Posts Tagged ‘cw transmitters’

SPECIAL DEAL ON 6V6 MC 80 M PASTIME PROJECTS TRANSMITTER KIT

August 9, 2016

Today we are offering a special on our pastime projects 6V6 MC 80 Kit. This kit includes a wound and tested
Output plug in coil tested on 80 meters in our shop. In addition, we will include a new 3.5795 crystal element assembled in a FT-243 or similar style vintage type crystal holder. These are assembled and tested here, both
on a communications monitor and in a completed 6V6MC 80 Kit. These crystals are performing well for us in the
lab here at Pastime Projects, especially using our QRP mode power supply at 200 volts. The crystals have been
tested at 350 VDC with good results, but we are not ready to warranty the crystals at this time. For a limited
time we will also offer free shipping within the US. Delivery may run a little longer depending on demand,
but we are starting to build stock in advance of orders. 73 best wishes Glenn Brown for http://www.pastimeprojects.com and pastimeprojects(at)yahoo(dot)com.

Pastime Projects Aluminum Chassis 6V6 6L6 CW Transmitter Kit Now Shipping

April 25, 2015

APRIL 24, 2015   The new aluminum chassis transmitter kit manufactured by Pastime Projects (www.pastimeprojects.com) is now shipping. This kit features a pre-punched aluminum chassis, a 15 page manual, tube sockets, variable capacitor, key jack, SO 239 chassis mount antenna connector, expanded metal bottom cover, chokes, capacitors, resistors, power and hookup wires, coil form with instructions, new tested 6V6/6L6 vacuum tube, power wire cable sleeving,  and hardware. The design is based on handbook designs of the 1960’s and allows band changing with coils and crystals. It has been tested on 160 and 80 meters and suitable coils will be released in the near future.

The 6V6 MC Model kit can be purchased from www.pastimeprojects.com.  See the web page for further details.

Pastime Projects 6V6 Transmitter Kit Features

April 1, 2015

The new 6V6 MC Transmitter being introduced by Pastime Projects is a single tube CW (code) transmitter for use in the HF Amateur Radio Bands. The initial offering will be for 40 Meter Band operation. It is a vacuum tube kit which the buyer assembles. A complete manual is provided for those with technical ability and experience to assemble and operate. The design is based on circuits commonly used in the 1960 era of amateur radio. Some features of this project are described on the home page of the Pastime Projects Home Page found at http://www.pastimeprojects.com.

If you are interested in purchasing one of these kit when they are released, you can get on the first come, first served list by contacting pastimeprojects(at)yahoo(dot)com.  73 Glenn for Pastime Projects

More on 6V6 and 6L6 Vacuum Tubes in Transmitters

January 26, 2015

We previously discussed how vacuum tubes are used differently in code (CW) circuits than in audio circuits. In simple code circuits, such as the Pastime Projects “Remember When” reproduction “breadboard” transmitter kit, or the new 6V6 MC  kit, the tube can be thought of as a switching amplifier/oscillator. The tube is biased and set so that it either operates at optimum capability or it is silent (off). On or off.  It’s that simple.

In a crystal controlled oscillator circuit, there are many other factors.  We quickly learn that crystals vary in activity, current carrying capabilities, stability, temperature drift and other factors.  In putting the cw tube type transmitter on the air, we are concerned in transmitter the best stable and chirp free signal we can.  The best signal may not occur at the peak output point, and it is important to sacrifice a bit of output for best signal.  Maximum power out with best possible signal quality is our goal.

While it may not be so obvious today, the “RST” code (Readability-Strength-tone) was derived to grade a signal on its quality at a distance station. The “T” portion of this report dealt with tone.  While this is not a consideration much today, back in the days of crystal control, especially in the novice days after World War Two, the tone gave us a good idea of how bad (or good) our surplus crystals were working in our homebrew transmitters.

