Author Archives: 13dka

1976 Japanese TV commercial for the National Cougar 2200

1976 Japanese TV commercial for the National Cougar 2200 (aka Panasonic RF-2200 aka National Panasonic DR-22)

by 13dka

(The commercial starts at the 1:00 mark. It’s part of longer video with Japanese commercials from that year, there is a whole collection on YouTube if you like those!)

Doing some research on other old technical gems from Japan I stumbled upon this 1976 National/Panasonic TV commercial running on the domestic TV networks back then. While watching, I smiled and thought “only in Japan…” …it would’ve been perfectly normal to advertise something like a shortwave receiver in this fun (and funny) way. Anyway, I think RF/DR/Cougar 2200 owners and collectors (also the resident one on this blog , the blog owner) may want to have this link in their bookmarks!

Spread the radio love

Reminder: The SWLing Post message board

Reminder:  The SWLing Post has its own little oldschool message board!

The SWLing.com Message Board front page

Here’s a friendly reminder that the SWLing Post has nice little message board to discuss SWLing Post articles, everything radio, ask for advice on all things radio or share logs, experiences and thoughts!  It’s online since almost a year now, but so far there wasn’t much traffic on the board except for the time when the SULA antenna was born on that board. 🙂

Here’s the link: https://swling.net/index.php

Yet another forum?

The idea for this message board came out of necessity: Thomas got swamped with emails asking questions of all sorts, and replying to them all became a very time-consuming chore because – you know what kind of guy Thomas is – he’s trying to answer all of them.  The message board is an easy (and probably faster) way to get the information you need, if Google doesn’t cut it!

Also, the comment section below each post is good for comments but not for discussions: You can’t quote key sentences or post pictures and comment threads are limited to n comments before the layout breaks apart and you can’t reply anymore.  If there are many reactions to a post, creating a new thread in the SWLing.com message board and posting the link to it in the comment sections here is a much better way to continue an in-depth discussion on articles posted here on the SWLing Post!

73s and always good reception,

Ollie (13dka)

Spread the radio love

High Noon: Belka MW shootout part 2, with a review of the AFA200C active MW ferrite antenna

High Noon: Belka MW shootout part 2, with a review of the AFA200C active MW ferrite antenna

by 13dka

When I reviewed the updated Belka (gen3, 2022) for its MW/LW performance in October last year, I just wanted to know if it’s any good with just the whip antenna and used the XHDATA D-808 as a reference radio because it’s a Jay Allen 2.5-star average performer on MW and my expectations were not high for MW reception on a short whip.  To my surprise that average bar turned out way too low for the Belka!

That was sure asking for a comparison with the most sensitive MW radio I have and gave me hope to use the Belka for ultra-portable MW DXing on the move.  The omnidirectional whip doesn’t allow me to null out unwanted co-channel interference though, therefore I wanted to find a reasonably sized loopstick antenna to pair with the Belka.  Continue reading

Spread the radio love

PSA: Your (new) radio’s filters may be wider than you think

AM bandwidth confusion: IF Filters today vs. yesterday

by 13dka

Whether or not a radio is a joy to listen to, or apt for difficult DX is decided to a large part by the last IF filter stage. Most radios of the past didn’t come with many IF filters to begin with, their quality varied a lot and harsh compromises had to be made in multi-purpose radios. With the advent of digital filtering and inexpensive DSP portables, we got spoiled by a rich choice of selectivity settings that came with an idiosyncrasy I had to wrap my head around first, namely a shift in how some (digital) filters are labeled now.

Continue reading

Spread the radio love

HAM – Official Documentary (YouTube)

Grazing the rich pastures of the interwebz I just stumbled upon this short documentary made by students of the School of Visual and Media Arts program at the University of Montana. It aired on Montana PBS in November 2022 and was uploaded to YouTube 2 weeks ago.

I like the modern style of this work, letting the images and the people in them speak for themselves, and radiate their fascination with the hobby. Enjoy!

Spread the radio love

Radio physics explained: The Luxemburg-Gorky effect

Get it while you still can: The Luxemburg-Gorky effect

by 13dka

The Radio Luxembourg longwave transmitter Junglinster in the 1930s [RTL Group]


“In radiophysics, the Luxemburg-Gorky effect (named after Radio Luxemburg and the city of Gorky (Nizhny Novgorod)) is a phenomenon of cross modulation between two radio waves, one of which is strong, passing through the same part of a medium, especially a conductive region of atmosphere or a plasma.” (Wikipedia)

That sounds pretty abstract, right? In my own words, imagine your radio is tuned to a station on let’s say 162 kHz, 500 miles away. Somewhere in the middle between your receiver and the 162 kHz transmitter is a station transmitting on a different frequency, let’s say 234 kHz. The Luxemburg effect is that you can hear the modulation of the 234 kHz transmitter in the middle, on the 162kHz station you are receiving.  The effect is not depending that much on the frequency/wavelength though, the longwave station could affect medium wave stations and it has been created using shortwave frequencies far apart.

