Monthly Archives: July 2018

Presentation at The Circle of HOPE conference next week!

Dear Post Readers,

If you live near or are planning travel to New York City next week, I would encourage you to check out the HOPE (Hackers On Planet Earth) conference at the Hotel Pennsylvania (July 20-22, 2018). The location couldn’t be more accessible: across the street from Penn Station and down the block from the Empire State Building.

The HOPE conference is diverse with an incredibly wide range of topics spanning technology, culture and so more. We’re talking about “hacking” in the best sense: those with the technical knowledge and ingenuity to overcome problems and better understand/explore the world around us. HOPE always has a strong contingent of radio enthusiasts as well–many of whom also attend the Winter SWL Fest in Plymouth Meeting, PA.

This will be my first HOPE conference so I’m especially honored to have been selected as a presenter.

HOPE Presentation

My presentation is titled: Creating a Radio Time Machine: Software-Defined Radios and Time-Shifted Recordings–here’s the description:

Since the earliest days of radio transmitting, individuals and organizations have made an effort to record and preserve radio signals in the form of broadcasts and other over-the-air communications, especially those of historical significance. Now low-cost software-defined radios (SDRs) coupled with today’s faster memory-enhanced computers allow us to record not just individual signals from one radio station at a time, but an entire broadcast band – a wide swath of frequencies – all at once. Each recording from a particular day and time can easily contain dozens, if not hundreds, of stations broadcasting and communicating simultaneously. Later, via a software-defined radio application, recordings can be tuned and listened to (decoded) as if they were live. This talk will discuss how you can build your own “radio time machine” which supports such virtual time shifts by utilizing an inexpensive ($25-$100) SDR, and also show how you can – for free – virtually “travel” through recent history on radio archivists’ preexisting radio time machines.

Time & location: Saturday 1900 Booth

My two main goals with this presentation are to bring more radio converts into our hobby by showing how accessible and dynamic radios are today and also to give The Radio Spectrum Archive some exposure.

HOPE Workshop

I’m also excited to co-host workshop with my good friend, David Cripe (NM0S). Our workshop is titled: Build the HumanaLight: A “Green” Lamp from Trashed Batteries–here’s the description:

This mini-lamp developed for use in impoverished regions where there’s no electrical grid is powered by a surprising, but ubiquitous, waste product – the residual energy in depleted (used) AA batteries. Workshop attendees will build a HumanaLight on a high-quality printed circuit board. The kit includes all necessary parts, even a “dead” AA battery! No experience required. There is a $15 fee for the kit, with the proceeds going to the nonprofit organization Ears To Our World, which developed this valuable and important technology.

Time & location: Friday 1900-2030 Hardware Hacking Village (Mezzanine)

No kit building experience is necessary! We’ll help and guide you as you build an incredibly useful tool!

HOPE Radio

In my spare time, I also plan to help with HOPE’s special event amateur radio station W2H. If you can’t attend the event, consider trying to work us on the air! Here are the details:

Amateur Radio Special Event Station W2H and 70cm Repeater

If you’re an amateur “ham” radio operator, you’re part of a hacker community that goes back over a century. Bring your handie-talkie to QSO with the many hams at HOPE to keep up with what’s happening. Visit Special Event Station W2H and operate on several HF/VHF/UHF bands in various voice and data modes to freely communicate with hams around the globe – sans telecom infrastructure! Our 70cm repeater input is 442.875 MHz (PL 167.9) and the output is 447.875 MHz which W2H operators will be monitoring. We also encourage simplex ops on 147.545 MHz and 433.545 MHz (PL 77.0).
More details at http://ham.hope.net.

Time and Location: Friday through Sunday – 18th Floor (next to the 2600 store)

If you can’t tell, it looks like an action-packed weekend! I’m super excited and (admittedly) a little intimidated! Should be lots of fun.

Come join the fun!

Full details can be found at The Circle of HOPE conference website.

Spread the radio love

BBC World Service: Global audience up, shortwave listeners in “steep decline”

8 Replies

(Source: The BBC Media Centre)

BBC’S Global audience rises to 376m

The BBC is reaching a record weekly audience of 376m people, new figures published today reveal.

The figures – the Global Audience Measure (GAM) – show how many adults the BBC reached weekly with its news and entertainment content in the year 2017/18.

The BBC World Service, which has just undertaken its biggest expansion since the 1940s, has seen its audience increase by 10m, to 279m.
The total global news audience has risen by a million, to 347m.

The GAM shows the way people access their news is continuing to change around the world. With the increased availability of cheap smartphones around the world, audiences are continuing to switch to digital platforms for news. Overall, online news website audiences have grown by four million, with social media audiences up by nine million.

