EQUINOX: A novel that blends sci-fi with ham radio

Note that the following is a cross-post from my other radio blog, The SWLing Post:

Many thanks to SWLing Post reader and author, DM Barrett (N4ECW), who recently shared the following press release which features his latest book:

FOR IMMEDIATE RELEASE

EQUINOX Blends Science Fiction And Amateur Radio

1 May 2019 (Tampa, Florida)

A new science fiction narrative, EQUINOX, has taken amateur and shortwave radio into the cultural mainstream in its version of a limited alien invasion story line.

“It’s been quite a while since the world depended on amateur and shortwave radio as lifelines. In EQUINOX, both are critical for the success of The Resistance.” – DM Barrett, EQUINOX author

DM Barrett, callsign N4ECW, lives and breathes amateur radio. He is well known in the ham radio community having developed and manufactured several different specialized radio antennas through his former company, Transworld Antennas.  He holds two earned doctorates with majors in law, economics, and religion.

The EQUINOX story line begins on a warm, slightly breezy day on Florida’s east coast as the vernal equinox marked the beginning of spring.  Suddenly, there was a thunderous crash, a blinding light, and a vortex swirling in the blue Atlantic. The invading alien army arrived. The world surrendered. The Resistance made a stand.

When the science fiction novel was recently released as a Kindle Unlimited eBook, it moved steadily into Amazon’s top ten science fiction eBooks in the United States, United Kingdom, Germany, Canada, and Australia.  After only a few days, the paperback version of EQUINOX was ranked in Amazon’s top third for science fiction paperbacks.

DM Barrett may be contacted at DMBarrettPHD@aol.com or by text to 931-239-3760.

EQUINOX and other books by DM Barrett can be ordered online through Kindle, Amazon, and Barnes & Noble.

If you are a radio amateur or shortwave enthusiast, or you are just interested in the topics, don’t miss the chance to join others that are enjoying the science fiction novel, EQUINOX.

I have been sent a paperback preview copy of Equinox and plan to read it in the coming weeks.

Equinox can be purchased from the following retailers:

Also, the author notified me that there are a limited number of paperback copies available on eBay for $14.95. These copies are a First Printing and are autographed by the author. Click here to view on eBay.

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The CR Kits FT8 DSB Transceiver: Some preliminary information

Many thanks to Pete (WB9FLW) who notes:

Adam BD6CR of CR Kits is getting close to releasing the FT8 DSB Transceiver. Below is some preliminary information:

D4D: A simple QRP transceiver for FT8

Adam Rong, BD6CR

D4D stands for DSB transceiver for Digital modes. It is a Double Sided Band transceiver kit designed for digital modes, especially for FT8. If have chance to try FT8, you will be amazed by the strong decoding capability offered by the communication protocol, digital signal processing and software. I still remember clearly a YouTube video by W6LG who communicated with bulbs. I started to think how much the transceiver could be simplified if you have a moderate antenna like a full sized dipole or EFHW.

A DSB transceiver is much simpler than a usual SSB transceiver, however it was never used for FT8 as far as I know. I did some experiments on my Choc perf board. I started with a direct conversion receiver for FT8 and it worked okay. Then I made a DSB transmitter and the transmitted signal can be decoded. By referring to the designs of AA7EE, VK3YE and ZL2BMI, I combined them using only one NE602 and a PTT switch and it gave me success to make a few FT8 QSO’s.

Personally I really enjoyed it because a manual PTT switch will save power consumption and circuit complexity, but you will need to well sync with computer, although it was not really a problem for me. Per request from a few hams, I found a VOX control circuit and modify the hold time to be compatible with FT8, and I put them together and made a few improvements on the signal purity and frequency stability, and it became our D4D. Do we have to worry about the unwanted Lower Side Band? Maybe, but for a transmitter of 1-watt, it is not really a big problem. Is it just a toy for a transmitter of 1-watt and only half of the power will be effective? Not really, as I can easily make a few QSO’s as far as 1500 miles range for 40-meter band.

