Category Archives: Guest Posts

RF75A Radio

Raddy RF75A Review – Pocket Radio with Interesting Bells and Whistles

Radioddity Raddy RF75A

By Robert Gulley K4PKM

The RF75A is an interesting little radio which (currently) retails on Amazon for ~$53.00 in the States. It can also be purchased via Radioddity directly for $53–if you use this referral code, you can save $15 off a $65 purchase.

Before we get into specifics, two things are worth mentioning right off:

  1. I was asked if I would be interested in reviewing this radio by our fearless shortwave listening leader, Thomas, and the copy I have was provided to me at no cost by Radioddity directly. (I have no other affiliation with them, but have recently purchased a GMRS mobile radio from them which I am looking forward to using when I finish my review of the RF75A.)
  2. This is, as you will see from the photos I am including, a pocket radio, not to be confused with a tabletop radio or a small portable radio such as the CCRadio Skywave or similar radio. I mention this because invariably there will be folks who expect tabletop or portable quality from a radio about the size of a playing card. It is not going to happen!

Having those thoughts out of the way, the quick and dirty answer as to the quality of the radio is, I am impressed. For those who have not read anything related to my past experience with radios, I have been a shortwave listener since I was about 10 years old, and now in my early sixties. So, I have seen a fair number of radios in my time (speaking as an old codger, or is that curmudgeon?) and have even moved with the times to incorporate SDRs into my radio arsenal.

Each style of radio has its place, and a pocket radio is designed to be the ultimate in portability and space savings. As light as this shirt pocket radio is, it still manages to feel reasonably solid, and of course, it could be packed into anything one was taking along for a trip.

Size Comparison with Playing Card and Cell Phone Battery

The radio measures 2.5″ x 3.5″ x 1″. Playing card and cell phone battery for comparison.

Here are some specs from the manufacturer’s website (saving you my long-winded descriptions!):

  • APP Control SW Radio: Thanks to the app intelligent remote control and Bluetooth 5.0 features, you can enjoy the convenience of RF75A. With its intuitive user interface and powerful wireless capabilities, you can easily control your radio from your devices (support iOS, Android, and HarmonyOS systems).
  • Wider Reception Range: Listen to FM, VHF, AM, SW, and WB, and stay up-to-date with your favorite radio shows and music with this powerful multi-band receiver. RF75A has a wider range of shortwave frequencies compared to the RF750.
  • Automatic Scan and Manual Storage: You can save up to 396 stations, so you can easily access your favorite stations. Experience powerful sound and crystal-clear reception with its 9.85′ wire antenna.
  • Personal Music Player: Boost your music experience with this all-in-one outdoor audio system. With Bluetooth 5.0 feature, a 3.5mm earphone socket, and a TF card socket, you can easily connect to your personal audio devices and connect to your computer as a speaker.
  • Outdoor Companion: This one-of-a-kind radio is designed to be small and lightweight, making it ideal for travel and outdoor activities. Use the flashlight and SOS for emergencies.

What’s in the box?

  • 1 x Raddy RF75A
  • 1 x Storage bag
  • 1 x Lanyard
  • 1 x Wire antenna
  • 1 x Type-C charging cable
  • 1 x Earphone

Reception

I always like to start a radio review by either listening to AM stations first, or WWV time stations for checking out shortwave reception. In this instance I started listening to AM stations in the daytime to see what I could hear on a typical day (no storms nearby, early spring, etc.).

Living in a fairly remote area I was surprised it captured as many stations as it did, making me think the ferrite bar inside must designed well for such a small radio. Evening and nighttime listening brought in many of the usual stations with which we are familiar, particularly the so-called Clear Channel stations. What was more impressive were the many small stations I was able to pick up, not only at night, but early in the morning around 8 a.m.

Ferrite Bar- Front View

Surprisingly effective Ferrite Bar

Ferrite Bar Side view

Side vide showing the magnetic wire wrap

One in particular caught my attention as I am quite certain I have never captured them before, was WHKY 1290, Hickory North Carolina. That’s a distance of about 285 miles, received in the morning. I am only about 50 miles from Cincinnati and cannot receive some of their smaller stations on any radio! Color me impressed!

Nighttime brought stations in from several thousand miles, as you would expect, yet I was likewise impressed with this little radio’s capabilities on AM.

FM

I confess to not being much of an FM listener, but I did tune around the band for FM stations to test its ability to “lock on” to signals (as indicated by a tiny red light) and to pick up stations from quite a good distance away with clarity and good sound.

This might be a good time to mention the quality of sound from the small 3 Watt(!) speaker and bass boost from the back. Again, this is not my Sangean 909 X2 with a large speaker, nor my CC Radio EP, but it has rather amazing clarity and volume capability for such a small radio. I cranked the volume up quite high with no distortion, and even though the speaker is small, the bass boost seems to round out the sound quite nicely, avoiding some of tinny sounding speakers common in such a small radio.

Weather

The radio has coverage of the NOAA weather radio stations and it surprised me with being able to receive 4-5 stations, more than I have gotten with most other radios. All but one of the signals were crystal clear, with the fifth having some noise, but still quite intelligible.

