PSK-80 "Warbler"
Kit Notes

Assembly and Operating Tips

See also...
Specs & Ordering -- Read all about the Warbler Kit and how to order
KIT Manual -- Download the Warbler manual  -- 680KB PDF file           

     For those folks who purchased Warblers in the Round 3 of kittings -- only those kits shipped/received in February have a significant printed-circuit board error -- our pcb  vendor made the boards with the silkscreening on the wrong side!.   All those who purchased the kits have now received a new board by mail during the week of Feb 5, including instructions for identification of the bad board and use of the new one.  In the meantime, please do not begin assembly using the bad boards and use the replacement boards that came in the mail as a second shipment to you.   We apologize for possible confusion, but the solution is quick and painless for most.  Thanks all! .... George N2APB and Joe N2CX.

     Some folks have reported difficulty in getting full power out from their Warblers. To that end the designer Dave, NN1G, has suggested changing C10 from 220 pf to 330 pf. This has helped some get 3-4 watts PEP on a 13.8 V power supply as opposed to 2 W before the change.
     Here's the word from Dave:  "The NJQRP club has already incorporated this change into the upcoming run of Warbler kits. If you already have a Warbler, there's no reason to make this change unless you're getting inadequate power output from the rig.  If you're already getting rated power out, this change will not yield more output from the rig."
     For what it's worth I've built two of them, a beta and a production version and both have produced full power with the proper power supply voltage. YMMV depending on component tolerances.  ... de Joe E., N2CX

I can't wait till the 2nd shipment of Warblers departs NJ!  I've sent my money -- but I have the fever now!!  I was so desperate after reading all the posts from Doug, Bill, et. al.,  that I actually went to Radio Shack and purchased a stereo-mini- to stereo-mini patchcord so I could listen to PSK! The DigiPan freeware is fantastic!!!  Even if you don't have a Warbler, or any other way to transmit PSK, YOU OWE IT TO YOURSELF TO LISTEN IN ON THE PSK QSO'S!!  The software is free (look for the links on ) and if you have a computer with soundcard in the shack, it is as simple as RCVR Audio output (headphone jack) - patch to - soundcard LINE input!   ... de Alan Kaul, W6RCL, LaCanada, CA 

One evening during a round table I asked several stations to check my IMD. I was dismayed to find it was only -15 dB. This had to be fixed. I discovered that the Windows 98 "volume" control setting changed in rather coarse steps, not linearly. I was already down to the lowest possible step that produced output but was still overdriving the sound card. The cure was to break the PC board trace between J2 and the junction of capacitors C1 and C101 and insert a 100k ohm pot. Audio from the sound card is fed to the outside pins of the pot (from J2) and the center (slider) connects to C1 and C101. Now with the Win98 volume control set to mid scale I can adjust the audio drive from zero to four watts output with DigiPan in Tune mode. I adjust the pot to the point where the rf output just stops increasing and then back down slightly. I am happy to report that my IMD has gone from - 15 dB to -24 dB. ... de Bill Jones, KD7S

If you use the 1/2" datum shown on the diagram for the audio jacks to the inside bottom of the enclosure "floor", and measure your Warbler, you'll note that a 5/16" standoff would be needed. That is, put the 1/2" mark of a scale at the center of one of the audio jacks and you'll see that the length of the scale protruding below the board is the length of the standoff you would use with the panel dimensions shown.  I think I used a 1" long 4-40 screw in each corner of the board, inserted from the bottom of the chassis and secured with a 4-40 nut to the chassis. Then I put another 4-40 nut onto each screw and ran it done tight against the first. I then carefully angled the board connectors into the panel cutouts and slipped the board onto the 1" screws. Finally I secured the board with another 4-40 nut on each screw. So as it turns out, two 4-40 nuts were about 5/16" high.  ... de George N2APB

