FT8 transceiver kit: CR Kits taking orders

The CR Kits DSB Transceiver prototype (Source: CR Kits)

Many thanks to Pete (WB9FLW) who writes:

Thomas,
Adam of CR Kits is now taking orders for his FT8 Transceiver Kit and the price is very reasonable.

From Adam at CR Kits:

FT8 transceiver kit

Folks,
I start to take email order now. The introductory price is 39 USD for kit including shipping to worldwide. As in the introductory period, you will get audio cable options for free. The earliest possible shipment date is now improved to May 13.

You can directly PayPal to rongxh@gmail.com and let me know 40m or 20m (80m not ready yet). I will ship based on the sequence of receiving your payment. I may delay shipment for one week or two due to workload.

This is the spec so far:

Summary: Crystal controlled single frequency DSB transceiver for 20m (14.074MHz), 40m (7.074MHz) or 80m (3.573MHz), other frequencies could be added per requestPower supply: 10-14V DC regulated power supply or battery pack, 12V is recommended, center positive, reverse polarity protection availableCurrent consumption in RX: about 15mA at 12VCurrent consumption in TX: about 300mA at 12VRF output: about 1W for 40m band at 12V, and a bit less for 20m bandSpurious suppression: no worse than -50dBcAntenna connector: BNC connector, 50 ohmAudio in connector: 3.5mm mono, at least 600mV to activate VOX, connects to headphone connector at PC sound card, no dedicated PTT connector is requiredAudio out connector: 3.5mm mono, connects to microphone connector at PC sound cardAmber LED: TX statusGreen LED: RX statusFrequency accuracy: -600 Hz ~ + 200 HzFrequency stability: Okay for FT8 mode per test. If the optional heater resistor R20* is added, after warm up, long term frequency stability in 10 min will be improved at the cost of acceptable short term frequency stability sacrifice in 30 sec.
Thanks, Adam

Click here to check out the FT8 DSB Transceiver via CR Kits.

Posted in FT8, Kits, News, Product Announcements | Tagged , , , , | 1 Comment

How To Convert QRP Labs QCX Transceiver to SSB

Many thanks to Pete (WB9FLW) who shares the following:

This is truly amazing, Guino PE1NNZ has converted the QRP Labs $49 CW Transceiver to SSB.

Not much to add, a ATMEGA328P plus some firmware and a few component value changes and you’ve got a $50 SSB Transceiver!

(Source: GitHub)

This is a simple and experimental modification that transforms a QCX into a (Class-E driven) SSB transceiver. It can be used to make QRP SSB contacts, or (in combination with a PC) used for the digital modes such as FT8. It can be fully-continuous tuned through bands 160m-10m in the LSB/USB-modes with a 2400Hz bandwidth has up to 5W PEP SSB output and features a software-based full Break-In VOX for fast RX/TX switching in voice and digital operations.

The SSB transmit-stage is implemented completely in a digital and software-based manner: at the heart the ATMEGA328P is sampling the input-audio and reconstructing a SSB-signal by controlling the SI5351 PLL phase (through tiny frequency changes over 800kbit/s I2C) and controlling the PA Power (through PWM on the key-shaping circuit). In this way a highly power-efficient class-E driven SSB-signal can be realized; a PWM driven class-E design keeps the SSB transceiver simple, tiny, cool, power-efficient and low-cost (ie. no need for power-inefficient and complex linear amplifier with bulky heat-sink as often is seen in SSB transceivers).

An Open Source Arduino sketch is used as the basis for the firmware, the hardware modification bypasses the QCX CW filter and adds a microphone input in-place of the DVM-circuit; the mod is easy to apply and consist of four wire and four component changes and after applying the transceiver remains compatible with the original QCX (CW) firmware.

This experiment is created to try out what can be done with minimal hardware; a simple ATMEGA processor, a QCX and a software-based SSB processing approach. It would be nice to add more features to the sketch, and try out if the QCX design can be further simplified e.g. by implementing parts of the receiver stage in software. Feel free to experiment with this sketch, let me know your thoughts or contribute here: https://github.com/threeme3/QCX-SSB There is a forum discussion on the topic here: QRPLabs Forum

Click here for full project details via GitHub.

73, Guido pe1nnz@amsat.org

Wow! What a brilliant modification, Pete! Thank you for sharing.

Posted in Homebrew, Kits, News, QRP | Tagged , , , | 2 Comments

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