Shortwave listening and everything radio including reviews, broadcasting, ham radio, field operation, DXing, maker kits, travel, emergency gear, events, and more
2014 “Off the Shelf” Regen Comes Off the Shelf (Two Videos)
Walter KA4KXX spotted an error in the schematic of my 2014 “Off the Shelf” regen receiver: The source resistor on the MPF-102 should be 2200 ohms, not 2.7 ohms. See:
Walter’s e-mail caused me to take this old receiver off the shelf. In this video you can listen to it in action on the shortwave broadcast bands. In a second video I put it on the 40 meter ham band and listen to some SSB.
Many thanks to SWLing Post contributor, Kostas (SV3ORA), for sharing the following post which originally appeared on his website:
Update June 1, 2024: Kostas is not currently selling the NR-1 as a product but has, instead, made the entire project open and available for everyone to build their own. You may contact him for more information.
The NR-1, a revolutionary noise blanker that works directly on the antenna!
I designed my own noise blanker because:
I was tired of that HF noise that could not be beaten otherwise.
I wanted to remove it before it gets into my transceiver.
I could not install a separate “noise” antenna/coaxial for diversity.
I wanted to remove noise interference from any direction.
NR-1 is a revolutionary Noise Blanker which is the result of two-years of development and extensive testing by Kostas sv3ora.
NR-1 works directly at the antenna. This has significant advantages over the classic noise blankers which work at the intermediate stages of the receivers. It does not require a second “noise” antenna for its operation.
Furthermore, it is not based on cutting-off of amplifiers, unlike common noise blankers
do.
Because of these, the NR-1 is superior, compared tocommon internal Noise blankers of radios:
NR-1 removes noise before it even reaches the receiver. Thus, the front-end RF
stages of the receiver are unaffected by noise, unlike a common noise blanker
which removes the noise after it has first passed through the internal circuits
of the receiver.
NR-1 removes high-level, high-repetition-rate noises that common noise blankers
usually cannot cope with.
NR-1 is not affected by strong near-by signals. Instead, common noise blankers
perform poorly when there are strong near-by signals and they distort the signal of the station we want to listen.
NR-1 can be used by many radios. Because it is an external device, it can be
connected to various radios/receivers without the need to modify them.
NR-1 has a built-in 8-band preselector and helps eliminate intermodulation (birdies)
caused by strong local medium and shortwave stations, on RF direct sampling
radios (eg IC-7300). The preselector is relatively wideband and does not affect
the sensitivity or the waterfall spectrum in the amateur radio bands.
NR-1 has built-in variable gain preamplifier and variable attenuator. Preamplification is
particularly useful in the high frequency bands, where some radios have limited
sensitivity. Variable attenuation helps to reduce band noise for more
comfortable listening to mid/high strength stations.
Comparison of the NR-1 with other noise removal systems (eg. QRM eliminator, X-phase etc):
NR-1 does not require a second (noise) antenna/coaxial-line to operate. Unlike QRM
eliminators, NR-1 does not require an additional “noise” antenna and
therefore no second coaxial cable out of the shack. The main transmit and
receive antenna you are already using is sufficient.
NR-1 is easy to set up. In contrast, QRM eliminators require systematic testing of
various noise antennas in different locations to perform satisfactorily.
NR-1 removes noise from every direction simultaneously. In contrast, QRM
eliminators, depending on the noise antenna setup and their configuration,
remove noise from one direction only each time. If the noise originates or
“travels” through cables and reaches the antenna from different
directions, QRM eliminators do not perform well.
NR-1 removes more than one noise source simultaneously because its principle of
operation is not related to the phase of the noise.
NR-1 does not require constant adjustment. Once set for one band, it usually does not need to be reset. In contrast, QRM eliminators require resetting every few tens of KHz or so.
Kostas has documented all the details of the NR-1 for his own future reference in hispage.
He has also created someYOUTUBE videosas demonstrations of the operation and the effectiveness of this antenna noise blanker.
I once again attended Four Days in May and the Dayton Hamvention this year–it was an amazing event and I believe attendance was at a record level (over 35,000 attendees!).
