Click Here for Schematic

Reggie is a one-transistor, 80m, QRP transceiver designed for the minimalist. It's a "dual-action" QRP radio; not only does it transmit a small signal, but the receiver converts every signal on the band into QRP. 

  • ~ 100mW output power 
  • Fessenden heterodyne receiver
  • Tunes from 3503 to 3563kHz
  • Full QSK
  • RIT 
  • "Chirpless" keying 
  • Clean output signal

I've named this radio in commemoration of the great Canadian radio pioneer, Reginald Fessenden


One-stage transmitters share a common difficulty; the necessity for clean keying generally limits their operation to quartz crystal-control on the lower bands. While it is possible to "rubber" the crystal, in order to retain reasonably good keying the total frequency excursion for each crystal is severely limited.

I recently found myself wondering if it might be possible to escape this limitation. The design offered in Reggie represents my solution. It's a simple idea that hearkens back to the earliest days of radio. The oscillator runs continuously. While the transceiver is receiving the oscillator delivers most of it's power into a dummy load, with the remainder used to feed the receiver BFO. When the key is depressed this RF energy is re-routed to the antenna via a simple switching network comprised of a pair 1N4007 rectifiers. This technique allows a wide-range, ceramic resonator VXO to be used as a single-stage CW transmitter without the disadvantage of keying chirp.

The VXO is a standard Colpitts oscillator. A forward-biased LED provides a stable DC bias to the base as well as the back-light for the tuning dial. The values of the Colpitts feedback-divider capacitors - C3 and C4 - are made large in order to "swamp" the capacitances external to the ceramic resonator. I used an FT50-43 core at T1 only because that's what I had in my junk box. The collector DC input power at Q1 measured 300mW. This indicates an efficiency of approximately 28%.  

With VC1 set at the middle of the frequency span, and with the key-up, adjust the slug at T2 to peak the oscillator signal at the 2-turn link. Now, re-adjust this slug until the oscillator frequency (measured at the T1 secondary) drops by 600Hz on key-down. The idea is to create the RIT by deliberately mis-tuning T2/C6 in order to increase the oscillator load (as compared with the antenna) while receiving. In my prototype, an RIT setting of 600Hz at mid-range (3540kHz) produced an offset of 608Hz at the bottom, and 557Hz at the top of the frequency range.

Please bear in mind that you don't have to use a transistor ceramic resonator VXO in this radio. I'd like to build a second Reggie transceiver for 40m using a subminiature triode, permeability-tuned-oscillator (PTO), utilizing the "brass-screw" tuning-trick. The keying method used in Reggie ought to allow even a VFO to key cleanly. However, if you increase the oscillator output power be sure to increase the bias voltage at the 1N4007 keying diodes, and be careful not to overdrive the receive mixer diodes.

The circuitry is built "Manhattan-style." The main circuit is mounted to the left-hand bulkhead in the above photo, while the input/output bandpass filter is affixed to the upper right-hand wall. The variable capacitor was salvaged from an old FM radio. It has a 6:1 ball-reduction mechanism built into the shaft. The extruded aluminum enclosure is a waste off-cut, taken from a section of overhead cable-tray used at the television station where I work. The narrow rectangular shape helps to conserve my limited shelf space.  

The harmonics are down by at least 59dBc at an output power of 83mW.


Reggie is outfitted with a Fessenden heterodyne receiver; a continuation of my experiments from last winter. A simplified version of the mixer used in my Das DereLicht Receiver directly drives a pair of ST-3 headphones made by the Japan Radio Company. The receive MDS measures -90dBm (7uVrms). A signal at -71dBm (63uVrms) provides excellent copy, while I'd characterize a -56dBm signal as "loud." 

You may click here to download a text-file of additional construction information. This short note was taken from my reply to a prospective builder.   

