February 2002
THE SQUELCH BURST a monthly publication of the STAMFORD
AMATEUR RADIO ASSOCIATION
President ..........Jim Murdock ............. N1NNG ........ 322-4707 Vice Pres ..........Andy Laska .............. KA1SLG ....... 531-9493 Secretary ......... Mike Cordelli ........... N1FOA ........ 838-3661 Treasurer ......... Dick Finn ................WA1VUU ....... 323-0982 Trustee ........... Spence Heath ............ W1BWK......... 322-7539 Editors ........... Marv Fleischman ......... N1AWJ ........ 438-7889 Mike Cordelli ........... N1FOA ........ 838-3661 Dick Finn ................WA1VUU ....... 323-0982 Y.O.J.B. Ed........ Marv Fleischman ......... N1AWJ ........ 438-7889 Circ/Pub. ......... Dick Finn ............... WA1VUU ....... 323-0982
Repeaters: W1EE/R........ 146.055 in; 146.655 out (PL. 1Z, 100Hz) W1EE/R.... 442.125 in; 447.125 out (PL. 2A, 114.8Hz)
Internet Home Page at http://www.qsl.net/w1ee/
Yearly membership $20.00 ($ 15.00 for retirees, senior members over 62, $10.00 for full time students, members under 16 years of age and members living over 100 miles from Stamford; $20.00 for family memberships.) This includes a copy of the club bulletin and a copy of the club roster.
Send your dues, membership applications, etc. to the club Treasurer, Dick Finn, WA1VUU, 27 Ivy St., Stamford CT 06902. Non-commercial ads are printed in the SQUELCH BURST on a no charge basis, club members only.
Send your ads for Ye Olde Jonque Boxxx and articles for the SQUELCH BURST to Marv Fleischman, N1AWJ, P.O. Box 113, Ridgefield, CT 06877-0113, or e-mail to Unless noted, meetings are held on the first Thursday of every month in the 4th floor cafeteria of the Stamford Government Center, Tresser and Washington B'lvds.,
Stamford, CT. Meetings start at 8:00 P.M. Free parking in
the Government Center garage with the entrance on Washington B'lvd. The Stamford
Amateur Radio Association is a tax exempt organization under section 501 (c) (3)
of the Internal Revenue code.
EMPIRE SLOW SPEED NET Join the Empire Slow Speed CW Net
every evening on 3590 KHz at 6PM local time. CW speed is between 6 and 8 wpm. A
great way to improve your CW proficiency and learn net operation. Joe, W1LUH is
one of the rotating Net Control stations.
MINUTES OF THE JANUARY MEETING Guests - None.
Introductions - Spence, W1BWK, Trustee, Mike, N1FOA -
Secretary, Dick, WA1VUU Treasurer, but unable to attend the meeting because of
an injury, Andy, KA1SLG- Vice President, and Jim, N1NNG President.
Squelch Burst - Mike N1FOA apologized for not getting the
last issue out in time with the holidays and the rest. Please check the Jonque
Boxxx to see if there is anything to clean out of it. Marv, N1AWJ is looking for
some ask Elmer Questions, and if you would like to write a story for the
publication please send it to Marv.
Public Service - No Report
Emergency - There is a drill coming up in the sprint (it is the same one that
was canceled in November), but we are not certain of the date.
RFI - No Report
Web Pages - There is now a message board on the site, and
the counter has indicated about 5,000 hits so far. Check it out, the address is
on page 2.
VE - Space is getting tight in Government Center on the
Saturday for the February exam, so the location will be moved up to the 6th
floor. there is a chance they will be closing the building down on weekends in
the future (which makes little since to me because it's obviously busy if we
can't get any space other then the EOC, they should shut it down one day during
the week when nobody is doing anything), so for the May session we may have to
consider another location. If anybody has any ideas please bring them to the
next meeting.
Old Business - Jeanine still has a Jacket, and if you
purchase it I will embroider it with your name and call sign for free.
