Author: Razvan

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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Elecraft KX3 vs Yaesu FT-817ND

Update:  After a few years of owning the FT-817nd and using alot of other equipment, I revisited this topic: Yaesu FT-817, Elecraft KX3 and other portable HF radios I am looking lately at a transciever for portable operations this summer, and after some reading and thinking I also found a discussion on one of the blogs I follow, where Roger G3XBM posted about the FT817 vs KX3.  This is an interesting issue as the Yaesu FT-817 is basically the definition of portable QRP transcievers, and the Elecraft KX3 is one of the hottest ones out there at the moment, offering a very high-performance reciever in a small and medium-priced package due to SDR-based technology, wich is one of my main interests in ham radio. The first issue one might look at is the price point; an assembled Elecraft KX3 + MH3 microphone + KXBC3 charger is US$ 1120, a standard FT-817ND already comes with mic, charger, battery and an antenna for about US$ 600. An external tuner is an option for both for about the same price, but the KX also has the option of an internal tuner. If you like to mess around with electronics, have some spare time and want to save about US$100 on the KX3, you can get it as a kit and assemble it yourself. Because the two represent different generations of ham radio...

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Lightweight beam antennas: Moxon vs Spiderbeam

The 2013 solar maximum is almost here, the 10 meter band will be booming soon and you cannot let it go by without using a decent antenna; it would be a shame, considering how cheap it is to build yourself a decent performing beam in this band.Today I am looking at two of the most efficient designs that a homebrewer can use for such an antenna: the 3 element Moxon and the Spiderbeam; both are variations of the 3 element Yagi and require just a mast, 4 fiberglass fishing rods and some wires to get going.  Of course, this will mean that both will offer a visible performance increase over a vertical, but either of them will be lightweight enough to use in portable operations or at home, requiring a much cheaper rotator and having less footprint than a solid full Yagi. Lightweight 10m band antennas: 3el Moxon and Spiderbeam The images speak for themselves as how these two antennas are supposed to look like and I won’t go into details about their history or building instructions, there is alot of that around the internet already. What i’m interested in is their performance, so I ran a few simulations with EZNEC; the settings are these: –  15 meters above medium ground (0.005 / 13)– 1mm copper wire with 0.3mm PVC insulation–  tuned for optimal SWR from 28 to 28.5MHz...

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