Tag Archives: Ham Radio

What’s your favorite general coverage transceiver for shortwave listening?

The Elecraft KX2 doing a little coastal SWLing.

Yesterday, at the (Virtual) 2021 Winter SWL Fest, I gave a presentation about QRP general coverage transceivers that I regularly use for shortwave broadcast listening (SWLing).

My discussion was limited to QRP–or low-power–transceivers designed for portable use, but they only represent a small fraction of the new and used transceivers on the market.

So what is “general coverage”––?

A ham transceiver with “general coverage” means that the receiver portion of the radio is not limited to the ham bands only; these receivers typically receive between 100 kHz and 30 MHz (i.e., the full medium and shortwave radio spectrum). Many transceivers, starting in the 1980s, employed a general coverage design as a feature of the radio. Some radios implemented general coverage receiving better than others. In most cases, there was a compromise to performance when the receiver was opened to general coverage reception, so many manufactures held to a ham-band-only platform to optimize performance where hams sought it most. Today, receiver architecture can better accommodate general coverage without compromising sensitivity and selectivity on the ham bands. This is especially true with new SDR-based transceivers that employ direct conversion or a hybrid architecture.

My favorite?

My current favorite is the new Icom IC-705. I purchased this rig last year and have done a tremendous amount of SWLing and MW DXing with it. I love its overall performance, portability and recording/playback features.

What’s your favorite?

I’m betting a lot of us use transceivers for shortwave broadcast listening.

What’s your favorite general coverage rig and why? I’m also curious how many of you almost exclusively use a transceiver for SWLing. Please comment!

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VisAir HF DDC/DUC Transceiver: Randy purchased one exclusively for shortwave radio listening

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Many thanks to SWLing Post contributor, Dan Robinson, who recently shared a message he received from his friend Randy regarding the VisAir HF DDC/DUC Transceiver:

I recently acquired a VisAir transceiver from Russia. It is an amazing SDR unit developed by two amateur radio operators. It is about the same size as the RDR55, but at about 1/3 the cost. While it does not have FM or amateur 2/6 meter, GPS, and a couple of features, this VisAir has other features not found on the RDR55 such as dual receivers, waterfall, receiving audio equalizer, CW decoder, etc. It is a true SDR receiver. The user manual was in Russian and I had to break it into thirds so that I could get it translated into English. Interestingly, the user interface is completely in English despite its Russian origins. While designed primarily for amateur radio operators, it works especially well on the shortwave bands.

[…]I have really been enjoying this “transceiver” and as you imagine, I use only the receiver portion of the unit. It has two antenna connectors and you can configure these however you prefer. I set one as a receive antenna and the other as a transmit antenna to avoid accidentally hitting the antenna match or some function and sending power into my equipment. I also disabled the transmitter portion to further protect against any accidental transmissions.

Unfortunately, virtually all the YouTube videos and information are in Russian and also its use is shown only on the amateur radio bands, but I can tell you that this is a very nice SW DX receiver with lots of interesting user defined menus whereby the unit can be modified to match the user’s preferences. Here is a website with some information on the unit.

As you know, I have enjoyed using a wide variety of communications receivers from simple beginner’s units to the more complex and highly esteemed units built to exacting standards for government use. This VisAir is built by two guys in Russia and amazingly it was designed by them in 2017 and not a whole team of design engineers such as found at Yaesu, Kenwood, and Icom. From what I understand, the unit sells in Russia in rubles for the equivalent of about $1800 USD. Unfortunately it is not exported to the USA and it only comes with a 220 VAC power supply and so I operate it exclusively off of DC current without any issue. It is my understanding that this low production transceiver has sold between about 200 – 300 units and virtually all of these were in Russia. To my knowledge, I am the only person in the USA with this unit. Further, it is my understanding is that there is a wait list of about 2 years to obtain the unit. The VisAir is upgraded via firmware and my unit has the latest firmware installed.

