Category Archives: Shortwave Radio

Roundup of software defined radios

 

RTL-SDR

Many thanks to several readers (including Mike and Greg) who have shared a link to RTL-SDR.com’s Roundup of Software Defined Receivers. The list gives an excellent, comprehensive overview of SDRs currently on the market. I encourage you to check it out.

Indeed, while you’re at RTL-SDR.com, take a look at their active blog and forum to get the most out of your RTL-SDR dongle!

Bonito adds new products

The Bonito MegaLoop ML200

The Bonito MegaLoop ML200

I’ve just heard from German manufacturer, Bonito, who has added several new products to their product line:

MegaLoop ML200: The MegaLoop is a 5 meter active stainless steel loop antenna that can be used outdoors. The MegaLoop ML200 ships with a Dual Power power supply (including the ability to power via USB).

Bonito notes that the Megaloop ML200 is currently available for a special price of 279,00€ (incl. 19% VAT)  at HamradioShop.net.

megactiv-83

The MegActiv 305

MegActiv 305: The MegActiv 305 is a compact antenna designed for low-noise reception between 9 kHz and 300 MHz. It has a radiating element of 18cm and can be powered with 5-15 VDC (max.120mA) or with the supplied Dual Power unit CPI 1000DP via USB.

The MegActiv 305 will be available for purchase end of April for an introductory offer of 174,99€ (incl. 19% VAT).

Fenu at fenu-radio.ch will review a sample of the MegActiv 305 in the near future.

OVP1000 Over Voltage Protector: The OVP1000 is an in-line over voltage protector for your receiver. It’s designed to dissipate current pulses caused by nearby thunderstorms. The OVP 1000 protects against high power surges in three ways:

The OVP1000

The OVP1000

  • A gas discharge tube with 60V firing voltage, max. pulse leakage current 1kA (8/20µs)
  • An ultra-fast ESD diode (30KV; max. pulse power 350W (8/20µs)
  • Blocking DC voltages (up to max. 100V) at the input and output.

The OVP1000 is available now for 59,00€ at Hamradioshop.net.

For full details about these new products, please visit Bonito’s blog.

And many thanks to Bonito who is a proud sponsor of the SWLing Post!

Vanuatu’s radio services restored

Vanuatu-Map

(Source: Radio Australia)

Broadcast communications that were knocked out by Cyclone Pam have been fully restored.

Francis Herman, the ABC’s program manager for the Pacific Media Assistance Scheme, says transmission engineer Steve White and local technicians have fixed Radio Vanuatu’s short and medium wave service to a level better than before the cyclone.

Listen to the interview on Radio Australia’s website.

Deutsche Welle to close Kigali relay March 28, 2015

DW's relay station in Kigali (Source: Deutsche Welle)

DW’s relay station in Kigali (Source: Deutsche Welle)

Many thanks to SWLing Post reader, Mike, who writes:

“I wanted to pass on a quick (and unfortunate) word that Deutsche Welle will be closing its Kigali, Rwanda relay on March 28th. This word came from the Wavescan program on WRMI. I would highly recommend that anyone who would like a QSL response from DW should get their correspondences in as soon as possible. It seems that the site will be dismantled shortly afterward. In addition it seems that tests are ongoing at RFI’s Issoudun site by DW to replace some of the broadcasts that used to originate from their Kigali relay.

I find the closing of another landmark relay a greatly displeasing event especially due to the short time frame between the announcement of the closure and the actual closure date. I find it surprising as well due to the lack of mention of any recent budget cuts at Deutsche Welle.”

As Mike mentions, the relay is scheduled to close on March 28, 2015–if you’d like to log this site, you’ll need to do so very soon. Click here for current schedules. Kigali is Deutsche Welle’s only remaining relay station.

RadioWorld magazine also posted a short news item about the Kigali closure–click here to read.

Wyn compares the SDRplay RSP and Airspy

SDR-PLay-RSP

After posting about the price reduction in the SDRplay RSP, Wyn Evans commented with his comparison of the SDRplay RSP and Airspy (another popular low-cost wideband SDR). Wyn writes:

I have both and Airspy and the SDRplay RSP. I like them both, but on balance I prefer the RSP. The pluses of the RSP over the Airspy for me are:

1. Sensitivity – At least with my Airspy, I find the sensitivity a bit disappointing. The RSP is on the other hand excellent. I read on another forum one user claiming that the difference between the two was as much as 3 dB. I can’t verify the number, but I would not be surprised if it were about right

2. HF support – Absolutely fantastic, no up-converter needed

3. ZIF or Low IF. In ZIF mode, with calibration, you can get image free reception

4. Programmable filters. You can change the selectivity from as low as 200 KHz to the full bandwidth of 8 MHz, This is a huge plus for DX-ing if you live in an area with very strong local stations

The plus for the Airspy is that there is does cover the gap between 380 MHz and 430 MHz, with the RSP doesn’t. For some people, this is a really big deal.

Both seem to have about the same dynamic range, which isn’t surprising as despite using different tuners, the ADCs seem to be virtually identical.

So in summary, I think both are pretty good products with pluses and minuses, but at this new price point, as long as you don’t need to use 380 – 430 MHz, there is really only one I would choose now.

Many thanks for your comparison, Wyn. As I stated before, my impression of the SDRplay RSP is quite good so far. I live in a very RF quiet area–I am curious if anyone has used the SDRplay in urban areas, near local broadcast stations and experienced any overloading or serious imaging.

