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•  Using solar and battery power
   

•  Operating with Morse code
   

•  My Vibroplex telegraph key collection
   

•  My bio
   

•  Field Day June 2010
   

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My QRP Rigs --
Low-power CW operation
 

One of the enjoyable aspects of the amateur radio hobby is that, with an amateur radio operator's license, you can build your own equipment from scratch.  In fact, back in simpler times most equipment was either homemade or was modified from old commercial or military equipment.  Now that 99.9 percent of electronic devices use integrated circuits, micro-computers, transistors, and tiny parts, and because it's often difficult to find suppliers who sell small quantities -- as in one or two of an item -- most amateur radio equipment is commercially made.  However, there are several individuals and companies that still produce kits and sell individual parts for the experimenter.

Another fun aspect of amateur radio is that not a lot of power is required to communicate with other stations.  While most amateur radio equipment operates at around the 100-watt level -- and amateur radio operators can run as much as 1,000 watts -- a lot of amateur radio operators enjoy using low and very-low power equipment. 

This is a long story -- I'll keep it short.  Originally all amateur radio operation used Morse code and, because Morse requires that every word be spelled out, a system of abbreviations was developed.  Some of these abbreviations are the "Q" signals -- for example -- QTH means "location."  If you send QTH?, that's the same as aksing "What is your location."  If you send QTH New York, that means "My location is New York."  The Q signal QRP means "reduce power" -- and over the years the term QRP has come to mean low power operation.  Generally, if a piece of equipment is described as a QRP rig, that means it runs 5 watts of power or less.

Currently I have six small QRP transceivers that operate on CW -- Morse code; I built each of these from kits that I purchased from the folks who designed them.  My current QRP rigs are:

•  SW+40 : 40-meter band; 1.5 watt CW transceiver; superhet receiver.
•  SW-80:  80-meter band; 1.5 watt CW transceiver; superhet receiver.
•  SW-20:  20-meter band; 1.5 watt CW transceiver; superhet receiver.
• S&S Engineering ARK-4:  40-meter band; 5-watt CW transceiver with built-in keyer.  (An EXCELLENT rig, no longer available as of December 2008.)
•  RockMite 40 and RockMite 20:  40-meters, or, 20-meters; CW; 400 milliwatts -- less than1/2 watt; fits into an Altoids box.
•  The FreqMite, a PIC-based frequency counter and readout from Small Wonder Labs.

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Over the years, I have had a number of QRP rigs, most of which I built from kits, some of which I bought on eBay or eham.net classifieds.  The following is a list of the QRP rigs I now own or have owned.

SW+40 from Small Wonder Labs

Go to this page to see my experience with the SW-40+ from Small Wonder Labs -- an EXCELLENT RIG!!!

SW-80 and SW-40 from Small Wonder Labs

Go to this page for details on these two rigs.

S&S Engineering QRP Rigs

Previously, I owned three QRP rigs that I built from kits manufactured by S&S Engineering.  I don't know the history or current situation of S&S; I encountered them at a hamfest in the Washington, DC, area in the mid-1990's and, over the course of a year, I bought and built two of their rigs:  ARK-4 40-meter CW tranceiver (5-watts), and, TAC-1 80-meter CW transceiver (4-watts).  In May 2010 I purchased an S&S Engineering TAC-1 for 40-meters on eBay.

After a few months I realized I was not using these rigs, so, I sold two of them on eBay and kept the ARK-4 that I purchased and built back in the 1980's.  I use it very rarely.

The company still has a website but their products are no longer available.  The kits produced by S&S Engineering are EXCELLENT pieces of equipment.  The guy who designed these rigs is an engineer who designed military and commercial communications equipment and his kits are made to the same quality as military and commercial equipment -- solid, top-quality components, very stable and reliable designs.  It's a real shame that these kits are no longer available.

Here's a link to their website:  S&S Engineering.  As of May 2010 they appear to be out of business but their website is still there.

S&S Engineering TAC-1

I had two of these, one for 80-meters, one for 40 meters -- sold them on eBay.  I built the 80-meter rig from a kit in 1994 and purchased the 40-meter rig on eBay in May 2010.

