[BC] How would you build it?

[Donald Chester]

> From: Rob Landry <011010001 at interpring.com>

> OK, here's a thought: if you had to custom-build an AM broadcast transmitter capable of, say, 1 KW, how would you do it?
>

Pair of 849s in link-coupled push-pull final, modulated by another pair of 849s in class B.

Pair of class-A 845s to drive the 849 modulators, transformer coupled of course, using UTC LS-48 driver transformer.

Drive the RF final with a pair of 211s or 203-As, drive those with a pair of 802s driven by type 59 crystal oscillator.

Use 1.4:1 total pri to sec turns ratio in modulation transformer, about 60 henries in mod reactor. Separate powers supplies or big resistor in series with mod reactor, so that there is about 20% more voltage on modulator than on final.

Balanced 2-wire OwL transmission line to ATU at base of tower.

BTW, you can still get new 833As, made in China (just like everything else). Reportedly, Chinese tube manufacturers have about made it through the learning curve and greatly improved QC; some of the Chinese tubes made now are said to be pretty good.

Don