February 2003
THE SQUELCH BURST
a monthly publication of the
STAMFORD AMATEUR RADIO ASSOCIATION
President .......… Andy Laska .............. KA1SLG ........ 531-9493
Vice Pres .……..Fred Cunningham...... K1FC …......... 322-8274
Secretary .....…. Mike Cordelli .....…... N1FOA .…..... 838-3661
Treasurer ...…... Dick Finn .…..............WA1VUU ..... 323-0982
Trustee .......…... Jim Markus ... ........... N1ZFS .......... 316-8585
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 www.qsl.net/w1ee/ctsara.htm
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 n1awj@ att.net.
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
February 2003 NJ “Islander” Pad Cutter While browsing the Internet, I came across a tool that seemed interesting and possibly valuable to those doing their own construction projects. It is called a NJ Islander Pad Cutter. It is a diamond coated tool that cuts a 5mm pad in PC board for construction of surface mounted large ( as compared to usual ‘surface mounted’ )components. The pads are located so as to mount the necessary parts and connect them directly or by leads to the various pads. It was developed by a QRP enthusiast but could be used for any small construction project. Besides proper layout, a drill press of some kind is required since there is no center pin for location and the unit will “walk” if no press is used. A Dremel tool is ideal for such use. Also, care must be taken that the cutter does not penetrate the board. A depth of 1/32 or 1/64 is adequate and can be set on the drill press. DO NOT attempt to hold the board and drill freehand– if the drill binds the board will rotate! All kinds of possibilities come to mind– such as using an inexpensive hot glue gun to fasten dip components to the board before drilling and soldering. I am not a salesman for this unit but it seemed worthwhile to share with others who may not have heard of it. The cost is $9.00 and it can be ordered from: George Heron, N2APB 2419 Feather Mae Court Forest Hills, MD 21050 (no credit cards– make check payable to George Heron, N2APB or pay electronically thru PayPal at [email protected]) (Dick,WA1VUU)
February 2003 ASK ELMER
Dear Elmer. All of the radios I have use a Phase Locked Loop Frequency Synthesizer for tuning. I can easily understand a crystal oscillator controlled radio, but how can a single quartz crystal produce all of the discrete frequencies needed to tune my radio? Signed Puzzled Dear Puzzled,
This month we will continue with the developing saga of the Phase Locked Frequency Synthesizer started in the December issue of the Squelch Burst. For reference purposes I will redraw the diagram of the PLL Frequency Synthesizer.
The frequency of the Quartz Crystal reference Oscillator is chosen based on the synthesizer's output frequency steps, so as to minimize the frequency divider's fractional division ratios as well as the range, response time and capabilities of the Phase Comparator and Voltage Controlled Oscillator. There are several other equally important considerations which we will not discuss at this time. When the Synthesizer is first turned on, the Reference Oscillator comes to its precise frequency (for our example this will be 10 KHz), but the Voltage Controlled Oscillator (VCO) can be anywhere within its operating frequency range. In our example anywhere between 21 MHz and 21.45 MHz. A sample of the VCO's output frequency is sent through the Frequency Divider, which happens to be set to a division ratio of 1420. The output of the divider is connected to one of the inputs of the phase comparator. The other input is connected to the reference oscillator. Any difference between the two input frequencies will produce a Continued on Page 5 February 2003 Page 5 ASK ELMER cont. voltage which would be varying at the difference frequency. This voltage would be smoothed by the Lowpass Filter and fed to the voltage control input of the VCO. This would cause the VCO to change its output frequency over its entire tuning range in step with the frequency difference. As the VCO's frequency varies, it approaches the frequency of the Reference Oscillator. As it does, its movement slows down (the frequency difference becomes less and less ) until ultimately the difference frequency between the reference and the VCO (through the divider) becomes less than 1 Hz. At this time, the output of the Phase Comparator will be a voltage, proportional to the phase difference between the two signals. Ultimately, the output frequency of the VCO will come to rest at one frequency, now determined by the Frequency Divider's division ratio and the Reference Oscillator's frequency. Since the Reference Oscillator is at 10 KHz, and the Frequency Divider is set to a ratio of 1420, the VCO's output frequency is at 1420 X 10 KHz. This equals 14.2 MHz. We want to operate at 14.25 MHz, so we move the dial on our radio to this frequency. This dial movement changes the Frequency Divider's ratio to 1425 from 1420. The Phase Comparator senses this change by outputting a voltage which varies at the new frequency difference. The operation repeats itself as previously described until the VCO settles to its new frequency. Voltage Controlled Oscillators are not the most stable devices. Their frequency tends to vary due to components changing their values from ageing, temperature changes, supply