Air Band

This radio includes the air band frequencies and amateur 2-meter frequencies (30.000-199.975 MHZ). I am usually able to receive some signals, but I am quite far away from any local airports or repeaters, so my main reception is from CVG, Greater Cincinnati Airport. While the radio scans the air band frequencies, like any other radio, it is best to find local frequencies you want to hear and program them into memory so you are not wasting a lot of time scanning dead air (these are country specific). Likewise amateur repeaters or GMRS, marine, or public service channels would be best used in memory channels except when scanning for new frequencies.

SWL

Shortwave listening is very respectable, with frequency ranges between 4.750-21.850 MHz (it does not have SSB capability). Tuning can be accomplished by pressing and holding one of the directional tuning keys for about 2 seconds, a long press scans faster. A single press of either directional button will move the frequency increment based on the band/mode chosen.

The radio also features something I have come to really like: a pause button which works not only in music mode, but also when receiving regular radio signals, activated by a quick press of the power button. The frequency is held while pause is active, and then releasing the pause with a second quick press of the power button resumes with all your setting still active.

When comparing this with another radio it was particularly useful instead of having to turn the volume down like most radios. This feature is also nice for answering a call or other interruption, and you resume right where you left off.

Sound Effects, TF Card, Audio in, Bluetooth Usage and other Errata

I have not covered these features as they do not impact radio reception, but I mention them just for completeness. All of these features are available and can be read about in the user’s manual. I will mention the flashlight feature and the emergency siren features, as these are useful for portable operation. The light is quite bright, and the siren will hurt your ears if you trip it accidentally, especially more than once. Ask me how I know!

There is a sleep timer as well as an alarm clock function, with the sleep timer adjustable by default starting at 90 minutes. Most buttons have multiple functions depending on the mode employed, so reading the manual is important for some of these features. I was able to get up and running without reading the manual initially, but some features were functional only in certain modes, so eventually you will need the manual which can be downloaded from the Radioddity site.

The App

A bit of a novelty in this size and type of radio is the Apple/Android app available to control radio functions remotely through Bluetooth connectivity. I have to say, on Android at least, the app is beautiful and I wish more apps used such a clear color scheme and large controls. Your mileage may vary based on your preferences, but I like it!

Phone App on Android

The free Phone app on an Android phone. I like the crisp, clear layout and colors, and the intuitive design.

As to function, the app gives you more information than the radio screen, such as the Bandwidth, SNR, received signal strength and the volume setting in one display. As a side note, the radio can still be adjusted at the radio, and then changes are reflected in the app almost instantaneously.

Of course, the main use for the app is to operate remotely, and the controls are easy to use, including, most importantly, direct keyboard entry of frequencies! This is always the biggest drawback to small radios without a keypad. There are instructions for using the app, but for the most part the app is laid out so well you can control the radio pretty much intuitively.

Negatives –

Yep, there are a few. When tuning with a single press each time there is some soft muting – fortunately it does not last long, but it is there. The buttons also make a clicking sound, not too loud, but it is there. If something like that annoys you, be aware all the buttons make a mechanical click.

I have noticed on several occasions that the band/mode button may stick slightly and take you past where you want to go. Not a big problem, but it does happen now and again. Of course, this could just be my unit.

Also, naturally, the buttons are small. And while I did not have much of an issue even with fairly large fingers, there were times when I pressed the desired button but also hit the one below it. Not a problem for me, but again, if you have very large fingers you may find the radio a bit tricky to navigate in some places. (This only happened on the front buttons for me, the tuning buttons are adequately spaced for most anyone I think.)

The telescoping antenna is probably the weakest point on the radio – similar to most radios, really. It is thin and could be bent easily. I had no difficulties, but I always took care to raise it gently and watched where I was moving the radio around. Then again, I do that will all my radios with telescoping antennas. Just a heads-up to be careful.

Concluding Thoughts

I like this little radio, and will probably keep it in my car for those times when I might want to listen to the radio out and about, check the NOAA weather forecast, use the flashlight, or (hopefully never need) to use the siren. The battery seems to last a long time on a charge when using the radio – I cannot speak to the MP3 drain or a prolonged flashlight/siren drain, but under normal use it seems excellent. It uses a USB-C connection like my phone, so charging is not an issue for me. It will almost fully charge in an hour; the instructions say 2 hours.

Pocket radios certainly have their niche, and I think this one does quite well in that role. If you are in the market for such a radio, I think you will be pleased, especially for the price and the addition of the free remote-control app. 73!

Click here to check out the Raddy RF75A at Radioddity.

Click here to check it out on Amazon.com (affiliate link).

Spread the radio love

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.

Continue reading

Spread the radio love

Can you hear that sound coming from the West?

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.

Spread the radio love

Can we have some quiet please

Hi SWLing Post community Fastradioburst23 here letting you know about a transmission of  The Shortwave Music Library this Sunday 2nd April 2023 at 2200 UTC on 9395 kHz via WRMI. DJ Frederick will be searching deep into his record collection to bring you some classic pop & library music. Expect some great tunes as always.

Spread the radio love

We’re off to the KZOO again

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. 

Spread the radio love

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

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

Spread the radio love

Clock-Watchers Need Not Apply

Fastradioburst23 here to let you know about our next imaginary Stations offering on Sunday 19th March 2023 on 9395 kHz at 2200 hrs UTC. This week it’s a WORK special. They’ll be a shortwave tea break with an assortment of biscuits*, training courses, interview tips and lots of tunes to get your through your shift. Clock in, tune in and then chill out.
*Subject to availability.

Spread the radio love