Please scroll down to view the "RAF Heterodyne Receiver" ("RAF" stands for Reginald Aubrey Fessenden) at "Figure 8" of this document. This little receiver was used aboard the scout cruiser, USS Salem, during a famous test carried out by the U.S. Navy in the winter of 1912-1913. As Leonard Fuller recollects in an oral history given to the IEEE

"...the Salem sailed from the Delaware River eastward across the Atlantic, recording alternately from the arc and the spark transmitter [located in Arlington, Virginia]. After about 1200 miles, 1200 to 1500 miles out, it became apparent that the arc was beginning to be superior to the spark, and the arc received signals during daylight in Gibraltar. One of the receivers on the Salem was a beat frequency reception type of receiver. Now, this was before the days of the vacuum tube, so the local oscillator for the beat reception was a small laboratory arc without magnetic field, about the size one could hold in one's hand."


The heterodyne receiver used in my Reggie transceiver is essentially the same as was carried on the Salem during the Atlantic receiving trials. However, in place of an arc BFO I use a Colpitts transistor oscillator. In place of the electrolytic detector I'm using a pair of 1N4148 signal diodes. Still, I've little doubt that "Old Man" Fessenden would have recognized the plan of my receiver. 

On my first evening on the air with Reggie I copied both G3WZT and DL1REM with excellent signals near the bottom of the 80m CW band. I was particularly pleased to have VE1QY/QRP reply to my CQ during my first week of operation. It's amazing that Barry heard my 75mW signal. Perhaps even more amazing is the fact that my antenna had intercepted enough energy from his 5 watt signal - at a distance of 665km - to enable me to copy his transmissions. While I do have some grasp of the physics involved, I believe there is no depth of explanation capable of vanishing the beauty and mystery of radio. 

"Miracles are explainable. It's the explanations that are miraculous." Tim Robinson  

January, 14, 2009

I received a FB email message from Jim, W1PID, following our exciting Rock Mite - Reggie QSO. I've posted it below (with his permission). The subject-line of his message was

"Reggie and The Rock Mites"

"I'm sitting here at my desk doing some work with the receiver on 3539... and I realize that's someone's calling CQ. Hey wait, I know that call; AA1TJ. So I answer him. Mike and I have a wonderful QSO. He's using the Reggie at 75mw and I'm running 5 watts. He's a good 559 and I'm copying him very solidly. 3:45 pm local.

Anyway, I'm a little embarrassed about 5 watts (QRO, and all) so I suggest we go to 3560 where I can try the Rock Mite. At 500mw it's the lowest power thing I've got in the shack. So we move, and it works pretty darned well. He's copying me well. He's solid, but it's a bit noisy on my end and every now and then broadcast stuff dumps a few letters. So it wasn't armchair, but it was pretty darned good. And a whole lot of fun." 

January 15, 2009

I received a pleasant note from ZL3KE (ex-G1HDQ), today. Kevin offered a great suggestion on how I might dispense with the second supply potential that I've been using up till now. His mod worked perfectly; "right out of the box." Thanks so much, Kevin!

I enjoyed a run of three QRP/QRPp QSOs in a row this afternoon. In particular, K4AXF's 5watt signal from the Washington DC area was nothing short of amazing; an honest 569! I came up from the shack later in the evening and found his email massage in my mailbox

"Michael, I copied your second and third transmission, solidly.  First transmission, I was getting my receive set up and missed some. Your transmit signal was clean with nice keying - just like store-bought."

February, 14, 2009

This evening I worked K3OXG at a distance of 478 miles. Lou was running an Elecraft K1 at both 5 watts and 100mW. I clearly copied two of his transmissons at 100mW. The fact that it was possible to copy a 4780 mile-per-watt signal using a non-amplified receiver is nothing short of astounding! Up till now, I would not have thought that was possible. Obviously, it's made me very happy. Thank you, Lou! 


February, 20, 2009       

First DX tonight; C6APG in the Bahamas at 80mW! 


February 24, 2009

Having told Dennis, K1LGQ, about my rig, he replied, "You Vermont cowboys really know how to ride rough." I liked that :o)

March 2, 2009

Tonight I worked six stations in the North Carolina QSO party; a new state for Reggie.

May 25, 2009

I've made a total of 143 QSO's with Reggie; working 18 states and 3 Canadian provinces. Western European and Russian stations have been copied on a regular basis. 

