Author Archives: Robert Gulley

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Paul Walker, Program Director: KSKO 89.5 FM McGrath, Alaska, USA and

Afternoon Host:       Hits 106 KLMI-FM Laramie, Wyoming, USA

Posted:

KSKO on shortwave today, 59000khz at 2100UTC for an hour via Spaceline Bulgaria to Europe!

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Thanks for the heads-up Paul!

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The Spectrum Monitor Cover Aug. 23

Meteor Scatter with WSJT-X

(This is an article from the August 2023 edition of The Spectrum Monitor, used with the kind permission of Ken Reitz, editor — Robert Gulley, K4PKM)

Perseid Meteor StreakPerseid meteor streak. (Courtesy: European Southern Observatory, via Wikimedia creative commons)

Incoming! An Introduction to Meteor Scatter Propagation
By Robert Gulley K4PKM

One of my all-time favorite quotes from Shakespeare comes from Hamlet: “There are more things in heaven and earth, Horatio, than are dreamt of in your philosophy.” When I first heard about bouncing a signal off the moon and back to earth I thought “how can that be?”
Then I heard some German folks had bounced a signal off Venus and received it back. “How can that possibly happen?” Indeed, there are more things in heaven and earth than are dreamt of in my philosophy! Enter Meteor Scatter.

Meteor Scatter is a propagation phenomenon where signals sent up into the atmosphere are reflected back down to earth by the ionization trails left by meteors as they cross our skies. As the meteors move through the atmosphere, they heat up vapor particles which can then reflect VHF and UHF signals in irregular patterns. These trails typically only last for a few milliseconds up to a few seconds, but with modern digital software, that’s enough time for a lot of information to be passed along. This occurs in the “E” layer of the atmosphere.

Likely you have heard of E-skip propagation, where VHF (and occasionally UHF) signals can travel much further than the typical line-of-sight propagation. Meteor scatter works similarly to allow much greater DX distances, typically up to 1000 or so miles, and occasionally even greater distances. Similar to other propagation modes, meteor scatter can occur as forward or backward scatter.

What’s even more exciting, it does not take a super-station to hear or make these contacts! An
antenna and radio capable of receiving 6-meter signals will work just fine with the right software. Radios that can receive 6 meters can have their audio sent to WSJT-X software using the MSK144 mode to listen in, and amateur radio operators can transmit using typical radio output power to either a 6-meter vertical or horizontal dipole. While a directed antenna will produce the best results, the variable nature of the reflected signals makes almost any antenna capable of 6-meter reception/transmission useable.

Unlike line-of-sight propagation which typically works best with matching polarization, there is no one pattern to meteor scatter. Elevation, meteor trail direction, location of stations, forward vs. backward scatter, all are variables that make working meteor scatter more fun and more frustrating!

As an aside, working distances of 1200 miles or so is considered DX on 6 meters, and definitely on 2 meters and above. DX is relative to the band and mode being used, not strictly working other countries. Where I live, 1200 miles is excellent, but won’t take me to Europe or over into the Pacific. However, the DX is just as exciting knowing I am pushing the limits of a given mode and frequency combination.

A Little History

In 1929 a Japanese scientist, Hantaro Nagaoka, first suggested observable propagation from meteors in a paper entitled: Possibility of the Radio Transmission being disturbed by Meteoric Showers. By the 1940s, meteor scatter was further established by Stanley Hey, a British physicist and radio astronomer. His work during WWII with radar led directly to discoveries of both meteor scatter and radio waves coming from the sun and other galaxies. I highly recommend reading about him!

Having close ties to military research, it was not long before the military started using meteor scatter as a means of long-range communication by the 1950s. Canadians developed a meteor scatter program called JANET. A NATO document from December 6, 1961, requests information on communications via “meteor trails.” NATO’s Supreme Headquarters Allied Powers Europe
developed a program of meteor scatter communications called COMET (COmmunication by MEteor Trails), with stations in the Netherlands, France, Italy, West Germany, the United Kingdom, and Norway. With the introduction of satellites, meteor scatter communications took a backseat, as satellite communications were assumed to be more reliable.

However, due to vulnerabilities of satellite communications being intercepted, meteor scatter has once again become a source of communication for the military as well as other governmental agencies. (This history, as well as much additional information on meteor scatter communications can be found by searching: Meteor Burst Communications: An Additional Means Of Long-Haul Communications by Major John P. Jernovics Sr., USMC.

