Bare-Essentials Transmitter
| See also: Home Intro Page 1 Page 2 Page 3 Site Map |
On The Air
[An image of the original text for this part of the article is not available at this time. The schematic diagram is repeated on this page for easy reference when reading the text.]
After mounting a coil mount and connecting its four leads, then check your work once more. If you're going to work 40, plug a 40 meter crystal into its pin connectors. Plug in the tube, connect an antenna (using 50-ohm coax) to the antenna nails and a key to the key nails. Be sure that you have a water-pipe ground connected to NL1.
Now plug in the transmitter. If NL1 glows, reverse the AC plug. Wait about 30 seconds for V1's filament to reach operating temperature and press the key. Quickly adjust C4 until oscillation starts. Oscillation can be determined by listening to a receiver tuned to the crystal frequency. Or hold a neon lamp against the plate transformer. If the transmitter is working the lamp will glow. Adjust C4. When the lamp glows at maximum brilliance, tuning is correct.
In loading the transmitter into an antenna some adjustment of T1's secondary may be necessary. Closer coupling can be achieved by moving the coil higher up over the primary winding. An input of about 50ma at about 350V (17.5 watts) is about right. Do not operate the transmitter without an antenna because this may cause C4 to break down if the key is held down for an extended period of time.
Design ©2002-2011, InfoWeb.net Content ©1971-2011 WA2IAC