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
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.
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.
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.
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
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.”
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.
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.”
ARRL report on a survey by Club Log’s Michael Wells G7VJR that shows significant growth in the use of WSJT FT8 during 2018
Wells reported that operators from some 270 DXCC entities were active on FT8 in 2018. “It’s quite a showing for FT8,” he allowed, pointing out that the figure is close to the computed 287 active DXCC entities.
Wells posits that FT8 may be the only way to stay in the hobby for operators living on small lots and confronting stringent zoning regulations.
The founder of the GQRP Club and Amateur Radio author the Rev. George Dobbs, G3RJV, of Littleborough, England, died on March 11. He was 75. Dobbs was reported to have been in ill health for some time and had been living in a care facility, where his condition deteriorated quite rapidly over the past few days. He was the honorary secretary of the GQRP Club (G5LOW), which he founded in 1974 to cater to those interested in low-power Amateur Radio communication. Dobbs served as the editor for the club’s quarterly, SPRAT. Dobbs was the author of QRP Basics, The International QRP Collection (co-authored with Steve Telenius-Lowe, 9M6DXX), and Making a Transistor Radio. He was a frequent Hamvention® attendee, and in 2015, he received the Hamvention “Technical Excellence Award.” — Thanks to Lee Boulineau, KX4TT
The WSJT-X 2.0 software suite has been released, and developer Joe Taylor, K1JT, is urging FT8 and MSK144 users to upgrade to what will become the new standard
The ARRL says:
The FT8 and MSK144 protocols have been enhanced in a way that is not backward compatible with older versions of the program. That includes any version 1.9 releases.
“The new protocols become the worldwide standards starting on December 10, 2018, and all users should upgrade to WSJT-X 2.0 by January 1, 2019,” Taylor said on the WSJT-X home page. “After that date, only the new FT8 and MSK144 should be used on the air.”
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