The technology behind WSJT modes & JS8, and the evolution of various kits that take advantage of them, is something I find very interesting. It's amazing to see the innovation of design that has occurred, in such a very short time, in the four kits described here.
Phasers were (they are no longer available) monobanders, available initially for your band of choice, 17 to 160 meters. Later versions made 10 and 15 meters available. Each kit would operate on either of two discreet frequencies to allow FT8 and (usually) JS8.
Power output was ~4 watts and audio cables were required to/from the PC. VOX keying took the place of CAT and a single-step alignment procedure was required for frequency calibration. Modulation was SSB.
Price with a case made from circuit-board material was $80.
This kit uses double-sideband modulation and therefore produces as much QRM as usable signal. Just what we need on crowded FT8 bands. The D4D is a monobander for 20, 40 or 80 meters and output power is 1 watt.
Audio cables to/from PC and VOX keying. The price, with aluminum housing - $35.
CR Kits also makes a new 13TR kit (pictured, and same website as above) for 40m FT8 - this time using SSB.
Output is 1 watt, price with housing is $59. I am unable to find a manual for either of these kits without being a member of the relevant Group.io.
The new AFP-FSK from QRPGuys and the new QDX from QRP Labs both use a novel method of frequency generation. The QRP Guys explain it in text here and QRP Labs does so in a video here (beginning at 2:10).
Although the two kits share that unique feature, there are some significant differences between them.
The AFP-FSK can operate on any band, 10-160 meters. Plug-in filters define the band in use, with three included in the kit - for 20, 30 and 40 meters.
Four additional filter boards, minus the components, can be bought for $10. Output power is 4-5 watts, depending on band, and audio is routed to/from the PC with two standard audio cables.
The price is $80 with 3 filter boards, no case included (or available).
What makes the QDX unique, even compared to the AFP-FSK, is its onboard soundcard for USB connectivity of both audio and CAT, 5-band operation (20, 30, 40, 60, 80 meters), tiny size and no alignment. And nothing compares to a G0UPL-written manual.
Power output is variable (in my case, from 750mW to 5 watts), based on input DC voltage. The QDX can be built to operate at full output with either a 9V or 12V input.
Discussion of the QDX takes place here.
Price with aluminum/aluminium case is $80.