AUGUST - SEPTEMBER 1998
Back to building, I had a need come up recently which had me somewhat
puzzled. I have an rather old, slow laptop that works
just fine for APRS & packet & the battery went to the "great
beyond". Being a ham is sometimes synonymous with being
thrifty (cheap), I decided I would not pay the enormous price tag they
want for the factory battery. So, in it's place I thought, I
could use a considerable less expensive VCR-variety sealed lead/acid
battery instead. The rating was close enough - 12VDC
@ 2A, instead of the 2.6 the original pack provided when new.
After a little cabinet modification (no hammers or saws were used in
this process), I proceeded to attempt charging the battery
for the first time. The instructions on the battery's label said 'Do
not use or charge this battery in anything not so designed".
What do they know? It's just like a car battery, only smaller. So I
threw caution to the wind (unwisely) and proceeded. An
initial voltage measurment said it was around 4 volts, so after making
a battery clip out of a clothspin & aluminum foil (don't
ask ... cheep cheep cheep), I connected it to my ammeter and the car
battery charger, on the low 2 Amp setting. That should
be good, I thought. I read the ammeter - to my surprize, absolutly
no current was showing, perhaps a milliamp (.001A) tops.
That battery won't get charged that way! After double-checking my high-tech
clip & finding it actually worked, I left it to
charge for a few hours.
Nothing - Nada - Zip - Nul. Still no current and I had about 14-15V
output from the charger. I tried the higher settings - still
no current. Hey - what gives? Obviously, this battery is either bad
or the overload breaker they frequently put in battery packs
is open.
I took another voltage measurment and found it had raised to about 6
volts, but dropped off quickly when I removed the
charger. Must be doing some good, but ....
After thinking about this a bit, plus realizing how light the portable
tool battery chargers are, there must be something easier to
this. I tried connecting it to this type of charger - the flashing
light told me the battery was bad & shutoff. Well, that won't
work!
I'd have to build a current-regulated charger so I could control the
maximum current to the battery and just let the voltage go
where it may, which can be scary to watch during the charging cycle.
I knew I would need a diode to convert normal AC
house current to DC, then a large wattage resistor to drop the current.
I decided to use about 0.1A (100 mA) of charging
current so I wouldn't overheat the battery and cause it to either burst
or pop the internal overload.
Doing the math - if I have (roughly)120 VDC minus the 12 I want on the
battery, I have to drop 108 Volts across something
at 0.1 A. Using Ohm's law, 108 Volts divided by 0.1 Amps = 1080 Ohms.
A 1200 Ohm is easier to find and leans towards
caution. I still had to figure the wattage of this resistor needed
- as the Power law states, Volts times Current = Watts, so 108
Volts times 0.1 Amps = 10.8 Watts. If I had a 20W that would be good.
But I didn't. Thinking of alternate items I could use (another story),
I thought if I could use light bulbs, which I had, that might
drop the current enough to do what I needed. I started with a 60W bulb
(since they are rated at 125V, I used that in my
calculations instead) - Doing the Power law in reverse, 60W divided
by 125 Volts = .48 Amps. That's worst case, if the
battery was shorted, which it wasn't - far from it. If I watched the
temperature, it might be ok. (Later when I got courageous, I
tried 75's & 100's with predicatble results).
I wired the circuit up as the diagram shows, so I could monitor both
the voltage & current simultaneously, and kept my hand
nearby both the battery and the power switch to kill it in case it
got too hot. But it didn't.
What's really neat about this circuit, is that while the battery looks
open to the rest of the circuit, the voltage is like 60 volts or
so (seems kinda scary across a 12 volt battery), but with only a small
amount of current at this time, .03 A (30 mA), and all
was ok. The bulb was dark and the battery temperature was warm but
not hot, which is what I hoped would happen. As the
battery chemistry came to life, the current through the battery increased,
but also the charging voltage across the battery
dropped, getting closer to the desired rating. The current finally
got high enough to light the bulb and show me that I was
actually "charging" this critter. This works to your advantage, as
the resistance of the bulb increase when hot, thereby limiting
the current further.
