[Amps] Econco closing

[David Colburn]

Do you recall when the FAA, finally, went all solid state?

On 4/5/26 14:15, John Lyles wrote:
> Also, a slight detour from this tube talk:
>
> "FM broadcast  went  SS back in the mid 70's.     AM broadcast went SS in
> the late 70's.    The later broadcast PA's  that went SS,  there was and
> still is  NO market for used tube broadcast  PA's.   The tube Pa's went
> straight to the landfill ...... including tubes."
>
> Broadcast FM didn't really have reliable SS rigs until DMOS and later 
> LDMOS were available. In the 1970s the biggest bipolar junction 
> transistors for 100 MHz CW were about 150 watts/300 watts PP. NHK, the 
> Japanese broadcast company, used early Hitachi DMOS transistors in a 
> complete 10 kW FM rig, in a paper presented at a IEEE broadcast 
> symposium in Washington DC in 1980. I was there. This was what 
> kickstarted Harris, Broadcast Electronics, Continental, Larcan, R&S, 
> Seimens, and other manufacturers to adopt DMOS parts from Motorola at 
> the time, derivatives of the MRF150 and push pull MRF151G. Those 151G 
> are the closest thing to 6146, as they continue to be made in 
> quantities by several companies (for science and broadcast). But to 
> get beyond 600 watts (MRF154) it took LDMOS, again from Motorola, and 
> now they and Ampleon make 1.8 kW PP parts for class C. Burle 
> Industries in Lancaster, formerly the huge 1 million ft^2 RCA tube 
> factory, is still in business. They were bought by Photonis in France 
> years ago, and continue to build some tubes, for science and industry, 
> but very little broadcast market since they never penetrated the AM/FM 
> transmitter business like Eimac did in the 1980s. One of their very 
> special tubes is the Coaxitron, a wideband device with multiple tubes 
> cascaded inside one vacuum enclosure. These were in AWACs and some may 
> still be supplied in the foreign market, whereas the US planes are 
> likely SS now. Photonis supplies big tetrodes and triodes to 
> Brookhaven for linac RF amplifiers at 200 MHz.
>