I stayed quite busy speaking with readers of the SWLing Post and QRPer.com. I really appreciate all of the kind words and support–it was great meeting so many of you. I was so busy this year, I didn’t have quite the opportunity to take as many photos as I have in the past, but I still managed to snap quite a few.
The following photos were all taken at the 2024 Hamvention and the Four Days in May QRPARCI Conference.
Many thanks to SWLing Post contributor, Kris Partidge, who notes that there’s a new shortwave radio station in: Radio Piko! The station is run by a hobbyist and transmits music, old time radio shows, and interviews. The station uses fixed frequencies and announces broadcasts on the website a day before.
Radio Piko even has a few test transmissions this weekend, per their website:
May 25 & 26, 2024 TEST TRANSMISSIONS:
1500-1600 UTC 9770 (Norway, Denmark)
1800-1900 UTC 5980 (Finland)
1900-2000 UTC 3990 (Finland, Sweden, Estonia)
Also, “Random tests on 3990, 5980 or 9770 [kHz]at random times.”
For more info about Radio Piko, including the summer schedule, check out their website: https://radiopiko.fi/ I recommend reading the FAQs.
At 10 watts, this will be seriously weak DX for those living outside of Finland. I, for one, love the format of pre-1950s music and shows. I may have to listen via a nearby KiwiSDR!
Note that this station only plans to be on the air until August 11, 2024.
Indy 500 Special Event Station: You Can Still Earn a Certificate!
by Brian D. Smith, W9IND
Not every Indianapolis 500 goes the full distance. Seven of the 107 races run since 1911 have been shortened by rain, notably the 1976 event that covered only 255 miles.
In the same spirit, the Indianapolis Motor Speedway Amateur Radio Club has decided to amend its usual policy of awarding a certificate only to those who work or tune in W9IMS during all three of the year’s special events. For 2024 only, contacts with two separate W9IMS special events – and that includes reception reports – will be sufficient to qualify for the Checkered Flag Award.
Extenuating circumstances prompted the decision for the revision. The first special event of the year, commemorating the IndyCar Grand Prix, took place May 5-11, but that was also the week of the strongest geomagnetic storm in two decades. The hyperactive sun zapped HF amateur radio frequencies, often making it difficult to even hear, let alone work W9IMS.
So if you missed W9IMS during the first race of 2024, for whatever reason, you now have a second chance at a certificate if you act fast. Catch W9IMS between now and the end of Race Day – 11:59 p.m. Sunday, May 26 (Indy time) or 0359 UTC Monday, May 27 – then repeat the feat during the Brickyard 200 NASCAR race during the week of July 15-21, and you’ll meet the new award criteria.
Of course, if you managed to bag W9IMS two weeks ago, you can clinch the Checkered Flag Award in the coming days. But you’ll still probably want to chase a Brickyard 200 contact in July, since W9IMS is offering unique and collectible QSL cards for each special event of 2024.
Tips on finding W9IMS:
Check DX Summit (www.dxsummit.fi) for spots listing the current frequency or frequencies of W9IMS. You can customize your search by typing “W9IMS” in the box at upper right.
Go to the W9IMS web page (www.w9ims.org) and look for the heading, “2024 Operating Schedule.” Click on the Indianapolis 500 link, which opens into a weeklong schedule of individual operators and their reserved time slots. Although operators frequently get on the air at unscheduled times, your odds of snaring the station improve significantly during hours with a listed op.
Prime time for weeknight operations is 6 to 10 p.m. in Indy (2200-0200 UTC) and sometimes at least 2 hours longer. That’s also your most likely shot at finding W9IMS activate on two bands – typically 20 and 40 meters. Preferred frequencies are 14.245 and 7.245 MHz, often varying by several kHz due to QRM. Other bands (especially 80 and 15 meters) are possible but rare.
Remember that the published schedule can be shortened by adverse circumstances, such as local thunderstorms, a lack of calling stations and, as we discovered earlier this month, solar flares! Don’t wait till the final hour to look for W9IMS.
But if you still haven’t worked W9IMS by Sunday night, you may find it more advantageous for stations like yours. Toward the end of the special event, W9IMS ops often call for “only stations that haven’t worked us this week” or switch to contest-style operations, exchanging only signal reports to put more contacts in the log.
