Monthly Archives: January 2025

A Timeless Receiver: Going Old School with the Lowe HF-150

Many thanks to SWLing Post contributor Dale (W4OP), who shares the following guest post:

Going Old School: The Lowe HF-150

by Dale (W4OP)

Lowe Electronics of Great Britain introduced their first shortwave receiver, designed by Jon Thorpe, in 1987: the model HF-125. The HF-125 was a 30 kHz to 30 MHz compact receiver with three filter bandwidths and AM/SSB/CW detection. As with all of the Lowe receivers, the HF-125 combined excellent build quality with no-nonsense operation. Options included a whip amplifier, keypad for direct frequency entry, and an AM synchronous detector. The diminutive receiver was an instant hit and was manufactured until 1989, when it was replaced by the HF-225. While slightly larger (9” x 10” x 4”), the HF-225 included the built-in whip amplifier, but AM sync was still an option. The HF-225 had a long run from 1989 to 1997. The front panels of the HF-125 and HF-225 were very similar and easy to operate.

There was also a “professional” version of the HF-225 called the HF-235. It was considerably longer than the HF-225 with rack handles, a front-facing speaker, keypad, and, I believe, a built-in 110/220 VAC power supply.

In 1991, Lowe, under the design of Thorpe, introduced the remarkable HF-150, the subject of this paper. Gone were the painted and bent metal enclosures, replaced by a beautiful anodized, extruded aluminum cabinet almost 1/8” thick. The HF-150 was also smaller (7.3” x 3” x 6.3”) and lighter. While the keypad was still an option, the HF-150 now contained built-in batteries and a built-in charger.* When the HF-150 came out, rechargeable batteries were NiCad, and typical capacity was 1000mAh. The HF-150 typically draws 250mA, so the NiCads in the HF-150 might give you 4 hours of run time. Today, we have NiMH batteries that have a higher energy density than NiCad cells, and I routinely see 2800mAh. That means around 10–11 hours of run time on a single charge.

In the HF-150, the whip preamp is built in, not an option. The whip and its preamp are equivalent to the short active antennas we often see in use today. This is a great feature and results in very good sensitivity from a very short antenna. A three-position slide switch on the rear panel allows for running from the active whip, a conventional antenna like a dipole, or a random wire. The slide switch also allows for introducing a -20dB attenuator to prevent overload. This was a condition often seen in Europe back in the day when there were so many high-power shortwave stations.

Also on the rear panel is a socket for the optional keypad, a socket for an external speaker, and a socket for a recorder output. The two battery boxes house a total of 8 AA batteries.

The front panel could not be simpler or more elegant in its design. There are only 2 knobs—AF Gain and Main Tuning—and three momentary push buttons. The use of these three buttons is the magic in this receiver.

The leftmost push button controls 60 memories. The main tuning knob cycles through the memories at about 25 memories per knob revolution.

While in the memory mode, the center and right-hand push buttons allow for recalling the current memory or storing the current frequency, respectively.

The rightmost push button changes the tuning speed to 100 kHz/step and allows for very fast QSYing through the entire receiver range. The frequency display in fast mode shows only the MHz and 100 kHz positions.

Press Fast again, and the display reverts back to displaying the 1 kHz least significant digit. The normal tuning rate depends upon the mode. In SSB, the steps are 8 Hz (1.6 kHz/revolution). Normal AM and AM Narrow are 60 Hz (12 kHz per revolution). There are four AM sync modes:

Double sideband sync 8Hz steps 1.6KHz/rev 7KHz filter
HiFi AM sync 8Hz steps 1.6KHz/rev 7KHz filter
AM Lower sideband sync 8Hz and .8KHz/rev 2.5KHz filter
AM Upper sideband sync 8Hz and .8KHz/rev 2.5KHz filter

Normal AM uses a 7 kHz filter, and there is also a narrow AM using the 2.5 kHz filter.

Recovered audio is the best I have ever heard on any receiver. I don’t make that claim lightly. It is just so smooth and wonderful to listen to—even using the internal 3” speaker.

