Category Archives: News

LZ1AQ Evaluates Impact of the Height Above the Ground on Mag Loop Performance

Source: LZ1AQ

Many thanks to SWLing Post contributor, Harald Kuhl (DL1AX), who shares the following article on LZ1AQ’s website:

Published on: 2018/11/20, Rev. 1.0 July 2018, Rev. 1.1 Nov 2018

Author: Chavdar Levkov LZ1AQ

Setup

Two identical small loops were placed one above the other according to Fig.1. One of the loops is very low – almost on the ground. The other one is placed at height which usually is used by the loop users. Two AAA-1C wideband active antenna amplifiers were used. Their gain difference was not more than 0.3 dB. The feeder was FTP cable each 20 m long. No cable baluns were used. The outputs were connected through two way antenna switch to a SD RX (Perseus). I used a measurement technique described in – A Periodic Switching Technique to Compare Receiving Antenna Performance in the Presence of Strong Fading. This is a precise method to compare two receiving antennas with real sky wave signals and the resolution can be less than a decibel. The idea is to switch periodically between two antennas and to estimate their difference on a calibrated graphic strength meter of a SD radio.[…]

Click here to read the full article.

I’ve often assumed height had little effect on the performance of an HF loop antenna–this evaluation seems to support that theory. Thanks for sharing this, Harald!

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Bill’s NJARC swap meet deal and some tailgate photos

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Many thanks to SWLing Post contributor, Bill Hemphill (WD9EQD), who writes:

This morning (Saturday July 20), I went to the New Jersey Antique Radio Club (NJARC) Summer Swap Meet.

They typically hold three Swap Meets each year at various locations This time it was at the InfoAge Science

History Learning Center in Wall, NJ. The InfoAge Center has many exhibits including:

InfoAge Space Exploration Center

World War II Radar

Marconi Wireless Room

Radio and Television Museum

Vintage Computers

plus much more

Check out this link.

If you are ever in the area, I highly recommend a visit to it.

The Swap Meet was held outdoors and it was a hot humid morning – 80 degrees at 6 am with 90 percent humidity. By 9 am it was 90 degrees. But it was worth the hour trip.

I acquired one new radio – the Nova-Tech Pilot II Direction Finding 4 Band transistor radio. It’s in great condition and is working. It’s an interesting radio.

The four bands are Beacon (190-400 kHz), Broadcast (550-1600 kHz), Marine (1.6-4.5 MHz) and VHF (108-136 MHz).

There is a rotatable antenna on the top that is used to get your bearing. The top of the radio has the Bearing in degrees. It includes Squelch and DF Level controls; both can be switched off. The DF Level is the RF Gain and I read somewhere that when it is activated the AGC is switched off.

I was very fortunate in that the radio came with the three telescoping antennas – all in perfect condition. It also included the original AC Power Adapter.

All for only $25. A great bargain.

The radio seems very sensitive on the Broadcast Band.

I tuned it to my standard test weak station – WALK, 1370, in Patchogue, NY. This station is a 500 watt repeater station to WHLI, 1100 in Hamstead, NY. With most of my radios, I can barely hear a station in the noise. The exception is the Panasonic RF-2200 which can pick it up the best. The Pilot II could pick up a readable signal of WALK.

Very impressive.

Below are some photos of the radio.

Bill also included the following photos from the New Jersey Antique Radio Club (NJARC) swap meet:

Thanks for sharing this, Bill! No doubt, you snagged a fantastic deal on the Nova Tech Pilot II. My dear friend Michael Pool (who passed away earlier this year) acquired one and loved it. Here’s a link to his guest post about this cool DF receiver.

Thanks for sharing the photos and links to the NJARC swap meet. Looks like an event I’d certainly love to attend!

Post readers: Have you attended any swap meets recently? Any good finds? Please comment!

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David Warren: Radio enthusiast who invented the “Black Box” flight recorder

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As a schoolboy, David was fascinated by electronics and learned to build his own radio sets (Source: BBC and the Warren Family Collection)

Many thanks to SWLing Post contributor, Paul W4/VP9KFPaul W4/VP9KF, who notes that David Warren, inventor of ‘Black Box’ recorders was a ham radio operator and radio enthusiast.

