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Sunday, April 18, 2010

QRP CW? Kit Building? Homebrew?

There is no greater feeling of accomplishment than to build your own rig, and then use it to make a QSO using low power plus your mode is CW! Now that’s a real high. Unfortunately for one reason or another we never get around to doing it. Now all our excuses can be tossed out the window. With the help of each other we can reach our personal goals that involve kits, CW, and homebrew.

How?

Let’s talk about QRP CW first. If you have a radio you can always turn down the power to 5 watts or less. That’s QRP. Next, as part of our group one or more other persons of like interests will set up a schedule with you so you can sharpen your skills and become more comfortable. Maybe you are better using paddles rather than a straight key. This would be a good time to dust off that old straight key and go at it. We could even have our own cw net!

Now for kits. I propose using Ramsey kits. They are QRP CW, easy to assemble, and low priced. You can work at your own pace, work with a partner, or collectively with the group. Test equipment will be made available for those not having any. We can begin from initial setup of parts, how to solder, on to the building of the kit. Lot’s of choices and all are yours.

Homebrew anyone? This is the art of building your rig from scratch. It’s for the more advanced but we have those who can advise us of the pros and cons of what we are trying to accomplish.

OK, so who is ready to really be a Ham? Let me know and we’ll get together at your convenience and make it happen.

Gary KS4JI

CHOOSING A KIT TO BUILD

There are many to choose from and each has its’ own benefits or negative aspects. What is good for one of us may not be for another. Having said this I thought it might help to present a few different products for us to consider. By no means are we limited to this selection.

The first rig is actually in two parts and is made by Ramsey Electronics. These kits are complete, with everything you need, and also simple. I really like the simple part don’t you?



Here we see the QRP receiver.

Now for the particulars:
Sensitivity of approximately one microvolt rivals the big rigs!
Covers 500 KHz of selected band
Receives CW, SSB and AM
Plenty of audio output, drives any speaker or phones
These little rigs are burning up the airwaves as young and old alike are rediscovering the fun in building their own equipment! Our detailed, step-by-step instruction manuals make building an enjoyable and rewarding experience. You're guided carefully to the completion of a unit that not only works, but will provide hours of operating pleasure. These trusty and proven Ramsey all mode mini rigs are routinely used worldwide by hams of all ages. You'll find you don't need high power - K71RK worked and QSL'd all states, plus global DX QSOs from Argentina to the former USSR-with only 2 mW! You don't need hundreds of watts, thousands of dollars or massive equipment, you'll find it's more fun with less! These little receivers are based upon the hot Signetics NE-602 that we read about almost every month in all of the ham magazines and handbooks. The receivers are true superheterodyne direct conversion - a simple design that does not require the use of fancy IFs, RF filters, or exotic mixers, in short, the ideal design for easy hobby building. Only recently have high performance ICs become available that enable such circuitry to be constructed. Beginners can easily build these receivers. And, experienced amateurs and QRP enthusiasts can use them as a reliable, economical, basic foundation for modifications. Our single PC board has plenty of room for lots of modifications and hook-ups, tinker to your hearts content. Suggestions and technical info are included in every receiver manual. Isn't this what ham radio is all about? Operates on 9 V battery (not included). Included case measures 5"w x 5 1/4"d x 1 1/2"h.

If this is your choice then I recommend that you do the receiver first and then move on to the transmitter. Nothing wrong with listening to QSO’s while building your transmitter is there?


The transmitter particulars:
Work the World...On a Watt!!!

4 Transistor circuit, oscillator, RF amp chain, and clean keying stage
RF output approx 1 Watt (.75W for QRP-20)
Pi-network output for good matching and harmonic suppression
Provision for two internal crystals, front panel switching
VCXO tuning, frequency can be tuned approx 7KHz around xtal freq.
These nifty little CW transmitters are practical and economical take-along rigs for trips, camping, teaching or just amazing yourself with just what a watt will do! With exceptional manual of over 20 pages, the detailed step-by-step instructions guide you to a perfectly operating finished transmitter. The rigs use a standard crystal that is connected into a VCXO circuit - which means that you can tune around the crystal's frequency by up to 20 KHz - thus giving you stable crystal control while still being able to tune around! A front panel switch lets you choose between two crystals, we include one, you can add another of your choice. A built-in T-R switch allows break-in operation. Of course, these transmitters interface perfectly with our QRP Mini-rig receivers and our CMOS CW keyer! And for the real ham, there's plenty of room inside the included case for your own circuit modifications and experiments, these little rigs are often the heart of many QRP operator's stations. Modify "till-the-cows-come-home," or just use 'em as they are - these little rigs pack a lot of performance into an economical package. Runs on 12 VDC at 200 mA.

Rig #2 for your consideration is the Rock-Mite.

The 'Rock-Mite '
A simple CW transceiver (Sorry no picture)

The Rock-Mite is a crystal-controlled direct-conversion transceiver available for 80M, 40M, 30M or 20M. It features an on-board 8-pin PIC microcontroller which controls a T-R offset on key-down. A brief tap of a pushbutton control switch reverses the offset to yield a second operating frequency. Pushing and holding on the pushbutton activates the speed adjustment routine for the built-in Iambic keyer. If you'd rather use an external keyer or straight key, there's a 'drop-through' mode which allows use of an external keying source.

Note that the Rock-Mite uses two crystals. The first is used in the local oscillator for transmitter and receiver. The second is used as a receiver front-end filter. This crystal significantly reduces the SWBC energy present at the receiver mixer; as a result, unwanted SWBC reception is dramatically reduced.

