300 KW tube audio amplifire-modulator

[davorin]

Hi! Here is some photos from 300KW audio-modulation PP-AB1 tube output from AM broadcasting transmitter ZadarSV1200. (2x600KW VF ClassD tube transmitters, plus 2x300KW audio-modulation tube outputs with 2 modulation transformers)

 

[Bas Horneman]

Wow..that is big...have you got any more pictures?

 

[davorin]

Yes, but I don't know how attachment more than one picture!

 

[davorin]

Here is more!

 

[davorin]

C1 and C2 from HV-PS (CLC filter) have 6x24microF/25kV parallel each.

 

[davorin]

HV rect. unit with 12 block (12 thyristor each bloch) for 12kV/120A.

 

[davorin]

L from CLC filter of HV-PS (8,6H/120A)

 

[davorin]

Main HV transformer 1,6MW(Prim.:3x20kV/Sec.:3x10,6kV)

 

[davorin]

Left output tube.

 

[davorin]

Filament transformer (Sec.:8,6V/860A) for left output tube and socket with parts of grid and screen socket connection.

 

[GordonW]

Man, that even puts the mighty WLW 500KW transmitter into a different scale!

In the pic of the filament transformer... are those vacuum capacitors on the top electrodes?

There was a show on PBS (American public TV) which did a short segment on radio transmissions, and the possibility of them reaching outer space and being received by other sentient beings... the consensus was that most radio transmissions were too weak to get out of the solar system. However, I would think that these type "big iron" transmitters MIGHT have a chance of getting into deep space... I bet that if beings from other planets do actually pick up something from us, it'll probably be those old WLW transmissions from the 500KW days of the 1930s, first...

Regards,
Gordon.

 

[davorin]

This transmitter was build 1983. as 1,2MW AM-broadcasting (manufactured by "RIZ"-"Radio Industria Zagreb") station with 4stacked 1/2lambda verticals (4x138m) with 7,2dB gain, and transmitting today program "Voice of Croatia". Transmitter have 2 separate blocks of 600kW with 2 anode-amplitude separate modulation 300kW amplifier.

 

[davorin]

No, this capacitors are "Silver Mica" type. Vacuum capacitors from VF output are much, much bigger!
...
Vertical angle of this stacked verticals system are very low (~12 degrees), but maybe something go out from Solar system?

 

[bigwill]

Finally something to power modern inefficient speakers!

 

[davorin]

Yes, but output (modulation) transformer is about 10,6 tons and 3,2m high...

 

[mod_evil]

Dear,

What wonderful capacitors are that! This is amazing!

Best Regards,
Felipe

 

[bays_9a5tt]

What a sight, thanks for sharing..
Don't want to hijack your thread, here is pic of first Radio Zagreb transmitter from 1926, with a pair of Telefunken RS15G tubes. Not impressive as your, though.
http://www.flickr.com/photos/nixiehr/1287498180

 

[Geek]

Finally something to power modern inefficient speakers!

Still can't push the subwoofers to full Xmax

 

[davorin]

Output impedance of modulation transformer (300kW amplifier) is ~150 ohms, so we can connect in serial/parallel combination 500-600 woofers to run! (EV-2226 or similar!).

 

[GordonW]

Output impedance of modulation transformer (300kW amplifier) is ~150 ohms, so we can connect in serial/parallel combination 500-600 woofers to run! (EV-2226 or similar!).

Heh. Take 1000 JBL 2226Js... wire them first as series banks of 10 (160 ohms), then parallel 10 banks per section (16 ohms), then series the resultant 10 sections (back to 160 ohms). That'd be about 300 watts per woofer... about perfect for long-life.

Now, what to do for high frequencies? Modulated Tesla coil? We could use the RF amp to drive that, maybe?

Regards,
Gordon.