September Squelch Burst attached.
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September Squelch Burst attached.
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September 2003
THE SQUELCH BURST a monthly publication of the STAMFORD AMATEUR RADIO ASSOCIATION President .......… Andy Laska .............. KA1SLG Vice Pres .……..Fred Cunningham...... K1FC Secretary .....…. Mike Cordelli ......…... N1FOA Treasurer ...…... Dick Finn .…...............WA1VUU Trustee .......…... Jim Markus ... ........... N1ZFS Editors .......…... Marv Fleischman ...... N1AWJ Mike Cordelli ......................................... N1FOA Dick Finn ................................................WA1VUU Y.O.J.B. Ed..…. Marv Fleischman ..... N1AWJ Circ/Pub..…...... Dick Finn ................... WA1VUU Repeaters:
W1EE/R........ 146.055 in; 146.655 out (PL. 1Z, 100Hz) 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. 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. Committee reports: VE: Marv, N1AWJ announced that there will be a VE session held on Saturday, August 9 in the cafeteria of the Stamford Government Center. He called for VE's to attend the session . Squelch Burst: Marv, N1AWJ said that Dick, WA1VUU is editing the Squelch Burst this month. Marv announced that he has no more Ask Elmer questions to answer. If questions are not forthcoming, there will not be an Ask Elmer column that month. Marv is still looking for articles from the membership to publish in the Squelch Burst. Emergency: Fred, K1FC said that there will be a drill sponsored by the Dept. of Homeland Security in the near future. He doesn't have the precise date as yet. There will also be an emergency drill with the Red Cross sometime in October or November. Fred, K1FC reported that Andy, KA1SLG has indicated that he must resign his presidency of the club due to poor health. We all wish Andy well and a speedy recovery. Public Service: Jeanine, KY1Q is looking for volunteers for the Stamford Denmark Friendship sailboat race. The race is scheduled for Sunday, Sept. 7. We need at least 8 more volunteers for the race. Call her at 203 324 6865. Make sure you keep your SARA Emergency in a save place and where you can find it. If you have any questions contact Fred K1FC. e-mail. Technical Committee: Fred, K1FC reported on the progress of finding and curing the interference with the repeater. There are 2 transmitters at the repeater site which when both are transmitting produce a spurious signal near our input frequency. Marv and Fred used a spectrum analyzer at the repeater site to identify the spurious signal. A photo of the analyzer screen was shown to the members present. One of the transmitters generates broadband noise which elevates the noise floor by 30 dB, masking weaker signals from the repeater. The committee purchased an inline lightning arrester for the repeater. A motion was made to purchase an isolator for $100 to help eliminate some of the interference problems. The motion was seconded, discussed and voted upon. The motion passed. Additional discussion on remedial actions for the repeater was held. The meeting adjourned at 9:35PM Marv, N1AWJ
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.
2M 30W AMPLIFIER, $25; 6M Amplifier, 10W in 150W out, $175: AM6155 2M
SSB Amplifier, 8930 Tube based, Cavity Tuned, 400 W Out (not TREASURER'S REPORT AS OF 8
AUGUST, 2003 Dear Elmer: Recently picked up a D-104 microphone, because I have always liked the looks of it and for the 'nostalgia' factor. It appears to be an unaltered crystal element.. Any chance I can alter the characteristics of the mike electronically so that I can use it with my Ten Tec Omni V or will it require a new element? Voice from the Past. Dear Voice, The Astatic D104 microphone was probably one of the most popular desk microphones used by Ham radio operators. There are many different ways a microphone can be constructed. Some of the more popular types are dynamic, ribbon, electret, ceramic and crystal. All of these have their advantages and disadvantages. The most common microphone construction is the electret. One of the considerations when using a microphone is its impedance. The dynamic and ribbon microphones, as well as the electret are generally low impedance microphones (600 ohms or less). The crystal and ceramic microphones are high impedance (10K ohms or more). Since we are discussing the D104, which has a crystal element, it is a high impedance microphone. The crystal element which is made of a piezoelectric material such a Rochelle Salts or Tourmaline, both naturally occurring elements. A piezoelectric material is one which generates a voltage when stressed mechanically. The piezoelectric device you are most familiar with is a Quartz crystal. It can generate a relatively high voltage but at an extremely low current, hence its high impedance. Older radios were generally made to accommodate these types of microphones. In the modern radios, the microphone input is usually a 600 ohms, to accommodate the dynamic or electret devices. Many of the transmitters supply a bias current for the electret microphone as well. The bad news is that you cannot connect the D104 directly to your radio. The good news is that it takes a simple external device to get everything working correctly. You don't need an amplifier or any other powered interface between the D104 microphone and transmitter, unless you want one. A simple matching transformer will do the job quite well. I would suggest that you adapt a Radio Shack 274-016 plug/adapter transformer to the D104 microphone. The 274-016 should be disassembled so that you can connect directly to the transformer leads. The high impedance side of the transformer is connected to the 1/4 inch plug and the 600 ohm line is connected to the XLR connector. You wan to connect the high impedance to the microphone output. The low impedance side is connected to the transmitters microphone connector. A jumper from the low side of the microphone and transformer primary (high impedance winding) to the low side of the transformer secondary (low impedance side) and the shield of the cable connecting the transformer to the radio. If you wish to construct an electronic interface for the D104, I recommend the June 2002 issue of QST on page 61 and 62, “Hints and Kinks”, “More on the D104” by G. Heidelman, K8RRH. You can construct as simple or complex an interface as you wish using this article. The D104, having a crystal element, may produce require some attenuation as it is quite sensitive. If your radio has a microphone gain control, no problem. If you don't have a microphone gain control, you may have to add an external one using a 1K potentiometer between the transformer secondary and the radio. The top of the potentiometer connects to the high side of the transformer secondary, the bottom of the potentiometer to the common/ground and the wiper arm to the transmitter's microphone input. I have had many QSO's with operators using the D104, and I was quite impressed with the audio “punch” that it had. I hope you have many enjoyable QSO's using the D104. 73, Elmer Send your questions to “ASK ELMER”, c/o Marv Fleischman, N1AWJ, PO Box 113, Ridgefield, CT 06877-0113 or e-mail. |
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Laws for Hams to Live by in Moments of Trouble
MURPHY'S LAW-If something can go wrong it will. |