Earlier 1929 shack page
|This station is currently finished.
The station consists of a breadboarded TPTG
transmitter, using a #245 tube. The TPTG can be used as either a
standalone transmitter or as an exciter for another #245 amplifier
stage turning the transmitter into a MOPA. The MOPA is quite
stable and is free of stability problems caused by outside influences,
such as antenna movement caused by high winds and the like. The
MOPA can also be grid modulated with a single #227 tube.
This station was built not just to operate the contests, but can be used as a day-to-day operation. The chirp is negligable and the note appears to be quite clean.
You may notice in the photos the 2 inch ground strap that runs down the wall and across the back of the operating desk. This is due to power line noise which is bad in my house. The ground strap actually connects to a ground rod just outside the shack, and the cold water pipe ground is also connected to it. By strapping all of the house grounds together, I was able to virtually eliminate all of the power line static which I had.
A 300V power supply, using a #280 rectifier powers the transmitter.
11/24/03 Station is complete. Here is the complete view.
See links at the bottom of this page for equipment descriptions.
With the addition of a new desk as the operating position, the shack has changed again. The desk will hold the receivers. The transmitters will remain on the old table, separated by the desk. This will allow for more stable operation. Most likely, the receiver desk will contain only the 2-tube receiver along with the audio amplifier & horn. This desk will provide a convenient operating position. Before this acquisition, the transmitters were on the same table as the receivers, and the key had to be removed to a makeshift operating position that was not at all convenient. The transmitter desk is located to the right side of the operator, within easy reach. The transmitter desk is currently being reworked, the TR switch was moved, and an additional shelf was added yesterday. The bottom, tabletop will contain the TPTG & Amplifier. The next shelf will contain various accessories, unknown at this time, the top will hold the AK20& speaker and the TX power supply. The TX supply will be visible because it uses a globe 80 tube and looks quite authentic. The audio amp supply uses a 6X4 rectifier and contains many more modern parts, and will remain hidden under the desk.
As of 27 October, I got the transmitter back on the air. The note appears exceptionally clean and stable. I worked one station that evening, but sigs were rather weak. I cheated and used a Hallicrafters Sky Buddy as the receiver.
October 29, I began a small 2-tube audio amplifier using a pair of #227 tubes. I built this amplifier so that I can try various detector circuits. This is how many early hams built receivers- with a separate speaker amp. I plan on using the horn speaker shown below with this amp. The wiring of the amp is done, but I need to build up a kind of "universal power supply" to power all of the misc. gadgets in the shack. This will contain a 2.5A filament supply, and a plate supply with taps at 22V, 45V, 67V and 90V. Suppose I'll use some kinda tapped bleeder resistor to get the various voltages. The amp should also allow me to hook up my monitor so that it will drive a speaker. Its not easy to wear 2 pair of headphones at the same time. Possibly switch audio inputs with the antenna changeover switch?
The picture below shows a 3 tube receiver, which was replaced with my old standby receiver which performs better than the one below. The 3 tuber consists of a #222 untuned RF stage followed by a 201 detector followed by another 201 audio amp. The current station receiver is shown in the photo above.
The current receiver consists of a 2 tube regenerative. The tube lineup is as follows:
#201A regenerative detector
#201A audio amplifier.
This receiver pictured above will not quite drive a speaker very well, especially on weaker signals. This is the reason for the new, above mentioned audio amp.
1929 shack as of 10/25/03
Top shelf left to right: Atwater Kent 20c with model E speaker, TX power supply, RCA Horn, 1V1 receiver
Bottom: TX PA, TPTG, 3 tube audio amp, under construction, misc projects.
Current views of the station:
Audio amp. Uses a pair of 227 tubes. Power supply will be placed under the transmitter table.
The 20c will remain a part of the 1929 station, as it provides a relaxing break from the day-to-day DX'ing. The radio works quite well. The speaker was restored, the driver is original, the cone was made from some black posterboard. The speaker plays and sounds quite good.