Now that it's charged up, I have to find me some of those battery connectors
I've seen at the next hamfest so I can actually
install it & put it to good use! This circuit is just so easy &
inexpensive to do, plus "work's the brain" a bit with the math, it was
a really enjoyable experience.
Has anybody built one of those wind anemometer's yet?
73's de Chuck / N9RZV
Vice President: Rick Kempf, WD9HRU
Secretary/Treasurer: Norman Huber, N9ZKS
The CIRC is a not-for-profit ARRL special service club whose purpose
is to advance the service of Amateur Radio. Located
in Central Illinois, CIRC and its members welcome all to use the 146.94
repeater and to attend club meetings.
Norm Huber
19268 E. US Hwy 150
Bloomington, IL 61704-5855
Permission is granted to Amateur Radio-related organizations to reproduce
contents of Short CIRCuits provided full credit is
given.
Primary topic will be the conduct of directed nets, particularly for emergencies.
McLean County Disaster Drill
Saturday 26 September
Remember they are using the hams for communications.
SHOW WE CAN DO IT!
A discussion followed of the support for WACC and JOTA. A list of volunteers
was assembled for WACC. The discussion
of JOTA is still in preliminary form but so far we know the location
will be at The Howard Virgin Forest just east of LeRoy on
US150.
A discussion of a request for information from Corn Belt Electric on
the contract allowing us to have the antenna on their
tower. Floyd, W9EX, will put together a history of the agreement which
was made as a verbal agreement. This was a perfectly
normal occurrence at that time.
The meeting was then adjourned.
There then followed an excellent presentation on the home made anemometer by Patrick Stowell.
After that work commenced on the construction of the attenuators for our future fox hunting.
The turn out was great, the members stayed late, and I think it was one of the best meetings we have had in a long time.
Prepared by N9ZKS, Norm
The minutes as published in the SHORTcircuits were read. Eldon - KB9PZA
made a motion, which was seconded by Everett
- W9LMJ to accept and they were approved as read.
There was a discussion of Field-Day fun.
There was then a discussion of the article being published in the Bloomington-Normal Community News.
The second guest, Jerry Erb of the McLean County Wheelers gave a presentation
on this year's Wheeling Around Corn
Country (WACC). He thanked us and pointed out that Hams were the first
to report the accidents which required medical
attention last year. In fact one of the hams, Dr. Zehr AA9LC not only
reported the second injury but provided diagnosis, first
treatment and transportation for the injured individual. We were needed
and appreciated.
The only comment from riders concerned the fact that for the most part
we were so unobtrusive that they said they hadn't seen
us on the course. I believe this may be a reason to get a jacket and
wear it or display it proudly.
The praise of last year's participation was followed by an earnest plea
for our help this year. We are invited to help, attend the
all you can eat dinner at Eureka, and are promised commemorative T-shirts
or ball caps. Please sign up by getting your name
and any time period of the weekend you would prefer to your club officers
as soon as possible.
Earl - WB9UWA then discussed the active attenuators for fox hunting.
We have 8 people who have already said they wanted
one. Earl suggested ordering 10 sets of components to save on shipping
costs using club funds and recovering the money from
the individuals when the get their kits. A motion was made to that
effect by Earl - WB9UWA and seconded by Eldon -
KB9PZA. It was approved unanimously. We will acquire the parts and
have a attenuator building party at the August meeting.
Earl made a motion to adjourn, seconded by Eldon. It was approved unanimously
and the members spent some time enjoying
the camaraderie of the group.
