Finally operational!
1941 HB Taylor PP T-40 transmitter
 


The way it was
front

After a couple of technical errors, the first QSO's were made 14 August, 2000.

A new incarnation is done, and working

A new cabinet has led to a new power supply design. This is around a Thordarson CHT plate transformer, matching swinging choke and fixed choke. 1250 VDC is the B+ with this capable of up to 650 mA!


1940 Push Pull Taylor T-40 Rig
Version II


A Thordarson speech amplifier using a pair of 2A3's in PP drive the Taylor TZ-40's via a 20A14 multi-match driver transformer from Antique Electronic Supply. With B+ at 1000 VDC, 220 mA of Class C plate current  about 175 watts output are delivered from the pair of Taylor T-40's. Modulator current
idles at 45 mA and swings up to 200 mA easily. Current experiment is to run up the B+ to 1250 vdc for both the class C and B decks. This will require -4.5 volts bias for the mod Thanks to Tom, NE8O for the QSO and FB signal report on 3880 khz.

The RF deck after restoration


Rear view of the RF deck. 6L6, 807 driver, Taylor T-40's
on left. A pair of VR 150's were added for screen regulation.


The 6L6 was replaced with a 6V6 oscillator; a B&W MEL was installed  as a OSC coil; 6V6 B+ is 300 VDC regulated; 500 VDC B+ to the 807 plate, 300 VDC regulated to it's screen and -45 VDC bias. The finals receive 1000 to 1250 VDC B+ and operate at -80 VDC bias.

The modulator (below) is my design, built to match the RF deck. A pair of Taylor TZ-40's are used as modulators with a Stancor A-3829 modulation transformer. The speech amp is a Thordarson unit with a pair of 2A3's in PP.

The "new" power supply
 

My thanks to Roger Place for the iron!
 

Rear View of the 1940 rig,
Version II


t40op


For a history of the rig and one of the original articles from
RADIO magazine, go to the next page !
Special thanks to: N8ECR, W9GT, N8JRJ, KI8BQ, WC9M, & W2ZM who all
contributed to the restoration project! This is what ham radio is about!
73 Steve,
W8TOW