Amateur Radio Weekly is curated by Cale Mooth K4HCK. Sign up free to receive ham radio's most relevant news, projects, technology and events by e-mail each week at http://www.hamweekly.com.

Online SDRs (Software Defined Radio) continue to grow in numbers and popularity.

Listening on a receiver that is running in another state, province or country can fulfill a number of functions for you, depending on your particular interest.

The network that I have explored several times and one that works nicely with most web browsers (no software to download or 'extras' required) is the SDR.HU network of Kiwi SDRs ... just choose your receiver and away you go in a matter of seconds. It's all very slick and if you have never played with an SDR before, it affords a nice introduction to this amazing technology. Although it won't work with my ancient version of Internet Explorer running on Vista, it did fine with Firefox and even worked very well on my old I-Pad! Here is a 30-second YouTube video to give you an idea of what it looks like.



There are a huge number of choices from all over the world available on the Kiwi network. As I write this, there are presently 199 receivers online! Any particular receiver can support a maximum of four users at a time so if the one you want is full, simply check back later or go to your second choice.

Although all receivers have the same appearance online, not all will offer the same performance. Although most seem to cover 0-30MHz, I see at least one that is limited to the VHF range and several that don't go all the way to the bottom of the VLF band. The antennas used seem to favor wideband loops, both large wire styles and smaller active versions as well as active e-probes.

The best way to determine any particular receiver's operating performance is to try it out using test target signals that might indicate good performance from that location. If you're interested in BCB capability, test some of the European ones to see if they can hear any TA signals around sunrise in Europe. Many SWLs will use these receivers to compare what they are hearing at home with a receiver located closer to the suspected DX target signal. I myself found the network particularly handy for listening to my Tri-Tet-Ten transmitter on 10m CW a couple of years ago when the muf was much higher than it is nowadays. I'll be trying a few of them out this winter, listening for my 630m CW signal, at various locations.

Some of the receivers appear to offer good, low noise reception on LF, MF and the BCB but the vast majority are not DX machines oriented for this part of the spectrum ... this was the opinion of one notable BCB DXer who checked many of those in eastern NA as well as western EU. The jury is still out on the westerern NA receivers and those in the Pacific / Far East ... a worthwhile listening project when there is some spare time. Even though the receivers used on these lower frequencies did not usually offer stellar performance, they may be real workhorses within the ham bands or on the international shortwave bands.

It would be worthwhile to see some form of 'performance rating' or feedback page for each individual receiver. Although there is a 'vote' tally associated with each receiver it's not clear what this actually represents as receivers that have been online for longer periods would naturally have a higher tally.

A lot of additional information about the KiwiSDR network can be found here.

No doubt you can think of your own good reason to have a remote listen to some of the network's growing list of online receivers and put them to the test ... there may be some real treasures to be found.


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

Welcome to Episode #200 of Linux in the Ham Shack. We've come a long way in the last nine years but thanks to all of our listeners and supporters, we have made it to this milestone episode. We talk about a variety of Linux- and ham radio-related topics as well as chat with some old friends and new. Please be aware this episode is being released unedited. We don't believe there's anything in it you need to protect your children from; it's just rambling and unstructured--mostly. Thank you to everyone for all of your support throughout the years and we look forward to bringing you fresh new content in 2018.

73 de The LHS Crew

Russ Woodman, K5TUX, co-hosts the Linux in the Ham Shack podcast which is available for download in both MP3 and OGG audio format. Contact him at [email protected].

Amateur Radio Weekly is curated by Cale Mooth K4HCK. Sign up free to receive ham radio's most relevant news, projects, technology and events by e-mail each week at http://www.hamweekly.com.

…with Arduino.

My relationship with computers is a love-hate one. They are too complex and fragile to be reliable and always let you down when you most need them. But there is a miniature computer I really love: the Micro Controller Unit (a.k.a. MCU). They are simple and reliable, because they do one thing and they do it well. For us hobbyist the two most well known are Microchip Technologies’ PIC and Atmel’s AVR. I dabbled with PICs before, but they are a pain to program and require special hardware to do so. Enter Arduino. These guys from Italy took Atmel’s AVR chips and put them on a board with an easy to use USB interface and an integrated development environment, which uses a dialect of C. Weehee, could it get any better?

MCUs are just like Legos: add some sensors and an LCD and you have made yourself a weather station. Add some wheels and a motor and you created a robot. The possibilities are endless. But just like Legos my Arduino projects have been build and then taken apart for the next project. This is about to change now. My loop antenna needed a way to switch between the 7, 14 and 28 loop turns and it had to do so remotely. “Well, use relays” you would rightly say and those happen to be one of the easiest things to hook up to an Arduino. Let me show you.

Two wires for power and one control line (here hooked up to the Arduino input/output “pin” number seven) so simple enough. But it won’t do a thing until you tell the Arduino to do something, using a program. For writing such programs there are computer languages, and they are just that: languages. Learn how to interpret a language into your own and you’re good to go. It might scare you off, but then isn’t electronics a kind of language as well? Remember, I honestly can’t call myself a programmer, but with a guide book and some advice from the experts I can go a long way in making something exciting. Don’t believe me? Let’s start with the basics.