It was observed first in 1932, when listeners of the Swiss Beromünster 60kW medium wave station built just one year prior also heard a bit of Radio Luxemburg’s longwave transmitter (250kHz) on the Beromünster frequency (653kHz until 1934).  Of course this was assumed to be some kind of crosstalk within the receivers and probably drove radio engineers insane until 1933, when Bernhard D.H. Tellegen, a Dutch electrical engineer and inventor suggested the true origin of the effect: The new (1932) 150kW Radio Luxemburg longwave transmitter in Junglinster was directly modifying the ionosphere hundreds of kilometers above, it “heated” the ionosphere in a way that it made the plasma’s charge and reflectivity follow the amplitude modulation of Radio Luxemburg, thus modulating waves of other wavelengths crossing this part of the ionosphere.

Practical demonstration

Even if you’re living in Europe, you may never have witnessed that effect and according to this article by Paul Litwinovich, chances to observe this in the US are rather slim, due to the relatively low power of the stations.  I’m in Europe but never noticed it either – until recently: Continue reading

Spread the radio love

13dka Reviews: The new 2022 “Belka” (generation 3) general coverage receiver

The new 2022 “Belka” (generation 3) general coverage receiver

by 13dka

Since its introduction in 2019, the super-tiny Belka (back then called “Belka DSP”) shortwave receiver sure gained an enthusiastic followership among SWLs and hams. The main reason for this is certainly the way how the Belka is incredibly small yet playing in a different league than the various consumer grade, Chinese mass-production radios, particularly the DSP-based ultraportables: The Belka is an all-mode shortwave communications receiver with a completely different (direct conversion SDR) architecture, developed and produced by a radio enthusiast (Alex, EU1ME) in a small mom&pop shop in Belarus.

In case you’ve never heard about it amidst all the buzz about more popular brands, here’s the skinny:

The Belka offers true allmode (including NFM and CW) reception with a proper 400 Hz CW filter and individual settings for the low and high filter slopes for AM, FM and SSB. It has an AM sync detector and comes with a 0.5ppm TCXO-controlled local oscillator for absolutely spot-on, calibration-free frequency precision and stability, which makes SSB or ECSS reception of broadcast stations a pure joy. The second iteration “Belka DX” brought a slightly extended coverage down to 1.5 MHz and an I/Q output for panadapter display and/or processing via your favorite SDR software.

All Belkas are quiet and very sensitive radios with a surprisingly robust front end, the filters are better and its AGC works like you’d expect it from a communications receiver, without the artifacts and distortion the DSP radios are infamous for, and of course smooth, non-“muting” tuning in variable steps down to 10Hz.

The Belkas have no built-in speaker (available as option tho) but really excellent audio on headphones and external speakers and they actually give my Icom IC-705 a run for its money in terms of reception quality, and they do that for up to 24 hours on a single charge of the internal Li-Ion battery. This stunning feature set is crowned by the best performance on a telescopic whip antenna ever – the Belkas have a high-impedance (>10 kOhm) antenna input optimized for this whip and taking it on a walk is (really!) like having a big rig with a big antenna in tow…

Despite all this goodness setting the Belka(s) quite fundamentally apart from most (if not all) current and former, even much higher priced portables and simultaneously putting it solidly into pricey tabletop territory, it hasn’t put Tecsun et al out of business for a couple of reasons: One reason is that it can only be obtained from Alex in Belarus, which is now often assumed to be impossible (it isn’t, more on that later). Another reason is that it doesn’t try to compete with aforementioned multiband radios from China, so there is no FM broadcast band and – until now – no AM BC band, but most owners and potential buyers particularly in the US really wished it had at least the latter. Well, Alex obviously heard us! After the Belka DSP and the Belka DX, the new Belka is just called “Belka”, so in order to avoid any ambiguity I’m going to refer to this model as “Belka 2022”.

What’s new?

The most prominent addition to the Belka 2022 is the extended 0.1-31 MHz coverage, the previous version only started receiving at 1.5 MHz. With LW and MW included, its “pseudosynchronous” detector (as featured in venerable radios from Harris, Racal or Drake), the great filtering and the great frequency precision for hassle-free ECSS reception are promising that the “squirrel” is now an ultra-ultraportable companion for MW DXers as well.

Continue reading

Spread the radio love