Amateur Radio and SWL Use

Amateur radio operators have for years been using various modes to take advantage of the expanded reach meteor scatter can provide, including SSB, Morse code, and digital mode software such as WSJT-X. Before our current digital mode software, CW was in common use, where data would be sent and recorded in bursts up to 800 words per minute. Specially modified tape recorders would then play back the messages at much slower speeds to allow copying the code at normal speeds. With the advent of personal computers, this made the sending/copying process much easier.

Fortunately, today we have readily and freely available software to allow communication in real time. The wildly popular WSJT-X software by Joe Taylor has meteor scatter software built in. Using the MSK144 protocol, signals are coordinated between both sending and receiving stations to allow for the most efficient transfer of information. While listening to meteor scatter transmissions has always been possible for shortwave listeners, today’s digital software makes it incredibly easy to receive these signals and log some very interesting stations and locations. Many SDR radios are capable of 6-meter reception, as well as the 2-meter and 70-cm bands. SDRs also have the benefit of digital filtering, allowing the signals to be pulled out more
cleanly.

On the transmitting side, if you are familiar with FT8 and FT4 then switching to MSK144 will not be much of a learning curve. If you are new to WSJT-X or similar software, I would advise spending some time getting comfortable with FT8 and/or FT4 before diving into meteor scatter
work. While one does not have to know these modes to use meteor scatter, I believe it helps.

For the sake of brevity, I will assume a basic familiarity with digital modes, and concentrate on how meteor scatter works within WSJT-X.

Unlike FT8 and other standard digital modes, meteor scatter MSK144 has standard frequencies which, while not absolute, are very widely acknowledged among users. When choosing a band, the default frequencies brought up by the software should be used, unless you know for certain a station is transmitting (or listening for you) on a non-standard frequency. I recommend starting with 6 meters, as it is by far the most active. If you have 2 meter/70cm all-mode capability, wait until you are comfortable with the back-and-forth flow of contacts before moving on from 6 meters.

Software Settings

These are the recommended settings for meteor scatter mode using WSJT-X.

Notice the default settings on the WSJT-X screen for meteor scatter in the screen capture. F Tol (frequency tolerance) is set to 200, RX (Receive) is set to 1500 Hz, and Report is set to 0. I would also suggest having your radio’s pre-amp turned on for this mode. You can adjust the Fast Graph shown below) brightness through sliders on the panel or use the auto level feature.

One place where this meteor scatter protocol differs from standard FT8 or similar modes is the mutually agreed upon standard practice of stations transmitting (pointing) to the east transmit on even cycles (each cycle is 15 seconds long: 00, 15, 30, 45, 00), so they would transmit on 00 and 30 second marks, while stations transmitting (pointing) west transmit on the odd cycles (15, 45).

You will notice there is a check box for TX even/1st – stations transmitting toward the east coast would have this box checked, whereas stations trying to work to the west would leave the box unchecked. Clear as mud, right?! Perhaps an acronym will help you remember the proper sequence. PETE = Point East Transmit Even.

This is of primary importance when calling CQ. When answering a CQ call (sometimes referred to as search and pounce mode), the software will handle transmitting on the proper cycle. This is the style of operating I use most, but I do occasionally call CQ in an effort to find out if anyone can hear me. This is when I need to make sure I am following the standard protocol.

Base-Level Reception

Reception Graph with Spikes

Top: The Fast Graph display shows a base level reception which can be adjusted for
brightness and contrast similar to an SDR waterfall. Bottom: Typical reception graph
with signals making vertical markings and sounds similar to static crashes.

The hardest part of working meteor scatter is waiting for a signal to show up calling CQ, or having one answer you if you are trying to initiate contact with CQ. This can take time. Remember, you are depending on wispy trails of ionization to reflect your signal to someone else on the planet, either to answer their call or reach someone with your call. Be patient! It is not uncommon for a station to call 5, 10, even 15 times before someone responds. And the waiting is not over . . . .

To complete a contact after hearing CQ, you may have to respond to that CQ call over a number of cycles before the meteor trail gods bring all those meteors into alignment so that your response reaches the person on the other end. It is not uncommon for contacts to range over 10 minutes or more. Fortunately, it is usually much less. However, this is not like a DXpedition where once you are called back the rest of the contact is over in 30 seconds.

