The 500 watt amplifier under cover

This is the same amplifier that I posted here on 25th January, and used to such good effect during my radio contacts with the Balkans mentioned yesterday. It occurred to me that if I am going to use it frequently, perhaps even every day, over the next few weeks, then I had better carry out some maintenance on it.
So today I disconnected it, removed its covers, cleaned the airways and checked that all the mechanical connections were secure. These can work loose in time owing to thermal cycling, and several needed further tightening.
With the bottom cover temporarily removed there was a rare opportunity, not to be missed, to take a picture. Pictures of the equipment I build are actually very useful to refer to if I want to make any changes, and are not just for blogging purposes of course.
To give an idea of the amplifier's size, it measures 50cm x 25cm x 25cm ( w x d x h ). Regarding it's weight; suffice to say that it's almost too heavy for me to carry !

Circuits

This evening I have been transmitting on longwave, waiting for a contact partner, but none appeared, although I know that my signal was being received in Nuernberg, Germany, 745 kms away.
While waiting, I realised that until now I had never placed on my blog a circuit diagram for any of my construction projects; and yet there might be some visitors who would like to copy some of my designs.
Although the picture can be enlarged by clicking on it, whether I do this again still depends on the clarity.
Anyway, I try it at least once, with the circuit schematic of my GS31B 50MHz amplifier from 4 years ago. ( see also 25th January 2010 ).

My Russian toys

Though not dolls, there is nevertheless a progressive increase in size.
They are Russian made high power triode tubes, ( thermionic vacuum tubes, valves ), ideal for use in VHF/UHF transmitter power amplifiers, and significantly cheaper than western alternatives.
So, from L - R, the ones I have are type GI46B, GS31B and GS35B; in each case the suffix 'B' denotes tube variant suitable for forced air cooling, with or without the finned anode cooler. ( An 'A' here would mean water-cooled ).
The GS31B is a spare in case the one in my 50MHz amplifier, ( see post of 25th Jan, 7.23pm ), fails one day.
I am currently building an amplifier for 144MHz using the GS35B.
I haven't decided what to use the GI46B for yet. If I can obtain a second one, then making an amplifier for 432MHz using both tubes with their outputs combined would be an interesting construction project.

50MHz transmitter power amplifier

This home-made amplifier for 50MHz uses the Russian ex-military GS31B triode tube, producing about 500 watts output. It really is a fantastic performer. I remember some noteable reception reports of my signal, namely, "599+++ on my ground plane", "599+30dB" and "remarkable signal", from Belgium, England and Norway respectively !