Distortion is under 1% in all modes.

The synchronous detectors lock and stay locked. If you tune fast in sync mode, the receiver reverts to regular AM mode at a faster tuning rate and then relocks in sync once tuning is suspended.

In any mode, variable-rate tuning is used. Fast tuning of the main tuning knob will result in a tuning speed of 8x the normal rate in SSB and 6x the normal rate in AM/AM Narrow.

AM sensitivity is 1 µV from 500 kHz to 30 MHz and 0.3 µV if the whip amp is enabled.

SSB sensitivity is better than 0.5 µV from 500 kHz to 30 MHz and under 0.2 µV with the whip amplifier enabled. I have verified these numbers in my lab.

Dynamic range (reciprocal mixing) and 3rd order intermod are also respectable.

The receiver is simply luxurious to use. I know that is not a technical term, but it describes the receiver very well. The previously described aluminum extruded cabinet can likely be driven over without damage. Encoder tuning combined with the heavy tuning knob is velvet smooth. Black button-head cap screws add to a professional look.

When the 8 batteries are fitted, the receiver weighs in at just over 3 pounds and stays put while tuning or pressing buttons.

Third parties are making the optional keypad, and they may be found on eBay or the Lowe IO group. The same goes for the PL-259-fitted telescoping whip.

Lowe also offered an SP-150 matching speaker and S-meter (audio-derived, I believe) and a very nice preselector (PR-150). Both bring premium prices today.

As the receiver was produced, the LCD did not have backlighting, making it difficult to use, say, bedside at night. As you can see from the first photo, I have backlit mine and those of a number of friends. It is not difficult, but also not for the faint of heart, as it involves delicately removing the silver film on the rear of the LCD display. The Lowe IO group describes a couple of methods for accomplishing backlighting.

There are no surface-mounted parts, and as the main board is uncrowded, repair is easy. There is a long service document that is so in-depth that you could build your own HF-150—assuming you could get the firmware into the microprocessor. I wish other pieces of gear I own were half this detailed.

Jon Thorpe designed one other receiver for Lowe, the HF-250. It is a thing of beauty, also with its 3D black anodized front panel. More filters and features and quite rare today. After designing the HF-250, Jon was hired by AOR, and the well-known AOR7030 was the result.

After Jon left, Lowe did not produce any other receivers I am aware of, but they did privately badge the Palstar R-30 under the Lowe HF-350 model.

I trust the numbers I have provided are reasonably accurate, and if not, Lowe documents will provide better information anyway.

*Note: Users must be very careful not to run the HF-150 from its AC supply while the receiver is fitted with alkaline batteries. The result will be corrosion of the two battery boxes.

Radio Waves: 35 Years of RNZ and Bulgarian National Radio’s New QSL cards

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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 contributor David Iurescia for the following tips:

RNZ Pacific – 35 years of broadcasting to the region (RNZ)

January 24, 1990, the same day the Auckland Commonwealth Games opened, RNZ International (RNZI) began broadcasting to the Pacific region.

Its news bulletins and programmes were carried by a brand new 100kW transmitter. The service was rebranded as RNZ Pacific in 2017. However its mission remains unchanged, to provide news of the highest quality and be a trusted service to local broadcasters in the Pacific region.

Although RNZ had been broadcasting to the Pacific since 1948, in the late 1980s the New Zealand Government saw the benefit of upgrading the service. Thus RNZI was born, with a small dedicated team.

The first RNZI manager was Ian Johnstone. He believed that the service should have a strong cultural connection to the people of the Pacific. To that end, it was important that some of the staff reflected parts of the region where RNZ Pacific broadcasted. He hired the first Pacific woman sports reporter at RNZ, the late Elma Ma’ua. [Continue reading…]

The BNR’s QSL cards for 2025 present the beauty of Bulgaria (BNR)

Dear friends, we are happy to announce that the Bulgarian National Radio’s QSL cards for 2025 are now available. The two series – one with 6 postcards and the other with 12 postcards – are entitled “The Beauty of Bulgaria.”

