Ed wrote:

I am recently retired, and am about to have some extra time on my
hands for some construction projects. With the re-surfacing of an old
news item about terrorists or certain nations who may attempt to launch a
nuclear EMP strike on this country, I was thinking about an old project I
had once wished to start many years ago; That is an EMP proof ham rig
for 75/40 .... probably CW only, for simplicity sake.

So I'm thinking of building a fairly simple tube rig, preferably
superhet Rx, with tubes that will run totally on a 12V supply. Assuming
that we never have such a terrible thing happen to us, a rig like this
would still be fun to use. Following the building of a Rx, I'll probably
build a simple one tube TX to match.

The QST Mobile Manual has a great project transceiver. The transmitter
is rockbound and based on a 1J6G tube, but it really gets out well. The
receiver I never built, but it didn't look like a bad design.

This thing WILL require a substantial B+... I think it needs a 67.V
battery. But you can put a few 9V radio batteries in series if you
really want.

Or you can build a vibrator supply. I think the Mobile Manual has an
article on vibrator designs as well.

The space-charge tubes are lousy... they worked well enough for cheap
car radios, but they never worked all that well. You can do a lot better
with a conventional tube design.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."