Hi Guys,
Since I have not asked permission from the authors, I have omitted their
last names and callsigns.
Ted K6HI
Kona, HI
<tleaf@hotmail.com>
>Subject: Fw: RF Burns
Dear Mike
>
> A very quick email while recovering from an incident in the shack
>earlier today -- a salutory lesson in shack safety and my first experience
>of RF burns.
>
> While following with extreme care the instructions in the ICOM 4KL
>amplifier manual for setting the ALC level , I stupidly overlooked the
>equally important instructions on RF safety for the new, replacement
>antenna tuner. I am currently using a long wire antenna which, of
>necessity, comes right into the shack and is connected to a ceramic lug at
>the rear of the tuner . With the 4KL amplifier set at full power, while
>leaning over the amplifier to adjust the ALC knob at the rear, I touched
>the ceramic lug connector with my foream. I'm sure that I felt no pain at
>the time; but a brief, loud hiss, together with the combined odours of
>singed hair and sizzling bacon made me jump back very quickly. My heart
>was really pounding and I thought that I must have sustained a powerful
>electric shock. In the event it was an RF burn. Something I have read
>about often but never experienced. The pain and discomfort throughout the
>day has been such that I will certainly never let vigilence slip like that
>again. I will certainly carry a scar to act as a salutory reminder
>because, although quite small, the RF burn has actually removed the tissue
>at the point of contact down to quite a depth.
>>While I nurse my forearm, have a good weekend.
>
> Norman
>
>
>Dear Norman -
>
>Thank you for the interesting and enjoyable e-mail. I'm very glad that
>you're recovering well from both of your recent adventures! It is a
>testimony to your strong consitution that the results were only scrapes,
>bruises, soreness and singed skin.
>Somehow I feel that the blame for your approach to RF and the like, rests
>with a few of us who unintentionally(?) infected you with our tendancies.
>Doubtless there was ample opportunity to have this happen early in the
>formative years of your ham career (during a visit to Atlanta, Ga and
>allowing several rebellious colonists-types in your home in 1992)!
>Therefore we share the blame and ought receive some of Mena's venom.
>To confess, I know first-hand that rf energy readilly arcs to points
>(fingers, elbows, nose, lips, hair, etc.) and burns down to the bone!
>As a 12 or 13 year old, not having the finances to own a wattmeter, I
>checked the tuning of my transmitter by drawing an arc from the plate cap
>of the final amplifier tube. The 6146 would produce about 60 watts out with
>B+ of 700 volts or so applied. A wooden pencil with number 2 lead worked
>nicely, provided the coating of paint was in tact, ones fingers were dry
>and the metal cap housing the eraser was not touched. The beautiful blue
>discharge of some inch and a half in length indicated maximum rf to the
>antenna and the best chance to QSO that VK or ZL.
>However, zzzzzzphtttpht on too many occasions signaled I was the
>uncooperative load. No ham activity followed for several days, as I nursed
>a charred and sore finger that would shed a section of tissue from the bone
>out.
>The blister on my left thumb remains unhealed from taking 850 volts to
>ground from the open hi-voltage cage in a Heathkit SB-102 Transceiver! The
>circuit was only an inch in length along the thumb, but the parasitic choke
>lead burned into the nail and flesh for almost that depth. At age 35 it
>seems that earlier lessons would have been learned?
>Perhaps, you and I have experienced our LAST close calls and the law of
>averages is now on our side??????
>>Mike
>
>
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