4 State QRP Group Bayou Jumper (Paraset inspired QRP XCVR)
Posted by Nate Bargmann
on Fri, Jan 27, 2017
Just before Christmas the 4 State QRP Group announced that
a new kit is available, dubbed the Bayou
Jumper. From its
introductory page:
“Return with us now to those thrilling days of yesteryear” and build the
Bayou Jumper. The name “Bayou Jumper” is a play on “Ocean Hopper”, a famous
regenerative receiver of a bygone era. It retains that great retro look but
with modernized circuitry. With it’s distinctive panel and wood box
enclosure it pays homage to the famous spy radios of WWII. It is designed
for the CW segment of the 40 meters.
4 State QRP Bayou Jumper kit
As the radio had received quite a bit of discussion on the 4SQRP mailing list
since its introduction last spring at Ozarkcon, my interest was piqued. Once
the announcement was made I put my order in to experience this homage to
yesteryear.
The kit of parts arrived just after Christmas but I put off beginning assembly
until after New Years. In the mean time I managed to get to the nearest Hobby
Lobby in Manhattan, KS to pick up the small wood case the boards are designed
to fit.
I estimate that I spent close to eight hours between all assembly and
alignment steps. Others may be able to do it much faster but I wanted to be
able to savor and enjoy the build. Still, despite careful work, I managed to
put a capacitor in the wrong place. Fortunately, I caught my error in time and
made the correction before finding out the receiver was not working correctly.
The regenerative receiver came up upon first power up which was a relief. But
where was it? Other builders had reported their receivers working at the upper
end of 40m or even in the SWBC band above 40m. I found mine operating above
40m and it was a matter of trial and error to squeeze the 19 turns on the
torrid enough to move it to the low end of 40m.
During assembly the builder is instructed to leave one capacitor out unless it
is determined to be needed later. Later during the alignment of the
regeneration advice is given for determining whether that capacitor is
required. My regeneration did not kick in until the knob was around the 3
O’clock mark which gave a rather limited regeneration range. After soldering
the capacitor in place the regeneration now kicks in around 10 O’clock
allowing for plenty of regeneration range.
The transmitter is a very simple crystal controlled circuit. Two crystals are
supplied with the kit, 7030 and 7122 kHz. The latter is sort of a 4SQRP
“watering hole”. As it worked out, the 7122 kHz crystal supplied to me is an
HC49S, the low profile version. Others noted that such would fit into an
FT-243 crystal holder. One of the locals gave me a couple of spare FT-243
holders and I gutted the one and soldered the 7122 kHz crystal into it.
The other builders noted that their transmitters were operating about 1 kHz
below the crystal frequency. Mine was no exception, transmitting a few Hz
above 7121 kHz.
Operationally, the regeneration is smooth (this is the first regen I’ve had
much experience with). The VFO is fast as it is a PCB mounted 50k Ohm
potentiometer with about 140 kHz covered in 270 degrees or so of rotation. A
slow and steady hand is required. Some builders have fitted verniers, a
multi-turn potentiometer, or digital counters to their Jumpers to slow the
tuning. Received note is clean and the regen is stable. The built in key is
not adjustable but usable. A jack is provided to connect an external key (some
caveats apply).
On Saturday afternoon, January 21, I heard KD9ELU calling CQ around 71212 kHz.
Upon my answering his call he came right back and we had a QSO that lasted
about half an hour. Signals were good and he reported solid copy on each over.
I did need to touch up the VFO once during the QSO. As I had already practiced
tuning it, I didn’t lose Eric’s signal. In practice the passband is wide
enough that concentration is required in the presence of other nearby signals.
I did have an external straight key plugged in for this QSO as seen in the
picture below.
I highly recommend this kit for the intermediate to the experienced builder.
Its regenerative receiver is easy to use and covers a narrow enough range as
to be usable through the lower half of 40m. Along with its crystal transmitter
it allows experiencing amateur radio from yesteryear in a compact package.
My Bayou Jumper set up for its first QSO with KD9ELU.
Today I received a nice QSL card from Eric, KD9ELU:
QSL card from Eric, KD9ELU, commemorating the first QSO made with my Bayou Jumper.