Here is the brief specifications I have measured (subject to change without notice):

Summary: Crystal controlled single frequency DSB transceiver for 20m (14.074MHz), 40m (7.074MHz) or 80m (3.573MHz), other frequencies could be added per request
Power supply: 10-14V DC regulated power supply or battery pack, 12V is recommended, center positive, reverse polarity protection available
Current consumption in RX: 15mA
Current consumption in TX: about 260mA(?) at 12V, and about 300mA at 13.8V
RF output: about 1W for 20m band at 12V, a bit more for lower bands like 40m and 80m
Spurious suppression: no worse than -50dBc
Antenna connector: BNC connector, 50 ohm
Audio in connector: 3.5mm mono, at least 600mV to activate VOX, connects to headphone connector at PC sound card, no dedicated PTT connector is required
Audio out connector: 3.5mm mono, connects to microphone connector at PC sound card
Amber LED: TX status
Green LED: RX status
Frequency stability: Okay for FT8 mode per test. If the optional heater resistor R20* is added, after warm up of about 3 min, long term frequency stability in 10 min will be improved at the cost of acceptable short term frequency stability sacrifice in 30 sec.

Let us briefly go through the circuit: The input audio will activate the VOX circuit of D2 (1N4148), Q5 (2N3906), Q6 (2N3904), Q7 (2N3904) and Relay. The relay is a DPDT type and controls both antenna and power supply. The LPF consists of L2, L3 and surrounding capacitors, and it is switched to either transmitter output or receiver input. The power supply is polarity protected by D1 (1N5817) and switched to either receiver circuit or transmitter circuit. The receiver circuit is only for audio amplifier consists of Q1 (2N3904) and optional heater resistor R20*, while the transmitter circuit is for RX muter Q8 (2N3904), TX driver Q3 (2N3904) and TX final Q4 (BD139). X1 is a filter in the receiver front end to help eliminate strong broadcast interference, and X2 is the crystal for the built-in oscillator in U1 (NE602). U2 (78L05) is the 5V regulator for U1, and Q2 (2N3904) is a buffer amplifier in the TX chain.

Thanks for sharing this, Pete! What a simple transceiver concept!

We’ll post updates as they become available.

Click here to view CRkits.com.

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FT4 digital mode now available in WSJT-X release candidate 5

(Source: Southgate ARC)

The new amateur radio digital mode FT4 is now available for download as part of WSJT-X Release Candidate 5 

You can download wsjtx-2.1.0-rc5-win64.exe (or for other O/S) from near the bottom of the page at 
http://physics.princeton.edu/pulsar/k1jt/wsjtx.html

FT4 Protocol document 
http://physics.princeton.edu/pulsar/k1jt/FT4_Protocol.pdf

See the WSJT Group at 
https://groups.io/g/WSJTX/

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New digital mode: Joe Taylor (K1JT) has announced FT4

(Source: Southgate ARC)

Joe Taylor K1JT has announced a new digital mode, FT4, which is 2.5 times faster than FT8 

FT4 is an experimental digital mode designed specifically for radio contesting.  Like FT8, it uses fixed-length transmissions, structured messages with formats optimized for minimal QSOs, and strong forward error correction.  T/R sequences are 6 seconds long, so FT4 is 2.5 × faster than FT8 and about the same speed as RTTY for radio contesting.  

FT4 can work with signals 10 dB weaker than needed for RTTY, while using much less bandwidth.

FT4 message formats are the same as those in FT8 and encoded with the same (174,91) low-density parity check code.  Transmissions last for 4.48 s, compared to 12.64 s for FT8.  Modulation uses 4-tone frequency-shift keying at approximately 23.4 baud, with tones separated by the baud rate.  The occupied  bandwidth (that containing 99% of transmitted power) is 90 Hz

Further information on FT4 is at  
http://physics.princeton.edu/pulsar/k1jt/FT4_Protocol.pdf

Posted in FT4, FT8 | Tagged , , , | 1 Comment

Ham Radio Digital Modes: Joe Taylor talks FT8 and introduces FT4

Many thanks to Pete Eaton (WB9FLW) who shares the following note and video:

Here is a You Tube Video of a presentation given by Joe Taylor last night at the Fair Lawn ARC Club Meeting on FT8 & Beyond an introduction to FT4.

Click here to view on YouTube.

Thank you for the tip, Pete!  FT4 looks like a fascinating iteration of the popular FT8 mode.

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The ALT-512: A new general coverage QRP transceiver

Note: The following has been cross-posted from our other radio site, the SWLing Post.

There’s a new QRP transceiver on the market: the twelve band ALT-512 by Aerial-51.

At first glance, you’ll see a similarity between the ALT-512 and the LnR Precision LD-11/Aerial-51 SKY-SDR. The LD-11 and SKY-SDR, are very similar, save the LD-11 is marketed to North America (via LnR) and the SKY-SDR to Europe. The SKY-SDR had several iterative upgrades, most importantly the dual-threaded software used in the firmware, which cut CPU latency in half. Both the LD-11, SKY-SDR and now the ALT-512 are made in Europe.