The Rock-mite uses one surface-mount part with fairly large spacing. There are no toroids to wind, so assembly should be a snap! The Rock-Mite uses subminiature epoxy-encapsulated RF chokes instead of toroids.

SPECIFICATIONS:

- Double-sided PCB 2.0" x 2.5", plated-thru-holes, solder masked & silkscreened for easy assembly

- 0.5W power output at 12V supply.
- Supply voltage range 8-15V

AVAILABLE FREQUENCIES:

3560 kHz
3579 kHz
7015 kHz
7030 kHz (QRP calling frequency)
7040 kHz
7122 kHz
10106 kHz
14060 kHz

-automatic T/R offset, reversible
-Built-in Iambic keyer, 5-40 WPM
-Built in sidetone, 700 Hz
- Includes assembly instructions and operating tips

There is no picture available at this time but you can get further information and a visual on the internet. There are numerous upgrades available. The kit does not include a case or connectors/knobs. Base price is $29 but with what I consider necessary items the total price would be around $60. To see a picture and more details go to the Small Wonder Labs website.

Rig #3 for your consideration: The Pixie II



Pixie Ham CW Amateur radio transceiver kit. The Pixie is a small CW (less than 2 inches square) QRP transceiver. Operates on one of several different bands (10 to 160 meters). Runs all day on a 9 volt battery, so this is a great transceiver for camping, hiking and backpacking. Has ample volume for standard "walkman" headphones. Can be constructed in one evening with a soldering iron and simple tools. Has easy to follow instructions. Includes all components, except for connectors and case. To operate on 80 meters, a 3.58 MHz colorburst crystal is included! A fun rig to build and operate! Includes an 80 meter crystal! $29.95

Accessories for your Pixie II Ham Radio Kit:
3.58 MHz crystal for the Pixie II ($6.00, Shipping Included)
7.040 MHz crystal for the Pixie II ($15.00, Shipping Included)
10.106 MHz crystal for the Pixie II ($13.00, Shipping Included)
14.060 MHz crystal for the Pixie II ($13.00, Shipping Included)
21.060 MHz crystal for the Pixie II ($13.00, Shipping Included)

NEW! 40 Meter (7 MHz) VFO kit for your pixie (and other rigs). This easy-to-assemble kit will allow you to be un-rockbound on the 40 Meter band. Tunes the popular CW segment of the band. Easily installs in an Altoid(tm) tin. $49.95 (Shipping Included in the US)

Connector kit (for power, antenna, key) for the Pixie II. Includes small coax and LED as a bonus. ($13.95, Shipping Included)

Buy an antenna kit for the Pixie II or other transmitter up to 100 watts. ($65.00, Shipping Included)

Good lightweight headphones for Pixie II and other gear. $15.00

Buy a 12 VDC (120 VAC input) power supply for the Pixie II ($35.00, Shipping Included)

Buy a morse code key for the Pixie II ($29.95, Shipping Included)

Buy a morse keyer kit for the Pixie II. Iambic CW morse code keyer kit with Memory - Selectable A or B iambic operation - 10 to 40 Words-Per-Minute speeds, Dot/Dash memory Paddle or straight key input - Selectable autospace on straight key - Positive or negative keying...MORE! ($39.95, Shipping Included)

Buy a metal enclosure for your Pixie II kit. ($12.00, Shipping Included)

In reality the Pixie II is very inexpensive until you start purchasing the accessories! When you are done you may find that you could have bought something with more whistle’s and bell’s at a lower cost. What originally started as simple can easily get out of hand if you are not careful.

Rig # 4 last but not least:

The TenTec 1300 series…..


RF Output: 3 watts, no external adjustment.

T/R Switching: solid state, full break-in.

CW Offset and sidetone: Adjustable 400-1000 Hz sidetone automatically tracks offset frequency. Sinewave sidetone has internal adjustment.

Frequency Coverage: VFO tuning of any 50 kHz segment of CW sub-band. Tuning range is selected during winding of one toroid in the VFO circuit.

Frequency Control: Varactor tuned oscillator with potentiometer control. Temperature compensated LC components stabilize VFO.

Power requirement: 12-14 Vdc, 35 mA receive (no signal present), 80 mA receive (S-9 signal), 800 mA on transmit.

Antenna: 50 ohm unbalanced, SO-239 connector.

Construction: Black texture painted clamshell type steel top and bottom. Aluminum chassis, sub-panel and heatsink. One 3.5" x 5" double-sided circuit board.

Board mounted-components: 216 including 4 IC's, 19 transistors, 13 diodes.

Front panel controls: main tuning, RIT, volume, power on-off toggle switch.

Connectors: front panel 1/4" stero phone jack; rear panel SO-239 for antenna, 3 RCA-style phono jacks for key, dc input, accessory dc output.

RIT: +/- 1.5 kHz.

Dimensions: HWD 2.75" x 6" x 6". Weight 2.25 lbs./1.02 kg.

This obviously is a totally complete and self contained unit. Over the years it has proven itself to be reliable and efficient. Cost is $119

Well, that’s about it. As I said before there are many other units out there. If you have any questions don’t hesitate to contact me and I will share with you what I know.

My email address is: KS4JI@yahoo.com

Oh, by the way. I’m hoping everyone will get a rig that operates on 40 meters. The reason is that we will be able to participate in our own net weekly. Also, it will give you the opportunity to make contacts both nearby and DX, plus it is open to all amateur classes.