Author: Razvan

V53ARC – multiband WSPR beacon in Namibia

In the last few days my station has been running continuously on WSPR frequency hopping between the 80m, 40m, 20m and 10m bands, and I got the chance to spot on 10 meters the V53ARC WSPR beacon in Namibia. Apparently it is on the air since 2009 and this is the first time I spot it, and by looking the callsign up over the internet I found it’s story. The beacon is maintained by the Namibian Amateur Radio Centre and it is installed remotely on a farm, running on solar power and using a vertical multiband antenna. It transmits continuously with 1W of RF power, cycling trough the 80m/40m/30m/20m/17m/15m/10m/6m bands, meaning it will transmit a WSPR sequence of 2 minutes every 16 minutes on each band. The transmitter is the work of Gernot Frauscher OE1IFM and it’s a smart design, properly built for the purpose, with a CPU controlling the AD9851 DDS, a GPS reciever for precision timing and frequency reference and a 15W final stage with switched LPF. You can find more details about it – including schematics over at OE1IFM‘s website; he also describes the multiband vertical he used for the beacon, wich seems a good solution for the space limited individual. Looking on the WSPRnet website I see it gets a fairly low amount of spots, about 10 each day; there aren’t too many WSPR stations...

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DXpedition videos – VP6T, 3D2C, BS7H, 5A7A, AH1A

 Ever since the beginnings of my ham radio adventures i’ve been curious about operating from parts of the world the civilisation hasn’t reached yet; I guess it’s one of the few ways you can still be a hands-on pioneer these days. Dxpeditions, SOTA, IOTA, you name it, I want to see how it has been done and how was the feeling to do such a thing, what equipment did they use and what challenges they had to overcome, how they laid out their antennas or how much planning was put into. Recently have been published two videos of DXpeditions that took place last year. The first one is 3D2C in Conway Reef, wich doesn’t have an embed option so you need to check this link out in order to view it: 3D2C Conway Reef 2012  The second one is VP6T Pitcairn Island, you can check it out below: There are also older DXpedition videos that I really enjoyed, made just like a documentary with plenty of info: 5A7A Libya (2006) BS7H Scarborough Reef (1997)  And finally, the oldest but best, AH1A Howland Island (1993) I will probably post more of these, I still have alot in my list of...

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Over the Horizon radars and ham radio interference

Since the early days of the cold war and culminating with the Russian Woodpecker, ham radio operators have reported powerful jamming-like wideband signals creating disturbance in the amateur short wave (HF) bands. These are created by powerful over-the-horizon (OTH) radars that use the HF spectrum to “visualize” significant portions of the entire planet in just one sweep by using the all-so-loved (by us amateurs) phenomenon of ionospheric reflexion. Thanks to my geographic location and to the fact that i use a SDR transciever with panadapter/waterfall, it so happens that almost daily i get to identify an OTH signal somewhere in the HF spectrum, so I got a bit interested; and when i saw EI2KC’s post earlier today about the incredibly strong OTH signal recieved by S57S just a few days ago, I thought I should put my thoughts in writing. The most famous OTH radar is of course the soviet cold-war megalomanic station DUGA-3, the fully grown brother of the smaller and experimental DUGA-1 and DUGA-2. This mutant is located in the Chernobyl exclusion zone, the transmitter and reciever being about 60Km apart. The sight of such an installation, taken offline in 1989 and now deserted, brings chills down my spine. The huge array of wideband Nadenenko dipoles and reflector plane coupled with the powerful transmitter managed to put out reported EIRP up to 40MW (!). The signal was...

