Category Archives: Radios

A review of the Radioddity RADDY RF320

(Almost) All-in-One in a Box

By Robert Gulley K4PKM

The RADDY RF320 is a rather attractive, if not slightly curious-looking radio, which breaks from the more recent offerings from Raddy and other small portable radios. Compact, but not pocket-sized, the radio comes in at roughly 3-3/4” x 4-1/2” almost square (not counting the tuning dial on the side, the slightly raised antenna on top, or the light on the side).

The radio can receive AIR, FM, VHF, MW(AM), SW, and Weather Band signals. (For those interested in the U.S. Aircraft Band, this model does feature AM modulation, so civil aircraft can be monitored). While the radio does have AM SWL bands, there is no SSB reception. SW bands run from 90m thru 13m, with tuning in 5kHz single steps and scan mode.

This is the IOS version of the Bluetooth App. Clean layout, keyboard frequency entry and radio control

There are four tuning methods if the user includes the Apple or Android app which feature direct keyboard entry in addition to the three modes found on the radio. As a rather cool feature, the QR scan codes are imprinted on the back of the radio for both IOS and Android apps, so if you are out and about you can easily download the app to your phone or tablet. A nice touch! No having to type an esoteric web address or search for the app. (I tried both codes and they worked just fine.)

In addition to the usual tuning methods, the RF320 has what they refer to as “fine tuning knobs” on the side and front of the radio, with the knob on the side a continuous tuning within a band mode. The knob on the front is something, well, a bit unusual. While it is a fine-tuning knob, it is designed to manually tune in search mode. A little explanation is in order.

Most radios which feature a search mode, this one included, allows the user to long-press a directional button or rotate a tuning dial a given distance to activate a search mode. When the typical radio finds a station, it may stop momentarily or completely, depending on the design. The search modes in this radio all do the latter- they stop completely. However, unlike most radios, this radio features three different methods of searching. The up/down arrows can be pressed for a second or two to start a search, or the tuning knob on the side can be rotated some distance quickly, and a search will begin. The third method is the tuning knob on the front. By manually turning the knob the radio will attempt to find the next signal within the current band or sub-band without stepping through each 5kHz frequency (of course it is doing this internally, but it is not really obvious visually).

For example, when in FM mode, this tuning method will jump to the next usable station. In SW mode, in a given sub-band (13m, 90m etc.), this knob will jump to what it senses as the next usable signal, rather than scanning every 5 kHz as done in the other modes. This allows for a very quick check of a given band (or sub-band).

As with any search mode on a radio like this, there will be false positives. Life is not fair – static crashes and birdies and digital signals can all fool a radio’s search mode.

Changing lights, Bass Boost, and QR Codes for Downloading Android or IOS Apps

The radio features excellent sound for its size, with a rather large front-facing 5W speaker, and a bass port on the back. I can crank the volume louder than I would ever want in a room and the audio remains clear.

Reception on all the bands is quite acceptable, keeping up with typical portables its size, and even ones with longer antennas and larger ferrite bars for AM reception. This is not a Panasonic RF-2200 or a GE Superadio, but for what it is designed to do, it does quite well.

The radio also has an abundance of memories, allowing you to save up to 995 stations, including 199 each for AIR, FM, VHF, MW, and SW.

Like some of the other radios from RADDY, this one has Bluetooth connectivity to Android or IOS for the App functionality, and takes a TF memory card to allow for playing music, podcasts etc., as well as having a flashlight and S.O.S. capability. There is a headphone jack and Aux. jack, as well as a USB-C charging port for the replaceable 18650 2000mAh battery (whoo-hoo!). Sleep mode, timer, wake to music and six sound effects are added features.

Lights, lights, and more lights. ‘Nuff said! (See images)

Pros and Cons

Pros: Good audio, AM receive for aircraft band, good sensitivity, multiple ways to tune, excellent App connectivity on my iPhone with direct frequency entry, good form factor, unit seems solid, replaceable battery, 18-month warranty(!), carry strap, aux. input to allow the radio to act as a speaker, included wire antenna and charging cable.

