July 2003 THE SQUELCH BURST a monthly publication of the

STAMFORD AMATEUR RADIO ASSOCIATION

  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/ctsara/ 

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.

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 JUNE MEETING

The meeting was called to order at 8 PM by Dick Finn, WA1VUU. The meeting was held in the Democratic Caucus Room on the 4th floor of the Stamford Government Center.

Committee reports: Squelch Burst: Marv, N1AWJ reported that this month the Squelch Burst will be edited by Dick Finn WA1VUU. The editors are looking for articles from the membership to be published. Any submissions to the Squelch Burst be made as early as possible. Ask Elmer is looking for questions to be answered. Currently there is no backlog of questions, which may mean that the column will not be published until some questions are submitted. Public Service: Jeanine, KY1Q reported that we provided communications for the Cancer Walk in Stamford on June 1. Even though it rained that day, the 5 mile walk and 5K race was held. 7 SARA members participated in the event. They were Mike, N1FOA; Ernest, KA1NGG; Marv, N1AWJ; Jim. N1ZFS; Bill, KB1IFY; Walter, N1NOO and Tom, KD1UL. There were no communications problems to report at the event.

The main topic of the meeting was the preparations for Field Day. The event will be held on June 28th and 29th. Our site will be on the Observatory grounds of the Stamford Museum. The entrance is located on Scofieldtown Road in Stamford. We are planning for 2 to 3 stations, all running Solar Powered QRP radios. Fred, K1FC has arranged with Solar Dynamics Co. of Hartford Ct. to borrow a “Harvester” 50W Solar Powered-100 AH Battery backed system to power the radios. Marv passed around a copy of the spec sheet on the solar source. Discussion continued on the type of stations and their operating mode. CW, SSB and PSK31 will be used. Antennas will be of the wire type, from a dipole to a Moxon Rectangle. Lunch and dinner at Field Day will be provided by the club. We also discussed publicity for the event.

The July meeting will be held on Thursday, July 10 in the Stamford Government Center. Thursday July 3 is too close to the July 4th holiday. The meeting was closed at 9 PM.

Marv, N1AWJ

SARA WEBSITE NEWS

I have removed the SARA Membership List on the web site. A Officers page is the one of two areas that has any information. Officers Page. Title, First Name, Call Sign and E-mail Address. The other is the monthly news letter which I will remove the information each month and add a link to: "The Officers Page." I Have a new page on the web site. “Add Your Own Membership Information On the SARA web site. Add Your Self To The Membership List!  Add as much about your self as you want.   Add as much or as little about your self as you want and write a short description about your self. You can add information like, Name, Call Sign, Phone Number, Location, e-mail Address, Web Site. John Sabin Jr., WB1GRB SARA Webmaster

ASK ELMER

Dear Elmer, Some operators was talking about adding a Isolator to a repeater. What is a Isolator? How does it work? Signed, Al One,

Dear Al, When designing a transmitter you would try to have the output amplifier terminate into its designed impedance (ie., 50 Ohms). Antennas, duplexers, etc are generally not that well made or ideally located, that they always present a constant impedance to their source (the radio). An ideal solution would be a device which would always present a constant impedance to the radio no matter what it was terminated into. One partial solution to the problem is the use of a Transmatch between the radio and the antenna. If the antenna impedance varied, you must retune the Transmatch. With the advent of ferrite materials. microwave engineers have found a solution to this problem (and several others that they have had) with a device called a Circulator.

