Category Archives: Guest Posts

Comparing the Watkins-Johnson WJ-8711 & WJ-8712 with TEN-TEC RX-340 & RX-331 receivers

Many thanks to SWLing Post contributor, Paolo Viappiani, who shares the following guest post:

The WJ-8711 & WJ-8712 vs. Ten-Tec RX-340 & RX-331 Receivers

by Paolo Viappiani, Carrara, Italy

In recent years, a renewed interest has grown in regards to the best HF receivers using “first generation” DSPs, typically the HF-1000/HF-1000A, WJ-8711/WJ-8711A and WJ-8712 models by Watkins-Johnson and the RX-340 and RX-331 models by Ten-Tec. Even today, the aforementioned receivers are considered among the best performers of all times; this is a well-deserved fame in the case of the W-Js, a bit less with regard to the units manufactured by Ten-Tec, a firm that once had a good reputation but that has been recently acquired by a new owner (who sold the old facilities by transferring the company and distorting the sales, support and assistance policies of the previous company [2]). I therefore believe that this article serves as a dutiful information for the readers who are potentially interested in these receivers.

A Bit of History

In the years between the last and the present century, two receivers very similar to each other in terms of design and structure were released almost simultaneously by Watkins-Johnson of Gaithersburg, Maryland [1] and by Ten-Tec of Sevierville, Tennessee [2]: the WJ-8711 (later upgraded to the A and A-3 versions and followed for a short period by the HF1000 and the HF1000A “civilian” versions [3]) and the Ten-Tec RX-340; both of them are shown in Figure 1.

Figure 1: The WJ-8711A (above) and Ten-Tec RX-340 (below). Notice the similarity of the front panels of the two radios.

The WJ-8712/WJ-8712A and the Ten-Tec RX-331 receivers were released by their respective manufacturers in that period also (the latter one was preceded by the RX-320 and RX-330 models). All these types were nothing more than “black-box” units, that in all respects corresponded to the WJ-8711A and to the Ten-Tec RX-340 receivers but that had not been provided with true front panels, as they were controlled by special hardware interfaces or from a PC, look at Figures 2 and 3.

Looking at the appearance of the WJ-8711/HF1000 receiver series and of the Ten-Tec RX-340 units, a relative similarity to each other is evident, and it has led to various speculations regarding the design of both devices.

One of the theories was revealed by James (Jim) C. Garland W8ZR of Santa Fe, New Mexico [4], about which he claims to have obtained information from a Ten-Tec employee directly. James claims that in 1991 the US Government Agency NSA (National Security Agency), which used to purchase numerous HF receivers for surveillance and interception, decided that the current cost of the receivers were too high and formed a special group in order to study how to obtain a possible price reduction.

At that time the high-end HF receiver market was dominated by a few manufacturers: Watkins-Johnson, Racal, Cubic, Rockwell-Collins and a few others, and Ten-Tec applied for joining the group.

Figure 2: The WJ-8712A (above) and Ten-Tec RX-331 (below). While the Watkins-Johnson model is two rack units high and half wide, the Ten-Tec develops less in height (only one rack unit) and more in width (standard 19” rack). However, both receivers are quite deep (more than 20”-50 cm.).

Figure 3: The Tmate unit of the WoodBoxRadio is shown here; it is one of the possible accessories which, together with a PC monitor, allow using the “black-box” receivers via an RS-232 interface.

According to the information provided by Jim Garland, the Watkins-Johnson and the Ten-Tec designers worked together for about one year in order to agree on the technical characteristics and guidelines of the “radio of the future” which must meet all the requirements that the NSA requested.

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Can you hear that sound coming from the West?

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Hi SWLing Post community Fastradioburst23 here letting you know in what direction Imaginary Stations will be going in this Sunday 9th April 2023 at 2200 UTC on 9395 kHz via WRMI.

In one word we’ll be going WEST, there’ll be some Westbound trains, themes from Westerns and some spoken word from Adam West. So get your compass out, tune in your shortwave radio and enjoy everything westward (and even something Clint Eastwood related) from 2200 UTC on Easter Sunday.

Can we have some quiet please

We’re off to the KZOO again

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Hi SWLing Post community, Fastradioburst23 here letting you know about a transmission of KZOO, another installment of the imaginary radio stations show to be broadcast this weekend via the good folks at WRMI.

It’s on Sunday 26th March 2023 at 2200 UTC on 9395 kHz and will feature those strange and wonderful instruments that wouldn’t be encouraged in your music class. After the broadcast the studio audio will appear on the KMTS mixcloud here.

Don Moore’s Photo Album: Cuenca, Ecuador (Part Two)

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A Cuenca Artisan Market

Many thanks to SWLing Post contributor, Don Moore–noted author, traveler, and DXer–for the latest installment of his Photo Album guest post series:

Don Moore’s Photo Album: Cuenca, Ecuador (Part 2)

by Don Moore

In the song Por Eso Te Quiero Cuenca (That’s Why I Love You Cuenca) the singer recites a litany of the many reasons to love this city. What do I love about Cuenca? Well, unlike the song, I won’t include well-roasted guinea pig.

The elevation of 2560 meters (8,400 feet) gives Cuenca a comfortable spring-like climate year-round. Daily highs are usually around 20C/70F. Nights are chilly but not cold. Most days have at least several hours of sun, even during the rainy season (as it is now). There are numerous green parks and plazas including long tree-lined walking paths along the two main rivers that run through the city. The drinking water, which comes from high up in the mountains, is the best in South America. Yes, you can drink it right from the tap.

