4 State QRP Group Bayou Jumper (Paraset inspired QRP XCVR)

Discussion in 'Homebrew and Kit Projects' started by N0NB, Jan 26, 2017.

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  1. N0NB

    N0NB Subscriber QRZ Page

    Just before Christmas the 4 State QRP Group announced that a new kit is available, dubbed the Bayou Jumper. From its introductory page:

    (picture linked from the 4SQRP Web Site)

    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 Bayour Jumper as used for my first QSO with it.
    K4YND, VK4FFAB, N4IAG and 3 others like this.
  2. W6ELH

    W6ELH Ham Member QRZ Page

    A Paraset has been near the top of my "want to build" list for some time. I may just have to order one of these kits for a near-term project.

    Looks like you did a very nice job on yours!

    Cheers, and thanks for sharing! Jim... W6ELH
  3. KC2SIZ

    KC2SIZ Ham Member QRZ Page

    I just built one of these as well. What a great kit! It fits perfectly inside the Hobby Lobby box. I love the manual switching between RX and TX. Wonderfully "retro".
  4. W6ELH

    W6ELH Ham Member QRZ Page

    My kit is ordered. N0NB - it's all your fault!

    I have started collecting parts for a proper Paraset build, but this looks like too much fun to avoid.

    Cheers... Jim
    N0NB likes this.
  5. N0NB

    N0NB Subscriber QRZ Page

    Welcome, Jim. I'll bow and take the blame with grace. :)
  6. K8WPE

    K8WPE Ham Member QRZ Page

    I have had a ton of fun building and using my Bayou Jumper. I experienced a few glitches but worked them out with help from the Four State Yahoo group. Made some friends along the way in doing so. A great idea, well designed kit, neat case idea too with Hobby Lobby box.

    Dave K8WPE
    N0NB likes this.
  7. N6RGR

    N6RGR Ham Member QRZ Page

    I will take the plunge soon. I enjoy building regens and xmtrs.

    Roger KK6IVD
  8. N3HEE

    N3HEE Ham Member QRZ Page

    Most fun I've had in radio in a while ! The Bayou Jumper is a winner. Get one before they are gone. - 021
    N0NB likes this.
  9. AE5KA

    AE5KA XML Subscriber QRZ Page

    Just finished my BJ build. Works very well and looks great. I substituted the Philmore S-38 vernier dial for the standard dial. Looks even more period and makes tuning the receiver easier. Hard to beat this for the money!
    N0NB likes this.
  10. W6ELH

    W6ELH Ham Member QRZ Page

    AE5KA- How about a photo?

    Still waiting on my kit. Larry, AB0AH who kits and ships these, was actually kind enough to call me and explain that he was short parts and that my kit would be delayed slightly. What a fine fellow!

    I have some ideas about modifying mine to look a bit more like the original Paraset, but first I need to get it together and working. Cheers... Jim W6ELH
    N0NB likes this.

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