Keep in mind that both hams and SWLs are eligible for QSL cards and the certificate. So if your ham station isn’t able to work the station by Sunday night, you can create an SWL report by copying down details of other W9IMS contacts – such as date, frequency, UTC, and a few of the stations you heard W9IMS working. SWL reports count as credits too, although the certificate may not feature your callsign.
The current weather forecast calls for thunderstorms on Sunday (Race Day). If the race is postponed, W9IMS will likely extend its operation through the new Race Day.
Many thanks to SWLing Post contributor, Bill Tilford, who shares the following announcement:
Uncle Bill’s Melting Pot, May 2024
This month, our guests are
1. Clay Ross, leader of the American Patchwork Quartet, an excellent multiethnic fusion project (including Falu, a previous guest on this show) sharing some of their debut album by the same name.
2. Eugene Pao in Hong Kong, China’s foremost jazz guitarist, with some of his most recent release which includes guest trumpeter Randy Brecker.
Times and frequencies for May 18, 2024 are
0900-1000 UTC 9670 kHz with beam D (Eastern Europe and Eurasia)
1900-2000 UTC 3955 and 6070 kHz (omnidirectional)
All on Channel 292 from Rohrbach, Germany.
Additionally, On May 18, 2300-2400 UTC, we are doing a test broadcast of the last From the Isle of Music on 3955 and 9670
On May 19, 2300-2400 UTC, we are doing a test repeat broadcast of the Uncle Bill’s Melting Pot on 3955 and 9670
Many thanks to SWLing Post contributor, Dan Robinson, who shares the following review:
[Note that all Amazon and Radioddity links are affiliate links that support the SWLing Post.]
Raddy RF-919 Receiver: Best Portable in Years – Held Back Only By Soft Muting While Tuning
by Dan Robinson
It’s quite extraordinary that in these days of reduced use of shortwave some manufacturers continue to develop portable receivers for the worldwide community of radio listeners. We have the Choyong LC90, which for the first time attempted to combine HF, MW, FM and Internet radio (still a work in progress). And now out of nowhere comes the Raddy RF919.
Like many receiver enthusiasts, I was excited when I saw the first photos and videos of the 919, by Shenzhen Hanrongda in China. The company has an amazing number of portables in its lineup–in addition to the 919 there are the: RF320, RF760, RF747, RF75A, and RF750 along with various hand crank emergency sets. The RF919 under the Raddy label also sells as the Retekess TR113 (which can be seen on its Amazon page).
It is interesting that the RF919 (TR113) appeared on the market just as the Choyong receiver continues to experience growing pains, but obviously both had been in the planning stages for some time. One of the strengths is its very decent SSB performance, though see my comments below about one of the issues with the RF919.
The number of reviews of the 919 by YouTube influencers is rapidly increasing as the radios get into the hands of more users. For the purposes of this commentary I won’t go into every single feature other than to observe the high points. And here’s a headline – from a software standpoint this is a very complex radio with a steep learning curve requiring regular looks at the manual. But enough use brings familiarity with the many features it offers:
Displays
The RF919 has two superb displays: a main information center under which there are buttons for activating various functions and options, and a second beautiful signal level screen that has a lot of information on its own, under which there are four buttons for TIME SET, ALARM, DISPLAY, and SLEEP. These displays are probably the best we have ever seen in a portable, offering 7 colors selectable from the front panel! The Eton Elite Satellit (no longer made) offered a few colors on its display but it was nothing like this. Raddy publicity materials focus on this:
“Unlike other radios, you can choose and set your favorite backlight color to match your style or mood, all while staying updated with a clear 3.54-inch main screen that shows reception status. It’s not just a radio; it’s an extension of your personality.”
Body Design
The 919 is quite a throwback to such classic receivers as the SONY ICF-5900W and other “military style” portables from decades ago – one user noted the similarity to the old National Cougar 877.