     If I moved the cables going from the sound card to the Warbler, I found that the output power would change slightly. I put a ferrite choke on the cables and the problem disappeared. Note that my antenna is a roof mounted vertical and one of the 80 meter radials passes directly over the ceiling of my shack. It is no more than three or four feet away. And the Warbler is sitting naked (no cabinet) on top of the desk.  ... de Bill Jones, KD7S

Post your own reviews, or see those of others PSK-80 builders on eHAM at
         ... de Ken N9VV

    Because of the fact that I am using a Toshiba 2595CDT Laptop for PSK-31 with the "Warbler", and the laptop does not have an audio "Line" input, only a "Mic" input, the receiver audio from the Warbler was much too high for the laptop, making the entire received spectrum bright yellow. Even with the laptop's recorder mic volume turned all the way down, the screen was still mostly yellow in the received spectrum area. So, after taking a look at the schematic, I changed R23 to a much higher value. After a couple of experimental tries, I settled on 56K as a new value. With this value, the audio level to the mic input now gives the proper amount of display adjustment, from almost totally blue to pretty heavily yellow speckled. So, if your waterfall display is mostly or all yellow in the received spectrum and your volume control won't take it to the level you want, try changing R23 to a higher value. ... de Wayne NB6M

    When the Warbler manual was done, the FETs were packaged in the familiar TO92 style package which has a pronounced "D" cross-section.  The manual and printed circuit board component marking was for that device.  However mid-way through the kitting we had to make a quick turnaround order for 2N7000 devices and we got them from a different distributor, what we got was in a different case type.
    So, if your Q1 and Q7 (2N7000 transistors) have the familiar pronounced "D" cross-section packages follow the manual and pc board markings. (This package style is the same as the 2N4401's used at Q2, Q3, Q4 and Q9.) That is, the flat side of the transistor with printed identification matches the flat side outline on the board and the rounded side matches the rounded outline on the silk screening.
    But if the 2N7000's you got have a flatter package with slightly beveled edges on one side, you mount it basically the same way so that the flatter side faces the flat side of the board marking, and the side with the beveled edges faces the rounded edge of the board marking.  On this "alternate" style transistor package, the printing is on the more rounded side while on the "original" style it is on the flat side.

    The values of R8 (150) and R10 (220) were inadvertently reversed on the Warbler Parts Layout diagram in the original manual (without a rev date on the cover). The Schematic is still correct, and we have now corrected the Parts Layout diagram.  And as a bonus, the updated PDF file on the website is now in color to help in viewing everything!

    I'm happy (so far) to report that effective with all new PSK-series shipments, the transceiver will use the female DB-9 connector to allow use of the ubiquitous serial-port extender (male-to-female) cable. This is *not* merely a matter of supplying the other connector flavor- the two genders are physically 'mirror-imaged' and they are not interchangeable on the printed-circuit board.  I'm awaiting a shipment of boards which incorporates a change in this regard.
    Along the way, I'd heard from several people who threw away the connector I provided and specified and installed one which matched the picture in QST. Bad move-  that picture made a QST deadline with only hours to spare, and once I actually applied power, quickly discovered that there was little Transmit Joy!
    Anyhow, there's nothing to 'vote' on.   Both the PSK-series and the Warbler will now use the female board-mounted connector. If you've already got a PSK-20 and want to switch back and forth to a Warbler or a PSK-40 <g>,  a 'gender-bender' plug (straight- not null modem)  is available from Radio Shack, Jameco, etc...
   ... de Dave, NN1G

In the Tech Manual, and during my PSK talk at Pacificon, we showed a nice and conveniently-sized Warbler enclosure called the LMB-139. There's really nothing special about this aluminum clamshell design from LMB -- one could use just about any handy enclosure in the junk box (or even make a NJ Homebrew PCB enclosure!!) -- but it just turned out that the LMB-139 fits snugly around the PSK-80 Warbler circuit board.  I've used these enclosures for several years for my QRP projects in the shack, and you can see some of the results at 
    Tom Jennings, KV2X tells us that you can order the LMB enclosure directly from LMB (  And NN1G reminds us that many other enclosures will work, so check out the Jameco (, Mouser ( and Digi-Key ( sites!     ... de George, N2APB

