In article ,
Chuck Harris wrote:
Scott Dorsey wrote:
C. J. Clegg wrote:
I need something that can be used on certain military HF networks outside
the amateur bands. I have been told that (for some goofball reason) I'm
not allowed to say exactly which networks, but it isn't anything that
would be particularly hard to guess if anyone cared to give it a few
minutes of thought. :-)

Skip the receiver and get a KWM-2. Receive performance is not as good
as the R-390, but it will work fine out of band (they used to be the standard
State Department issue rigs at foreign embassies) and they are a lot easier
to work on. Also, it's a lot more convenient to use.

Yes, it is, but it has a point contact diode balanced modulator/demodulator.
EMP would kill one in a heartbeat.

Any reason why a 1N4007 wouldn't be happy in there?
--scott

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

Let me enter the fray just once more. Although I did not fall off the
onion wagon recently and have been at all this for a while now, it was
not until contemporary times that I came to really appreciate the
R-390A. Yes, I knew they were tough birds, well designed, and had
worked on them from time to time but I did not realize their full
potential until I got on the air with the components of a GRC-26D. On 75
and 40 meters, and at all times of day and night and in conditions of
severe QRM and N, my R-390A's have provided nothing short of outstanding
service. I cannot say that of many of the others I own.... One simply
will not lose money nor be dissatisfied by investing in a good one!

Scott Dorsey wrote:
In article ,
Chuck Harris wrote:
Scott Dorsey wrote:
C. J. Clegg wrote:
I need something that can be used on certain military HF networks outside
the amateur bands. I have been told that (for some goofball reason) I'm
not allowed to say exactly which networks, but it isn't anything that
would be particularly hard to guess if anyone cared to give it a few
minutes of thought. :-)
Skip the receiver and get a KWM-2. Receive performance is not as good
as the R-390, but it will work fine out of band (they used to be the standard
State Department issue rigs at foreign embassies) and they are a lot easier
to work on. Also, it's a lot more convenient to use.
Yes, it is, but it has a point contact diode balanced modulator/demodulator.
EMP would kill one in a heartbeat.

Any reason why a 1N4007 wouldn't be happy in there?

Well, yes. When functioning as a demodulator, the diodes take the
IF frequency (455KHz), and the BFO frequency (453.65/456.35KHz), and
make audio. When functioning as a modulator, the diodes take the
audio, and the BFO frequency, and make modulated IF.

A 1N4007 cannot switch at even audio rates, let alone at 455KHz.

-Chuck

Chuck Harris wrote:

Well, yes. When functioning as a demodulator, the diodes take the
IF frequency (455KHz), and the BFO frequency (453.65/456.35KHz), and
make audio. When functioning as a modulator, the diodes take the
audio, and the BFO frequency, and make modulated IF.

A 1N4007 cannot switch at even audio rates, let alone at 455KHz.

Okay, so we need a fast Schottky diode, with outrageously high breakdown
voltage. Something like that has to be out there, right?
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Scott Dorsey wrote:
Chuck Harris wrote:
Well, yes. When functioning as a demodulator, the diodes take the
IF frequency (455KHz), and the BFO frequency (453.65/456.35KHz), and
make audio. When functioning as a modulator, the diodes take the
audio, and the BFO frequency, and make modulated IF.

A 1N4007 cannot switch at even audio rates, let alone at 455KHz.

Okay, so we need a fast Schottky diode, with outrageously high breakdown
voltage. Something like that has to be out there, right?
--scott

Shottky, and outrageously high breakdown voltage don't go together.

What you think of as a normal diode is a slab of P, and a slab of N
semiconductor bonded together to form a junction. A shottky diode
is a slab of N semiconductor fused to a piece of metal. 100V is a
really high voltage for a shottky diode.

What you could do, is put some of your favorite diodes in a metal can,
and install them after your radio has died from EMP. Something which
will never happen anyway.

-Chuck

On 1/8/07 3:29 AM, in article ,
"Dale" wrote:

On Mon, 08 Jan 2007 00:12:51 -0500, "C. J. Clegg" wrote:

On Sun, 07 Jan 2007 08:49:06 -0500, K3HVG wrote:

What's not been said is what you really want
to do with the gear. Is it simple short-wave listening or serious
collecting?

Technically, it's neither, but it's more the former than the latter.

snip

reasonable EMP distance of a few large cities, I would like to have set up
at least a basic communications capability that has a chance of surviving
that. A really good receiver is a first step that, as you all have noted,
shouldn't cost too much.

This is disappointing. I was expecting you to say something like that
you prefer radios that glow in the dark. But you're preparing for a
future in which everything glows in the dark for a while.

OK, you've got your tube rigs, and found a way to power them (maybe
a steam-powered generator fueled by the corpses?). Who do you plan to
listen / talk to, and why? Are they making preparations as well?

73's, but geez...

Dale
KJ7SL


On the Beach. Good book and movie.

On Mon, 08 Jan 2007 04:58:58 -0800, Dale wrote:

Sorry about the snotty remark re the corpses. I hope you found that
objectionable, despite your lack of comment

I did ... but saw nothing to be gained by commenting. :-)

Are you a ham? Given your interest in radio
communications- if you aren't, I'd encourage you to become one.

I have an interest in doing that but it's only really limited. I'll
probably do it sometime this year. I do a lot of listening, but the fact
of the matter is I don't like to talk much. And I really think the modern
ham licenses have been dumbed down (no, I REALLY don't want to start
another thread on that topic, though). Whenever I have any doubts about
that, I go listen on 3910 for a while. :-(

I have received the "now that there's no code requirement anymore..."
speech but the fact is I could have passed the old Extra code test (20
WPM) in my sleep, back in the day. Nowadays I'm only comfortable around
15 or so.

Don Bowey wrote:

On the Beach. Good book and movie.

Yes. I especially liked the part where the mysterious CW operator turned out to
be a window shade...

"C. J. Clegg" wrote:
And I really think the modern
ham licenses have been dumbed down...
Whenever I have any doubts about
that, I go listen on 3910 for a while. :-(

the fact is I could have passed the old Extra code test (20
WPM) in my sleep, back in the day. Nowadays I'm only comfortable around
15 or so.

So get a ticket and work CW. There's not any 3910 stuff there...

"C. J. Clegg" wrote:

So get a ticket and work CW. There's not any 3910 stuff there...

Or AM.

AM attracts a different breed of operator. You'll find them to be (for
the most part) gentleman who appreciate a real conversation.

With the new voice allocations, AM activity will increase.

Terry
W8EJO