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
>
>
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