Posts Tagged ‘crystal control’

Pastime Projects rights to copy

July 10, 2018

The Pastime Projects (www.pastimeprojects.com) web site contains warnings about copyright
terms and conditions. This may frighten away those experimenters who are inspired by the
vintage makeup of our kits. That is the last thing we want to do! Please email us at
pastimeprojects(at)yahoo(dot)com for permission to copy or request copies of our materials.
We are “Makers” “do it yourselfers” handy men, or what ever you call yourself!
Let us hear from you! How can we help you?

Advertisements

What is next at Pastime Projects?

July 5, 2015

Got an email from one of our customers wondering why we didn’t make the output on our 6V6/6L6
transmitter kit a pi-network instead of link output. Very good question! Probably one factor
in our decision was the cost of the change. Variable capacitors are expensive. The chassis size
would probably have to be larger also. But, these are not big issues. He is probably right; we
should revisit the pi-output design.
Some of the projects underway now include:
1. Regenerative receiver with tube(s) and toroid coils – Short Wave design with capability
to tune ham radio cw, am, and ssb in a rudimentary fashion. Status at this time is a prototype
6 – 10 MHz model that is very promising. Needs to be simplified for easy duplication as a kit.
Current model runs on 12 volts dc. No project completion date set.
2. Our low pass filter design converted to PCB configuration. We have the tools but not
the talent or time to complete this task. Interested in volunteering your expertise in this
very basic board design?
3. Vacuum Tube T-R switch based on vintage Handbook designs for handling our transmitter/
receiver interconnection automatically transferring from transmit to receive mode. Well underway
with this project.
4. Simple receiver design, probably solid state, to allow reception of cw along with our
transmitters..

Any ideas or suggestions? Let me know. Glenn W8JZI(at)ARRL(dot)NET or go to contact us
page of http://www.pastimeprojects.com7.28.09 prod

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