AmateurRadio.com

As Steve announced a week ago, CLE192 was a special NAVTEX edition. I like NAVTEX for several reasons. It’s an open format, easily decodable and messages are mostly in plain English. Then it’s just like fishing with a fish pod: you can leave your setup on over night and in the morning see what nice DX you have caught.

Normally I use the FRISNIT software for decoding NAVTEX. It’s plain and simple and messages are stored in plain text files. This time I tried YaND (Yet another NAVTEX Decoder) and found it to be better in decoding weak signals than FRISNIT. I don’t like the interface and message handling, but those are minor issues.

Here is my list of catches:

YYYYMMDD HHMM KHz ID CALL STATION,COUNTRY DIST (Km)
—————————————————————-
20150327 1604 518 $13A UIK Vladivostok,RSE 2377
20150327 1656 518 $11F HAS Bangkok (Nonthaburi),THA 2525
20150327 1700 518 $11G JNB Naha ,JPN 723
20150328 1500 518 $11H JNR Moji,JPN 1359
20150327 1507 518 $11I JGC Yokohama ,JPN 2199
20150330 1737 518 $11J JNL Otaru ,JPN 2730
20150326 1519 518 $11K JNX Kushiro ,JPN 3010
20150327 1812 518 $11N XSQ Guangzhou,CHN 773
20150330 2218 518 $11O XSL Foochow ,CHN 235
20150327 2234 518 $11P XSX Keelung,TWN 1600
20150328 1053 518 $11Q XSG Shanghai ,CHN 704
20150327 1901 518 $11R XSZ Dalian ,CHN 1656
20150330 2150 518 $11L VRX Hong Kong, HKG 0
20150327 1801 518 $11M XSI Sanya, CHN 0
20150330 1900 518 $11S XSV Tianjin, CHN 0
20150328 1613 518 $11U 9MG Penang, MLA (tent.) 0
20150326 1933 518 $11V HL.. CHUKPYONG, KOR 0
20150329 1942 518 $11W HL.. PYONGSAN, KOR 0
20150327 1740 518 $11K JNX Kushiro 0
20150327 2140 518 $11K XVT, Da Nang Radio (tent.) 0

The catches with 0 km distance were not automatically identified by YaND and the two tentative catches were identified by the content of the message, so 99% sure it was them.

The last reason I like NAVTEX is the content being broadcast. It provides a window on a world that most of us don’t know much about. Most messages are warnings about military exercises, weather reports and changes in locations of buoys, etc. But occasionally you see distress messages and then you realize how much hardship and suffering there is out at sea and how mighty it is. I’ll leave you with two of those messages from the last few days. 73

—–

2015-03-28 13:20:15> ZCZC ID86
2015-03-28 13:20:19> 281320 UTC MAR 15
2015-03-28 13:20:21> OVERBOARD NO.141
2015-03-28 13:20:26> ONE PASSENGER FELL OVERBOARD FROM
2015-03-28 13:20:33> FERRY ISHIKARI ALONG TRACKLINE BETWEEN
2015-03-28 13:20:36> NAGOYA PORT AT 261000UTC
2015-03-28 13:20:41> AND SENDAI PORT AT 270740UTC OR
2015-03-28 13:20:46> SENDAI PORT AT 271040UTC AND
2015-03-28 13:20:51> TOMAKOMAI PORT AT 280200UTC.
2015-03-28 13:20:57> SHIPS ARE REQUESTED TO REPORT ANY
2015-03-28 13:21:03> INFORMATION TO 1TH REGIONAL JAPAN COAST
2015-03-28 13:21:08> GUARD. PHONE 81-134-276172.
2015-03-28 13:21:09> NNNN

2015-03-27 17:40:15> ZCZC KD57
2015-03-27 17:40:18> 271740 UTC MAR 15
2015-03-27 17:40:20> CAPSIZE NO.139
2015-03-27 17:40:27> TUGBOAT CAPSIZED IN 41-45N 140-44E
2015-03-27 17:40:30> AT 270610UTC.
2015-03-27 17:40:33> CREW WENT MISSING.
2015-03-27 17:40:39> SHIPS IN THE VICINITY ARE REQUESTED TO
2015-03-27 17:40:46> KEEP A SHARP LOOKOUT AND REPORT ANY
2015-03-27 17:40:52> INFORMATION TO 1ST REGIONAL JAPAN COAST
2015-03-27 17:40:56> GUARD. PHONE 81-13427-6172.
2015-03-27 17:40:57> NNNN

Hans "Fong" van den Boogert, BX2ABT, is a regular contributor to AmateurRadio.com and writes from Taiwan. Contact him at [email protected].