Long Contact Span

Left: While not always typical, contacts can take 10 minutes or more to complete on days when meteor activity is low; typically contacts last over several minutes or more.

In the screen capture showing a typical contact, notice I initiated my response call at 10:09:00 (as I was pointing east), and the contact continues over 36 cycles (I counted for you!) and spans 12 minutes. Now before you tune out and say “Whoa, no way, man! That’s crazy!” I have two very valid points to make. 1) If you are chasing a rare DX station as I often do, it is nothing for me to try for 20 minutes or more to break the pileup and make the contact. I have actually spent 3 hours or more attempting to work a really rare DX station. Compared to that, 5, 10, or even 15 minutes is not a long time. 2) Stop and think about how totally cool it is to be using meteors to be making a contact with someone!! That’s definitely worth some real bragging
rights to your ham buddies who have never done this, and just the cool factor alone keeps me coming back to see how far I can make a meteor scatter contact!

If you are like me, radio is still magical, and meteor scatter is all the more so – we are interacting with particles that have travelled thousands and thousands of miles to get here! That’s awe inspiring!

While perhaps not quite as amazing as bouncing your signal off the moon to contact someone halfway around the world, it is still really exciting to think you can send massive amounts of data in a short burst before a meteor trail fizzles out in a matter of seconds or less. MSK144 transmits a complete data package, including redundant data features, every 70 milliseconds!!
This is why you may see a half dozen or more repeats of a signal in the same cycle as each data package is received and decoded. The redundant nature of the transmission helps to deal with the chaotic randomness of the meteors. If even one data package gets through, then the receiving station can answer accordingly.

You might be wondering, “How can I react fast enough to respond to packets sent in 70 millisecond intervals?” You do not have to. Remember we are dealing with 15 second cycles,
so once a CQ comes through and you double click on it to respond (just as with FT8 etc.), the software does the rest, assuming Auto Sequence is checked. The software then follows the
same pattern as when making auto-sequenced FT8 or FT4 contacts. If you are calling CQ, the auto sequence is even easier once someone responds, again, just like FT8.

You can see why I said it is best to get familiar with FT8/FT4 before trying meteor scatter. You will be a lot more relaxed making these amazing contacts with some real digital mode experience to fall back on.

Strategies for Working/Catching Contacts

The best time for hearing or working other stations is during the early morning hours, typically between a little before dawn until several hours after daylight. By the time the sun comes up in your area the signals will mostly fade away as the atmosphere heats up and signals are absorbed.

Don’t expect every day to produce lots of signals, conditions vary a great deal. As I discuss further down, there are times of high meteor activity, but most days have varying opportunities, much like normal contacts and propagation vagaries. If the atmosphere is disturbed by  geomagnetic storms, solar flares, CMEs and the like, then listening conditions will be adversely affected with this mode just as with other modes. However, don’t just assume conditions will be poor based on the typical propagation reports (good advice for any mode!). Because we are dealing with extremely short data bursts, signals may come through even when conditions
seem difficult for other modes.

The main thing is to not get frustrated with trying to hear or work meteor scatter contacts. It is a very special mode, and with some experience and understanding of how the mode works, you will hear and/or make a good number of contacts over time.

Unlike FT8 or other digital modes, I turn the volume up on the radio to a reasonable level to hear the meteor signals. With FT8, FT4, JT65 or similar modes, I keep the volume off unless I am wanting to try to identify something causing interference, such as a different mode being used or something local. Meteor scatter (MSK144) signals sound like static bursts rather than the familiar tones of FT8. By having the volume turned up I am able to quickly tell when there are signals present. This allows me to do other things while monitoring the band, useful when
there are slow signal days. As a matter of fact, I am listening to the band and switching screens as needed while writing this article – actual multitasking!

Contacts are made in much the same way as other digital modes, but with a couple of notable exceptions. As shown in the screen capture with contacts happening over 9 minutes, there is often a lot of repetition. Even when signals seem strong coming into your station on the receive cycle, it does not mean the other station is going to hear your response on the next transmit
cycle.

Here’s an example of a typical contact. I hear A8XYZ sending CQ. I respond to his call on my next transmit cycle. I then hear him calling CQ again on his next transmit cycle. This may go on for several cycles or more, but since he is a new grid for me, I persist.