The series of 6 cards confirms that you have listened to Radio Bulgaria’s programming in any of its languages.

To receive this series, you need to send reports, indicating the date and the language of the programme you have listened to, as well as content details. QSL cards are sent upon receipt of the necessary number of reports, irrespective of the language in which the programmes were heard on our website. [Continue reading…]

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120 Years of XSG: Special World Radio Day Event and QSL Card

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Many thanks to SWLing Post contributor Michael (BD4AAQ), who shares the following announcement:

Notice from Shanghai Coast Radio Station (XSG) on Hosting the Global Amateur Radio Communication Event

Dear Amateur Radio Enthusiasts,

To celebrate World Radio Day and foster communication and interaction with amateur radio operators worldwide, Shanghai Coast Radio Station (XSG) is pleased to announce a global amateur radio communication event. The event will take place from 12 to 13 February 2025, using the station’s long-standing callsign, XSG.

Established in 1905, Shanghai Coast Radio Station celebrates its 120th anniversary this year. The station has used the callsign XSG ever since and, apart from the Global Maritime Distress and Safety System (GMDSS), has maintained Morse code telegraph services, preserving its historic significance and operational excellence.

Event Schedule:

The scheduled period will be from 00:00 UTC on 12 February 2025 to 24:00 UTC on 13 February 2025.

XSG Transmission Frequencies and Modes:

4105 KHz CW/A1A
6780 KHz CW/A1A
8502 KHz CW/A1A
12871.5 KHz CW/A1A
17103.2 KHz CW/A1A

Prior to the official event, intermittent schedule announcements will also be broadcast on the above frequencies.

XSG Receive Frequencies and Modes:

3521.3 KHz – 3526.3 KHz CW/A1A
7021.3 KHz – 7026.3 KHz CW/A1A
10121.3 KHz – 10126.3 KHz CW/A1A
14021.3 KHz – 14026.3 KHz CW/A1A
21021.3 KHz – 21026.3 KHz CW/A1A

QSL Confirmation:

Due to differing regulations set by amateur radio licensing authorities across the globe, XSG will only confirm amateur radio QSOs and SWL reports via paper QSL cards delivered by mail. If you wish to receive an XSG QSL card, please send your card to: No. 1 Diantai Road, Zhangjiang Town, Pudong New Area, Shanghai 201206, PR China. Email: hadt@shhadt.com.

Important Reminder:

To be clear, contacts with XSG will be cross-band contacts where XSG will operate on its authorized frequencies outside of the amateur radio bands, and any amateur radio operator making contact will operate within their own allocated amateur frequencies as listed above. Operators should exercise caution when operating split cross-band, ensuring they do not accidentally transmit on top of another station within the amateur bands. It’s a good practice to regularly monitor your transmit frequency.

Please note that amateur radio operators are not permitted to transmit on XSG’s dedicated frequencies. Operators must adhere to the transmission requirements in their respective licenses. It is recommended that amateur radio enthusiasts consult their national licensing authorities regarding applicable regulations before engaging in communications with XSG.

We warmly invite amateur radio operators worldwide to participate in this event and look forward to celebrating this milestone together.

Shanghai Coast Radio Station (XSG)
19 January 2025

Information provided by BD4AAQ (Michael Ye) and BH4BFS (Xusheng Niu)

ORF: Moosbrun rotating antenna to be demolished

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Drehbare Hochleistungsrichtantenne ORF Moosbrunn (Daniel Csiky – Wikimedia Commons)

Many thanks to SWLing Post contributor, Adi, who shares the following news about Austria’s historic 500-kilowatt shortwave transmitter in Moosbrunn:

ORF has Austria’s 500-kilowatt short-wave transmitter blown up

This massive, unique rotating HF antenna, capable of broadcasting to the furthest corners of the globe, is set to be demolished. The article explores its rich history, technical capabilities, and the broader implications of its loss for global communications.