When I got information about the transceiver to consider for purchase, there was only a Russian user manual available. I have access to an online PDF translator, but it can only accept up to 10 MB files and so I had to break the Russian manual into 3 sections, translate each section into English, and then stitch the 3 sections back together to make a complete English manual (which is too large to email as a whole). Attached are sections 2 and 3 of this English user manual for the VisAir:

Section 2 [PDF]

Section 3 [PDF]

You can look at the manual and see what features are available with this transceiver. While the translator worked nicely overall in getting the manual from Russian into English, there are issues whereby the illustrations have Russian language information and these did not translate, but this did not thwart me from understanding and using the VisAir as most of the Russian information relates to connecting the transmitter to microphone and other devices.

As with most all low production units from small producers, the user manual is good at pointing out controls, but lacks in explaining what is the purpose of settings or offering suggestions on the settings other than telling you what is a “default” setting from the factory. I found this same dilemma with the manuals for the Fairhaven RD500, the Reuter RDR55, the Kneisner & Doering KWZ30, etc. But an experienced DXer can generally figure out operations and establish the appropriate settings with a little time. For the first 3 days of operation, it was a discovery for me as I kept learning about new features that I didn’t know about previously and weren’t highlighted in the user manual. It was like reading the user manual for my Toyota Highlander in that there are options and controls that are found in menus and not particularly obvious at first glance or with casual use.

Randy

Thank you, Randy, for sharing your comments about the VisAir transceiver here on the SWLing Post. Looks like a fascinating tabletop SDR.

Click here to check out VisAir’s website.

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We may be looking at severe shortages of some new ham radio gear due to AKM factory fire

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AKM Factory Fire (Image (Strata-Gee.com)

Recently, I’ve received a number of emails from readers who are frustrated because new ham radio transceivers are out of stock and used prices have increased.

At first, I thought this might be due to supply chain and logistics issues due to the continuing Covid-19 pandemic. If it is, it’s only a partial explanation.

As of this morning, I’ve heard from three trusted sources in the radio industry (from retailing and manufacturing) who tell me that the lack of inventory is a supply chain issue, but directly linked to the October 21, 2020 fire at Asahi Kasei Microsystems (AKM) Nobuoka semiconductor Plant “Fab2”.

According to Converge:

“This factory mainly produces large-scale integrated circuits (LSI) used in audio equipment, home appliances, TCXO oscillator, and other products. Due to the recent fire, AKM has been forced to stop production and delays are to be expected.”

Fortunately, according to the article, AKM has been moving some IC production to external companies, but it could take some time to re-tool. A number of markets have been affected by this disruption including the pro audio industry.

There’s no need to panic

If you’ve been looking for a specific radio model, you may find that retailers have been back-ordered and can only offer a vague shipping timeline; 2-6 weeks out, for example.

Some models (including the popular IC-7300, IC-705, Yaesu FT-DX10, and Yaesu FT-991A) are still in-stock at some retailers.

Several readers have been trying to purchase the popular Yaesu FT-891 and found that no one has inventory at present. We may be looking at extended delays for this model and others once inventory is depleted.

But again, I don’t think this is a panic situation. This supply chain disruption has been in play for a number of months already and you can bet the industry is already working on solutions.

My advice would be that if you’re getting close to pulling the trigger on a new transceiver, if it’s in stock, I’d jump on it now. Otherwise, you’ll simply need to be patient as new inventory eventually makes its way back to retailer shelves. Used prices on some of these models may be inflated until new inventory returns.

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Listen to a live ARISS contact on Friday, February 2021

How to build a PC keyer and AM modulator for the EMTX emergency transmitter

PC keyer and AM modulator: A 15-components versatile keyer and powerful PSU modulator for the EMTX (Emergency Transmitter)

by Kostas (SV3ORA)

Schematic of the keyer and modulator (on the left) for the EMTX. The EMTX schematic is shown as well on the right, to determine the connections to the keyer/modulator.

