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november 2019
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HF & VHF propagations

WSJT en Ham-satellieten

In de zomer van dit jaar is er bij radiovriend Thetmar, PD5TW, gewerkt aan het optimaliseren van de antennemast. Er is een dubbele bredere zijdrager gemonteerd op een Yaesu Elevatierotor. Op de drager zit een 70 cm beam en een mooie 12JXX2. Het doel is om met deze antennes goed te kunnen dx-en op 70 cm en 2 meter. De vakwerkmast heeft een hoogte van 16 meter inclusief antenne opbouw. Het installeren van de antennes gebeurde met een hoogwerker die we tot onze beschikking hadden. Dat scheelde ons een hoop gedoe om met hulp van een tractor de mast op zijn voetstuk te lieren. Tenslotte gaat het in een bakje omhoog een stuk eenvoudiger om op hoogte te kunnen werken. Na drie uur werken was het belangrijkste installatiewerk gebeurd en tijd om naar huis te gaan. Het was inmiddels toch alweer 23.30 uur. Een paar dagen later is de bedrading in de shack op de rotor aangesloten. En werkte perfect.

Half augustus heb ik s’avonds de caravanshack bezocht met de bedoeling om voor het eerst met WJST te gaan ontvangen en misschien ook wel te gaan zenden. De perseïden waren toen net langs onze planeet op tournee om ons weer van hun jaarlijkse douche te trakteren. 🙂 Dus een prima moment om de 12JXX2 beam uit te testen. Alleen werd het in het cluster wel heel druk op 144 Mhz. Na een perioden van rx met WSJT ben ik overgaan naar phone usb om me met die drukte te gaan bemoeien. Wat een pile-ups op verschillende frequenties. Een sporadisch E met signalen uit EA7 en CS die opliepen tot S8. In Portugal zit een Nederlandse radioamateur Fred, CS/PD0HNL, die ik ken vanuit EA7, Malaga, met twitteren en Facebook. Laten we elkaar toch spreken in de pile-up. Het was voor mij ook de eerste keer dat ik met een amplifier werkte. De Naigai 144 XL met een 4CX350F deed zijn werk prima.

De dagen na de vakantie heb ik me verdiep in satellieten voor radioamateurs. Met de mooie app ISS Detector uit de Google Play Store kan ik met een eenvoudige configuratie de omlopen controleren van OA7,Hamsat SO50,ISS, etc. Dinsdagavond 1 oktober heb ik samen met Thetmar de apparatuur aangesloten die nodig was om signalen van boven te mogen ontvangen. Het navigeren van repeaters op hoogte is voor ons enigszins nieuw. Het eleveren luistert nauwkeuriger dan azimut. Wanneer je een paar graden te hoog of te laag eleveert ontvang je niets. Wanneer de hoogte goed is ingesteld heb je met de azimut rotor wel een grotere openingshoek ten opzichte van elevatie. Na een eerste avond leer je snel. Volgende keer moeten we een duplexer aansluiten met de FT817 of 7000 of twee sets die voor geprogrammeerd zijn i.v.m.het doppler effect. Onze apparatuur bestond nu uit een Icom 251 om te zenden ( zonder tone 🙁 ) en een Yaesu FT817 voor ontvangst. De Icom heeft een RPCB 251ub Replacement board van http://www.ssbusa.com onboard voor een betere selectiviteit. Toen de satelliet passages voorbij waren hebben we de avond afgesloten met nog paar leuke dx verbindingen op 144 Mhz met stations die riepen om puntjes i.v.m. een contest. De gelukkige collega’ s kwamen uit G/DL/OZ/SK en ON. Het is heerlijk werken met de 12JXX2. We verheugen ons op de volgende momenten om onder andere deze disciplines van onze hobby goed te kunnen leren beheersen.

RIG: RX: Yeasu FT817 – TX: Icom 251 – COAX:Ecoflex 15 – ANT: 12JXX2 & Tonna 70 cm – AMPLIFIER: Naigai 144XL ROTOR: Yaesu

D is for Digital

D is for Digital

BY WAYNE YOSHIDA,* KH6WZ

A “Ham Notebook” Look at D-STAR and the “Mini-Industry” of Products It has Inspired Hams have always been an innovative group, so it comes as no surprise that when Icom introduced its implementation of D-STAR in 2004, early adopters saw something useful in this new digital communications protocol. (Notice I said protocol, and not mode. D-STAR is not a mode, it is a digital protocol.) I am not going to discuss DSTAR pros and cons; instead, let’s take a look at what Icom has brought to the amateur radio community by planting the D-STAR seed.