Auto-patch - Andy, KA1SLG is working on getting the patch
removed from the machine and repaired so it's functioning good as new.
Elections - Because we were a few people short of quorum,
we have postponed the elections to the February meeting (shows what happens when
you hold a meeting during the championship game). Please make every effort to
attend the meeting on February 7th for the election of officers.
2002 HAS ARRIVED and IT'S TIME TO RENEW YOUR MEMBERSHIP IN SARA!
Note the revised dues schedule above and send your dues to
our Treasurer Dick Finn, WA1VUU, 27 Ivy Street, Stamford, CT 06902.
ASK ELMER
This Ask Elmer is a continuation of last months question.
In brief, the question was "How do you measure the value of a capacitor or
inductor" without elaborate test equipment. One of the early and powerful
methods of measuring electrical components was by ratio and comparison. The most
popular, and easiest methods of measurement is by using a circuit called a
"Bridge". You may have heard of Whetstone, Hay, Maxwell or other bridges in your
readings. They are some of the many bridge configurations which can be used to
measure the value of a component. The names, of course, are in honor of the
scientist who configured that particular type of bridge circuit (and
subsequently wrote about it in some scientific journal). Many of the more common
bridge configurations work on a very simple principal. There is an elegance in
simplicity. The principal is that there will be no current flow between points
at the same voltage in a circuit. Going back to Ohm's Law, there must be a
voltage difference to have a current flow. I am not considering a current
flowing through a piece of wire connecting two points in a circuit. For this
discussion, either end of the piece of wire is considered to be the same point.
The simplest bridge to consider is the Whetstone Bridge. It consists of 3 known
resistors and can measure a fourth unknown resistor. In its simplest form, the
top 2 resistors are of the same value, the third is a calibrated variable
resistor and the forth resistor is the unknown to be measured. The procedure is
quite simple. Adjust the calibrated variable resistor until there is no tone in
the headphones. Refer to the diagram.
At this point, the bridge is in balance, and the voltage drops across the top
two resistors are equal to each other. There is no voltage difference across the
headphones, so no sound is heard. The value of the unknown resistor is the same
as the value of the known variable resistor. As this bridge works on the
principal of being in balance when the voltages on the opposite arms are equal,
you can extend the range of measurement by using unequal values for the known
resistors. If we assign designations such as R1, R2, R3 and Rx (for the
unknown), The following relationship will allow you to find any value of Rx if
you know the other values:
Rx = ( R2 * R3 ) / R 1
The only requirement for the tone generator is that it be in the audio range (so
you can hear it) and its voltage be reasonable so that you don't get shocked or
over dissipate the components under test. You just as easily can substitute
capacitors or inductors for the arms of the bridge, and the relationship and
operation is the same. Going further, R1 and R3 can be resistors, and R2 can be
a capacitor or inductor. This bridge will measure the impedance of the unknown
inductor or capacitor. In this simple approach, only capacitors and inductors of
good quality can be accurately measured. For low quality reactive components,
you still use a bridge, but the arms of the bridge have more elements in them.
If R2 is changed to an inductor, you can measure an inductor or if a capacitor
is in place of R2 then you can measure a capacitor. If you know the impedance,
and the frequency of the audio generator, you can calculate the value of the
inductor or capacitor. In all cases, the bridge relies on your knowing the
values of 3 of the arms to find a fourth. One of the nice features of the bridge
method of measurement is that its accuracy is limited only by the accuracy of
its known elements. Under certain conditions (the equal arm condition), only the
value of the variable element need be known accurately, because if R1 and R2 are
identical in value, they can be of most any value and the bridge still works
accurately. Over the years there have been many papers and books written on the
design and use of the various bridge configurations. These days, for resistance
measurement, it is easier to use an ohmmeter than a bridge to measure resistors.
