Free Near-Field Analysis Software

[Jerry Fray]

JimW9WU at aol.com wrote:
> 
> In a message dated 96-08-09 18:15:09 EDT, Brian, K6STI wrote::
> 
> <<
>  As a result of the recent FCC ruling that mandates RF-exposure limits for
>  amateur stations beginning January 1, 1997, I'm making available at no cost
>  a special version of AO Antenna Optimizer software that calculates electric
>  and magnetic near fields.  NF.EXE requires a 386 or better, math
>  coprocessor, VGA, and DOS 3.0 or later.
> 
>  You can download the 245K NF.ZIP file from ftp://n6nd.nosc.mil.  You may
>  copy this free software for others as long as no charge is involved and the
>  software is used for amateur purposes only.
>   >>
> 
> Brian is to be congratulated for taking the time to help us all.
> Unfortunately, I'm
> unable to access the ftp://n6nd.nosc.mil site to download the software. I
> have
> visions of the Navy's west coast underwater submarine detection system being
> ground to a halt because of the demand for this software.  Visions of YI/EP
> subs sneeking up on California aren't pleasant!!
> 
> 73, Jim W9WU  (ARRL Volunteer Counsel--and I'm keeping track of all those
> defaming us attorney's for when you need our help to keep it up.)

Jim -
	Don't feel left out in the cold on this one. I tried several times and
can't even access the FTP site direct from the WWW page they have! 
Maybe someone can post this gem on a site we can access?!?!?!?!

-73-
Jerry KB9NMU

>From vr2bg at asiaonline.net (VS6BrettGraham)  Sun Aug 11 05:13:56 1996
From: vr2bg at asiaonline.net (VS6BrettGraham) (VS6BrettGraham)
Date: Sun, 11 Aug 1996 12:13:56 +0800
Subject: RF Exposure limits
Message-ID: <199608110413.MAA15460 at asiaonline.net>

Books, clothes, wine, bread & cut flowers are fine by me - except for the
wine maybe, but only because I had too much last night.  It'll be fine
again later today, I hope.  But back to the point, these are all visible,
tangible objects that you could avoid if you had a problem with them.  The
various substances, pollutants & the like we subject ourselves to are not,
RF included.
 
Limits were inevitable - unfortunately, everybody is not responsible &
prudent.  Hopefully, we'll learn in time that the typical amateur station
is down in the noise compared to other sources.  In the meantime, if the
limits really can accomodate the majority of us, good.  If the rule turns
out to be a tool for the neighbor from hell, then it better be fixed - but
remember this is a fault in the implementation, not the limits themselves.
 
I hope we'll have another VS6-W6 opening on 6m next cycle & that I'll be
here for it.  That Q was the first of 19 of some of the best Qs I've had in
my life.  Thanks for being there - wish these kinda openings would happen
during the June VHF contest or VHF WPX! Instead, all we get is sync buzz &
the odd JA, like right now...
 
Radio sure is cool, isn't it?
 
73, VS6BrettGraham vr2bg at harts.org.hk

>From kj5yf at wt.net (Larry Johnson)  Sun Aug 11 13:27:12 1996
From: kj5yf at wt.net (Larry Johnson) (Larry Johnson)
Date: Sun, 11 Aug 1996 05:27:12 -0700
Subject: Don't take anything for granted...
Message-ID: <BMSMTP8397619350kj5yf at pop3.wt.net>

While this isn't applicable per se to contesting, it is very applicable to ham
radio. My apologies to Trey if this is inappropriate for the reflector but if
nothing else, perhaps this will serve just to remind all of us once again of
those words to live by...never take anything for granted...particularly when it
comes to electricity. Now that my hands have quit shaking enough so that I can
send CW and type this note...

The other night, I cut the A/C back a bit via the thermostat as it was getting
a bit too cool. After several hours, I noticed the A/C was on but that it was
starting to get warm in the house. I went outside to check the
condenser/compressor, and sure enough, it had not kicked back in. Standing on
my deck, I can reach the breaker box w/ no problems, and the A/C is about 10
feet away. I didn't bother to walk around the deck to the unit as I could
see/hear it from the deck...and it's a good thing I didn't. I flipped the 55
amp breakers several times to see if they had tripped, and they hadn't. Went
back in, turned everything off, waited a few minutes, and repeated the whole
thing. Again, no luck and the breakers weren't tripped. So, shut the whole
thing off at the thermostat and went to bed. The next day, when the A/C guy
came out, he started checking, flipped the breakers, same thing. After more
looking, he said no power to the unit. Now it gets interesting...

He started tugging at the breaker, wiggling it, etc. Then he pulled out his
screwdriver and started to take the cover panel off. At that point, I stopped
him and said, if you're going to do that, we're cutting the main power and told
him to wait. I came inside, shutdown my computer, and got my VOM. I went back
out, flipped the main power off, and then I took off the cover panel and pulled
out the VOM to check to make sure there was no power to the bus bars. He asked
why I was doing that and I simply said "I don't like it when my chest buckles".
He made some comment about not being a problem with switches and breakers.
Anyway, we started looking at the breaker and attempted to pull it off. It
wouldn't budge. We finally had to remove the two breakers below it, and then
use a screwdriver from below to leverage the A/C breaker off. During this
process, the plastic on the breaker was crumbling, including the breaker switch
which I thought was odd. As soon as we got it off, I saw what had happened. The
breaker had burned up...there were holes in the top, and it had arc-welded
itself to the bus bar. And the bus bar, which is about 1/8 inch thick angle
steel had a V about 1/2 inch wide and deep cut into it from the arc'ing. It
looked like someone took a torch and just cut a v-notch out of it. 

By now, I was trying to decide whether or not I should have heart failure
having realized how close to being fried I had been simply by flipping the
breakers on and off...giving how burned and brittle the breaker was...not to
mention how close I had been to having a serious fire on the side of my wooden
house. It's not clear to me the A/C guy realized how close to disaster either
of us had been.

He then took my VOM, put one probe on the power terminal, and another on the
side of the compressor. Dead short. I looked at him and said "We have a big
problem...a short between the hot lead and the whole A/C unit and the circuit
breaker didn't trip. Why?" So then we started looking...and what we found made
me almost throw up. Whoever put the A/C in before I bought the house 15 years
ago ran two hot leads off the 55 amp breaker to the unit and NEVER grounded it.
There was no ground back to the breaker box. The only ground it could have had
would have been through the wires to the thermostat (if there's a ground in
there) and via the copper tubing back to the evaporator coil and the rest of
the unit in the attic.

And it gets worst...the A/C guy goes to his truck and comes back with a piece
of 14 gauge 3-wire romex. When I asked him what that was for, he said we could
just pull out the two wires (#6) that were in the conduit and replace them with
this because it had a ground. It was all I could do to civilly inform him that
we would not put #14 wire on that circuit (all the time thinking this guy's
been sniffing too much freon). I told him I would take care of the
electrical...and did...got a replacement breaker and ran a #6 ground while he
replaced the unit.

Think about that the next time you flip a circuit breaker off.  
 
 

* Larry Johnson
* KJ5YF @ WT.NET
* Houston, Texas   U.S.A.