First, we should begin at the beginning. D-STAR stands for Digital Smart Technologies for Amateur Radio. It is an open standard digital communication protocol for digital voice (DV, 4800 bps) and digital data (DD, 128 kbps) established by the Japan Amateur Radio League (JARL). The JARL is an organization similar to the American Radio Relay League, ARRL, in the USA.

Up until just one year ago or so, Icom was the only radio manufacturer that produced ham radio equipment using this technology, so it may seem like the system is a proprietary offering in Icom radios and repeaters. I think Icom took a brave and risky step in committing the resources and finances to develop and sell off-the-shelf ham radio equipment for D-STAR. I am sure other radio companies are watching the Icom line of D-STAR capable radios from a business perspective, but we can watch those other companies from a consumers’ perspective to see if anyone else will step to the plate and introduce equipment for D-STAR. Some healthy competition will be good for this communication protocol, since it can help drive further innovation and continue to expand the number of users.

Since D-STAR is a digital thing, and digital means computers, it may be something mysterious and scary to analog-and RF-oriented folks. Think of this protocol as a wireless version of a computer network in your office, where various terminals are interconnected and each has access to the internet. In addition, there are levels of network connections, and stations can be configured to include or exclude certain individuals or groups (other D-STAR stations).

Since D-STAR operates on the VHF and higher bands, the radios look like traditional FM mobile and hand-held portable units, and so many may think D-STAR is “FM,” but it is not. In fact, the DSTAR modulation scheme is not compatible with FM. However, repeater and simplex operation does occur with D-STAR. But, because D-STAR is incompatible with standard FM, operations must be coordinated and comply with local band plans (a topic for another day; for a general discussion of repeater coordination and coordinators, see the “Riley’s Ramblings” column in last month’s CQ).

*28181 Rubicon Court, Laguna Niguel, CA 92677

e-mail:

Technically Speaking

Bob Witte, KØNR, “FM” columnist for CQ’s sister publication CQ VHF, published an introductory article on D-STAR in the Winter 2009 issue of CQ VHF magazine. In addition, on his blog site, Bob explains that D-STAR uses Gaussian Minimum Shift Keying (GMSK), the same modulation format that Global System for Mobile communications (more commonly known as GSM or “2G”) cell phones use. Therefore, for those of you who, like me, find it hard not to call D-STAR a mode, its mode is GMSK.

As you look at the products briefly examined in this article, keep in mind what D-STAR is: It is a protocol, or in other words, a specification or definition of how a signal must be configured in order to be understood by the receiving party as it goes from one point to another. In addition, understand that D-STAR consists of two layers—a “transportation” layer (the RF channel) and the “encoding” or “digital” layer. Just like the computer term compatible, we should define what or how much compatibility there may be. If one defines compatible as “it just works,” we must understand how much compatibility there may (or may not) be: Does it work for both voice and data and text, or does it work only for voice? For example, many devices may be called a gateway to a D-STAR system, but only handle the DV portion, and may ignore the DD portion of the D-STAR protocol. Yes, the device may “work,” but there may be some limitations. For example, an e-mail or text message may or may not be received because a routing feature in the digital layer is missing. This is an oversimplified explanation, and the more technical articles mentioned in the References section provide more detail on the D-STAR specifications.

For units that use traditional “analog” FM radios, bear in mind that D-STAR uses a very narrow bandwidth of 6.25 kHz, while a typical FM signal occupies about 16 kHz.

Who’s Using This Stuff and Where are They?

Now that we basically know what D-STAR is, the next question is: Where are all these D-STAR stations located? A quick Google search finds sever-al pockets of D-STAR activity, and there is an interesting DSTAR repeater location map to see where these folks are. See the screen capture, fig. 1.

I asked my good friend and digital radio expert George Zafiropolous, KJ6VU, what he knew about D-STAR. He pointed me to his local radio club and its library of presentations. The Bay-Net radio club has been pretty busy with D-STAR projects. Take a look at its presentations, saved on its website, for some introductory information and interesting club project ideas.

Hot Spots

Meanwhile, those inquisitive and creative hams have been busy developing accessories and other items to supplement D-STAR activity. One example of the more popular gadgets is the D-STAR hot spot. Hot spots are a great way to get started with D-STAR, since they create a “gateway” into a D-STAR network without having to buy a complete radio.

Generally speaking, if you can gather and properly interface an analog FM rig with a 9600-baud data port (or access to the FM discriminator and modulator; . . . → Read More: D is for Digital

Raspberry Pi

Onderstaande tekst kwam ik tegen in CQ AMATEUR van maart 2013. Een leuk project om mee te experimenteren. Zowel met XBMC, Linux en hamsoftware voor digimodes.