•  40-meters, synthesized; tuned by the TUNE knob in the top right corner.  Turn the knob to tune up/down in 1 KHz steps -- push the knob in and the tuning switches to 100 Hz steps -- push again to return to 1 KHz steps.
•  7.000 - 7.199 MHz
•  4 watts output
•  Built-in keyer with adjustable speed and weight.  The keyer defaults to 12 WPM.  When the rig is turned on, the LCD display shows the keyer speed -- 12 WPM -- then shows the frequency.  On the rear of the rig is a small push button -- push the button and the LCD display shows keyer speed -- turn the TUNE knob to increase/decrease keying speed -- push the button again to adjust keyer weight -- push again to return to frequency display.
•  Very sensitive and selective receiver
•  Very good keying characteristics.
•  The 80-meter TAC-1 is identical to the 40-meter version except for frequency coverage;  3500 - 3750 KHz.

S&S Engineering ARK-4

Here's a picture of the rig.

 

•  40-meters, synthesized; tuned by the push-buttons on the left.
•  7.000 - 7.199 MHz
•  5 watts output
•  Built-in keyer
•  Very sensitive and selective receiver
•  Very good keying characteristics.
•  The pushbutton tuning is a bit cumbersome -- notice the frequency indicator, it's now reading 7.041 -- reading left to right:
  •   The 7 MHz is fixed.
  •   Next is a slide switch that selects one of two 100 KHz band segments -- 7.000 to 7.099 or 7.100 to 7.199.
  •   Next are two pushbutton switches -- pushbuttons are located above and below the numbers.  These select the 10 KHz and 1 KHz -- pushing the button above the number decreases the frequency, the bottom button increases the frequency.
  •   The knob to the right of the pushbuttons is fine tuning and tunes between the 1 KHz points.

I purchased this kit from S&S Engineering in 1994 or '95. 

Here's a link to their website:  S&S Engineering

S&S Engineering ARK-20

I no longer have this rig -- sold it on eBay

• 20-meters, synthesized; tuned by the push-buttons on the upper right.
•  14.000 - 14.500 MHz
•  3-4 watts output
•  The kit had a built-in keyer option but this rig does not have the keyer
•  Very sensitive and selective receiver
•  Very good keying characteristics.
•  The pushbutton tuning is a bit cumbersome.  There are four pushbutton BCD switches.
  •   The 14 MHz is fixed.
  •   There are four digits, each with one button above and one button below the digit.  Pushing the button above the digit increases the frequency, the lower button decreases the frequency.
  •   Tuning step is 100 Hz.
  •   For example, if the digits read 1251, the, the frequency is 14.1251 MHz
  •     The RIT knob in the bottom right corner tunes the receiver between the 100 Hz points.

I purchased this kit from an individual on eHam classifieds in 2010. 

From time to time S&S Engineering rigs show up for sale on eBay or in the eHam.net website classified ads.  The ARK-4 and ARK-20 sell for $150 - $200 and the TAC-40 and TAC-80 sell for $175 and up, usually around $225.

Wilderness Radio SST

Here's a picture.

•  40-meters; varactor-tuned oscillator with two ranges
•  2 watts output
•  Built-in keyer with two small memories
•  Superhet receiver with crystal filter.
  •  While the receiver has a three-stage crystal filter, I have had occasional problems with strong signals being broad.
•  Very good keying characteristics.

Note the switch in the top center of the front panel -- this switch selects between two tuning ranges.  This rig covers from approx 7.033 MHz to 7.045 MHz.  The front panel switch switches between two varactors -- the value of these varactors establish the tuning range.  If you wanted to change the tuning range, you could swap out varactors.

The knob on the right tunes the rig; knob on the left is volume control; headphones plug into the jack to the right of the volume control.  I made a tuning chart that mounts on the top of the rig.  Look at the skirted knob on the right -- see the numbers on the skirt?  Those are reference numbers that can be used as a tuning guide.  For example, this is how my rig tunes:   

For example -- when the front panel switch is flipped to the right and the tuning knob is turned so the number 3 is up, the rig is tuned to approximately 7043.50 KHz.

Here's a link to the SST website:  Wilderness Radio SST

Now, I really don't want to say anything negative, but, I am not completely happy with this rig. 

First, the frequency coverage is not what I'd like.  Most QRP operation on 40 meters centers around 7030 and 7040 KHz.  My SST does not cover down to 7030. 