Many places in the world, low power transmitters in the medium wave band are allowed. I am talking about regulations like in the US where FCC part 15 allows up to 100 mW input.

In Norway we have a particular permission for members of the Norwegian Radio Historic Society to transmit up to 500 mW on 216 kHz. I’m not sure if this is output or input power. The permission is meant to cover a collection of historic radios. The frequency is the one used by the main transmitter north of Oslo from 1954-1995 running 200 kW. The frequency is still allocated to Norway, so I guess that is why we may use it this way.

I grew up close to this transmitter and have fond memories of my first homemade crystal set receiving this station.

There are several low power transmitters around that can be purchased, but most of them only cover the mediumwave band and not longwave (153-279 kHz). Further they are quite complicated as the frequency necessarily has to be user settable.

I looked for a simpler way to make a single-frequency transmitter and found that the function generator chip XR-2206 which I happened to have in my junk box could both generate this frequency and do the amplitude modulation. The RC-oscillator seems to be stable enough for this low frequency although I haven’t tested this much.

Here are the first results with images of the circuit on a Veroboard and the oscilloscope picture of the modulation with my Tandberg TP41 70’s radio on top of it listening to Dire Straits from Spotify streaming over longwave.

The circuit has very little output power, lacks antenna tuning and harmonic filtering, so there is room for improvement, but at least it works.

Too bad that the XR-2206 is obsolete and not recommended for new development!

Sverre Holm, LA3ZA, is a regular contributor to AmateurRadio.com and writes from Norway. Contact him at [email protected].

Today’s Sun (artificially-colored in red) seen at the 304-angstrom wavelength (Extreme Ultraviolet, or EUV), as viewed by the Solar Dynamics Observatory (SDO), by the Atmospheric Imaging Assembly (AIA).

At this wavelength, at a wavelength not seen by the un-aided eye, we can see the Sun through the 30.4 nm (304 A) filter. This Extreme Ultraviolet (EUV) waveband is used to monitor the chromosphere and lower transition region. It is useful to see plasma and filament activity, including filamet eruptions and coronal mass ejections (CMEs).

The image is a “false color image”, meaning that observed data are in a range outside of what human eyes can see, so the data are digitally recast into colors that emphasize physically important features. This view is created from data gathered by the Solar Dynamics Observatory (SDO) satellite that flies above Earth”s atmosphere in an inclined geosynchronous orbit.

Emissions captured in this image come from helium (He), the second most abundant element in the solar atmosphere. Singly ionized Helium (He II) emits Extreme Ultraviolet (EUV) light when heated to temperatures of ~70,000 deg K. In the upper solar atmosphere the temperatures are so high that most chemical elements have lost many of their electrons. The remaining electron, which is still attached to the atom, emits EUV radiation in narrow wavebands or lines when it is in an excited state.

The 30.4 nm filter (also called channel or bandpass) is dominated by emissions from singly (once) ionized helium which has missing 1 electron–He II. The roman numeral descriptor is consistent with spectral notation: the level of ionization for a given roman numeral is one unit larger that the actual number of missing electrons. The temperatures associated with this level of ionization is range from 6 x 10^4 K to 8 x 10^4 K.

The bright regions in this image correspond to regions of closed magnetic field loops that trap the hot, emitting plasma. Large bright regions are often called active regions. The dark regions correspond to cooler temperatures and possibly to locations where magnetic field lines open into the heliosphere, and thus, do not trap hot plasma.

View live data and images at http://SunSpotWatch.com

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Deutsche Welle (DW) is closing its last relay station, which is in Kigali, Rwanda. In recent years DW like many shortwave broadcasters, has been facing financial cutbacks. Also there are far fewer broadcasters using shortwaves these days.