Introduction

My very successful emergency transmitter (EMTX) was only capable of CW or other slow speed ON/OFF keying modes. Then I thought, why not “give voice” to the design? CW is good, but it is half of the fun. If you could use your simple CW transmitter to send out your voice as well, this would be great. You could now chat comfortably on the nets or use any digital radio amateur mode and have much more fun. The simplest modulation you can apply to an existing CW transmitter, is the AM modulation. And whereas this is an old modulation, mostly abandoned by HAMs due to beeing inefficient, there are still AM nets on HF. But do not forget, AM can also be heard by SSB receivers by zero-beating the receiver to the AM carrier. So you could still use your simple AM transmitter to QSO with the SSB guys!

Along with the modulator, there is also a versatile keyer embedded to the circuit, so that the EMTX can be manually keyed with different ways or automatically keyed by audio tones from the PC. For more information on the keyer, keep reading.

The AM modulator

In the old days, the most common way to apply AM modulation was to modulate the high voltage to the plate of the tubes, using a transformer and a powerful audio amplifier. In low voltage solid state circuits, you can still do it using transformers, but you can also use series transistors instead of the transformer. All these things require many components and/or powerful AF amplifiers if one is to modulate higher power transmitters. This does not match the keep-it-simple design I am trying to achieve here.

So I thought of a simple trick with the use of the extremely common LM317 regulator, used as a modulated power supply. This modulator uses just a few common cheap components and it is able to achieve remarkably good modulation levels for it’s parts-count, just from line audio input. It juices every bit of the internal circuicity of the LM317, just look at where the base current of the 2N2222 comes from.

The AM modulator is a kind of novelty. Whereas there is nothing special in a modulated power supply, this circuit has some interesting properties. It is amazingly sensitive and it is able to provide lots of modulated current to any low power transmitter that it can feed. It can be easily driven by the line output of any laptop (around 20% volume) and provide a very good depth modulation to the transmitter. Charles Wenzel was kind enough to do a simulation on the circuit I developed, which is shown below.

His simulated circuit is a slight variation (for measurement purposes). The resistor to ground on the base stabilizes the bias and the ratio of R1 and R2 set the output voltage (0.6 volts across R2 gives about 8 volts across R1). He put in an emitter resistor just for good measure. Same for the series resistor from the source. Charles words, “I don’t know how believable these results are but it looks pretty darned good!”.

The circuit is being used as a current booster, the current being the supply to the transmitter and dependent on the voltage it produces. The LM317 always tries to keep 1.25V between it’s output pin and “adj” pin but where we benefit here is the current at the “adj” pin is very low, so it is easier to apply audio to it. Effectively, the error amplifier inside the voltage regulator is used as an additional amplifier stage. The output pin voltage varies according to the voltage on the “adj” pin so if we use it to bias the transistor we get negative feedback which improves the quality of the modulation. More output voltage = more bias current = lower output voltage. The result, is a very cheap, low components-count, very sensitive AM modulator that can supply lots of power to easily drive the transmitter and produce a clean and deep AM modulation!

The AM modulator bias is set with the 1M potentiometer. Depended on the bias level, the idle carrier on the EMTX can be set from about 0.5W all the way up to 8W. Needless to say that this modulator can modulate any similar power transmitter, not just the EMTX.

The keyer

If it is to modulate the EMTX from the PC, so as to use the different digital modes, there must be a way to key it also from the PC. This is why I decided to embed into the same circuit, a PC keyer which is triggered by the line audio of the PC, but also triggered manually (internal or external key). Keying by audio tones was decided, because modern PCs do not have LPT ports to trigger directly by DC. This keyer uses a reed relay to reliably, fastly and scilently key the EMTX, which is activated by a transistor. The base current for the transistor is derived from the audio signal after rectification. The incoming audio from the PC line passes through the mini audio transformer to increase its voltage, it is rectified and then charges the shunt capacitor to drive the base of the transistor. The keyer “speed” (decay) is determined by the shunt capacitor size. The circuit starts to trigger from about 50-60% of my sound card output signal level.