The 919 has a solid, confident, body with a space at the top rear that functions as a hand grip. On top are two jacks for a LOOP ANTENNA, and a mobile WHIP style antenna with an OFF/ON rotary switch. That switch is awfully close to the LOOP jack. On the back is a 3.5 mm antenna jack with a three position slider control for specific tuning ranges. The backstand is basically the same type found on the Tecsun H-501. One wishes that there would have been a rubber friction grip placed on it and that it had some additional tension to allow it to hold the radio up in other degree positions.
Antenna
The telescopic whip antenna is impressive – robust, and notably designed to work while the radio is positioned on a desk using its backstand, something that the Choyong LC90’s antenna is not able to do.
I will note that the whip antenna cannot be extended up and out of the radio cabinet which limits it to a single angle when the radio is used with the backstand – placement of the 919 left carrying strap hook on top left is the limiting factor here.
Again the 919 telescopic design is a contrast to the LC90 which both lacks a backstand, and flexibility in the antenna.
A major headline is the manual antenna tuning feature on the RF919. Utilizing the rear antenna jack and switch with MW, SW 1, and SW 2 options, along with the side adjust knob, the user can fine-tune signal strength, with the secondary screen providing real-time viewing of signal strength changes. On top of the radio, there is a mini jack input next to an ON/OFF switch that, according to the instruction card explanation, enables selection of the LOOP (they call it “ring”) position. Wow. The last time we saw this kind of peaking capability on a portable was the SONY ICF-2001 back in the late 1970’s and perhaps the Grundig Satellit 700. Hats off to Raddy for this design!
Controls
The RF919 has a large central concentric tuning outside “shuttle” knob for fast tuning, and a smaller center knob for fine tuning – the center shuttle doubles as a selector with a push function. I am not a fan of encoders that rock back and forth as the outside concentric ring does. At least one user remarked that this feels flimsy. Time will tell whether these hold up in daily use. The keyboard, which is nicely backlit, appears to be quite good. Frequency entry is accomplished by hitting ENT, then the frequency, then ENT again. You can enter in MHz or kHz. There are buttons for VOLUME UP/DOWN, and for TUNE/NEXT, TUNE/PREVIOUS.
One curious thing: if you’re tuning to 22 MHz you can just hit 22 and ENT. But you can’t do that at 23 MHz and above – you have to enter 23.000 and ENT. If you don’t, you get 2.300 MHz. At least that is what I notice on my 919 – perhaps Raddy will be able to clarify why this is so. Another point on controls: the MW/SW1/SW2 switch on the back of the radio is very flimsy and should be improved by Raddy.
Audio
The huge front-firing speaker on the 919 produces superb audio in all tuning ranges. Rated at 20 watts, it rivals the wonderful audio of the Choyong LC90 and combined with the 10 position EQUALIZER makes the 919 even more attractive for someone purchasing it for this level of sound production not to mention a receiver that tunes from LW all the way up to 999 MHz.
Fire up the BLUETOOTH on the 919 and you can not only use it as a speaker linked with your phone, but it will play tracks from the microSD.
ATS/Memories
We have all become accustomed to the convenience of ATS, from the excellent performance on Tecsun radios, and the 919 falls right in line. A scan conducted on FM here in Maryland stored 23 stations and I found sensitivity to be excellent.
Though noise levels were still high from the recent solar activity, a scan on HF yielded a number of stations. It did take quite a long time to complete ATS on shortwave – about 15 minutes, so one hopes this could be improved in future firmware versions. And there is this: when scanning with ATS, the 919 scans the entire HF range rather than just bands. In comparison, ATS on a Tecsun S-8800 takes about 3 minutes, and includes only the main SW bands.
I am not yet sure if the 919 can be made to scan this way, but if not it’s something Raddy should consider. Both displays remain on during ATS. This avoids the need to mess with the display functions while scans are ongoing.
Presets
There are 1600 memory channels on this radio! Once stations are memorized, they can be accessed by hitting the PRESET button on the lower right edge of the main shuttle dials and using the TUNE/NEXT and TUNE/PREV buttons on the keyboard. Note that when going from one present to another the first thing that appears on the display is the CHANNEL number, followed by the frequency. That seems logical but it prevents the user from seeing first exactly what frequency has been memorized without having to wait for the display to shift to the frequency itself.