A walking/bike path runs along the Yanuncay River for over six kilometers through the south side of Cuenca. A similar path runs along the larger Tomebamba River in the center of town.

The people of Cuenca are among the friendliest I’ve found anywhere. It’s a well-run, educated city with lots of civic pride. The metro area population is only about a half-million so it’s small enough to easily get anywhere but large enough to have the benefits of a city. Cuenca has several good universities and theaters and the symphony orchestra gives free concerts most Friday evenings. It’s a pleasure to simply stroll through the beautiful architecture in the old centro neighborhood.

One of many beautifully restored buildings in Cuenca’s old centro.

Getting around Cuenca is easy. A ride on the excellent bus system costs just thirty cents and taxi rides usually run under two dollars. And, unlike the much larger cities of Quito and Guayaquil, Cuenca has a mass transit system. In 2013 city leaders voted to put in a light rail line. Doing so required digging up two of the main streets through the old downtown but rather than just dig up two streets they decided to dig up the entire old downtown … to replace the aging water and sewer systems, move all electric lines and cables underground, and install high-speed fiber optic Internet. (Fiber optic Internet was also run above ground in the newer neighborhoods outside the centro.) The result is one of the few places in Latin America where one can enjoy beautifully restored architecture and colonial churches without the views being marred by powerlines. And the Internet here is better than most places I’ve stayed at in the United States.

Those are just a handful of the reasons that I love Cuenca.

Early Radio in Cuenca

Radio broadcasting in Ecuador started in 1925 with Radio El Prado in Riobamba, a small city in the center of the country. Other stations soon started up in Guayaquil and Quito, including HCJB in 1931. Broadcasting came to Cuenca in 1934 when a group of friends purchased a homemade ten-watt transmitter from an engineer in Guayaquil and put it on the air as La Voz de Tomebamba. The name came from the main river flowing through Cuenca. At the time there were only four receivers in the city so the audience was rather sparse. La Voz de Tomebamba initially broadcast for only one or two hours a night and most of the musical selections were done live as there weren’t many 78 RPM records in town. Years later one early listener reminisced, “It was sixty percent noise. Only radio fanatics could be entertained by listening to such a thing.”

Old studio equipment from La Voz de Tomebamba

Gradually, the owners added new equipment and expanded the daily schedule. A fifty-watt transmitter was added in 1938 and by 1947 the power had been increased to two hundred watts. The first frequency listing that I’ve found for La Voz de Tomebamba was for 4200 kHz in a 1944 FBIS newsletter. The 1947 WRTH listed it as on the air from 0000 to 0430 GMT on 4200 kHz. And that was the station’s only frequency. Until the 1960s it was very common for radio stations in Ecuador to only broadcast on shortwave and not on medium wave. For example, the 1957 WRTH lists eighty Ecuadorian stations on shortwave (not counting HCJB) but only fifty-nine on medium wave.

Sometime in the early 1960s La Voz de Tomebamba made the switch to medium wave and left shortwave. Their 4200 kHz frequency is not listed in the 1965 WRTH, nor are they listed in any later ones. (I would be interested to hear from anyone who remembers listening to them on shortwave.) The changes may have had to do with financial problems the station was having. It closed in 1967 and remained off the air until returning under new ownership four years later. Today La Voz de Tomebamba is one of the most popular radio stations in town and has an excellent news department. Their sister station, Super Rock FM 94.9, is very popular with younger listeners.

La Voz de Tomebamba today.

The second station in Cuenca was Radio Cuenca, which began broadcasting in October 1945 on 2830 kHz with two-hundred watts. It was included in a 1953 list of stations logged by the Universal Radio DX Club of Indiana. To the local audience, Radio Cuenca was best known for its many live music broadcasts. Continue reading →

Clock-Watchers Need Not Apply

Guest Post: Listening to LRA 36

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Many thanks to SWLing Post contributor, TomL, who shares the following guest post:

Listening to LRA 36

by TomL

I finally had time to go outdoors to listen to LRA 36, Antarctica. People were gushing about how well it is being received. My location was a park across the street from the Forest Preserve I usually go to (the Forest Preserves are shutdown and gates locked after sundown). Even though it was after sunset, this Park has no gate or chain to prevent people from parking there. In the dark, I setup the trusty amplified Loop-on-Ground antenna, SDR, and laptop. Solar Flux Index about 179, K index 2.

Started recording and, NOTHING! ARRGH. But I had just heard it at home in the noise!?!? Waited about two minutes and all of a sudden music started playing in the middle of a song. S6 – S7 strength with lots of fading. Very cool. 20 minutes later, went off the air. Then 10 minutes later, came back on again in the middle of another song. They must be tweaking the transmitter. This feels like the 10 kW transmitter; no way could a 1.5 kW be this loud over 12000 kilometers! Also, an advantage with IQ recording of a spectrum is I could tune into it later. Good thing because between their tweaking the transmitter, my SDR, and the crazy propagation, I had to tune to 15475.983 kHz in order to get the USB signal perfectly in pitch.

For your listening enjoyment if you have not had a chance to hear it clearly, I have uploaded both recordings to archive.org where you can listen as long as you want. Worth listening to, playing music of Argentina music bands. Happy Listening! Here is the link to Archive.org and the audio files are also embedded below: