at5

00readme

The Codar AT5 is a British 1960s 10W 160/80m AM/CW transmitter.
Information by courtesy of Dave Gordon-Smith, G3UUR.

Codar was a small British manufacturer which made a series of budget priced
short-wave receivers throughout the '60s and '70s. The AT5 was the only
transmitter they marketed, although they did develop a higher power transmitter
which was never sold.

The AT5 was extremely small, when compared to other transmitters of the era,
and really caught the imagination of British amateurs who enjoyed operating AM
on 160m.  It was very popular for mobile operation and Codar also marketed a
matching mobile receiver, the T28.  The AT5 uses 5 valves(tubes) and has plate
and screen modulation of a 6BW6 PA by a single-ended class A  6BW6. The
American 6CM6 is electrically the same as the 6BW6, but with a different pin-out.
The VFO and buffer are EF80 valves and these are equivalent to the 6BW7.  

Some Codar AT5 transmitters were exported to Canada, so American amateurs
may, on rare occasions, come across one of these transmitters.

The information on the AT5 consists of a Word document, giving modifications and
general details, and the Instruction Manual which is AT5P1 thru AT5P5, AT5SCH
and AT5PS.  Page 1 (AT5P1) gives details of the operation and frequency coverage
of the AT5.  Page 2 describes the operation and details of the power supply.
Page 3 (AT5P3) is Installation and Tuning.  Page 4 (AT5P4) gives general operating
notes and typical voltage readings. Page 5 (AT5P5) shows the rear apron connections
of the AT5 and 250/S power supply. AT5SCH and AT5PS give the circuits of the
transmitter and power supply, respectively. 

Note from K4XL:  The manual has been converted to DjVu format.  The mods page has been converted to html so that it can be opened with a web browser.