The English language international website, BBC.com, continues to perform well even in competitive markets like the USA, adding two million weekly users this year.

More people listen directly to World Service English via the internet than by any other method – a total of 27m. And World Service English podcasts now reach one million people every week.

However, shortwave radio listening continues its steep decline, with shortwave audiences virtually disappearing in Pakistan, and down substantially in Nigeria.

Jamie Angus, Director of the BBC World Service Group, says: “This has been an exciting year for the BBC World Service, with the launch of 12 new services, new programming, and the opening of new and expanded bureaux across the world, so it is great to see international audiences continuing to turn to the BBC for independent and impartial news.

The figures highlight not only the successes of our global news operation, but the challenges that lie ahead for us. We still need to grow the share of women engaging with our news services globally, and we need to ensure we have the right services to continue to attract young audiences.

At a time when Britain is forging a new relationship with nations around the world, the BBC’s global news services are more important than ever.”

The figures also show:

More than a quarter of the BBC World Service’s audience is aged between 15-24 years old.

In Afghanistan, more than 60% of the adult population consumes BBC News; in Nigeria the figure is just under 40%

The top ten markets for the BBC’s international news services are Nigeria (41m), USA (33m), India (30m), Bangladesh (16m), Egypt (16m), Iran (13m), Afghanistan (12m), Tanzania (10m), Pakistan (9m) and Indonesia (8m).

More people are consuming more than one BBC service, or using more than one platform to access BBC News; 24m people consume the World Service in English as well as other languages.

Notes to Editors
The Global Audience Measure is an annual update of how many people are consuming the BBC weekly for all services in all countries across all platforms (television, radio, website and social media). Key to this is de-duplication i.e. ensuring that a person who consumes multiple BBC services or platforms or on multiple devices is not counted many times in the top level totals.

The total figure includes audiences for all BBC News services outside the UK and branded entertainment content on TV, BBC websites and social media pages for BBC Studios.

PR

Spread the radio love

US Army Training Film: Circuit Testing and Signal Generators (1951)

Lilian decodes SSTV images from International Space Station

2 Replies

Many thanks to SWLing Post contributor, Lilian Putin?, who writes:

Greetings, my name is Lilian Putina and I am from Moldova. I’ve been following your blog for a long time, with the help of it I’ve purchased a short wave radio, SDR, and WRTH almanac.
I take everything a little bit: shortwave, FM DX, weather images from meteorological satellites, decoding of NAVTEX, WSPR and FT-8 etc.

I’m sending you two SSTV images received from ISS on June 30, 2018.

Many thanks, Lilian! I’m also very pleased that you’re enjoying all aspects of radio–to me, that’s what makes this all so very fun!

Spread the radio love

RNZ and the “Chinese shortwave foray into the Pacific”

2 Replies

(Source: Radio New Zealand via Mike Hansgen)

China is taking up a lot of the Australian Broadcasting Corporation’s former shortwave radio frequencies into the Pacific region.

In response to budget cuts, the ABC last year ceased shortwave broadcasting in the Asia-Pacific region ahead of a transition to FM transmission.

Since that withdrawal, frequencies on which Pacific Islanders listened to ABC radio for many years are being filled up by China Radio International.

Radio New Zealand Pacific is of course still broadcasting to the Pacific region on shortwave.

Its Technical Manager, Adrian Sainsbury, spoke to Johnny Blades about the Chinese shortwave foray into the Pacific.

Click here to listen to this story via RNZ.

Spread the radio love

Guest Post: SM0VPO’s 3D Printed 10KV Tuning Capacitor

2 Replies

The completed antenna.

Many thanks to SWLing Post contributor,Harry Lythall (SM0VPO), who shares the following update to his excellent homebrew 20 meter magnetic loop antenna post:

3D Printed 10KV Tuning Capacitor

by Harry Lythall (SM0VPO)

Introduction

You may have seen my 20m (14MHz) loop, or frame, antenna, and the ease of construction with just a bit of wire and a bit of plastic tube. The tuning arrangement is a little primitive, using just a “gimmick capacitor”, comprising two bits of wire twisted together.

The original “Gimmick” capacitor that burns.

This arrangement works very well for QRP, where the average RF power is about 5 Watts or less. If you exceed this power level, then the twisted-wire capacitor tends to warm up and the tuning drifts a little. But if you use more than about 10 Watts of continuous RF power, then things start to burn. Cheap insulated wire also smokes. This is because the impedance at the ends of the coil is so high that you can get many 100s of volts and the insulation, normally intended for house wiring, breaks down.