Finally, he responds to my call with a signal report as part of the auto sequence feature of the software, once he has heard me calling him. His computer then sends me his signal report over multiple cycles as needed until my computer sends him a RRR or RR73 depending on my settings. Since he does not receive my RR73 the first time I send it, his computer continues to send a signal report. When he finally does receive my RR73, he sends his 73 to indicate the completed contact. He likely does this for only one or two cycles because otherwise we would end up in a continuous loop of 73s back and forth.

Unfinished Contact

Here’s a case where the contact was not completed, and so it is up to you and the other station as to whether the contact is confirmed.

Sometimes the whole contact is over in a couple of minutes, sometimes longer. Then there are the times as indicated in the screen capture with WA4CQG, I never received a 73 from him after repeatedly sending my RR73. Since he continued to send a signal report, he does not know that I have acknowledged his signal report, and thus is not a full, standard contact.

To Confirm or not to Confirm, that is the Question!

Now, here’s the tricky part in terms of the contact with WA4CQG; technically we made a valid contact and can log it as such, even though we never got past his signal report. Since he was calling CQ, and I answered his CQ with a signal report (which he obviously received based on his then sending a signal report), that is all that is needed for a valid contact. Many people will not log it as such because they do not feel it was a full contact, but some will. Since I was sending RR73 to his signal report, my computer automatically logged the contact to my logging software, and I will upload it to LOTW and eQSL. Now it will be up to WA4CQG as to whether or not he logs the contact on his end to determine if we have a completed and confirmed QSL in our respective logs. (And yes, this is happening in real time as I write this article!)

I use this contact as an example to make an important point: just because you know it is a valid contact does not mean the other station sees it as such, and thus diplomacy is the order of the day if you choose to pursue the issue with the other station (I won’t in this case, it’s not a rare contact I need in my log). The choice to confirm the contact, and it is definitely a choice and not an obligation, rests solely in the other station’s hands.

[Additional Note: He did end up confirming the contact!]

Good operating etiquette requires that if you contact the other station requesting confirmation, you do so knowing full well it is purely the other station’s prerogative to confirm or not. I typically say something like “I show us making a contact on [date] and [time] with a signal report of [xx]. Since you apparently did not receive my 73, the call is yours as to whether or not you confirm the contact, and I will respect your decision either way. If I can provide more info, please let me know. Thank you!!” Good manners and friendly attitudes are far more important than a log entry!

Awards: If you like chasing awards, one of the more fun ones, and relatively easy to achieve over time, is the ARRL’s VUCC award for working 100 or more maidenhead grid squares. You can combine 6-meter E-skip, trans-equatorial contacts, and meteor scatter VHF contacts, as well as other VHF propagation/mode contacts for this award (but not contacts made using a  repeater). If you happen to use the excellent program JTAlert, you can set alerts to indicate new
grid squares, allowing you to more quickly achieve the 100 needed grids for the award (assuming the other stations will confirm on Logbook of the World or through QSL cards).

Web Resource for Tracking/Scheduling/Posting: A great resource on the internet is Chris Cox N0UK’s site, pingjockey.net. From there you will want to go to the Ping Jockey Central page and put in your details under “User Details” where you can then read and send messages with other meteor scatter users. There is good camaraderie there, as well as the opportunity to see who’s active, and possibly set up a scheduled contact with another station. [Or, if you are just monitoring the meteor scatter frequencies, you can let folks know you have heard them, which is a big help to them.]

Additionally, while you are not allowed to short-circuit the contact process, it is common to let another station know you are receiving them and trying to call them back. This helps the other station at least know they are being heard, and they can continue to call in hopes of a contact. It also allows you or the other station to decide when to stop trying for the contact, so that neither are wasting time calling someone who has moved on.

Meteor Showers

I have saved the best for last! If you are reading this August issue as it comes out in 2023, the annual Perseids meteor shower is already underway, and is expected to peak on August 13 with up to 84 meteors per hour – that’s prime meteor scatter communication time! (As a bonus, for the purposes of viewing the Perseids, the moon will be a waning crescent, meaning a darker sky on the August 12-13).