The following short biography comes from this memorial website:

David Warren (full name David Ronald de Mey Warren) was an Australian inventor. He is most famous for his invention of the Flight data recorder (invented in 1956), or more commonly known as the “black box”

The “Black Box” is a device that records in-flight conversations and data. Warren came up with the idea of recording the flight crew’s conversation on a device that could be protected to increase its chances of surviving the crash. Although it has the name “Black Box”, it is coated with heat-resistant bright orange paint for high visibility in a wreckage, and the Black Box is usually mounted in the aircraft’s tail section, where it is more likely to survive a severe crash.

David Warren was born on the 20th of March, 1925, on Groote Eylandt, an island off the coast of the Northern Territory. He was the first child of European descent born on the island. When he was at the age of four, he was sent to Tasmania and Sydney to spend most of the next 12 years in boarding schools (Launceston Grammar School in Tasmania and Trinity Grammar School in Sydney).

Australia’s first major air crash in 1934 claimed the life of David’s father.

Warren had received a crystal set from his father just before the disaster that started his interest in amateur radio and electronics. Almost 20 years later, when the age of commercial jet aircraft was just beginning, Warren worked as a chemist, specialising in aircraft fuels at the Aeronautical Research Laboratories.

Dr Warren was working as a scientist at Melbourne’s Aeronautical Research Laboratory, where he was helping to investigate the 1953 mystery crash of a Comet jetliner. New fuels being used in Jets in the early 50’s were more likely to become explosive at altitude than conventional aircraft fuels and this was identified as a possible cause of the Comet crash. While listening to the arguments over possible causes of the Crash, Warren realised that the solution could be at hand if someone on the plane had been carrying a device similar to the then newly released “Protona Minifon” portable recorder that he saw at a trade fair.

The device would be fire proof (using steel wire as the recording medium like the “Pocket Recorder”) and erase itself so that the last hours of the flight were always recorded. The device consisted of a single steel wire as the recording medium and provided four hours of recording and automatically switched itself on and off with the aircraft. It was during this period that Dr Warren incorporated the idea of recording instruments on a separate channel – his interest in electronics as a schoolboy was brilliantly applied to turn instrument readings into recordable dots and bleeps.

The recorder was well received in England (where the name “Black Box” was made up by a journalist at a briefing) and also in Canada where the idea was seen as a potential addition to beacons being developed there.

Warren continued to lead the project, developing the Flight Memory device to record more instruments with greater accuracy. This led to the first commercially produced flight recorder-the Red Egg.

A further disaster at Wintoon in 1967 saw Australia become the first country to make both flight data and cockpit voice mandatory on all jets.

While a student at the University of Sydney, David met Ruth Meadows, who became his wife and lifetime supporter. Together, they raised a family and shared an interest in science and education. When he retired, David and Ruth lived in Caulfield South, Victoria, in regular contact with their four children and seven grandchildren.

David died at the age of 85 in 2010, 19 July, Melbourne, Australia. After his death, He was buried in a casket bearing the label “Flight Recorder Inventor; Do Not Open”.

Then in June 2012, the ACT Government named a road, David Warren Road, in the suburb of Hume in recognition of Warren. On 25 March 2014, the Defence Science and Technology Organisation renamed their Canberra headquarters to the David Warren Building.

Thanks for sharing this, Paul! Fascinating…

Note that the BBC recently published an amazing piece about Dr. Warren on the 9th anniversary of his passing–click here to read.

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Apollo 11 ham radio special event stations

From the Shortwave Radio Audio Archive: VOA and BBC on the anniversary of moon landing

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Eagle in lunar orbit photographed from Columbia. (Image: NASA)

There are a hundreds of fascinating off-air radio recordings in our Shortwave Radio Audio Archive.

One of our frequent contributors, Tom Laskowski, has digitally converted numerous magnetic tape recordings from his personal collection to share with the archive. Tom made the following recording of the Voice of America on July 20, 1979 at 0500 UTC on the 31 meter band.

Tom notes:

The first 4:30 is from a VOA newscast that aired before the main part of the program.

The main recording was presented on the 10th anniversary of the Apollo 11 moon landing. I enjoy listening to this every year on the landing anniversary.

I’ve enjoyed listening to this 10th anniversary presentation as we, today, celebrate the 50th anniversary of the moon landing::

Click here to download this recording.