Station Log  (partial)

Date        Station    His/Mine   QTH               Miles per watt    My Power         Comments 

1/8/09     VE3CBE   559/559   Ottawa, ON              5316            60mW          Solid QSO, 20 minutes

1/9/09     N8NA       579/449   Wilmington, DE       5393            60mW

1/12/09   VE1QY      229/339   Kentville, NS          5520            75mW          5watts, 15 minute QSO

1/12/09   K3SEW      579/549   Howard, PA           4347            75mW

1/13/09   K3JT         579/579   Morgantown, WV    6453           75mW           50watts to vertical, "...75mW doing vy nice job"

1/14/09   KA3TGV     569/439   Strodes Mills, PA    4653           75mW

1/14/09   W1PID      339/559    Sanbornton, NH      893           75mW           SWL Rock Mite running 500mW; Thanks Jim!

1/14/09   W7JW       599/599    Plymouth, MI        7413          75mW           default "contest" reports

1/15/09   W1GUE      569/579   Fremont, NH          1400          80mW           5watts, Ed raised my signal report to 599

1/15/09   K4AXF       569/569   Strasburg, VA         5044          90mW           5watts, Amazing signals on both ends!

1/15//09  W2SH       569/549    Millington, NJ        2789          90mW            5watts, Ten Tec Argo V; Tnx for FB QSO, Charles!

1/16/09   AC9X        599/599   Twelve Mile, IN       8987          80mW            default reports, 719miles/1157km

1/16/09   W8PBO     569/449    Ravenswood, WV   7300          80mW            580miles/940km

1/19/09   K1TMJ       539/329    New Sharon, ME     1787          80mW            5watts, "1929 breadboard xmtr"

1/21/09  K3MRG      569/549   New Bloomfield, PA  4237          80mW              100watts to delta loop

1/21/09  K3MM        599/559      Damascus, MD     5012          80mW

1/21/09  W1KX        579/559      Monmouth. ME    1950           80mW              Elecraft K2 @5watts, briefly 1watt; 45min. QSO

1/21/09  VE3AZA      569/219      Brampton, ON     4387           80mW

1/21/09  VA2GU  569/599+20dB  Cacouna, QC      3850           80mW             30min QSO

1/22/09  W3DP        579/339      Camp Hill, PA     4250            80mW            90watts to G5RV

1/30/09  K4EJQ        559/459      Bristol, TN           9666            75mW           Heathkit DX-60 @45watts, invee; 15min. QSO

2/3/09   W4PM        569/569       Richmond, VA      5578            90mW          100watts to dipole; 17min. QSO

2/4/09   W3KC         449/569      Kensington, MD    4600            90mW          Elecraft K2 @ 10watts

2/4/09   W3JT          579/569      Olney, MD           4511             90mW         100watts to a vertical

2/10/09 WA1JWJ      339/379      Bethel, ME           1111             90mW         Jack ran 500mW start to finish! 24min. QSO

2/14/09 K3WWP       559/449      Kittanning, PA      4578             90mW         John, of NAQRP; 5w to a random wire in his attic

2/14/09 K3OXG        569/559      Waynesburg, PA   5311             90mW        K1 at 5watts/100mW to invee; 4780MPW on rcv!

2/14/09 WB8YYY      579/559      Eldersburg, MD     4300             90mW        K2 at 100watts, 26 foot vertical

2/18/09 WB9DLC      569/559     Columbia City, IN  8450             80mW        100watts to a vertical; "ruff cpi"

2/18/09 K8CIT         569/339     Hillman, MI           6925             80mW

2/20/09 C6APG        599/599      Bahamas           16775              80mW       1342miles/2159km; First DX!

2/20/09 KM4BI        559/449     Chattanooga, TN  11370              80mW       910miles/1464km

2/24/09 WA8YXA     569/339      Midland, MI          6800              85mW

2/24/09 WBØTUA     569/459     St. Louis, MO       12287              80mW      983miles/1582km, 100w to a doublet

3/3/09  K8JRO         579/119     Clio, MI                 6937             80mW       Peaked at 449; 100w to a G5RV

3/4/09  NN8R           559/349     Freemont, OH        7000             80mW       Peaked at 549

5/21/09 NG3W         339/559  Shinglehouse, PA       3887             80mW      Elecraft KX-1 @ 1watt