license. The experimental license is open to both “N” and “G” license classes.
