1,25kW tube amplifier/modulator

[davorin]

Here is some photos of 1,25kW tube audio amplifier/modulator (2,5kW AM-broadcast transmitter with same tubes) in class B1.
First photo shaw audio output pear of tubes.

 

[davorin]

Audio and HF output tubes.

 

[davorin]

Driver unit.

 

[Boris_The_Blade]

Neat! What are the driver tubes?

 

[nhuwar]

What are those 4-400a's They look like it.
And t hey were used in tons of transmitters.


Nick

 

[davorin]

Audio output/modulation transformer.

 

[davorin]

HV power suply.

 

[nhuwar]

What's with the Jacob's ladders in there. Never seen that before usually have sphere's there for overload gaps.



Nick

 

[davorin]

Spark-gap on audio transformer.

 

[davorin]

Complete 2,5kW AM-broadcast medium vave transmitter (about 2 meter high).

 

[davorin]

Output tubes are QB5/1750 (2 in HF, and 2 in AF), and driver tubes are PE1/100 (1 in HF and 2 in AF).
Photo shaw side look.

 

[davorin]

Audio output tubes, closer.

 

[davorin]

Antenna coupler.

 

[davorin]

Sorry, forgot attachment!

 

[davorin]

Plate tuning.

 

[LineArrayNut]

+1 for propaganda!
I was able to tour a VOA transmitter back in the day, not quite as big as this one, though...

 

[radiostar]

Nice monster! Still works?

I used QB5/1750 linear amplifier on MW 10 years ago for few QSOs ...

 

[davorin]

Nice monster! Still works?

I used QB5/1750 linear amplifier on MW 10 years ago for few QSOs ...

No, MW-transmitter-2,5kW is only for shawing in the hall of hause with big transmitters (MW-AM-600kW and MW-DRM-50kW).

 

[artosalo]

....I used QB5/1750 linear amplifier on MW 10 years ago for few QSOs ...

3,2 kW output but only single phase 230 VAC power supply.
This means clearly over 4 kVA input power.
How is this possible ?

 

[hpeter]

Audio and HF output tubes.

QB5/1750 ?
nataudio uses it in se monoblock