    A number of QRPers have written to ask if there's a software program for the Macintosh equivalent to Digipan on the PC that controls the PSK-xx boards. Well there is!  Check out Multimode at  There is also a neat new one for Linux by a German, but the link eludes me at the moment.   ... de Skip KH6TY/4

   I have slapped on some of the things I have said about a group building project of PSK-80's for West Central Indiana and East Central Illinois at    ... Jim, WD9EYB

   I've always wanted to coin a new word or phrase, so here goes:
Warblier (warbel-ear), n 1. One who operates PSK-31, esp. with a NJ QRP Club PSK-80 Warbler transceiver. 2. Anyone running PSK-31 (BPSK or QPSK) with any kind of transceiver, QRP or QRO.
    George Heron sold a hundred Warbler kits at Pacificon [and another 100 via mail].  I would guess that 50% of those kits went to west coast QRPers who live within a couple hundred miles of the bay area.  If you're one of those, how about joining Doug (KI6DS), Dave (AB5PC) and myself (KD7S) in a round table chat on 80 meters.
    Set up DigiPan on 80 meters at 3582 kHz, BPSK, LSB and a 1,500 Hz tone. Activate AFC, NET and SNAP.  If you chose to use Squelch, set the threshold fairly low (no more than 2-3 notches from the bottom). 
    I'd like to suggest we create a "Western Warbliers" round table QSO party on Sunday evenings beginning at 7:00 p.m. PST.  No net control, no formal check-ins, just a round table discussion using PSK-31 running 5 watts or less from any rig (but especially the Warbler).  Who's in?
    ... de Bill Jones - KD7S, Sanger, California 

    I monitor the receive audio output with a small amplified speaker and can tell if there is activity on the frequency without using the computer.
         ... Dave Epps, AB5PC, Fresno, CA

    To allow for spacing between the crystals and the board I cut a strip of heavy paper (or whatever) the thickness of the crystal. I then cut a slot in the center of this strip and slide it between the crystal and the board. Solder and pull out the strip.
    ... Dave Epps, AB5PC, Fresno, CA

   I've heard talk about how some PSK-80 Warblers that don't hear well or have low power output.  One possible explanation is that they are not aligned properly.  The manual  touches briefly on alignment usingW1AW as a frequency marker.  Unfortunately, some of us on the west coast can't hear W1AW on 80 meters.  I used my own transceiver to align my Warbler.  Here's how ...
   1.  In DigiPan, click on the "Configure" menu.
   2.  Click on "Band."
   3.  Click the "Activate" button for 80m under "Band."
   4.  Under Spectrum Start" type 3582.
   5.  Under "Spectrum Options" click on LSB.
   6.  Click "Okay."
   7.  Fire up your Yaecomwood, set it up for QRP and CW operation.
   8.  Attach a dummy load to the Yaecomwood.
   9.  Set the dial to exactly 3581.00 kHz.
   10. Key the Yaecomwood.  You should be able to see its signal in the DigiPan waterfall.
   11. Adjust trimmer C3 on the Warbler board until the signal is directly under 3581 on the DigiPan display.  Your Warbler will now be calibrated to the accuracy of the frequency display on the big rig.
    Click the waterfall at about 3580.5 kHz.  From the DigiPan menu, click "Mode" and "Tune.  With a 13.8 volt power supply you should see about3 or 4 watts output. Your transmitter output power should drop off below 3580 and above3581 kHz.  That's  normal.  On my Warbler, the "sweet spot" is right at 3580.5 kHz and is fairly flat 400 Hz either side.
    ... de Bill KD7S