Click here to read my review of the LnR Precision LD-11.

ALT-512 Waterfall display (Photo: DJ0IP)


According to Aerial-51, the new ALT-512 is built on the LD-11/SKY-SDR platform, has the same chassis design but has many improvements over the SKY-SDR:

  • 4m Band
  • 4.5 in. Color Display
  • Improved receiver pre-amplifier
  • 2 transistors in the transmitter PA (was 1)
  • Waterfall in addition to the Pan-Adapter Bandscope
  • 4 additional front-panel buttons
  • User friendly front-panel adjustment of often used parameters (formerly embedded within the software menu)
  • FULL TS-2000 command set implementation
  • Built-in Sound Card; Digi Modes run using only one USB-2 cable connected to the PC. No additional hardware required.

If the ALT-512 performs as well as or better than its predecessor, it’ll certainly be a great little QRP radio and an excellent general coverage receiver for HF broadcast listening.

Pricing has not yet been posted, but Aerial-51 plans to make this transceiver available in the next few weeks.

Click here to check out the ALT-512 on the Aerial-51 website.

Posted in News, Product Announcements, QRP | Tagged , , , , , | 1 Comment

New Product: Kev-Flex Stealth Kevlar Antenna Wire

My good friend David Cripe (NMOS) has recently informed me about a new product he’s offering to the radio community via his eBay store: Kev-Flex Stealth Kevlar Antenna Wire. Kev-Flex looks like a superb option for field antennas of all stripes especially since it has an incredibly high tensile strength. It’s available in 75′ bundles, but Dave can also cut custom lengths. NM0S is also a trusted retailer in the ham radio world, so you can purchase with confidence.

Here’s the product description and link:

Kev-Flex is a unique antenna wire manufactured exclusively for NM0S Electronics. The lightweight center core of the wire is made from Kevlar fiber, giving the wire its incredible strength. The Kevlar core is wrapped with six tinned strands of 30 AWG copper. The effective surface of the wire creates an effective skin area capable of handling well over 100W.

The cable is protected from the elements by a coating of UV-resistant black polyethylene. With a total diameter of only 1/16″ (incl. insulation) and a weight of just 16 feet per ounce, the tensile strength 125 lbs allows lengthy unsupported horizontal runs. Kev-Flex is ideal for extremely long LW-antennas and Beverages and is great for balloon or kite-supported antennas. Its low weight and high break-load makes it most suitable for SOTA activations and other field operations.

The outer insulation makes the wire kink-resistant, and its slippery finish makes it ideal for stealth antennas that must be passed through trees or other obstacles without snagging.

This antenna wire is sold in 75 foot long bundles, which is enough for a 40M dipole or EFHW. Two 75 foot bundles would make a great 80M dipole. Custom lengths are available on request.

Specification

– Kevlar fiber core wrapped with six 30 AWG copper strands
– Weather-proof black polyethylene (PE) insulation, 1/16″ O.D.
– Weight: 16 feet per ounce
– Breaking-load: 125 lbs
– Velocity factor 0.97

Click here to view on eBay.

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A Simple and Low Cost FT8 Transceiver

Many thanks to Pete (WB9FLW) who writes:

Adam Rong BD6CR has designed a simple DSB Transceiver for FT8. Crystals are available for 7.074 MHz. and 14.070 MHz (which can be “pulled” with a trimmer to 14.074 MHz).

Using only 4 Transistors, 2 IC’s, 3 Toroids, 5 Diodes/LED’s and a handful of resistors and capacitors this one watt wonder will get you on the air in no time.

Click to enlarge.

One could build this on Perfboard (see above), or use Ugly/Manhattan style construction. There are no plans for a circuit board.

Adam posted this on groups.io crkit:

“I built this 7074 DSB 1-watt radio and made 6 FT8 QSO with JA stations in 15 mins last weekend. It is fun to operate by switching PTT manually to keep it simple and lower current consumption.”

For more info check out crkits groups.io.

Wow! Thank you for sharing this Pete. I’ll have to give this a go myself!

Posted in FT8, Homebrew, News | Tagged , , | 2 Comments

Building a 20M mag loop antenna

(Source: Southgate ARC)

Antennas come in many shapes and sizes, with a variety of characteristics making them more or less suitable for various applications. The average hacker with only a middling exposure to RF may be familiar with trace antennas, yagis and dipoles, but there’s a whole load more out there. [Eric Sorensen] is going down the path less travelled, undertaking the build of a self-tuning magnetic loop antenna.