Read the full story on heise online.

Don Moore’s Photo Album: Museum Findings – World War II

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Along US Highway 550 in southwest Colorado

Don Moore’s Photo Album
Museum Findings: World War II

by Don Moore

More of Don’s traveling DX stories can be found in his book Tales of a Vagabond DXer.

Learning should be a life-long pursuit for all of us. One of my ways of doing that is by visiting museums while traveling, whether in the USA or abroad. Cultural, historical, and science museums are my favorites. And if a museum’s theme includes the 20th century, there is a good chance that something related to radio will be found in the collection. In this edition of the Photo Album I want to share some findings related to radio and World War II that I’ve recently found in museums here in the USA.

Do A-Bombs QSL?

I’m based in Pennsylvania but my daughter lives in western Colorado and my son in Texas. So in September and October of 2024 I made a 45-day road trip to visit them both and see sites along the way. One stop was Santa Fe, New Mexico. The New Mexico History Museum downtown has an excellent exhibit on the development of the Atomic Bomb and the effect on the local area. The real place to learn about this, however, is an hour north of the city at Los Alamos, where the project actually happened.

In addition to the historical sites, Los Alamos has one of the best science museums I’ve been to anywhere. That’s not surprising considering that not many places have as many scientists per capita as Los Alamos does. And there I learned that radio was closely involved in dropping the first A-Bomb on Hiroshima.

The scientists at Los Alamos developed two types of atomic bombs. The bomb dropped on Hiroshima used a uranium-gun to initiate the explosion. The scientists were certain this would work so this was not tested beforehand. The bomb dropped on Nagasaki used the second method with a with a plutonium-implosion as the trigger. But they were uncertain as to whether or not this would actually work so it had already been tested in the New Mexico desert in July 1945. That was the first atomic explosion and the scientists collected lots of useful measurements.

But the developers had no such measurements for the uranium-gun bomb as it hadn’t been tested. But how to get them? They obviously couldn’t place monitors on the ground at Hiroshima beforehand. Physicist Luis Alvarez was tasked with finding a solution. Alvarez’s team built three canisters filled with monitoring equipment and VHF transmitters to be carried by The Great Artiste, the observation plane that would accompany the Enola Gay to Hiroshima. The three canisters were to be dropped by parachute at the same moment that the Enola Gay dropped the bomb.

The signals from the canisters were to be picked up by a bank of Hallicrafters S-36 VHF receivers on the plane and then feed to oscillographs to record the results, which would simultaneously be recorded by movie cameras.

It all worked according to plan and data was received from two of the three canisters before they were engulfed by the explosion. But, to the best of my knowledge, no QSLs were issued for the receptions.

The WASP Museum

My next destination after Santa Fe was San Antonio, Texas, 700 miles (1100 kilometers) away. To make the road trip more interesting I wanted to find some things to see along the way. While perusing Google Maps I came across the National WASP World War II Museum in Sweetwater, Texas. The museum has nothing to do with insects. The acronym stands for Women’s Airforce Service Pilots.

The use of women pilots in support roles to the US Army Air Force began in 1942 with the Women’s Flying Training Detachment (WFTD) and Women’s Auxiliary Ferrying Squadron (WAFS). In 1943 the two programs were merged to form the WASP program and the airfield at Sweetwater was chosen for the four-month training program. In total, 1,830 women started WASP training and 1,074 finished, about the same success rate as with male military pilots of the era. Continue reading →

Jeff rediscovers the Tecsun PL-660

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Many thanks to SWLing Post contributor Jeff McMahon over at The Herculodge for his recent post, “Dude, You Really Love Radios: A Nostalgic Ode to the Tecsun PL-660.”

Jeff reflects on rediscovering the Tecsun PL-660, a “Pre-DSP Glory Era” classic, sharing insights about its design, performance, and the irresistible pull of nostalgia. Like many of us who love radios, he’s already contemplating buying a second one!