    One of the questions that I had about my warbler once I got it built was how to hook it up to the computer and the outside world.  Bill Jones, KD7S and Paul Maciel, AK1P have been my PSK gurus.  You will need the following to connect and get on the air:
1.  Power cord (NJQRP supplies the cord and the plug, NICE touch)
2.  BNC cord to connect to your antenna.  If your antenna coax ends in a PL259, then you will need an adapter to connect to the BNC connector on the Warbler.
3.  DB9 Male to DB9 Female cable to connect between the Warbler and the serial port on your computer.
4.  Two shielded audio cables with stereo 1/8" plugs on both ends.  One connects to the Mike input of your sound card and the audio output of the Warbler, and the other connects to the audio ouput of the computer and the audio input of the warbler.  (Hope I got that right, grin). 5.  Digipan or similar software installed on your computer.  (Available from a link on Dave Benson's Small Wonder Labs page, look under PSK31)
    The antenna that I am using is a Skelton Cone up about 30 feet at the apex and 6 to 10 feet at the end of the radiators.  A skelton cone is basically a double dipole.  Think of having 2 radiators on each side of the center insulator spread apart, instead of just 1.  It is fed with ladder line and tuned with a tuner.  Works on all bands. The legs are 51 feet long, and the feedline is about 50 feet.
    With my setup, I am able to work both close in and dx stations, having solid copy on the locals, and being able to work NW7DX from Washington and KI0RO from Colorado.  Hope this helps.  ... de  Doug KI6DS

    I'm using a low dipole at my Connecticut QTH - it's up only 12-13' at the center. Copy is solid out to 200+ miles, although it varies some with conditions. My 2-way with Joe, N2CX, near Philly was about 80% both ways with our Warblers, and I've had a rock-solid QSO with a VE2 in Sherbrooke-about 250 miles.  Best DX to date has been the Atlanta area but it was a struggle.  Distances seem comparable to what you'd work using CW.
    Just since I first put the Warbler prototype on the air last spring, I've watched the PSK31 activity growing on 80M. Here in the Northeast, you'll usually see one or more traces on the display at night, especially during W1AW's quiet period (9-10 PM Eastern). I've seen as many as 4 simultaneous traces in the Warbler's 1 Khz passband.  That doesn't even begin to fill that slice of spectrum with PSK31! We've got a unique opportunity here to "make it happen".
    Don't let the fact that it's 80M, as opposed to a 'DX' band, deter you in the slightest. Many of us are running short (or low) antennas and still getting out.  Joe Everhart's 'Squirt' antenna is half-sized and gets out quite well- look for it in the next issue of the NJ QRP club's 'Homebrewer' journal.   From the sound of Doug's recent post, none of the antennas in their wonderful 3-way QSO was a 'killer' skywire.
    This is the season to begin thinking about the low bands, and enthusiasm for 80M yields creativity in the antenna area. This is something we all enjoy hearing about, whether we're WarbleHeads or not, and this enthusiasm gets us off our computers (maybe) and *on the air*.
    ... 73- Dave, NN1G

Here's a convenient diagram showing hole dimensions for the "rear panel" of any enclosure you might happen to put the Warbler into. As illustrated, the enclosure happens to be of the LMB-139 aluminum clamshell, but the dimensions are really only specific to the edge connectors of the PSK-80 board.  Hence, you can use this diagram as a template (when reproduced at actual size) for making the cutouts in your own panel, or just use the dimensions to map out the holes needed on any panel you might want to use.  Also shown are a couple photos of the LMB-139 enclosure used in the manual, but shown without the board in place this time.  These shots illustrate two things: (1) the board standoff scheme I used for this enclosure, and (2) the imperfection of my cutouts ... but they are "good enough", as N2CX would say! :-)   ... de George N2APB

   Cut a piece of heavy paper (file folder stock) to the exact dimensions of the front of your enclosure.  Then using an inexpensive (plastic, $1.00) calipers, or even a ruler, measure the positions of your controls, etc. with reference to some landmark, such as the bottom right corner of the PC board.  Lay these dimensions out on your paper replica and make the holes with a paper punch.  Then test it out, moving the holes as necessary.  When everything is right, cut a new replica and transfer your accurate dimensions to it to make a template.  Then proceed as you would with a "real" template.
     With regard to the using nuts as a standoff.  You can make this adjustable if you run a screw (4-40 size, for example) up through the bottom of the enclosure and secure it with a nut (and possibly a lockwasher).  Then thread another nut down the screw to achieve the desired height.  Leave some space between the nuts, and you can make very fine adjustments of the standoff height.  Then mount the board on the screws and secure it with a third nut.
     ... de Richard Meiss, WB9LPU