Arduino programs are made up of three blocks of code:

1 – a block to declare and define the things you need later
2 – a block to set up those things
3 – a block that does stuff with those things over and over and over again

Can you spot the three blocks in this example?

The first block features only one line: “int relayPin = 7;“. Let’s put that in plain English: we use pin 7 of the Arduino to connect the relay to, and instead of “pin 7” we now call it “relayPin”. And because “7” is an integer we also declare that.

Every pin on the Arduino board can be used to either get signals in or out, so that’s what we define in the setup block: set the pinMode of the relayPin to OUTPUT.

Since we set the relayPin as an output pin we can activate it and that is what happens in the loop block. First we write to the relayPin and make it active, or HIGH. Then we have a slight delay of 1000 milliseconds, after which we write to relayPin and make it inactive, or LOW. After another 1000 millisecond delay the whole sequence in the loop block starts all over again. After compiling and uploading the program to the Arduino the result looks like this….

It might not seem very useful to have an oscillating relay, so we need other ways to control it. I’ll cover that next time.

In the mean time, Arduinos are pretty cheap and together with a breadboard, a bunch of wires and some LEDs you can already start playing around. At Banggood.com you can get a bare Arduino Uno for US$3.99. This is a knock-off version, but they work equally well. A whole starter kit is only a little more, so it won’t break your bank.

On the internet there are tons of tutorials, YouTube videos and forums to help you with your first Arduino/MCU steps. I’m sure that after the initial steps MCUs won’t be so intimidating anymore. So, try it and have fun.

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

A recent posting to the Yahoo AWAGroup, reminded me of a wonderfully simple transmitter that would easily get anyone on-the-air for the Bruce Kelley '29 QSO Party coming up in December. The AWAGroup is largely composed of '29 builders and operators and is often the source of much good discussion related to these activities.

When builders first tackle a '29 style rig, eligible for the BK Party, the first thought is often about finding an affordable tube that might make the transmitter a 'legal' entry. A suggestion of tubes and their relative availability can be found here in one of my earlier blogs. Although some of the tubes may not be typical junk-box items, one that is often very readily available and inexpensive is the '27' or the '227' / UX-227.

The '27 was a popular audio tube used in receivers back in the 20's and can easily be pressed into service as a self-excited oscillator on HF. When properly adjusted, the '27 can produce up to 4W of RF, more than enough for you to join the '29 fun a make plenty of contacts over the dual-weekend event.

Scott, WA9WFA, has produced a great article describing the construction of a 1929 Hartley oscillator using the 27. There is no need to utilize period-appropriate parts, other than the vacuum tube itself. If you are pressed for building time or just want to get something on the air, there's no need to be overly concerned about construction aesthetics ... there's plenty of time for that later, and besides, the uglier ones often work and sound the best!

WA9WFA's 27-Tubed Hartley

Power supply requirements for the transmitter are pretty minimal and could even be an old receiver supply ... something that delivers 250-300 VDC at 35ma. An effective way to easily double the power of this transmitter is to add a second tube in parallel with the original one, providing your power supply can supply the extra current (~35ma) required. Although Scott's information describes an 80m Hartley, there is no reason why you could not wind a coil for 40 or for 160 and take advantage of any activity on those bands as well. Like most of these link-coupled outputs, you'll probably squeeze a little better efficiency from the circuit by adding a variable capacitor (~365pf) in series with the pick-up link and the hot-side of the coaxial feedline.

Nick, WA5BDU, wrote his description of building the 27 Hartley which can be found here. He also includes information on running the 2.5V filament from a 5V transformer.

WA5BDU's 27-Tubed Hartley

ABØCW uses two 27s in parallel for the oscillator section of his 1929 MOPA. Details of his interesting Hartley can be found here.

ABØCW's Parallel 27s

As further proof that you don't need a lot of power to have fun in the 1929 BK Party, here is the rig that Kevin, WB2QMY, used when we worked on 80m CW. His little TNT, just barely putting out 2W, made it all the way from New York!

WB2QMY's 80m 2W TNT

When it comes to the BK ... if you build it, they will come. Hopefully you can join the fun this winter as well.


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

One of the mantras of us old hams is; where are the youth? Many club meetings are consumed with the question of how do we connect with youth and get them exposed to Amateur Radio? One very simple way to get involved is to participate in the Worldwide Scouting event Jamboree on the Air (JOTA). This is the 60th Anniversary of the event.  Over 1 million scouts around the world participate. There are numerous ways to participate either hosting a station or getting on the air to talk with the scouts. Check out www.K2BSA.net/jota for information on the event. The dates are October 20 -22, 2017.

Another source of information is the recent Episode of HamRadioNow which is a round-table  of Scout leaders on the benefits and some methodology of JOTA. I was honored to be asked to participate. I think you will find the show to be informative with regard to JOTA.

Here is the link:

https://www.hamradionow.tv/episodes/2017/10/2/hrn-347-old-jota

Participate if you can.

                                              




Mike Crownover, AD5A, is a regular contributor to AmateurRadio.com and writes from Texas, USA. Contact him at [email protected].