[Eric]’s build is designed to operate at 100W on the 20 meter band, and this influences the specifications of the antenna. Particularly critical in the magnetic loop design is the voltage across the tuning capacitor; in this design, it comes out at approximately 4 kilovolts. This necessitates the careful choice of parts that can handle these voltages. In this case, a vacuum variable capacitor is used, rated to a peak current of 57 amps and a peak voltage of 5 kilovolts.

The magnetic loop design leads to antenna which is tuned to a very narrow frequency range, giving good selectivity. However, it also requires retuning quite often in order to stay on-band. [Eric] is implementing a self-tuning system to solve this, with a controller using a motor to actuate the tuning capacitor to maintain the antenna at its proper operating point.

If you’re unfamiliar with magnetic loop builds, [Eric]’s project serves as a great introduction to both the electrical and mechanical considerations inherent in such a design. We’ve seen even more obscure designs though – like these antennas applied with advanced spray techniques.

Read the full article
https://hackaday.com/2019/03/17/building-a-magnetic-loop-antenna/

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FCC invites comments on ARRL Technician Enhancement proposal

(Source: Southgate ARC)

The FCC has invited public comments on ARRL’s 2018 Petition for Rule Making, now designated as RM-11828, which asks the FCC to expand HF privileges for Technician licensees to include limited phone privileges on 75, 40, and 15 meters, plus RTTY and digital mode privileges on 80, 40, 15, and 10 meters.

Interested parties have 30 days to comment. The Technician enhancement proposals stemmed from the recommendations of the ARRL Board of Directors’ Entry-Level License Committee, which explored various initiatives and gauged member opinions in 2016 and 2017.

“This action will enhance the available license operating privileges in what has become the principal entry-level license class in the Amateur Service,” ARRL said in its Petition. “It will attract more newcomers to Amateur Radio, it will result in increased retention of licensees who hold Technician Class licenses, and it will provide an improved incentive for entry-level licensees to increase technical self-training and pursue higher license class achievement and development of communications skills.”

Specifically, ARRL proposes to provide Technician licensees – both present and future – with:
* Phone privileges at 3.900 to 4.000 MHz, 7.225 to 7.300 MHz, and 21.350 to 21.450 MHz.
* RTTY and digital privileges in current Technician allocations on 80, 40, 15, and 10 meters.

The ARRL petition points out the explosion in popularity of various digital modes over the past 2 decades. Under the ARRL plan, the maximum HF power level for Technician operators would remain at 200 W PEP. The few remaining Novice licensees would gain no new privileges under ARRL’s proposal.

ARRL’s petition points to the need for compelling incentives not only to become a radio amateur in the first place, but then to upgrade and further develop skills. Demographic and technological changes call for a “periodic rebalancing” between those two objectives, ARRL maintained in his proposal. The FCC has not assessed entry-level operating privileges since 2005.

The Entry-Level License Committee offered very specific data- and survey-supported findings about growth in Amateur Radio and its place in the advanced technological demographic, which includes individuals younger than 30. It received significant input from ARRL members via more than 8,000 survey responses. “The Committee’s analysis noted that today, Amateur Radio exists among many more modes of communication than it did half a century ago, or even 20 years ago,” ARRL said in its petition.

Now numbering some 384,500, Technician licensees comprise more than half of the US Amateur Radio population. ARRL stressed in its petition the urgency of making the license more attractive to newcomers, in part to improve upon Science, Technology, Engineering, and Mathematics (STEM) education, “that inescapably accompanies a healthy, growing Amateur Radio Service.”

ARRL said its proposal is critical to develop improved operating skills, increasing emergency preparedness participation, improving technical self-training, and boosting overall growth in the Amateur Service, which has remained nearly inert at about 1% per year.

The Entry-Level License Committee determined that the current Technician class question pool already covers far more material than necessary for an entry-level exam to validate expanded privileges.

ARRL told the FCC that it would continue to refine examination preparation and training materials aimed at STEM topics, increase outreach and recruitment, work with Amateur Radio clubs, and encourage educational institutions to utilize Amateur Radio in STEM and other experiential learning programs.

How to file your comment

(Source: ARRL)

Those interested posting brief comments on the ARRL Technician Enhancement proposal (RM-11828) using the Electronic Comment Filing System (ECFS) should access FCC Electronic Comment Filing System Express. In the “Proceeding(s)” field, enter the number of the PRM, i.e., RM-11828 (using this format), complete all required fields, and enter comments in the box provided. You may review your post before filing. All information you provide, including name and address, will be publicly available once you post your comment(s). For more information, visit “How to Comment on FCC Proceedings.”

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