The last several weeks of July and most of the month of August, the atmosphere will be primed for some great meteor scatter contacts. Give it a try while the “gettin’s good” as they say. And while meteors are in the sky literally every day, special times like the Perseids offer the chance to rack up a large number of contacts in a relatively short time, and that will make the experience all the more rewarding! While the Perseids are the largest meteor show, there are a number of meteor showers throughout the year. You may want to research other meteor showers and mark your calendar accordingly.

Wrap-up

Meteor scatter signals are a lot of fun to receive and to fill your logs with some very interesting contacts, whether as a shortwave listener or an amateur radio operator. With modern software the process is about as easy as one can get, and our radio forefathers would be quite jealous of our capabilities.

Something I did when starting out was to leave my radio on overnight to see what stations were being heard, and this gave me an idea of when signals were the most active. Keep in mind the various time regions and when they might start getting active or ending.

For me, in the Midwest portion of the United States, as morning comes and the sun gets stronger, I turn toward the western part of the country to try to work stations which are just approaching dawn. This allows for a longer contact period, and thus more opportunities to hear more distant stations. I believe my longest contact has been 949 miles. I can’t wait to reach over 1000!

Meteor scatter is a mode that rewards patience. Admittedly, it takes some getting used to in terms of repetition and the duration of contacts, but it is well worth the effort. Even if you only work the mode during known meteor shower opportunities, there will be many interesting contacts possible. And who knows? You may just find the mode as addicting as I have!

Robert Gulley, K4PKM, is the author of this post and a regular contributor to the SWLing Post.

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Weather Station and Display Unit

WF-100SE Weather Station Review

WF-100SE WEATHER STATION

By Robert Gulley K4PKM

Weather stations have always intrigued me, particularly ones that sent information to the Internet. They are often more revealing than the local weather forecasts, and certainly can be used to augment NOAA weather reports. When living near a big city there were enough stations around I didn’t feel I could justify the expense, but living out in the country now there are only a few stations in the county, so I decided I would get one eventually.

About that time Radioddity came out with the WF-100SE and it seemed to tick most of the boxes I was looking for, and, as a amateur radio operator, had the Internet connectivity I sought. Since I suspected I would not be the only radio aficionado who might be interested in it, I approached Radioddity to do a review of the station and they promptly sent me a unit to review at no cost. I have reviewed other products for them, and they understand the ground rules – I tell it like it is, good or bad.

Here is a feature description as found on their website:

  • Easy-to-read Display: The WF-100SE features a large and clear 13-in-1 color display that presents weather data in a user-friendly format. Check temperature, humidity, rainfall, UV index, feels-like temperature, dew point, sunshine intensity, weather forecast, wind direction and speed, barometric pressure, and moon phase at a single glance.
  • Effortless Setup & Maintenance: Set up your weather station quickly with intuitive controls and straightforward installation instructions, and benefit from smooth operation with minimal maintenance requirements.
  • 7-in-1 Accurate Outdoor Sensor: The WF-100SE is equipped with a highly accurate outdoor sensor with upgraded rain collector, thermo-hygrometer radiation shield, and a solar panel that precisely measures weather conditions in your area. The system offers an impressive communication range of up to 330ft.
  • Sync with WeatherCloud & Wunderground: Stay updated with these platforms’ latest weather updates and forecasts via Wi-Fi. Access real-time data and make informed decisions wherever you are.
  • 24-48h Weather Forecast: Rely on the WF-100SE’s accurate sensors to provide reliable 24-48 hour weather forecasts. Whether it’s sunny, cloudy, rainy, or snowy, get prepared for any weather condition that lies ahead. Plan your activities in advance.

__________________________________________________________________________________________________

Since photos often do more justice to something than just mere words, I have taken images of my display screen, as well as screen captures of my unit as it appears on the Internet. As you can see from the display unit, the image is bright, easily readable, and contains a lot of information in itself. In addition to the wind, rain, indoor/outdoor temperature, I also like that the unit displays the UV and solar radiation levels, and even the moon phase, as I like to take the telescope out now and again when the moon is not too full and obscuring things.

Display Unity

Clear, easily readable display with large print for these old eyes!

Where the unit really shines as far as information goes, is what can be displayed over the Internet. As can be seen in the images below, there is a lot more information available online, including Day/Week/Month totals and averages. These can be viewed as graphs or as a table.

Weather Underground Display of Information

Basic Information similar to the Display Unit

Weather History on Internet

Weather history can be viewed by Day/Week/Month, a really nice feature to look for trends.

