[Lowfer] Lowfer TAG

[John Andrews]

JD,

Wow. Must have been painful. At least painful is better than fatal! RF 
burns take forever to heal, though. My worst one was while reading base 
currents one night. In the dim light I reached for the knife switch that 
shorted the thermocouple meter. There was a black wasp on the black 
handle, and he got me good. I jerked my hand, and hit the switch blade 
with the same finger.

We had an RCA 5D as the full-power auxiliary when I started at my call's 
namesake station. One 892R modulated by two 891R's. RCA's first 
air-cooled 5 KW, if I remember correctly. The 5 kW section was installed 
in 1939, and the exciter and a not-needed 1 kW amp/mod were installed in 
1934. Low speed blowers, and quite quiet. "Loud" was defined as what 
happened when it tripped an overload.

Among the many fond memories of that rig are some nightmares I have had 
over the years, when I dreamed of waking up INSIDE the cage and 
realizing the rig was on the air. Never ended well, but at least the 
dreams were short.

Neat stuff.

John, W1TAG

On 6/4/2024 2:11 PM, J D wrote:
> Well, JA, a pair of 892R tubes should certainly produce reception 
> reports ...if the loop antenna could handle the current long enough to 
> complete a transmission, anyway.  I have both very fond memories of our 
> 892R-equipped Westinghouse 10 kW backup transmitter at KOAM in the late 
> Sixties and early Seventies, and the occasional night terror.
> 
> Fond memories for its visual beauty, quietness (blowers were in the 
> basement) and reliability (as few mercury vapor rectifiers as absolutely 
> necessary; all medium DC voltages were from those new-fangled copper 
> oxide solid state rectifiers), that made it such a joy to do the 
> required weekly auxiliary transmitter test.
> 
> Terror, because of discovering an undocumented and not properly 
> interlocked modification in the RF amplifier cabinet one fateful day in 
> 1971. While dusting he components with a soft cloth and admiring the 
> tubes, with all grounding sticks in place, I was distracted by a sudden 
> flash of yellow light and the smell of something unpleasant burning. It 
> turned out to be me.
> 
> The tip of my right middle finger was puffed up like a kernel of 
> popcorn, and I no longer had about a third of my fingernail! It turns 
> out that during installation of the new RCA rig during the preceding 
> decade, someone took a shortcut when running the new RF feed to the 
> changeover contactor, such that several inches of heavy copper wire 
> carrying 100% amplitude modulated 10 kW RF on 860 kHz was exposed inside 
> the cabinet, unmarked, and with no barrier or shield to prevent 
> accidental contact.
> 
> With prompt care and close observation for some weeks after, all turned 
> out well. Even the fingerprint returned to normal in a few months. But I 
> guarantee, a very intense eidetic memory of those tubes at that exact 
> moment is etched in my head.
> 
> JD
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