Admirable AVO

[telectrix]

The two Voyager craft use valves for the transmitters (X-band TWTs) and they are both still working after 43 years of continuous use under "interesting" conditions!

so you watched Star Trek The Movie as well?

 

[DPG]

Believe it or not, even into the 2000s many of the police radio transmitter sites were still using an RF transmitter with a valve as the final amplifier. Didn't look very 'valvey' though as it was sleeved with a metal heatsink. Can't remember the type.

This was prior to the Airwave digital system being installed.

 

[Lucien Nunes]

Nothing wrong with valves, still a popular technology; you've got one in your kitchen.

I have a couple of big'uns that you might have had some use out of without knowing it. Prior to the digital switchover in 2012, if you watched BBC1 on analogue in London / South East the signal was coming from a pair of 40kW Harris Sigma transmitters. It was the control unit for those that we saw Mark Thompson switch off ceremonially to mark the end of 75 years of analogue TV in London.

You might be able to guess where one of the transmitters ended up. They didn't let me take the mast, apparently that's still in use.

London analogue TV signal switched off

Analogue television is switched off in London, 75 years after it was first invented.

www.bbc.co.uk

 

[Zerax]

We're not married, but in any case this pic is an old one, taken before we met.

Managed to find a pic of the same dining room shortly after they met...

 

[telectrix]

Managed to find a pic of the same dining room shortly after they met...

that's nothing. my missus insists on placing a vase of flowers or some other tat directly in front of the TV's remote sensor, so you need to be a contortionist with the hand unit. then says it's my fault she can't switch from Emmeroids to Eastidiots, to Constipation Street.

 

[Lister1987]

no bloody chance. he'd have us pickled in brine and put on display in his museum.

Surely your brain already pickled Tel?

 

[telectrix]

Surely your brain already pickled Tel?

brain was pickled in 1975 ( i got wedded to the Poison Dwarf). OK now she's long since gone. brain back to normal state of useless.

 

[Lister1987]

brain was pickled in 1975 ( i got wedded to the Poison Dwarf). OK now she's long since gone. brain back to normal state of useless.

I wouldn't say that Tel, "I'm not completely useless, I serve as a shining beacon in how NOT to do things"
?

 

[Mike Johnson]

We're not married, but in any case this pic is an old one, taken before we met.

I don't think any self respecting woman would have put those curtain up. ?

 

[telectrix]

maybe it was a condition of sale thea the buyer took them off of the vendor's hands.

 

[marconi]

I’d like to move this thread away from the world of Laurence Llewelyn Bowen by asking who do we think the apprentices telectrix and pete999 employed in the 1930s might be now in the EF and why?

 

[pc1966]

Believe it or not, even into the 2000s many of the police radio transmitter sites were still using an RF transmitter with a valve as the final amplifier. Didn't look very 'valvey' though as it was sleeved with a metal heatsink. Can't remember the type.

It is still very much the case that for very high RF power levels, and/or very high frequencies (in the 10s of GHz and above, not "VHF") that valves are still the best choice in many cases.

Of course when ever you ask for the "best" choice it is very dependent on the criteria you are using for it, and the trade-off changes as technology advances, but they still have a very special place in some areas.

 

[littlespark]

I once worked at Leuchars when it was an RAF base. Doing some not very interesting mundane work in their communications centre.
3ft thick bomb proof concrete walls.

A lot of their equipment still used valves as it wasn’t able to be hacked as well as modern digital electronics could