Bandwidths
The 919 provides bandwidth options not only on shortwave, varying depending on whether one is using AM or LSB/USB, but also in FM – a truly great feature for a portable, and something seen on Malahit SDRs. Bandwidth clarity in SSB is excellent. Maximum bandwidth in AM mode is 6 kHz, similar to portables by Tecsun, with 4 kHz the maximum in SSB. Some users have observed that they would like an 8 kHz AM filter position.
Manual
An extensive manual goes over all of the controls, modes, etc. – the drawback here is that the printing is so small as to make reading it impossible, so better to download the manual in pdf form from the Raddy website and print it out. A bonus is that a three page card guide comes with the radio showing the circuit design and tips for manual antenna tuning and the antenna switching on the back. A very thoughtful addition to the package!
Battery
The 919 continues the trend of radios using 18650 batteries, familiar to professional flashlight users and also seen in Tecsun and other receivers. It takes not one, but two 18650s like the Tecsun H-501. I recommend purchasing a good quality multi-bay battery charger in addition to the ability to charge the radio directly on its USB-C port. Keep in mind that using these radios while charging will create noise, so don’t expect to have the best reception doing it that way.
Recording Capability
Wow! After years of seeing radios with a microSD slot but no recording function, Raddy has gone ahead and done it. You can record any audio to the card and play it. Seems like we could have seen this feature years ago from receiver manufacturers, but we didn’t. Thank you Raddy! That said, I have not yet been able to get recording to work on my unit, using a 64 GB microSD (see below).
Reception Performance
I am very impressed so far with the 919. Sensitivity on HF and AIR appears to be excellent. MW reception is good as well and can be further improved using the antenna tuning feature and the ability to use a loop antenna connected to the receiver. FM reception appears to be quite good. On long wave I was able to hear beacons at levels equal to what I hear on some premium communications receivers.
One observation: when using the RF919 inside my home here in Maryland, I noted what appeared to be some break-in on shortwave from AM or FM signals. I am still investigating this and will report later.
There are many more details to discuss for the RF919. But I need to talk about what I would call the elephant in the room on a relatively short list of CONS, but this is a big one and a bit of a disappointment. The 919 suffers from the issue that is so familiar to us from other portables: MUTING WHILE TUNING. See my video discussing this at:
This is more noticeable when in 1 kHz and 10 Hz increments, and at times of the day when signals are less strong, and seems to be a bit better in the evening when signals improve. But it is there nonetheless.
It’s not the worst soft muting I have ever heard on a portable. It’s certainly survivable. But for those of us who value what I call a continuous listening experience, even the slight muting experienced on the 919 is annoying. It may well be that this can be improved with a firmware update – it’s unclear though whether firmware can be updated via the microSD if new versions were made available on the Raddy website.
Ironically, what soft muting on any receiver does is make the receiver more useful for those of us who over decades of shortwave listening have memorized multiple SW frequencies – using the 919 I prefer to use the keypad to go directly to a frequency rather than put up with the frustrating experience of using the two shuttle knobs specifically because of the soft muting problem.
I should note that there is a harshness one hears from this radio when using the shuttle dials to tune – what I would describe as AGC crashes when going from frequency to frequency. This is nothing new for DSP radios, though some do a better job than others, such as the Tecsun PL-990 and 501 and Data/Sihuadon D-808. It’s clear that when a manufacturer decides to build a radio around these chips, such as the Si4735, there is very little that can be done to smooth out how the chip handles AGC, though I do not claim to be an expert in this area.
Zero Beat Variations
The other issue I observed on the unit sent to me is also familiar – in SSB, the radio isn’t calibrated well enough, so zero beat in LSB or USB vary quite a bit off the actual tuned frequency. While we don’t usually expect DSP portables to be exactly on frequency, this can be annoying as well since in an ideal world we don’t want to have to off-tune from a known frequency of a broadcaster, or amateur operator, to achieve clarity. Tecsun provided a recalibration feature on its portables that enables the user to adjust zero beat. One wishes that other manufacturers would do the same – if the 919 were to have this it would be a welcome addition.