As a youngster in the 1960s, I recall shortwaves crowded with AM broadcast stations, many from all over the world transmitting in English, with their distinctive interval signals. There was a magic about shortwave broadcasting back then. Quite a few could be copied with very simple receivers too. There is something quite nostalgic about listening again to those long-gone interval signals from behind the Iron Curtain. I remember getting some excellent freebees from China back in the early 1980s. Of course, it was all to spread the propaganda.  All I really wanted was their QSL card!

These days, users are often reached using the internet. Of course, it begs the question, “who is now filling the empty, vacated channels?”  In the long run amateur radio might gain some allocations, although the noise floor on HF is increasing too. SMPUs, cable TV and numerous other sources are mainly to blame.

See http://www.dw.de/deutsche-welle-closes-kigali-outpost/a-18340960.

Roger Lapthorn, G3XBM, is a regular contributor to AmateurRadio.com and writes from Cambridge, England.

My assembled 40m Pixie

The Pixie is a very simple HF transceiver. Usual power out is in the 200-1000mW region, depending on band and DC power source.  It was first developed some years ago but the basic concept is using a PA transistor as a mixer in a simple direct-conversion receiver. On TX this is used as the TX PA.

Being simple, it has a number of limitations but it certainly works. A major issue can be AM broadcast breakthrough, although my 40m version is perfectly usable. I was very impressed with my little kit that came with all parts including a silk-screened PCB, all sockets and a crystal. It needed low-Z Walkman type headphones, a morse key and battery – that was all. On 40m the sensitivity is pretty good with 0.5uV clearly audible and my RF power out is around 400mW. A lack of both RF and AF RX selectivity is also noticeable.

Kits are available from several sources at prices that are hard to beat. I recently bought a kit for $10 with free airmail from China. It is available for less than half this price I subsequently found out. Unbelievable for a fully functional HF transceiver. Of course, being so simple you may prefer just to build it dead-bug fashion. I bought a kit as I wanted to see how my building skills were.

As a mature design, it has been through several iterations, some improve the basic design, but most do so at the expense of increased complexity. You’d be hard pressed to find a circuit for a complete HF CW transceiver much simpler.

See www.gqrp.com/The_Sprat_Pixie_File.pdf .

Roger Lapthorn, G3XBM, is a regular contributor to AmateurRadio.com and writes from Cambridge, England.

at your next Club meeting?  Plan a presentation or an activity! Publicize it well and ahead of time and you're sure to draw out some people - new faces as well as old.


Thanks to Drew Moore W2OU for arranging for Mike Terruso WA4LOQ to come to our ETS of NJ meeting last Friday evening to talk about his high altitude ballooning experiments.  What started out as a science project for his son is turning into a combination of ballooning and Amateur Radio for Mike. In fact, ballooning is what got Mike in gear to earn his Amateur Radio license, as he realized it's potential to help him in his endeavors.

The technology that he uses is interesting. A combination of radios, cameras, Raspberry Pi's, GPS devices, temperature and humidity sensors - it was all fantastic to listen to. I've embedded his YouTube video which is a compilation of stills (taken at 5 second intervals) of his maiden launch last October.  The balloon was released near Lebanon, PA and landed in Boonton, NJ. It's an hour long video, but you can skip around it if you wish to see the "near space" photos which clearly show the black sky of space and the curvature of the earth's horizon. As Mr. Spock would say - "Fascinating!"


Larry Makoski, W2LJ, is a regular contributor to AmateurRadio.com and writes from New Jersey, USA. Contact him at [email protected].

SDR Sharp GUI

DXer John Bellini in Colorado, and maker of those informative Low Noise Vertical videos, has been at it again.


This time it's a good demonstration of a pair of filters that he built to mitigate the front end overload experienced on his SDR receiver.

John is one of many radio hobbyists that have been playing with the very inexpensive RTL 2832 SDR dongle receiver. Being very close to several high-powered broadcast stations has been a bit problematic for him when using the low cost SDR but his new video shows exactly what was needed at his location to solve the problem:


It looks like John is using the SDR Sharp GUI (graphical interface) to operate the dongle SDR receiver. Those wishing to learn more about this might find this 'getting started' page of interest.

Good stuff John.
Steve McDonald, VE7SL, is a regular contributor to AmateurRadio.com and writes from British Columbia, Canada. Contact him at [email protected].