[Elecraft] kpa100 and handkey

[Ron D'Eau Claire]

Egad! There isn't enough voltage or current to burn out a flashlight =
bulb
flowing through the key in a K2/100, much less heat up the key or burn =
you.=20

John, I suspect that you are getting RF on the key line. That can =
happened
if your antenna is presenting a high impedance at the rig and you don't =
have
a good RF ground on the rig. A "mains" ground is NOT an "RF" ground. You
might be showing a 1:1 SWR thanks to your ATU, but if the rig isn't =
grounded
it can cause a "burn". RF burns feel hot, and if you get a bad one it =
can
take a long time to heal and quit hurting. Even a tiny one that is a =
round
dot can be painful for hours or even days.=20

Just to give you an example how RF gets around, one time I was =
installing a
30 foot (10 meter) fiberglass self-supporting whip on a SeaLand =
container
ship in the Port of Oakland. We used one of the giant container cranes =
to
carry the whip from the dock to the ship. I was waiting at the mounting
point near the f'castle. The antenna had a brass flange on the bottom =
where
a number of holes that lined up with the base on the ship and it was =
secured
with a bunch of brass bolts. The Port Engineer was helping out by riding =
the
crane to guide the antenna as it settled on the flange on the ship. As =
the
gap closed to an inch or less, he shifted his hand to he could brace =
himself
against the flange on the ship. He yelped and jumped and I saw a blue =
flash
between the flanges. The antenna began to careen around on the line =
holding
it and I popped a bolt in before we lost the darn thing over the side. =
The
flange felt very hot to my hands as well.=20

After we were all done, the Port Engineer accused me of having power on =
the
antenna, but I showed him that everything was disconnected. His palm had =
an
ugly black burn across it that hurt like H.... well it hurt! I could see =
it
in his eyes. Then I saw the reason. Not 200 yards away next to the San
Francisco Bay Bridge was a commercial broadcast station pumping out
kilowatts of RF. That giant crane and floating mast were an excellent
"antenna" and the ship, sitting in salt water, was an excellent ground. =
That
was a flash of RF voltage I saw as the flanges mated, and it was RF that
burned the Port Engineer in the instant before they touched. Weeks later =
he
was still in a lot of pain with an ugly-looking burn.=20

Even a "ground" wire a few feet long can have enough inductance to make =
a
lousy RF ground. The "safest" RF ground is a 1/4 wave long wire =
terminated
right at your rig or ATU. Other things you can try if RF on the key is =
the
only issue is to wrap your key cord through one of the "RF Choke" cores =
sold
by Radio Shack and others to keep interference out of radios, TV, etc. =
That
should isolate the key from the rig, but it is still best to have the =
rig
itself at RF ground.=20

Of course you can always move your shack to a big steel ship sitting in =
salt
water (Ah... don't I wish????)=20

Ron AC7AC
K2 # 1289

-----Original Message-----
with a k2/100 at 100 watts output is it normal for the hand key to warm =
up
while transmitting??? ie if you hold down for bout 5 seconds is it =
supposed
to burn u? the swr is showing 1-3 power at 100 watts.  hand key is fed =
with
small guage phone cord wires. should these be a thicker gauge when using
high power?

john wt5y=20