[Update:] Tom also shares another recording that marks this anniversary:

I thought this might be [another] appropriate file to upload considering we are marking the 50th anniversary of Apollo 11. I recorded this program thirty years ago on July 20, 1989 [5.975 MHz at 0400 UTC] the 20th anniversary of the Apollo 11 moon landing. Omnibus takes a look back at the historic Apollo mission and how and why it happened:

Click here to download the recording.

Thank you so much for sharing this, Tom!

Readers: Note that you can subscribe to the Shortwave Radio Audio Archive as a podcast via iTunes or by using the following RSS feed: http://shortwavearchive.com/archive?format=rss You can also listen via TuneIn.

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More than mere nostalgia: why vintage technology still has appeal

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Many thanks to SWLing Post contributor, Kim Elliott, who shares a link to this CNN Business article that briefly explores why consumers still invest in vintage electronics:

New York (CNN Business) – That beaten up Walkman buried in your basement might be someone’s hot new accessory. The retro tech market is alive and kicking.

In May, Apple refreshed the iPod touch for the first time in four years. Vinyl record sales clocked in at 400 million on average over the past four years, according to data from data tracker Statista.

[…]Other gadgets that have stayed the course: camcorders, radios, clock radios, desk phones, and DVRs. Millions of these are still in use in US households in 2017, according to Statista.
What drives people to continue purchasing vinyl records, instant film cameras, and iPods, long after new products have made those objects irrelevant?

Older gadgets have a lot of staying power because they allow people to unplug from the constant ping of smartphones and tablets.[…]

This short article and accompanying video are worth reviewing. I for one, can certainly relate.

When I was a kid in the 70s and 80s, shortwave radio was simply wireless magic. Even though the medium had been around for many decades, when my friends learned about what I could receive at home with my Zenith Transoceanic (which by then was a good 15 years old) they couldn’t wrap their minds around it.

Today, of course, international communications are effortless and nearly free via computers, tablets and smart phones.

And, I don’t know about you, but the shock value of what new technologies can do has worn off. A phone app that can control the lighting an appliances in your house? Sounds useful. A voice-activated wireless home camera system that allows you to talk to and feed your dog while you’re at work? My neighbor has one of those. A car that can drive itself? Sure. Why not?

Major technological leaps are happening at such a rapid pace that innovation is hardly appreciated…it’s expected. Ask any Apple stockholder.

And digital technologies are often incredibly affordable–but I would argue there’s a directly relationship between affordability and a loss of privacy.

As the article points out, vintage electronics have appeal because they effectively do their job without monopolizing your attention or personal space. “Vintage” tech can be with you for the long run and doesn’t necessarily rely upon an app developer or company that may or may not exist tomorrow.

Maybe this article struck a nerve…

Like TV, digital devices tend to monopolize your attention. Almost all new apps, for example, default to “push” notifications that beep, buzz and effectively turn one into Pavlov’s dog. Human beings are wired to respond to this stuff!

It’s sad to have lunch with a friend that is constantly checking their phone because it’s pinging them with notifications. It’s like having an attention-deprived two year old in the room while you’re trying to carry on a meaningful conversation. I have a rule: the only time I’ll answer a text or call when I’m with someone is if I’m expecting something urgent. Even then, I usually mention the possibility in advance and apologize when it happens. It’s an intrusion and I treat it as such.

Besides the nostalgic factor, I turn to “vintage” technologies because they lack the insidious nature of internet-connected digital devices.

When I turn on a radio, it’s on. When I turn it off, it’s off. It’s not listening to me, not reporting my shopping habits and not sending me notifications. It’s a companion.

Listening to a vinyl record is a proper experience too–one that’s high-fidelity, has unique character and won’t stop what it’s doing to tell you that you lost an eBay auction or that a friend took a photo of their Tiramisu.

Am I shunning internet-connected digital devices? No. [In fact, I’m sure I’ll get called a big fat hypocrite when I review the Google Nest Hub soon!] But I do advocate taming these devices and educating yourself about what they can do while they’re in your home.

Consider turning off their notifications, their microphones, their cameras, and even creating a single-use throw-away user account to tie to devices. Do what I do and unplug them when not in use.

I’m sorry for the Friday soap box and what seems to be an issue of Thomas’ Pet Peeves, but I’m willing to bet other radio enthusiasts feel as I do. Do you still use vintage tech in your daily routine? Do you attempt to tame digital devices? Or do you embrace notifications, automaton, and all things connected?

How do you strike a balance? Please comment!