BY MATT STULTZ,* KB3TAN

Raspberry Pi: A Tiny Computer for Big Projects

In 2011 at World Maker Faire, many makers got their first chance to see a little board that we had just begun hearing whispers about on the Internet. No bigger than a deck of cards, the Raspberry Pi is a fully-functional, Linux-powered computer- with the added bonus of including a set of general purpose I/O pins that can be accessed easily from the command line or with the help of a couple of simple scripting languages. The Raspberry Pi launched in March 2012, and soon makers across the globe started pumping out exciting projects using the device.

The Raspberry Pi Foundation

The Raspberry Pi was created by the Raspberry Pi Foundation with the goal of developing a small, low-cost computer that would be a useful platform for teaching kids how to get started with computer programming. The organization has designed two boards: the lower cost and less functional Model A and the currently available Model B board.

The Raspberry PI Foundation is a registered charity from Cambridgeshire, UK. It has set up distribution deals with multiple electronics suppliers around the world to help distribute the boards.

The Hardware

The Raspberry Pi Model B has a 700-MHz ARM processor with 512 Mb of RAM and a dedicated GPU unit capable of delivering full 1080P HD video. Two USB ports provide access for a keyboard and mouse, along with other USB accessories. HDMI video out allows you to have HD (high definition) video, but analog video is also supported with a composite RCA plug. Audio can also be sent over the HDMI, but an audio out jack is present as well. Onboard Ethernet gives your Pi and projects access to the Internet. Storage is solved with an SD card slot rather than using a full bulky hard drive. 17 GPIO pins round out the hardware. All this can be yours for the low low price of just $35. This price point is helping fuel the demand for the boards. [fusion_builder_container hundred_percent=”yes” overflow=”visible”][fusion_builder_row][fusion_builder_column type=”1_1″ background_position=”left top” background_color=”” border_size=”” border_color=”” border_style=”solid” spacing=”yes” background_image=”” background_repeat=”no-repeat” padding=”” margin_top=”0px” margin_bottom=”0px” class=”” id=”” animation_type=”” animation_speed=”0.3″ animation_direction=”left” hide_on_mobile=”no” center_content=”no” min_height=”none”]

The Model A is similar but with less RAM, one USB port, and no onboard Ethernet. This helps drop the price down to $25 and reduces the amount of power that is required to run the device by half. At the time of the writing of this article, the Model A boards are not yet available for sale.

One criticism of the board is its lack of analog inputs. These would allow for easy access to many different types of sensors. This has largely been solved with the use of an extra external chip that can read analog sensors and then transmit the data back over a serial interface to the Raspberry PI.

The Software

The Raspberry Pi is designed to run a Linux operating system (although some users have shoehorned other operating systems on board). The standard OS is called Raspbian and is based on Debian Wheezy. Variations on this OS have been created to help users with specific desired operations for their device.

The Raspbmc distribution allows you to use your Pi as a media center with your HD television. Once everything is connected and configured, users can easily stream videos, music, and pictures across their network, right to their TV. Many commercial systems give you this functionality, but often at double the price and with fewer options and configurability.

Occidentalis was created as the hardware hacker distribution. Occidentalis gives greater access to the GPIO pins and enables common serial protocols like I2C on them. New updates have included such things as servo libraries and greater support for sensor modules. The Python scripting language comes pre-installed, allowing users to quickly get up and running writing their own apps to interact with the on-board hardware and any device connected to the GPIO pins.

Toppings for your Pi

With the popularity of the new system, it wasn’t long before many creators began releasing accessories to help users with their Pi needs. Maker extraordinaire Limor Fried (named 2012 Entrepreneur of the year by Entrepreneur magazine) of Adafruit Industries began selling small screens, keyboards, WiFi modules, and many other useful items along with their own custom creations. The Pi Cobbler is a breakout board that allows the user to easily be able to connect their Pi to a breadboard for prototyping new projects.

For those wanting a little more I/O power from their Raspberry Pis (or just don’t want to rewrite all of their Arduino code), the Wyolum open hardware group created the AlaMode Arduino compatible shield. The AlaMode shield is pin-compatible with a standard Arduino and is capable of accepting any of the numerous shields that have been created for the Arduino.

One downside to the design of the Pi that bothered me initially was how much the SD card stuck out of the side of the board. Of course I was not the only one who disliked this and Rick Winscot decided to turn to Kickstarter.com to help him fix the problem. Rick ran a successful campaign to build a micro SD card adapter that would allow you to plug a memory card into your Pi without having it stick out of the device <http://kck.st/OsmYH7>. I received my boards after backing the project and couldn’t be happier with them. They do exactly what they are supposed to and the build quality is excellent.

Bushels of Apps

In December of 2012 the Raspberry Pi foundation launched the “Pi Store,” an online venue for developers to give away or sell their applications for the Pi. Unlike some systems though, the Raspberry Pi does not require that you download your apps from the store. Apps may be downloaded from many sources around . . . → Read More: Raspberry Pi