Second, the receiver is not as sensitive as I think it should be.  I can listen on the SST, then, switch the antenna to any of the other QRP rigs and hear many, many more stations.

These problems may be unique to my Wilderness Radio SST because I have read many very favorable reviews of the rig, but, mine does not seem to measure up.  Maybe I did not build it properly, maybe I got some parts that were out of spec.

The Rock-Mite 40

This rig is produced by Small Wonder Labs located in New Hampshire.  Dave Benson, K1SWL, operates SWL where he produces kits for various pieces of equipment.  Dave's equipment is miniature, high-quality, and well-designed.  One of his most popular items is the Rock-Mite Transceiver -- a tiny transmitter and receiver (transceiver).  The Rock-Mite puts out less than 1/2 of a watt -- about the power to light a flashlight bulb.  The RM operates on only two frequencies but comes in different models for different amateur bands; it transmits CW (Morse code) only.  The RM includes an electronic keyer.

Here's a link to Dave's website and a link to his Rock-Mite page.

I have built three Rock-Mite rigs. 

• Two are for the 40-meter amateur band (7.000 - 7.300 MHz).  One operates on 7030 KHz and the other is on 7040, plus or minus a bit. 
•  The third RockMite is for 20 meters (14.000 - 14.350 MHz); this one is on 14.030 MHz.
•  Dave produces Rock-Mites for the 80, 40, 20, and 30 meter bands.

These rigs are VERY small -- in fact, the rig was designed to fit in an Altoids box -- here are some photos of my Rock-Mite in an Altoids box.

On the left end of the box are, top to bottom:  Power input (requires 9-12 volts, DC); jack for the paddle that operates the keyer; and, jack for headphones.  On the right end of the box, top to bottom:  antenna connector; button switch that when pressed does several things -- changes frequency, switches between paddle or straight key, or, changes speed of the internal keyer.  The RockMite keyer chip does not have memory -- that is, you cannot load CW messages into the keyer as is common with electronic keyers.  There are a couple of places who sell replacements for the keyer chip that have message memories.

(Left) Rock-Mite with the lid not quite closed                          (Right) End view of the Rock-Mite

Because the Rock-Mite runs such a tiny amount of power, making contacts with it is a challenge because it's signal is usually so weak that it is swamped by higher-powered stations.  My experience varies -- sometimes I call and call and never get an answer and there have been times when I have called and was answered right away.  Still, operation with this low power takes a lot of patience.

Here are some Rock-Mite resources I have found helpful:

•   Join the Yahoo Rock-Mite Group.

•  The Rock-Mite Files -- somewhat dated but lots of good info.

•  How one person built his Rock-Mite.

•  Here's another Rock-Mite.

•  And another.

•  A very nice box in which to mount the Rock-Mite if you don't want to use an Altoids tin.

•  And here's a keyer paddle just the right size for the Rock-Mite -- built like a tank.  if you get this paddle, you should look at the base -- the paddle is fine without the base but the base makes it really stable.  Here's a photo of the miniature paddle mounted on the accessory weighted base:

Rockless QRP

The Rockless QRP rig is based on the very popular RockMite.  The RockMite rigs (RM; shown above) are crystal-controlled with a method of moving the crystal frequency up or down, giving you two frequencies from one crystal.  Still, it would be great to be able to cover a much wider frequency range.  That's what the Rockless does.  Bob Patzlaff designed a stable VFO (Variable Frequency Oscillator) that enables the rig to tune a portion of the 40-meter band.

While building the Rockless, you are given the choice of selecting the frequency range.  I set mine to cover 50 KHz of the band and adjusted the VFO to cover 7.005 to 7.055 MHZ.  By changing one resistor on the VFO, you can extend coverage to a full 100 KHZ of the band.  There's a trimmer capacitor on the VFO that is used to set the lower frequency, then, the upper frequency is set by the value of the selected resistor.  All this is explained in the QST article and in Bob's instructions (links below).

For details and photos, go to my Rockless QRP page, and, visit these links:

•  QST article:  http://www.arrl.org/files/qst-binaries/QS1109Patzlaff.pdf
•  Bob's website devoted to the Rockless QRP: http://www.rocklessqrp.com/index.html