In this page I will show you how to build a super-cheap tuning capacitor that will tolerate up to 10,000 Volts of RF and allow you to use up to about 100 Watts of RF into my 14MHz (20m) antenna. The capacitor is also tunable so that you can adjust it by hand (when the RF is removed, of course :-). The tuning range is about 8pf to well over 30pf when really compressed. The normal range for the antenna is about 12pf to 15pf.

Construction

My prototype does not look very pretty, and it is not supported on anything other than the connection wires from the antenna. Very few components are used:

two plastic foam pan scrubbers or one thick plastic bath sponge
two pieces of metal 4cm x 6cm. Copper-clad board works fine
one plastic nut and bolt – see text
one heavy-duty 3-pole block connector with centre-pole removed

Components for the 10KV tuning capacitor

The plastic nut and bolt need to be about 6cm long and totally non-conductive. If you want to make my bolt, then do NOT use black plastic because some black plastics use carbon as a colouring agent. You can use a nylon bolt, as used to secure IKEA toilet seats, but you will also need a washer to spread the stress, otherwise the copper-clad board tends to bend under the stress with time. I chose copper-clad board because it is easy to solder – no need for drilling or connection bolts. I made my plastic compression tuning bolt using my 3D printer. I have included the project files for you to download.

Ikea toilet-seat bolt

Note that the connector for the wires needs to be well spaced between the metal inserts, in order to tolerate up to 10KV, so I used a 3-pole connector and took out the centre pole. At 100-Watts continuous there is a very slight warming after a few minutes, but no sign of smoke, sparks or corona. 🙂

The connector with the centre-pole removed.

I tried a few different types of plastic dielectric and all worked well, providing they are 100% dry. The best ones those I stole from the kitchen cupboard (when Maj-Lis was not watching). I think it costs about $1.50 for a packet of 10 pieces. Perhaps I should have used a nicer colour? A pretty pink? Heart-shaped? No! maybe that would be going a bit too to far ;-). Here is my finished capacitor using my 3D printed tuning screw.

The assembled 10KV capacitor.

3D Files

Once more, this project is ridiculously easy to make with a 3D printer. The hardest part was to get the pitch of the threads right, then clone/connect the pieces to get a longer thread. They were printed with the bolt vertical, so the slope under each thread is a steeper angle than the upper slope. This makes the printout a lot easier to print. If the angle is too steep, then it may extrude PLA into mid-air. My nut and bolt heads are about 3cm Diameter, and the 10mm thread for the nut was cut using boolean subtraction. I then enlarged the nut by about 3% so it still fits but there is a little slack so that it does not bind. I may have overdone it a little, but not much.

Project rendered in 3D Studio Max

Here are the files:
3D studio MAX file – 3d-cap-01.max
ASCII STL file – 3d-cap-01.stl
ASCII OBJ file – 3d-cap-01.obj
the GCODE file for my Wanhao (Prusa) Duplicator i3 – 3d-cap-01.gcode

Just right-click on the file and select “save as”. Some web browsers try to open ASCII files instead of saving them. I usually export STL files, but on this occasion, I tried comparing OBJ files since CURA slicer will accept both. Although I use a WANHAO replica of the PRUSA Duplicator i3 printer, the GCODE files are rather generic and will probably work on most printers.

My printer settings in this GCODE are:

Nozzle temperature = 200°C
Bed temperature = 60°C
Support structure = brim
Layer height = 0.1mm
Print speed = 60mm/s
Fill density = 40%
Shell thickness = 1.2mm

The printer temperature is 200°C, which is 5°C hotter than recommended for PLA filament. I find that I get a better print at 200°C as it sticks to the bed a lot easier. When printing this screw thread, it may be advisable to start at 200°C and then turn down the nozzle temperature to 195°C after a few layers have been printed.

I hope that you find this project interesting. It is a bit small, but it gets me active on 14MHz from my car with this portable antenna. I have a new car and I don’t want to start throwing long aluminium tubes in it that scratch the interior to bits.

Don’t forget to visit my messageboard if you have any questions about this or any other project. I always look forward to receiving feedback, positive or negative ?

Very best regards from Harry Lythall
SM0VPO (QRA = JO89WO), Märsta, Sweden.
EA/SM0VPO (QRA = IM86BS), Nerja, Spain.

Thank you so much for sharing this, Harry! I love both the frugality and ingenuity in this unique capacitor design!

Post Readers: be sure to check out Harry’s website which is loaded with radio projects of all stripes. You’ll easily spend a few hours digging through his tutorials and downloads. Harry also maintains an alternate mirror server located here.

Spread the radio love