[Amps] Memorial Day weekend amplifier fun/work

[Steve Thompson]

It was a public holiday here too. At the other end of the 
technology spectrum, I did a bit of fiddling with coax 
transformers and got a BLF578 transistor running cw (continuous 
wave, not Morse code) at 2W in 1000W out at 144MHz. No, that's not 
a typing error. It will glow white like a 4-1000, but only for a 
ms or so.

Steve

> After a week of troubles with the plate water flow interlock, we changed 
> technologies, and got no more trips. I started a long term heat run Saturday 
> morning, for the TH628 VHF power amplifier that I have reported about recently. 
> Now at 56 hours continuous, key down, planning to shut down this week. So far 
> nothing in the cavity amplifier or driver has faulted. The 9 3/16 inch 
> transmission line to the water load is
> running between 140-150 deg F on the surface, and load temperature is 139 deg 
> F, with water cooling and a large fan added. Coincidentally, we've had a 
> mini-heat wave this weekend, so the building is about 84 F inside. 
> Peak power is still 2 MW, but the average power to the load is 240 kW. 
> Efficiency is 68%, gain 15.3 dB in grounded grid. Still, I cannot get the plate 
> to glow like a 4-1000 would. 
> 73
> John
> K5PRO
> 
>