A Circulator allows RF energy to flow in one direction only. A special case of the Circulator is called an Isolator. The circulator consists of 3 transmission lines, each 120 degrees in electrical length, connected end to end (as in a circle or triangle). Some microwave engineers call this configuration a “Rat Race”. Each connection point is a port into which you can either introduce or extract an RF signal. The transmission line is surrounded by a block of ferrite material, and a small permanent magnet. When an RF signal is introduced into one of the ports, an electromagnetic field is generated in the transmission line. The purpose of the ferrite material is to direct the RF electromagnetic field to travel in one direction. The permanent magnet is used to magnetically bias the ferrite material so that it can direct the electromagnetic field. There is also some shielding to prevent the earth's magnetic field from affecting the ferrite material. Let us call each of the ports by a number, such as port 1, port 2 and port 3. With our ferrite material the RF travels in a clockwise direction. It does not make any difference which junction we start with, as long as we go in one direction. If we were to introduce an RF signal into port 1, it would travel to port 2 and then to port 3 and back to port 1. If we terminate port 2, all of the RF energy would flow to port 2, and nothing would continue to port 3. If we were to move the termination from port 2 to port 3, all of the RF would bypass port 2 and go to port 3. If we were to permanently terminate port 3 with 50 Ohm load, we have magically changed the device from a Circulator to an Isolator. If the output of your transmitter is connected to port 1, and the antenna is connected to port 2, all of RF will flow to the antenna. If the antenna is mismatched (not 50 Ohms), the reflected signal from the antenna will enter the isolator at port 2 and flow to the 50 Ohm termination at port 3. None of the reflected RF will flow back to the transmitter at port 1. This effectively isolates the transmitter from its load (antenna), hence the name Isolator. There is a caution when using any ferrite device in a transmitter.

Nothing is perfect. Ferrites are not a linear material. Doubling the RF does not necessarily double the magnetic field in the ferrite. Local temperature changes can effect the ferrite material, especially if it absorbs some of the RF. This can cause harmonics to be generated as well as the possibility of other RF products. It is important to always follow an Circulator or Isolator with a low pass or band pass filter to remove these unwanted signals.

I hope this brief explanation helps you to understand the workings of a Circulator and Isolator. Any further information would be obtained from researching texts on Microwave passive coupling structures using ferrite materials. Be prepared for a lot of math.

73, Elmer Send all your questions to “Ask Elmer”, c/o Marv Fleischman, N1AWJ, PO Box 113, Ridgefield, CT 06877-0113 or e-mail.

VE EXAMINATIONS The next scheduled SARA VE Examinations will be held on Saturday, August 9, 2003. They are held in the 4th floor cafeteria of the Stamford Government Center. Check-in is at 9:30 AM and the exams start at 10 AM. The fee for the test session is $12. Those upgrading must bring a photocopy of their current license to be attached to the NVEC 605 form. For all applicants, two forms of ID are required, one is a photo id .  VE Testing

TREASURER'S REPORT AS OF 10 JUNE, 2003 INCOME EXPENSE Dues 45.00 Phone 24.90 Rptr Fund 15.00 Postage 74.00 Int. 3.72 _______ _______ Totals $63.72 $98.90 Balances Checking: $1,150.94 Savings: $3,000.04 De WA1VUU

CHANGE OF SCHEDULE

Due to many reasons, the usual club picnic will not be held this year. Instead, a regular meeting will be held at the Government Center, at 8:00pm but on the second Thursday of July.

REMEMBER!

The July meeting will be on JULY 10th. At the usual time and place. MARK YOUR CALENDARS NOW!

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

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.

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, K1DLT, (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

COMET CX-333, 3 Band Vert., 2M, 220 & 440, Like New, No Tuning Req'd., $ 100. Triplexer for use w/Comet Ant w/Leads $60; Icom T8A HT w/slow charger & 2 extra Batt's., $150; Radio Shack HTX 242 2m 10/45W Mobile w/o mounting bkt., $85 Call Chris, N1YNO at (203) 359-0570 evenings

ESTATE SALE (N1CML) Yaesu FT-980 HF Xcvr, $475; Yaesu FT 726R 2M all mode Xcvr $325; Yaesu YS-60 SWR-Pwr Mtr, $50; Yaesu MD-1 Desk Mic, $45; MFJ Versatuner II (300W), $100; Eldorado Mod. 1615 Freq. Counter, $25; Larson 2M 1/4 wave Mag Mt, $15;Tram Reflectometer Auto VSWR mtr, $15; Heathkit Memory Keyer $25; HP 5301AFreq. Counter, $25; Azden PCS3000 2M mobile w/o Mic., $25; Many other items, call for listing. Call Marv, N1AWJ, e-mail.

Send all your ad's for YE OLDE JONQUE BOXXX to Marv Fleischman, N1AWJ, PO Box 113, Ridgefield, CT 06877. E-mail  must be in by the meeting night of the month prior to the publication. (December meeting for January publication)