Cons: Telescoping antenna a bit frail, side tuning knob feels a bit wobbly (but I experienced no problems), back colored lights seem unnecessary (nit-picking and just a personal opinion, YMMV), EQ effects seem weak as only a few seem to make much of a difference (and not needed in my opinion, since the standard audio is quite good), no SSB (not a problem for me but will be a deal-breaker for some), and typical for this type of radio soft muting while tuning.

Conclusion

This is a good, solid radio with lots of options in terms of modes and bands, as well as extras which make it an almost all-in-one radio. This is a radio one could take to the beach or a park, or use in an office or on the coffee table or night stand. It is small, portable, packed with features, and controllable from your phone or tablet. At a price well under $100 ($71.99 special price from Radioddity at the time of publication), this may well be the radio you have been looking for to fill that portable niche!

Note: Using this link to purchase the Raddy RF320 will include a $15 discount for you and a small commission to the SWLing Post.

Guest Post: Review of an affordable, compact DAB+ portable radio

27 Replies

Many thanks to SWLing Post contributor, Mangosman, who shares the following review:

DAB+ digital audio/FM receiver and Bluetooth Audio Player with 2.4 inch LCD Display

by Mangosman

Digital Audio Broadcasting with improved audio compression and error correction is called DAB+. I have had this radio for a few years.

Retail in Australia DAB+/FM radios are generally double the price and more. There has only been one model of DAB+/FM/AM radios which is now no longer trading.

This is a size comparison, the sound is very clear and is surprisingly good on music as well, despite having such a small speaker. Even at maximum volume there is no audible noise or distortion. The stereo program HE AAC compressed and FM and Bluetooth and is available on cabled headphones. Such a small speaker cannot produce much in the way of bass, but it is present on headphones. Since DAB+ is a pure digital system, there is, full stereo, no noise as the radiated signal deteriorates, until the receiver mutes when error correction fails. The radio has a 400 mm long telescopic antenna.

On FM this receiver will decode Radio Data System data, I have had more sensitive FM reception.

This is the most sensitive DAB+ receiver I have owned. I am also currently also using two BUSH clock radios. I also have used older headphone radios, but push buttons and headphone sockets haven’t been very reliable.

This screen shows a full colour album cover which can fill the screen and title. Smooth FM is the broadcaster’s name because it is simulcast in some other cities on FM and DAB+. The indicators on this screen are level of battery change, muting, stereo indicator, when decoded and the signal strength. Continue reading →

Bob’s Bespoke “Rack of Radios”

8 Replies

Many thanks to SWLing Post contributor, Bob Colegrove, who shares the following:

A Rack of Radios

by Bob Colegrove

You simply cannot have enough radios – a principle I learned a long time ago. The difficulty occurs when it comes to storing them and yet having them at the ready when necessity calls. Turns out several of my portables fall within a dimensional range that they can be conveniently stored in a rack on the table.

I would like to say I made a project out of this choosing a fine hard wood for construction, carefully routing each divider into a finely milled slot, tastefully finishing the whole thing off with appropriate stain and varnish, and perhaps lining each slot with felt of finest virgin wool. However, never having been one to let form triumph over function, instead, I found a couple empty cracker boxes of the right dimensions, made a few cuts with a hobby knife, and applied some hot glue. Whalla!

Wait a minute. Is that an unused slot at the end? Hmm!

I love it, Bob!

I mean, you know those cracker boxes just wanted to become a custom radio rack–! I say save the fine wood working to build the shelf upon which you’ll place your bespoke cracker box radio rack.

Thank you!

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

10 Replies

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 →

Raddy RF75A Review – Pocket Radio with Interesting Bells and Whistles

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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:

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.)
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.

Surprisingly effective Ferrite Bar

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!

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).

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

16 Replies

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.