> 7.5V Zener Diodes are 1N5236B
Bruce Prior, N7RR pointed out a helpful hint for the Parts List in the manual ... D1 and D2 part numbers are 1N5236B.  This should help distinguish them from the other diodes in the package.  Thanks Bruce! 

Thanks to the early-on assembly of the production board by Dave Epps AB5PC, and to the artistry of designer Dave Benson NN1G, we have some clarifying diagrams for the construction and installation of transformer T2.  Click HERE for picture details.

Although Chuck Adams, K7QO had the first production-version Warbler contact last week right after Pacificon, Bill Jones KD7S and Dave Epps AB5PC had the first production-version Warbler-to-Warbler 80m PSK31 contact on October 28.  And to top it off, Doug Hendricks, KI6DS hopped in for the first Warbler round table QSO with Bill and Dave!  Read more about it HERE.

A small number of manual and parts list corrections (listed in the next section) have been made to the Warbler Technical Manual to create a "rev B" of the manual.  If you'd like to see or possibly print this revised manual, you may download the Warbler Technical Manual - Rev B.  You can also download the Schematic and Parts Layout diagram. (Note:  You'll need to have Adobe Acrobat on your computer in order to read this 330K PDF file.)

1) Heatsinks ...
The heatsinks provided in the kits sold at Pacificon were the wrong size. Contact N2APB by email ( to receive the correct heatsinks. (All kits received by mail already contain the correct heatsink.)
2) Magnet Wire ...
The kits supplied at Pacificon didn't have enough magnet wire (used in creating T2 and L2).  A 6" length of magnet wire will also be sent in the package containing the correct heatsinks.
3) Stranded Wire ...
Stranded multi-color telephone wire is supplied in the kit, instead of the specified solid conductor wire.  The stranded wire will work just fine.
4) T1 winding clarification (Step 7 on page 7) ....
"T1 is wound using three 4-inch lengths of wire (leave insulation on) removed from the 4-conductor cable supplied. Four (4) turns of these three wires are wound ‘flat’ on a dark grey core, with no wire crossing over its neighbors."
5) T2 winding clarification (Step 8 on page 7) ... "T2 has a primary winding and separate secondary winding. The secondary should first be wound using 8 turns of magnet wire distributed uniformly around the circumference of a dark grey core. ... The primary is wound next using two 4-inch lengths of distinctly-colored wire from the 4-conductor cable. The two wires are 'bifilar wound', wound together for 4 turns over the magnet wire secondary already on the core. ... The magnet wire winding connects to the output harmonic filter and should be installed in the rightmost pair of T2 holes."
6) Surface Mount IC orientation (Step 2 on page 5) ... "When the lettering on the IC reads 'upright', the chip is in the same orientation as shown in the Board Layout diagram. Then, pin 1 is in the lower left corner of the device."
7) Final Transistors ...
2SC2166 transistors are supplied for Q5 & Q6 in the kits, instead of the 2SC2078 devices noted on the schematic. For our purposes, they are equivalent.
8) Theory of Op "typo" ... the last paragraph (on page 4) in the theory of op section should reference Q8 as being turned on in the T-R switching.
9) Parts List "typos" ... 
- the 2N4401 transistor is used for Q2, Q3, Q4 and Q9
    - the 2N7000 transistor is used for Q1 and Q7.
    - C11 & C12 may be blue or yellow
    - W3 should be 20"

   Thanks go to Chuck Adams (K7QO), Dave Meacham (W6EMD), and Dave Epps (AB5PC) for their careful attention in assembling the kits and noting clarifications for everyone.

Back to the Warbler home page


Last Modified:  March 6,2001