Other Issues
Though the 919 manual states that the receiver accepts up to 256 GB microSD, my first attempt to get a 64 GB card did not succeed. The card is correctly formatted so I am at a loss to determine why this is. Obtaining the Radio-C app was also an adventure – it comes up as an APK file which then installs. Two Bluetooth connections appear, but understanding the process is complicated. I was finally able to get the app working with the radio and continue to experiment with the flexibilities it provides.
Overall, the app provides some great controls over the radio, but the fact that it does not appear on Google Play and has to be downloaded via a QR code may give some users pause. Additionally, temperature appears to display only in Celsius – something I am sure will be corrected in future firmware updates. Also, on the phone app, pressing CB brings the radio to 25 MHz rather than the CB range. When initiating a scan inside one of the SW bands, the scan does not stop at the top of that band. And there does not appear, based on my first tests, to be a way to control SQUELCH from the phone app. Hitting V-UHF on the app screen brings the radio to 20,000 kHz. So, there need to be refinements to the app to clear things up.
Conclusion
So, here’s my summary of the RF919:
Swooping down on us out of the blue, this is an extraordinary entry into the portable category, taking us by surprise with its thoughtful design, seemingly high quality construction, and features that set it apart from other radios on the market today.
Whoever designed the 919 surely had to have some significant experience as a listener because the features included in the receiver move it straight to the top of the list of portable receivers available in 2024.
Comparing the 919 with a receiver such as the Sangean ATS-909X2 there really is no contest. Where coverage is concerned, the 919 blows Tecsun and Sangean offerings out of the water – on this receiver you can listen from LW all the way up to 999 mHz, along with AIR band, weather frequencies, public service, and CB (though as observed by users there is no FM mode reception for CB).
I have not been impressed by other Hanrongda (labeled Raddy/Retekess) offerings. At one point I tried a 747 only to be thoroughly disappointed with its hard-to-see display, terrible SSB, and thin telescopic antenna along with laborious thumb wheel tuning. I was cautious when I saw initial videos of the RF919. But this receiver truly is a major step forward for a portable: superb displays, wide coverage, excellent SSB (aside from the zero beat/calibration issue), wonderful audio, bluetooth capability and phone app control, microSD recording capability – all of these add up to one hell of a radio.
In response to my initial comments on the soft muting and calibration issues, Raddy responded:
“We would like to thank you for bringing two important concerns to our attention: muting during tuning and frequency accuracy. Please rest assured that we are actively discussing these issues with our technical team to gain further insights and potential solutions. We value your input and will keep you updated on any progress made.”
At a price of $269 as this is being written, the RF919 could be a 5 star radio were it not for the aforementioned issues of soft muting while tuning and calibration variation. We can only hope that the designers can address these issues with future firmware updates and possibly make updating something we can do after purchase. The 919 website by the way also offers antennas for the 919 including the Radioddity RD-771 which is described as an upgrade of the popular Nagoya NA-771, and the Radioddity RD-371 “Tri-band” antenna for 144-220-440 mHz.
As of this writing I am not aware of any reviews of the Retekess version of the 919, the TR113, but have to assume that there are no differences. It will be interesting to see how firmware updates occur and again, one would hope that this will be a simple process of being able to download the updates from Raddy/Retekess and be installed on the radio. But so far, there is no sign of this so clarifications from the manufacturer would be appreciated.
It is amazing that in 2024 we still have ANY radios coming to market as advanced as the RF919. This is a receiver that obviously was influenced in design by someone who knows their stuff and included numerous features such as antenna tuning, decent SSB, and the ability to record content. It is frustrating that there have been no advances in chip technology that would allow SSB performance that more closely matches what we had in many classic portables of decades past. But for those who don’t mind things like soft muting while tuning, and can tolerate harsh AGC characteristics of DSP, right now there isn’t anything on the market that matches the RF919 in terms of just wide tuning range and reception tools as well as superb audio.
As for BUY or DON’T BUY, I would edge toward the former with a caution to perfectionists like myself who would be bothered by muting.
If Raddy can fix that issue, and ensure a calibration process that brings LSB and USB closer to zero beat on frequency, and/or include a recalibration function as Tecsun has on its radios, the RF919 would then be an easy YES recommendation. Right now it gets a 4.5 from me, but could easily be a 5.0 if those issues are resolved.