This is not the case when measuring inductors or capacitors. This completes my
discourse on measurement of inductors and capacitors. There are many other
methods of component measurement, which are well beyond the scope of this
article. 73, Elmer Send your questions to “ASK ELMER”, c/o Marv Fleischman,
N1AWJ, PO Box 113, Ridgefield, CT 06877-0113 or e-mail them to
LICENSE EXAMINATIONS
Amateur Radio License examinations will be held on Saturday, February 9 in the
6th Floor EOC Training room of the Stamford Government Center. The Government
Center is located on the corner of Tresser and Washington B'lvd's in Stamford.
Check-in time is 9:30 AM and the examinations start at 10 AM. Free parking is
available on the ground floor garage under the Government Center. Entrance to
the parking garage is on Washington B'lvd. Examinations for all classes of
license will be held. The fee for the examination session is $10, and we
appreciate a check made out to the ARRL/VEC. We do accept cash, but prefer a
check. New applicants bring with you 2 forms of ID, one being a photo ID
(drivers license., etc). Those planning to upgrade, bring a photo copy of your
current license, your original license and a photo ID. You should also bring any
CSCE's (Certificate of Successful Completion of Examinations) or other documents
needed for advanced element credit. If you are registered on the FCC CORES
database and have your FCC issued License number, this may be used in place of
your Social Security number on the NVEC605 form. NVEC605 forms will be available
at the test site. Use of non-programmable calculators is permitted during the
examination. For more information contact Marv Fleischman, N1AWJ. Contact
information is on Page 2 of the Squelch Burst.
CALL TO ALL VE's We need you at the next test session.
YE OLDE JONQUE BOXXX
ICOM IC-2AT 2m HT w/Charger, Batty., & SS-32MP micor-min.
CTCSS Encoder kit, VGC, $100; Simpson 260 VOM, VGC, $50. Call Geoff, N1CAT,
(203) 966-7444 evenings
HALLICRAFTER SX-28A RECEIVER, recapped, $275. Works good.
Call Joe, N1GWO, (203) 322-4061 Evenings
PARTS GALORE- Xerox 3000 Word Processor (antique)
w/transformer, p/s, etc., connection to Diablo printer. FOR FREE!!! Take it
away! Call Mike, KA1VWP, (203) 838-8089
AOR 1000 XLT, 1000 Channel HH Scanner, 5KHz to 1.3 GHz
continueous coverage. Exc. cond. $ 275. Call Rick, N1LYK, (203) 531-1756
YAESU FT-757 GXII, HF Rig, FP 757 HD Power Supply, FC 757
AT Tuner and MD 1B8 Desk Mike. Call George, N1HIX, (203) 357-1879
ICOM IC-25A 25W , 2M mobile Xcvr. w/PL, good for packet
$75 obo. ICOM IC-02AT with BP-5 and BC-30 charger, Exc. Cond. $120 obo. Mac
Laserwriter printer, best offer. Call Jeanine, KY1Q, (203) 324-6865
ICOM IC-02AT 2M HT w BP-3, BP-5 & BP-8 Batty Packs, BC30 Charger, Spkr-Mic, Manual, $125 obo.
FatMac Computer w/ 1Meg Ram, Free!!! FOR PARTS..Olevetti
Accounting Machine. FREE!!!!! Take it away!!! Call Marv, N1AWJ, (203) 438-7889
ROTOR w/CONTROL & CABLE, $50; Cushcraft 10-40M Vert. Ant., $15; Ringo Ranger 2M Antenna, $10;
Heathkit Station Monitor Mod. 614, $50. Machinist's Tools
for Sale, 2 South Bend 7.5 HP Go-Cart Engines. Lots of Tools, Hardware and Craft
supplies, etc. Call for Info. Call Irv, N1ATS, 348-3425
QST on CD ROM. 1989 to 1994 Unopened-$20 Call Dick, WA1VUU, (203) 323-0982
Send all your ad's for YE OLDE JONQUE BOXXX to Marv Fleischman, N1AWJ, PO Box 113, Ridgefield, CT 06877. E-mail to Ad's must be in by the meeting night of the month prior to the publication. (December meeting for January publication)