Author Archives: Thomas

KiwiSDR network adds Time Difference of Arrival direction-finding functionality

There has been some fascinating functionality added to the excellent KiwiSDR network of online software defined radios: Time Difference of Arrival (TDoA) direction-finding functionality.

RTL-SDR.com has posted an informative article about this new feature and how effectively it works:

The KiwiSDR is a US$299 HF SDR that can monitor the entire 0 – 30 MHz band at once. It is designed to be web-based and shared, meaning that the KiwiSDR owner, or anyone that they’ve given access, can tune and listen to it via a web browser over the internet. Many public KiwiSDRs can be found and browsed from the list at sdr.hu or by signal strength and location on this website.

One thing that KiwiSDRs have is a GPS input which allows the KiwiSDR to run from an accurate clock, as well as providing positional data. Time Difference of Arrival (TDoA) is a direction finding technique that relies on measuring the difference in time that a signal is received at over multiple receivers spread out over some distance. In order to do this an accurate clock that is synchronized with each receiver is required. GPS provides this and is able to accurately sync KiwiSDR clocks worldwide.

Just recently all KiwiSDRs were pushed with a beta update (changelog) that enables easy TDoA direction finding to be performed with them. Since many KiwiSDRs are public, this means that right now anyone can browse to a KiwiSDR web interface and start a direction finding computation. You don’t even need to own a KiwiSDR to do this so this is the first freely accessible RF direction finding system available to the public.[…]

Of course, as the KiwiSDR network grows, TDoA accuracy will increase.

If you’d like to host your own KiwiSDR, you can purchase the full setup at SeedStudio or Amazon.com for $299 US (affiliate link).

Check out RTL-SDR.com’s full article and TDoA tests by clicking here.

Click here to go to the KiwiSDR portal.

“Night of Nights” Returns Tonight!

Impressive Transatlantic FM DX: Newfoundland to Northern Ireland on 88.5 MHz

2 Replies

(Source: Southgate ARC)

88 MHz Trans-Atlantic signals heard in Ireland

On Sunday the 8th of July 2018, there was a remarkable opening on the VHF bands across the North Atlantic. While there were plenty of strong multi-hop Sporadic-E signals on the 28 MHz and 50 MHz bands, the maximum qusable frequency did reach as high as 88 MHz at one stage.

Paul Logan in Lisnaskea, Fermanagh, Northern Ireland managed to catch CBC radio 1 on 88.5 MHz from Newfoundland, Canada at 22:35 local time (21:35 UTC). It is very rare for openings on Band 2 across the Atlantic and to date, only two people have managed to succeed in hearing North American radio stations.

Click here to view video of reception on YouTube.

Click here to read the full article on EI7GL’s blog.

Radio propagation may improve soon with region of solar flux

Share your photos on Boat Anchor Tuesday!

3 Replies

Yesterday, as I took a little time to curate a massive collection of photos I took at the Museum of Radio and Technology, I posted a few “boat anchor” (heavy metal vintage radio) photos and labelled them “Boat Anchor Tuesday” on Twitter and Facebook.

Much to my surprise, I received a number of comments and emails with readers asking for more Boat Anchor Tuesday pics!

So I’ve decided to make it a feature here on the SWLing Post. After all, anyone who knows me knows that I’m a massive fan of boat anchors!

Your photos on Boat Anchor Tuesday!

Please send me a photo (or a few) of your favorite boat anchor. Every Tuesday, I’ll feature a reader’s boat anchor here on the SWLing Post.

If you can, include a few sentences about the radio: how you obtained it, what you like about it or any memories. We radio nostalgic people love this stuff!

Please send photo(s) and radio blurb to my email address found on our Contact page. I only plan to post one radio per week, so these will be scheduled far ahead to post automatically.

Jeff discovers that the Sangean WR-2 loses time when playing radio

19 Replies

Many thanks to SWLing Post contributor, Jeff McMahon, who writes:

I wanted you to know that my Sangean WR-2 keeps perfect time when I don’t play the radio, but when I do play the radio I lose 25 minutes; the clock is 25 minutes slow in other words. I’ve read other complaints from Sangean owners, including from those who own the Sangean HDR-18. Some say it has something to do with RDS. Have you heard of this problem? It’s annoying because I have to reset my clock every morning.

Wow–an otherwise excellent radio that prominently features a clock should never have this problem. This problem essentially renders the clock useless. I’m not sure what would cause this unless it’s incorrectly pulling time data from the RDS function?

Post readers: Have you noticed this fault in the WR-2, WR-18 or other similar models? Please comment.

Presentation at The Circle of HOPE conference next week!

7 Replies

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.