Dxers Unlimited’s  Edition for Tuesday  22 January 2019

By Arnie Coro
radio amateur CO2KK

Hola amigos radioaficionados all around the world.. I am Arnaldo, Arnie, Coro your host here at the middle of the week edition of Dxers Unlimited, the one and only radio hobby program covering almost all of the 91 different ways we can enjoy playing with our radios antennas and accessories…

First news item.. very low solar activity for many days in a row, now scientists are asking if the Sun will be making a come back of sorts, after stalling at zero sunspots count for many days at the beginning of 2019. Tuesday UTC day brought a new sunspot now flaring up to class B flares

Item two…. good news coming from the European Broadcasting Union… They are announcing a New dot radio Internet Domain. The EBU is launching a new Top Level Domain (TLD) name -dot .radio – aimed at the radio community including Radio Amateurs.

The European Broadcasting Union says this new TLD domain will progressively change the way people are reaching internet resources linked to radio.

These categories will be accepted for the use of a dot .radio domain:
• Radio Amateurs
• Radio broadcasting stations
• Unions of Broadcasters
• Internet radios
• Radio professionals (journalists, radio hosts, DJs, …)
• Radio-related companies selling radio goods and services

Item three: More and more radio amateurs around the world are learning standard electronic workshop procedures, like soldering , measuring circuit parameters, reading circuit diagrams , also learning how to visually identify electronic components, and all that new knowledge opens the way to start building the new generation of user friendly radio kits…

Yes I am very pleased to say that several of the most recently advertised via Internet amateur radio transceivers kits intended to be assembled at home using simple hand tools and standard measuring equipment like the now classic digital multimeters have proven to be very reliable after proper assembly. One  example is the Bayou Jumper solid state QRP transmitter receiver rig, that was derived from the World War II Paraset rig used by paratroopers launched behind enemy lines and by fighters in countries occupied by the Nazis to communicate vital information to the Command Posts.  The twenty first century version uses all solid state components for the regenerative detector receiver and the power transistors transmitters… Limiting the coverage to a narrow segment of the 40 meters band has proven to be a very wise decision, because it has helped to create more activity on the 40 meters band segment between 7100 and 7125 kiloHertz…

Of course that this little rig is a CW only transmitter… and it is able to receive also single side band voice signals as well as digital modes. Among the bright ideas brought forward by the radio club that is promoting this kit of parts we must include the use of coils that are part of the printed circuit board supplied with the kit of parts. Coil winding to exact specifications has proven to be a long time problem for home builders. The Bayou Jumper, spelled B A Y O U  J U M P E R, uses an single easy to wind toroid coil for the receiver… The Bayou Jumper Transceiver was designed by two American radio amateurs Jim Giammanco N 5 I B and David Cripe N M Zero S —-

Here are now some specifications and Design Features of this very interesting amateur radio 40 meters band transmitter and receiver set.


N5IB: Original prototype development, receiver development, PCB and panel layouts, part sourcing.

NMØS: Transmitter design, PCB, panel, parts sourcing, assembly manual.

RXTX Design: Separate receiver and transmitter, built in RIT..

T/R Switching: Hand switched with a chicken head knob, just as in the old days.
Single Bander: 40M as supplied.

Toroids: Only one toroid to wind in the receiver, and none in the transmitter. Only ONE for the whole rig!

NO SMT: All parts are through hole, there are NO surface mount devices in the kit.

Current Requirements: Receiver 20ma, Transmitter 750ma

Enclosure: Beautiful silk screened panel and commercial wooden box, for a very retro look. Dim. L x W x H, 7.75″ x 5.5″ x 3.25″

Stay tuned for more radio hobby related information coming to you from Havana, Cuba where we received on Monday  a powerful cold front that changed  our weather flipping the switch into winter…

This is Radio Havana Cuba, the name of the show is Dxers Unlimited, I am Arnie Coro, radio amateur CO2KK , and here is more about how volunteer groups around the world are promoting the home assembly of ham radio equipment by designing rigs that can be successfully completed thanks to the use of high quality electronic components , extremely well designed and made printed circuit boards as well as excellent step by step instruction manuals…

The Bayou Jumper solves many of the problems found in previous attempts of making kits by addressing the most frequent failures of those projects, like for example the need to wind several toroidal ring inductances using very fine wires… a task that is quite a challenge for the older radio amateurs and also to younger less experienced home builders ….

Now I am going to share with you the specifications of the performance achieved by the Bayou Jumper kit…. Amazing as some of them may seem to be … they were all fully verified with advanced electronic test instruments… here we go:

Tuning and Regeneration: Grounded front panel, and insulated shafts on the controls, so hand effect detuning is minimized.

Sensitivity: -120 dB (approx S1). Well below the typical rural band noise level of approx. -100dB (approx. S4).

Tuning Range: Tuning range approximately 120 to 150 kHz.

One Knob tuning: No bandset/bandspread needed.

Varactor Tuning: Varactor tuning employing readily available Schottky diodes as varactor diodes.

RF Gain: Optional RF attenuator control, useful when employing full-scale antennas.

Audio: Plenty of headphone audio, and will drive a small speaker.


NS-40: Integrated into the PCB is Dave’s famous NS-40 Class E transmitter.

Crystal Controlled: The rig has a socket for the old-style FT243 crystals, plus 7030 and 7122 kHz crystals and included crystal adapters.       If you have old 7MHz Novice crystals, you can use them with this rig!

Output Power: Solid 5 Watts.

No Toroids: No toroids to wind, all inductors are etched on the pc board.

Keying Options: Straight key built into the front panel, just like the original Paraset! Also includes a 1/8″ jack so you can use it with  your favorite mechanical key, or an electronic keyer with an interface.

Spotting: You can activate the crystal oscillator at low power to allow zero beating the receiver to the transmit frequency.

Final Amp: Cool running robust MOSFET.

Spectral Purity: All harmonics and spurious emissions are 50dB or more below the carrier.

Using a half wave 40 meters band dipole antenna fed via a one to one balun with 50 ohms coaxial cable, my 5 Watts output QRP transceiver provides good two way contacts under normal propagation conditions…

Now at the end of the show… a short form HF bands propagation update:  solar activity very low but one new sunspot active region in sight Tuesday morning local time…

See you all at the weekend edition of Dxers Unlimited next Sunday and Monday UTC days  just after the top of the hour newscast here at Radio Havana Cuba.


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