The relay used to key the EMTX, must be able to tolerate at least 1A of switching and carrying current. Note that the relay contacts switching current is not the same as the contacts carrying current. Reed relays are the best especially if you want long relay life, noiseless operation and very fast switching speeds, like the ones used in Hellshreiber. If you can’t find such a relay, you can use a reed switch capable of 1A of switching and carrying current and then place a suitable electromagnet close to it, so you can build the relay yourself. If you do so, find the best point where the reed switch responds to the electromagnet.

The keyer relay must be as close as possible to the emitter of the transistor used in the EMTX. The connectors at the back of the EMTX and the keyer/modulator have been physically placed so that when the two units are side by side, a very short link cable is required for this purpose. With the two devices placed close together, you can now use any length of cable for your manual external key, which is now connected to the “EXT” connector of the keyer/modulator.

The keyer does also have an internal mini straight key. I find this idea very nice, to avoid extra cables. It is not the most convenient key in the world, but it is there along with the transmitter every time you need it. By using a special panel switch from apem, I was able to triple this switch usage for the different modes of the keyer. The vinyl lever cap you see in the next picture, is the original part of the switch, to make it easier to key with your finger. But you may build such a part on your own, to fit on other switches types.

The switch is an ON-OFF-(ON momentary) switch type. In the default (middle) position, only the PC keying action is activated. In the top position (ON), the keyer is always active, which is useful for broadcasting audio (into a dummy load). The bottom (ON momentary) position, is the manual PTT action. This is used as a straight key on OOK operation, or as a PTT on AM voice operation. Simple and effective!

Initially, I used one channel of the PC sound card for triggering the keyer and also as an AF signal for the AM modulator, but this caused several problems of unreliable keying or distortion. So I decided to use a second separate AF input (KAF) to key the keyer. This second input, uses the other channel of the stereo sound card. With the addition of this input, there is no interaction between the keyer and the modulator. The AF levels that the keyer and the modulator require, can be set independently. Instead of adding more hardware for the purpose, I have chosen to set these levels by adjusting the volume and the balance of the sound card, which works great. Also, programs like Fldigi, have options for using one of the two channels of the stereo sound card as a keying interface (PTT channel), which makes the keying efen more reliable. When the program is in transmit mode, a continuous tone is heard on the PTT channel. This steady tone, is used by the keyer as a reliable keying signal, independent of the audio signal of the digital mode that modulates the modulator. This solution works very reliably for any mode. But if the program you are using does not have an option for a PTT channel, that is ok, as the keyer works reliably even without this feature. For voice communication or broadcasting music (into a dummy load) you just use the internal key switch as a PTT to handle these modes.

Results

Prior to building the keyer and the modulator in the same device, I had tested the circuits independently quite a few times, to ensure the results can be reproduced. The modulation quality and depth out of the AM modulator have to be listenned to be believed. I have not made any linearity measurements, I just trust my ears on this one. It works great on music as well as on voice. Apart from that, this is the most sensitive AM modulator I have ever built, requiring only a small fraction of the line level output of the PC sound card.

When modulated by this modulator, the EMTX shows no audible signs of FM modulation. I switched my receiver to SSB and I could perfectly zero beat the AM modulated music signal which stayed on frequency and it’s tone did not change during loud audio signal music. Switching back and forth from SSB to AM modulation on the receiver, I did not notice any difference in the audio quality, apart of course from the narrower bandwidth on SSB modulation, due to the narrower IF filter inside the receiver on SSB.

The AM/OOK switch is used to select the modulation applied to the EMTX. When the keyer is set to be triggered by audio from the PC, at the OOK position, the EMTX is just switched on and off by the audio tones applied to the keyer, or by the manual key, internal or external (connected to the “EXT” connector). At AM position, the EMTX is switched on by the audio signal applied to the KAF connector and at the same time AM modulated by whatever audio signal is applied to the AF connector. On voice communications, the momentary position of the internal key is used as a PTT. On music broadcasting (into a dummy load) the non-momentary position of the internal key is used to keep the keyer always active.

Photos

Back connections to the EMTX.

Pictures of the finished keyer/modulator. You don’t have to build it that nice-looking if you don’t care.