Graph of weather history

Visual graph of weather history requested

Table view of weather history

This is a partial Table View of the weather History

Setup and Internet Connection

Setup was remarkably easy, and connection to the Internet was simple. Setting up the station on the Weather Underground and Weathercloud was just a matter of entering some basic information. Between the two sites I prefer the display of the Weather Underground, but that’s just me. Both worked fine.

I have ben testing the unit for several months now and it has performed flawlessly. I have compared my readings with nearby stations and they essentially agree, with slight variations as you might expect.

For those curious about the station working with APRS on the aprs.fi site, there is a process for setting up the station so that it can appear on the Google maps site for APRS, but I have not done that yet.

Conclusions

I am very pleased with the performance of this weather station, and find it’s features comparable to other well-known brands. The current price is $179, again, pretty much in line with (or less than)  other established stations, and if you sign up for their email list you will get various coupon offers throughout the year which should save you some money.

Anyone familiar with my typical reviews knows I normally try to list pros and cons, but honestly, I can think of no cons I have encountered with this unit. If you have specific features you are looking for that are not mentioned or displayed here, I would encourage you to contact Radioddity with your questions, as I have found their customer service to be quite helpful.

Update One Day Later:

I had a bit of a storm pass through this morning with some heavy wind gusts which knocked down my Weather Station. It was on a PVC pipe clamped into a tripod, no stakes, so blowing over was my fault. (Fixing that today!)

Good news is that falling from a height of 8 feet or so, no damage to the unit, everything working fine. Whew!!

Purchasing the WF-100SE ($15 Discount)

If you purchase the WF-100SE weather station via our affiliate link, you will receive a $15 discount and Radioddity will send a small commission to the SWLing Post. Click here to make your purchase (simple search for WF-100SE).

Robert Gulley, K4PKM, is the author of this post and a regular contributor to the SWLing Post.

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Pirate Radio QSL Card

Beautiful emailed QSL card from Undercover Radio

This QSL card just came today from a broadcast on Halloween, station Undercover Radio. There were a number of broadcasts that night, but this was by far the most unusual that I heard!

 

Robert Gulley, K4PKM, is the author of this post and a regular contributor to the SWLing Post. Robert also blogs at All Things Radio.

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RADDY RF320

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.

IOS APP

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.

Bass Boost, Back Lights, QR Codes

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.

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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).

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Military Reliance on HF on the Rise?

I am sharing an email I received from Jeorg at Klingenfuss.org regarding increased solar propagation and the threat to satellite and wired communications in times of war. For those who may not know, Klingenfuss aggregates utility, shortwave, military and other HF frequency lists in book and CD form. I received this email as a customer having purchased their latest “Super CD” earlier this year. I am not affiliated with them other than as a customer, and this email did not come to me as a sales pitch. I do however think their software is a good value for the money. for what that may be worth! – Robert, K4PKM

Dear friends,
solar activity is increasing rapidly and provides excellent HF
propagation conditions on frequencies above 20 MHz as well. Sunspot
numbers have ramped up pretty fast: in February 2023, the NOAA number
already reached more than 200 – while the maximum of the current
solar cycle 25 is expected not before mid-2025! See our screenshot of
2 April 2023 at
www.klingenfuss.org/kiwikiwi.gif
In these times of war, remember the key fact: shortwave = HF is the
only medium for inter-national and inter-continental communication
that, unlike e.g. SATCOM, landline connections, and submarine cables,
cannot be blocked, censored, or cut off. What’s more, there are no
call costs or monthly fees.
Increased vulnerabilities to cyber and SATCOM – coupled with state-of-
the-art HF communications capability and capacity – is making
military services worldwide rethink their communications planning.
Says DA Reporter at
www.defenseadvancement.com/news/australian-defence-force-upgrades-hf-
communications-system
“In a modern threat environment, access to local communication
infrastructure or satellite communication cannot be assured. Having a
communications capability that can work seamlessly with the
Australian Defence Force and its allies is essential. Starting in
October 2023 under the JP9101 – Enhanced Defence High Frequency
Communications System program, the new system will provide Australian
and allied armed forces with the ability to securely communicate
using voice and other data from almost any location across the
globe.”
Robert Gulley, K4PKM, is the author of this post and a regular contributor to the SWLing Post.
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