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WSPR and antenna radiation pattern

WSPR seems to be not just a tool for actively monitoring the propagation status, but it can also help you trace the radiation pattern of your antenna. Of course, for a reasonable trace we would need WSPR stations all over the world using all types of antennas, but I guess we will have to make do with what we have for now. This is the result of about 6 hours of WSPR in the reliable 40m band, from 04:00 to 10:00 local time, running 10W, 10% transmit cycle and a Windom antenna. The north-west / south-east patterns seem to be predominant, but we must also take into account the fact that there are just a very few WSPR stations in Russia, Africa or South America, some of them were active (like PY2FLP) as I could see in the WSPRnet.org spot database, but no spots for me. Then there is also the antenna’s takeoff angle, wich makes the wave “land” at a certain distance from where it’s transmitted; lower angle means your signal will go further, so the fact that I got alot of spots from the East coast of the USA but none from the West means my takeoff angle should be a bit lower if I want to work that region.   This can also be observed by looking at the closest spots, OK3SAM, IK3NLK or USP041 all...

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SDR Basics explained

I just found a great video that explains exactly how Software Defined Radio (SDR) works, directly from the guys at FlexRadio. If you’re interested in SDR, in ham radio or radio communications in general, this is one educative piece of material you can’t miss. It’s about 1 hour long though, so you might want to bookmark it for the weekend. Thanks K9ZW for the find...

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Kenwood TS-990S revealed

The long awaited contest-class rig from Kenwood, the TS-990S, is bound to make the grand debut probably this month, after a series of teasers have stirred up the spirits and imagination of amateur operators all over the world. Kenwood openly states they tried to put their best into the TS-990S, trying to achieve the ultimate contest and DX legend transciever status, and this reflects just by having a quick look at the black button-fest beast. But, the specs are just as overwhelming: dual independent recievers, +40dBm IP3 for the first mixer thanks to a double balanced grounded switch type architecture, triple DSP (2x Analog ADSP-21363 @ 333Mhz and one ADSP-21369 @ 260MHz), double AGC (analog and digital),  double TFT displays and 200W output from a pair of VRF150’s, just to list a few of the most interesting figures. Of course, all you need to know at the moment cand be found in the detailed 16 page brochure kenwood has released: Kenwood TS-990 Detailed Brochure Another figure you might be interested in is the recommended retail price, wich is about 6300EUR + VAT over here in Europe, or US$ 8000 for our friends across the pond. An older official Kenwood video popped up some time ago, showing the heritage behind the TS-990S as well as a few of it’s key points of interest: While it looked nice and dandy, it...

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Flex SmartSDR revealed

SDR technology is probably the biggest thing in ham radio in the years to come, and the direct digital sampling based transcievers can offer a whole new range of posibilities to the avid amateur operators. The Flex-6000 series looks to be a great exponent of this technology and probably a key turning point in amateur radio equipment history – for us folks that follow such a thing of course, and recently FlexRadio has released more details about how the new concept will work and how the software needed to operate the new transcievers looks and feels.   The software’s name is SmartSDR and it is a completely new concept, not some refresh of PowerSDR like I thought it would be. The interface is very clean and well designed, showing just the important things you need to see and doesn’t fill the screen with unnecessary buttons as long as you can drag or expand. It looks too reciever-oriented though, but I must assume there is some kind of panel that you can reveal in order to properly operate it as a transciever or better yet, an external interface with buttons and knobs such as the Woodboxradio Tmate2. The fact that you can use multiple recievers on the same speakers at the same time *might* be something awesome, the left-right balance allows for good space sound positioning and the human brain...

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Tmate2 – external CAT console

SDR recievers and transcievers often suffer from the lack of a proper interface with the user;  the computer’s mouse and keyboard do not offer the same warm feeling of direct control as a proper knob and a nice set of firm buttons for some users, therefore external consoles have found their way to the market. One of those consoles is the Woodboxradio Tmate, wich is out there for some time now, connects to the computer via USB and can control anything CAT/Vcom compatible, PowerSDR and most transcievers included. It is basically a nice little box with one knob and 4 programmable buttons, nothing fancy, and for 189 Euro it fill your need to grasp something not virtual while you talk to your other ham radio friends. Now enter the Tmate2, wich is the same thing on steroids and Chernobyl radiation at the same time: it grew a few more smaller knobs, a few more buttons and a nice LCD display with frequency indication, mode, s-meter and a few other useful bits. No other info on what it can or should do, but looks like a nice complement to the latest SDR transcievers and i dare to say, almost necessary if you plan to do serious operating with your PC-based...

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