Modulator prototype and EMTX built on a breadboard. Yes it worked just fine onto a piece of wood.

Thank you so much for sharing this brilliant and simple project with us, Kostas. Your handiwork is absolutely brilliant too!

Click here to check out Kostas’ website.

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Icom IC-705 firmware v1.20, programming software v1.10, and a new 3rd party remote app for Android

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Many thanks to SWLing Post contributor, Markku Koskinen, who notes the following new and updated programs for the Icom IC-705 general coverage transceiver:

First, Icom has published firmware version 1.20 which includes a number of new features. We’ll post the full announcement below. Click here to view the release notes and download.

Secondly, Icom has published a new version (1.10) of their IC-705 programming software. The new release also includes a number of additions. Click here to view the release notes and download.

Finally, Markku notes that there is now an IC-705 Remote application on the Google Play app store.

The app appears to control basic functionality like tuning, band, mode, filter, and CI-V address switching. The app is free and should work on most Android devices.

Thanks for the tips, Markku!

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Radio Waves: Michael Pack Resigns, FCC Enforcement Advisory, Upcoming ISS SSTV, and Prowling TV Detector Vans

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Radio Waves: Stories Making Waves in the World of Radio

Because I keep my ear to the waves, as well as receive many tips from others who do the same, I find myself privy to radio-related stories that might interest SWLing Post readers. To that end: Welcome to the SWLing Post’s Radio Waves, a collection of links to interesting stories making waves in the world of radio. Enjoy!

Many thanks to SWLing Post contributors Eric McFadden, Ronald Kenyon, for the following tips:

Defined By Scandal At Voice of America, CEO Resigns At Biden’s Request (NPR)

Michael Pack resigned Wednesday as the CEO of the federal agency over the Voice of America and other federally funded international broadcasters after a turbulent seven-month tenure. He leaves the U.S. Agency for Global Media with a Trumpian legacy of ideological strife, lawsuits and scandal, his departure effective just two hours after the swearing-in of President Biden, who requested him to leave.

Biden has named senior VOA news executive Kelu Chao as acting CEO.

Pack came to lead the U.S. Agency for Global Media with the support of former President Donald Trump; his appointment was delayed more than two years in the U.S. Senate by lawmakers who feared he was too ideological and also who questioned his finances. The soft-spoken conservative documentary maker proved to be an ideological warrior in the mold of his patron, taking to one conservative news outlet after another to denounce his own staff, all in the name of fairness.

In his resignation letter, Pack said he was “solely focused upon reorienting the agency toward its missions.” And he attacked the request for his resignation as “a partisan act,” saying the leadership of the agency and its networks “is meant to be non-partisan, untethered to alternations in the political regime.”

He added, “I had no political agenda coming into USAGM, and I still do not have one.”

NPR conducted scores of interviews over the controversies Pack’s actions engendered. And few at the agency or its broadcasters agreed with Pack’s characterization of his mission or performance, instead characterizing him as seeking political control over their coverage. Just last week, a VOA reporter’s insistent questions to then-Secretary of State Mike Pompeo and VOA Director Robert R. Reilly over the siege on Congress after a public event led to her demotion and an investigation.

Pack routinely accused journalists of anti-Trump bias, sought to fire top executives as part of a “deep state,” ominously accused the networks of being receptive to foreign spies and denied requests for visa extensions from his own staffers who are foreign nationals.[…]

FCC Issues Enforcement Advisory: Radio Users Reminded Not to Use Radios in Crimes (ARRL News)

The FCC has released an Enforcement Advisory for licensees and operators across radio services.

[Complete text of FCC Enforcement Advisory follows.]

FCC ENFORCEMENT ADVISORY

DA 21-73

Released: January 17, 2021

WARNING: AMATEUR AND PERSONAL RADIO SERVICES LICENSEES AND OPERATORS MAY NOT USE RADIO EQUIPMENT TO COMMIT OR FACILITATE CRIMINAL ACTS

The Enforcement Bureau (Bureau) of the Federal Communications Commission issues this Enforcement Advisory to remind licensees in the Amateur Radio Service, as well as licensees and operators in the Personal Radio Services, that the Commission prohibits the use of radios in those services to commit or facilitate criminal acts.