Submitted by Norm Huber - N9ZKS
WHY RADIO AMATEURS ARE CALLED " HAMS " From Florida Skip Magazine -
1959Have you ever wondered why
radio amateurs are called "HAMS " ? Well,it goes like this:The word
" HAM " as applied to 1908 was the station CALL of
the first amateur wireless stations operated by some amateurs of the
Harvard Radio Club. They were ALBERT S. HYMAN,
BOB ALMY and POOGIE MURRAY. At first they called their station " HYMAN-ALMY-MURRAY
". Tapping out such a
long name in code soon became tiresome and called for a revision. They
changed it to " HY-AL-MU ", using the first two
letters of each of their names. Early in 1909 some confusion resulted
between signals from amateur wireless station "
HYALMU " and a Mexican ship named " HYALMO ". They then decided to
use only the first letter of each name and the
station CALL became " HAM ".
In the early pioneer days of unregulated radio amateur operators picked
their own frequency and call-letters.Then,as
now,some amateurs had better signals than commercial stations. The
resulting interference came to the attention of
congressional committees in Washington and Congress gave much time
to proposed legislation designed to critically limit
amateur radio activity. In 1911, ALBERT HYMAN chose the controversial
WIRELESS REGULATION BILL as the topic
for his Thesis at Harvard. His instructor insisted that a copy be sent
to Senator DAVID I. WALSH a member of one of the
committees hearing the BILL. The Senator was so impressed with the
Thesis that he asked HYMAN to appear before the
committee. ALBERT HYMAN took the stand and described how the little
station was built and almost cried when he told the
crowded committee room that if the BILL went through they would have
to close down the station because they could not
afford the license fees and all the other requirements which the BILL
imposed on amateur stations.
Congressional debate began on the WIRELESS REGULATION BILL and little
station " HAM " became the symbol for all
the little amateur stations in the country crying to be saved from
the menace and greed of the big commercial stations who
didn't want them around. The BILL finally got to the floor of Congress
and every speaker talked about the " ...poor little
station HAM ". That's how it all started. You will find the whole story
in the Congressional Record. Nation-wide publicity
associated station " HAM " with amateur radio operators.from that day
to this,and probably til the end of time in radio; An
amateur is a " HAM ".
Glen & Helen Mays N6JNS & KD6ZAF
Anyone who becomes aware of something of interest to the group is requested
to send me an email for forwarding. I have all
the email addresses which were entered on those applications I keep
annoying you all about in a folder and can forward mail
to all members with email with a couple of key strokes. Chuck and probably
many others who work and do not make the
coffee klatch are late to find out the news affecting the club members.
If there are any questions phone 309-263-8620 (day) or 309-925-3141 (evenings) My email is redavis@dpc.net
All Morton exams begin at noon on Saturdays at the Morton Public Library.
Oct 17
Dec 19
73 de Bob AA9MY
I am requesting that anyone who plans to sit for an exam pre-register
by calling or contacting myself or one of the other
examiners. They may call my home and leave a message 309-662-3910.
If I am not available and a message is left on the
answering machine, I will put them down as being registered and will
expect to see them on exam day. We just need to have
some idea on how many to expect. The examine's help with this will
will be greatly appreciated.
Walk-ins are ALWAYS welcome for Amateur exams.
Here is the schedule for the 1998 year.
September none
Sunday November 15th 1:30 p.m.
73's Ken NX9M
10/10 Breakfast
First Saturday of every month at 8 a.m. in the Steak and Shake at Vernon
Ave. and Veterans (Just south of College Hills
Mall).
Fourth Wednesdays of the month at 7:30 p.m. at the Red Cross building
in Bloomington (Just north of the airport).
Tuesday 7:00 P.M. 146.910 Tazwell County ESDA Net
Tuesday 9:00 P.M. 146.940 CIRC Open Net
Wednesday 9:00 P.M. 147.060 Open Net Has Newsline
Wednesday 9:00 P.M. 442.250 123.0 PL ARES Open Net
Wednesday Varies 147.100 Trader's Net follows ARES Net on 442.250
Thursday 9:00 P.M. 146.760 Open Net with Newsline
Thursday 9:00 P.M. 146.895 North central IL Traders Net
Friday 7:30 P.M. 147.345 Open Net with Traders Net
Sunday 8:30P.M 147.075 Open Net with Newsline
(Please help me correct this list. I know it's not up to date at this
time. Norm N9ZKS)