Software Defined Receivers (SDRs) for the visually impaired listener

Spectrum Display 31 Meters on the WinRadio Excalibur

At the 2015 Winter SWL Fest, I co-hosting a forum on Software-Defined Radios.  Afterwards, a radio friend–who happens to be visually impaired–approached me to ask:

“What is the best SDR for those who are blind or visually impaired?”

I’d never been asked the question before, and replied that I’d have to do a little research. In truth, I suspected that research would turn up very little that was useful:  after all, SDRs require a lot of pointing and clicking, and some of the interfaces are rather complicated. Spectrum and waterfalls displays, often at the heart of the SDR app, are visual displays.

But I kept thinking of my friend’s question. Upon my return, I set out to do a little research and possibly pose the question here on the SWLing Post.  Then assistance stepped in…in the form of medium wave DXer Tore Johnny Bråtveit.

If Mr. Bråtveit’s name sounds familiar, that would be because I recently posted a link to an Oregon Public Broadcasting interview with him. In the interview, he mentioned that he uses SDRs to chase MW DX, and that he is visually impaired.

I reached out to Mr. Bråtveit via his website and asked for any advice he could give about SDRs for those who are blind or visually impaired.  His enlightening response:

“In the interview I mentioned screen reader software and the need to find SDR software that plays well along with such screen reader software. For those visually impaired who have some eyesight, this aspect may not apply, since many of them are well helped by a screen magnifier software package.

For those without eyesight at all, or with so little left of the eyesight that they cannot make practical use of the screen, there are these screen reader software packages. They all do the same, but they solve the job in a somewhat different way and are good at different tasks.

I began using SDRs back in 2007. First I used some [RFspace] SDR-IQs for a few years, until I purchased a Winradio G31DDC in 2010. The user experience with Winradio was so good that I have stayed with those radios since then, using both G31DDC and G33DDC receivers at my remote listening places.

I think I can say that all the software packages delivered with SDRs have issues and challenges when it comes to using them along with a screen reader. The worst example of unusable native software I have seen so far, is the software package delivered with the [Microtelecom] Perseus. I had a thought purchasing one some years ago and make some scripts for my screen reader JAWS to see if I could make the Perseus possible to use effectively, but I dropped the idea at that time in favor of Winradio.

The SpectraVue software delivered with SDR-IQ was usable, but I had to script it quite extensively, especially to be able to use the timeline when playing back recordings. Also the frequency selector was a bit tricky, so I had to assign some hotkey combinations to it. Otherwise it worked fine.

The Winradio software for the G3x series works quite fine right out of the box. They have apparently thought [through] keyboard operation, and there are shortcuts for almost everything. Such shortcut keys are necessary, as navigating the program interface with a screen reader can be a bit too complicated, especially for those only using speech output from the screen reader to access the screen content.

I personally am living in a country where we have good access to refreshable Braille displays, which gives me the opportunity to turn off the speech entirely if I want and only use Braille output. This way I can navigate the program interface quite effectively to understand how things are laid out.

The only real issues I have had with Winradio software, is:

1. Changing shortcut keys:
Normally, the Tab key is used to move between elements on a screen, so it would be natural to think that pressing the Tab key will bring me to the next shortcut key definition. Not in Winradio. Tab can be defined as a shortcut key itself, so trying to navigate the shortcut keys dialog with that key gives you a number of options, all connected to the Tab key. My way around this was to navigate with the Braille display until I found the shortcut key definition I wanted to change, focus on it by pressing a cursor routing key in that position and changing the definition. Then navigate further down to the OK button and activate it.

2. The timeline:
The timeline used when playing back recordings can be hard to locate when using a screen reader, and even more difficult to work with, since when you press a cursor routing key on the Braille display to simulate a mouse click on it, the focus often moves to somewhere else on the screen. Then you have to work hard to locate back to that timeline again. My solution here was to script my screen reader with a hotspot at the timeline with a shortcut key assigned to it, so that I could move focus back there by pressing a key.

Among the third-party software packages developed for SDRs, I have found few that I can recommend. The only one I can think of, is HDSDR. Especially in the current version from November 2013, there are a number of useful shortcut keys, and the program seem to work very well. I have used it a bit with an AFEDRI SDR I have, and have also used it to play back older SDR-IQ recordings.

So, if nothing else works, Iwould say that HDSDR is the solution, since it is both easy to use and have support for a number of receivers. And it is free, as you certainly know.

[…]Please write back if I can help you any further”

Brilliant!  What a treasure trove of information for our visually-impaired SDR listeners and operators.  Thanks so much, Mr. Bråtveit, and please keep in touch with us here at the SWLing Post.  73s!

Radio Vanuatu back on the air

Radio-Vanuatu

My friend and fellow DXer, Rob Wagner, writes:

R. Vanuatu has been off the air for ages. It has suddenly come back on in the last hour or so on 7259.95 kHz and 3945 kHz with post-cyclone assistance and information. There is also a report from a visiting R. New Zealand transmission engineer talking about the SW and MW txers at Port Vila; interviewed on RA – quite interesting. Just thought I’d let you know. details at MEDXR:

http://medxr.blogspot.com.au/2015/03/station-news-and-log-book-march-20-2015.html

Many thanks for the information, Rob! Very good news indeed!

On a side note, SRAA contributor, Julie (also based in Australia) has done a fantastic job posting cyclone coverage recordings from Solomon Islands Broadcasting. She’s also posted pre-cyclone Vanuatu recordings as well. Click here to browse her contributions on the Shortwave Radio Audio Archive.