We have been testing each of our tubes in a transmitter circuit before stocking for our kits. The 6L6 tubes are a heavier duty tube than the 6V6 tubes. We have found either work very well in our transmitters, with the 6L6 giving a little more output than the 6V6 with the same power voltages.  (The current draw is a little heavier with the 6L6, but our power supply can handle the difference with ease.)

Please consider our 6V6/6L6 tubes next time you are in the market.  Of course, one will be included in your new Pastime Projects 6V6 type transmitter kit.

We have a few new “Coke-bottle” style 6L6 tubes (which are no longer available) left in stock. They are great performers and they add to the vintage look of our “Remember When”  6V6 Slat Board transmitters.  Contact us for more information.

http://www.pastimeprojects.com or  pastimeprojects (at)yahoo(dot)com.   73  Glenn W8JZI

“LookMa” 12K5 Oscillator kit gets Review from CQ Magazine

April 8, 2014

Pastime Project’s little 12K5 “transmitter” kit was originally written up in May 2006
CQ Magazine. Seven years later Rich Moseson, W2VU, Editor of CQ Magazine, writes of
his experiences with the Kit described in the original article.
It is highly recommended reading. You can learn more at http://www.cq-amateur-radio.com
We still sell the little kit on our web page. It can be useful as a code practice oscillator
by listening to the output in a nearby receiver. Great fun constructing and following
the do-it-yourself instruction manual. Please read Rich’s article. Visit http://bit.ly/1lI0hlp
Might want to send
along your subscription to CQ magazine at the same time!
Live outside US Postal Service? Contact us for quote.
73 Glenn NN8G for Pastime Projects…

Prototype Pastime Projects Metal Chassis 6V6/6L6 transmitter on sale.

June 30, 2013

Assembled and Tested!

Assembled and Tested!


The new Pastime Projects 6V6 transmitter kit has been built and tested as a prototype. The difference between the prototype and the production models is the chassis. The metal chassis on the prototypes was machined by hand. The production chassis are cut in a high pressure water jet precision tooling machine. The prototypes were assembled and tested here and look and work great! Allow us a little time to get these out the door to you. There was a total of
7 or 8, and when they ship we will start packing the production kits with parts, manuals, and instruction manuals. This design is based on conventional handbook
designs of the late 1950’s and 1960’s. Operating on 40 meters. 3 to 10 watts of cw output into 50 ohms..
COME AND GET’EM Glenn for Pastime Projects
http://www.pastimeprojects.com

Use of light bulb dummy loads in Vintage Amateur Radios

May 29, 2013

We recently reworked a Johnson Viking Adventurer CW transmitter and an EICO 723 transmitter, both manufactured in the 1960’s. They can be seen at http://www.pastimeprojects.com on the Special Sales page.
A common failure of these transmitters was the power transformers.
They can overheat from current draw in excess of specified limits. This is often caused by not tuning the transmitter quickly or by mistuning and operating out of resonance.
Back in the 1950 and 1960’s we often used an incandescent light bulb for a load. It was cheap, and the resistance was close to 50 ohms or so required for the output of the transmitter. Tube type transmitters are a lot more forgiving from misstuning than solid state types. Never use a light bulb for a dummy load on your new
solid state rig! Choose a light bulb that has a wattage higher than the expected output of your transmitter. Watching the light bulb as you quickly tune to resonance will get you properly tuned without
too much time passing. Brightness is an indicator of power out. After tuning make sure you are not exceeding the recommended current draw. If you are, decrease the antenna coupling until you
are lower than maximum recommended power. Remember the old transmitter were rated in power input, now output. Output will always be lower. Input is plate current times plate voltage. This discussion is very simplified. Stay away from high voltage and high r.f wires. It’s hoped that it will help you see how to tune your boatanchor radio. Look for more detail in our newsletters and we may put out a video on disc or YouTube.
Questions are always welcome. Glenn for Pastime Projects.
pastimeprojects(at)yahoo(dot)com..