voltage changes, etc. It is the job of the Phase Comparator to quickly sense these small changes in frequency and generate a correction voltage so that the VCO's output frequency appears to remain unchanging. The rate at which it can sense and correct for these small variations is determined by the response of the Lowpass Filter. The response of the filter is chosen to permit the relatively slow variations in the VCO's frequency to be fully corrected, but to filter out all of the high frequency noise generated within the system, not related to the VCO. Any small change in the VCO's output frequency will be immediately corrected and the VCO will appear to have the stability of the Reference Oscillator, and still be able to change its frequency on command. I do hope this clears up your quandary. 73, Elmer Send your questions to “ASK ELMER” c/o Marv Fleischman, N1AWJ, PO Box 113, Ridgefield, CT )6877-0113 or e-mail them to [email protected]
February 2003 MINUTES OF THE MEETING– JANUARY, 2003 Meeting was called to order at 8:10pm by Vice-President Fred, K1FC. Reports: Public service– none Marv, N1AWJ issued his usual plea for questions for Ask Elmer– and this time warned that if no questions were forthcoming then there would be no Ask Elmer!! Also reported that the next VE session would be on Saturday, February 8th. New fee is $12.00 which goes to the League, nothing is retained here. Fred, K1FC discussed developments in the purchase of the new repeater. A model has been chosen and the new repeater and a new duplexer have been ordered. Marv, N1AWJ reported on his search for new transistors for the power amplifier. Finally found a source that did not require him to purchase surplus Motorola units to scavenge out the transistors He said the previous repair efforts did not include using heat transfer material on the transistors which probably led to their demise. He indicated that he had repaired the unit and had operated at key-down for five minutes at full power without any indication of heat. He will install the unit shortly and will back off the output somewhat. Dick, WA1VUU reported that the repeater fund letter had resulted in a total to date collected of $1,752.00, representing about one third of the membership of the club. He also requested that dues be paid as soon as possible so that our financial condition can be known for the year. A well attended Holiday Party followed. Dick, WA1VUU (without notes!!) ********************************************************** On a personal note, I wish to thank all those who contributed to the Holiday Party, brought food , ice and party supplies. You all contributed to the success of the party! Dick, WA1VUU
TREASURER’S REPORT AS OF 14 JANUARY, 2003 INCOME EXPENSE Rptr. Fnd. $2,255.00 Postage $74.00 Txfr. In 500.00 Txfr. Out 500.00 Dues 490.00 Rptr. 1758.72 Phone 25.70 ————– ________ Totals $3,245.00 $2,358.42 Balances Checking-$2,290.30 Savings- $2,986.72 (Repeater fund to date $2,732.00)
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.
The Stamford Amateur Radio Association will be holding examinations for
Amateur Radio Licenses on Saturday, February 8, 2003.
The examinations will be held in the 4th floor Cafeteria at the Stamford
Government Center. The Government Center is located on
Washington Blvd. at the corner of Tresser Blvd. Check in is at 9:30AM, and the
exams start promptly at 10 AM. The fee for the test
session is $12 (last month it was erroneously reported to be $10, but the new
$12 fee started on January 1, 2003). We would
appreciate a check made out to the ARRL/VEC (we do accept cash, but a check is
easier for us to handle). Bring 2 forms of ID, one
being a photo ID. Those upgrading must bring a photocopy of their current
license which will be submitted to the ARRL with the NVEC
605 form. Please bring any CSCE's that you may have to verify previously passed
test elements.
For any further information please contact Marv, N1AWJ at (203) 438-7889, or
email at [email protected]
February 2003
YE OLDE JONQUE BOXXX
ICOM IC-2AT 2m HT w/Charger, Batty., & SS-32MP micro-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 cont. 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
Mac Laserwriter printer, best offer.
Call Jeanine, KY1Q, (203) 324-6865
FatMac Computer w/ 1Meg Ram, Free!!!; FOR PARTS..Olevetti Accounting Machine.
FREE!!!!! Take it away!!!
Call Marv, N1AWJ, (203) 438-7889
HD-73 ROTOR w/CONTROL & CABLE, $50; Cushcraft 10-40M Vert. Ant., $15;
Heathkit Station Monitor Mod. 614, $50. 2 South Bend 7.5 HP
Go-Cart Engines. Call for Info.
Call Irv, N1ATS, 348-3425 or e-mail http://by1fd.bay1.hotmail.msn.com/cgi-bin/compose?curmbox=F000000001&a=80e9d5401a467e78b9c4aee33a7fb789&mailto=1&[email protected]&msg=MSG1043966866.214&start=2096946&len=58780&src=&type=x
2M 30W AMPLIFIER, $25; 6M Amplifier, 10W in 150W out, $175: AM6155 2M SSB
Amplifier, 8930 Tube based, Cavity Tuned, 400 W Out (not
cont. duty) $325.
Call Andy, KA1SLG, (203) 531-9493
MFJ ANTENNA TUNER A-1 Cond. $100; Cushcraft R4 Ant , New, $25; ¼ ? Mag. Mt.
Ant., $12; ? ? Mag. Mt. Ant, $15, ? ? Trunk Mt. Ant.,
$10; Measurements Grid Dip Meter, $25; HP Signal Gen.; $15; Code Pract. Mach.,
$15
Call Milt, K2DLT, (203) 324-2723
MICROTEK SCANMAKER, Flat Bed Scanner Mod. E3 w/cables, software and ISA SCSI
card. FREE to a good home
Call Dick, WA1VUU, (203) 323-0982