The Bureau has become aware of discussions on social media platforms suggesting that certain radio services regulated by the Commission may be an alternative to social media platforms for groups to communicate and coordinate future activities. The Bureau recognizes that these services can be used for a wide range of permitted purposes, including speech that is protected under the First Amendment of the U.S. Constitution. Amateur and Personal Radio Services, however, may not be used to commit or facilitate crimes.

Specifically, the Bureau reminds amateur licensees that they are prohibited from transmitting “communications intended to facilitate a criminal act” or “messages encoded for the purpose of obscuring their meaning.” 47 CFR § 97.113(a)(4).

Likewise, individuals operating radios in the Personal Radio Services, a category that includes Citizens Band radios, Family Radio Service walkie-talkies, and General Mobile Radio Service, are prohibited from using those radios “in connection with any activity which is against Federal, State or local law.” 47 CFR § 95.333(a).

Individuals using radios in the Amateur or Personal Radio Services in this manner may be subject to severe penalties, including significant fines, seizure of the offending equipment, and, in some cases, criminal prosecution. 47 U.S.C. §§ 401, 501, 503, 510.

Media inquiries should be directed to 202-418-0500 or [email protected].

To file a complaint with the FCC, visit https://consumercomplaints.fcc.gov or call 1-888-CALL-FCC. To report a crime, contact your local law enforcement office or the FBI.

To request materials in accessible formats for people with disabilities (Braille, large print, electronic files, audio format), send an e-mail to [email protected] or call the Consumer & Governmental Affairs Bureau at (202) 418-0530 (voice), (202) 418-0432 (TTY).

Issued by: Chief, Enforcement Bureau[…]

ISS SSTV 145.800 FM Jan 28-29 (Southgate ARC)

Russian cosmonauts on the International Space Station (ISS) are planning to transmit Slow Scan TV images on 145.800 MHz FM using the SSTV mode PD-120

The transmissions are part of the Moscow Aviation Institute SSTV experiment (MAI-75).

Jan 28 – Starts after 12:10 GMT and ends at 17:15 GMT*

Jan 29 – Start about 13:10 GMT and ends at 18:05 GMT*

*Dates and times subject to change.

ARISS SSTV Blog
https://ariss-sstv.blogspot.com/

Useful SSTV info and links
https://amsat-uk.org/beginners/iss-sstv/

TV Detector Vans Once Prowled The Streets Of England (Hackaday)

The United Kingdom is somewhat unique in the world for requiring those households which view broadcast television to purchase a licence for the privilege.

Initially coming into being with the Wireless Telegraphy Act in 1923, the licence was required for anyone receiving broadcast radio, before being expanded to cover television in 1946. The funds generated from this endeavour are used as the primary funding for the British Broadcasting Corporation.

A typical TV licence invoice. Separate licences for black and white and color sets still exist, with 6000 B&W licences issued in 2019.

Of course, it’s all well and good to require a licence, but without some manner of enforcement, the measure doesn’t have any teeth. Among other measures, the BBC have gone as far as employing special vans to hunt down illegally operating televisions and protect its precious income.

THE VAN IS COMING FOR YOU

To ensure a regular income, the BBC runs enforcement operations under the TV Licencing trade name, the entity which is responsible for administering the system. Records are kept of licences and their expiry dates, and investigations are made into households suspected of owning a television who have not paid the requisite fees. To encourage compliance, TV Licencing regularly sends sternly worded letters to those who have let their licence lapse or have not purchased one. In the event this fails, they may arrange a visit from enforcement officers. These officers aren’t empowered to forcibly enter homes, so in the event a homeowner declines to cooperate with an investigation, TV Licencing will apply for a search warrant. This may be on the basis of evidence such as a satellite dish or antenna spotted on the roof of a dwelling, or a remote spied on a couch cushion through a window.[…]