Voyager 2 Commemorative Plans, by Dick Piety, K6SVP
The JPL ARC is now in the middle of planning for the second of our two announced operating periods this year. Voyager 2 is fast approaching Jupiter, and the amateur world is, we think, waiting for more commemorative activity from W6VIO in support of this event. Beginning on July 6th and continuing through the encounter phase to the 15th of July, we'll need operators. As before, we need help on all modes, not just SSTV.
If you have not tried commemorative operating before, come on out anyway, we'll give you a fast lesson and start you out. I guarantee you will enjoy it. If you can spare a few hours, please let me know. During the Voyager 1 encounter we worked over l500 stations, and could easily have doubled this total with more operators. So that I can plan on your participation, give me a call on x2298 and tell me you'll come.
CB to 10 Meter Conversion, by Bill Wood, WB6FXJ
Recently Sears offered an excellent SSB CB rig at a rock-bottom close-out price: $89.95 each. Ads in QST and elsewhere offer conversions for about $50, but you can do your own for much less.
The Sears Roadtalker 40 channel SSB/AM mobile (model 3826) is a PLL rig that uses two reference crystals to determine the output frequencies; X701, a 12.32 MHz unit is used for AM and USB, while X702, a 12.319 MHz rock, is used for LSB. The selected crystal is tripled to 37 MHz and mixed with the PLL VCO output to produce a difference frequency between 1.28 MHz (for Channel 1) and 1.72 MHz (for Channel 40). The VCO normally works between 38.24 and 38.68 MHz. When used with the 11.275 Mhz IF it all works from 28.965 to 27.405 MHz (CB channels 1-40).
If X70l and X702 are replaced with 12.83167 and 12.83067 MHz units and the rig retuned, it can work well in the 28.5 - 28.94 MHz range. (Crystals are available from CAL Crystal locally for about $10 per pair.)
To replace the crystals, remove the small tin box, mounted by three screws just behind the channel switch. Unsolder the bottom cover and remove the crystals with dewicking braid or solder sucker. After installing the new crystals, peak up T701 using an RF voltmeter or a counter on pin 2 of IC701. If the VCO is locked up the frequency at pin 2 of IC 702 will step from 1.28 MHz on Channel 1 to 1.72 MHz on Channel 40. It may be necessary to tweak T702 very slightly to get proper operation over the whole channel range.
Note that almost all transformer and coil cores have a special square hole. To minimize core breakage, either make your own tool by grinding down an old tuning tool, or get the proper tool.
Next peak up T705 and Tl02 for the best receive signal on Channel 20. Then peak T703, T704, T402, T403, T404, T405, T406, and T407 for maximum transmitter output. Finally, set RT402, the SSB power control, for the highest undistorted output (about 20 watts PEP). If you want to work AM as well set RT01 for maximum output at the same time.
For the added luxury of using the fine tuning knob on both transmit and receive, move the top of the RV70l potentiometer from the RB bus to the BB bus and disconnect R702 from the TB bus and let it float. If more fine tuning range is desired, reduce the size of R70l. If you want to save money, just replace the X70l crystal and stick to USB and AM (who uses LSB on 10 meters anyway).
When you are all done you will have an excellent mobile 10-meter rig for under $100. You will get complete coverage between 28.5 and 28.94 MHz, with the exception of 28.53 (between Channels 3 and 4), 28.58 (between Channels 7 and 8), 28.62 (between Channels 11 and 12), 28.68 (between 15 and 16), and 28.73 (between 19 and 20). There is also a slight quirk in that the frequency for Channel 23 (28.79) falls after Channels 24 and 25 (28.770 and 28.78 MHz, respectively). Those of you with a digital background and some time may be able to fill in the holes and straighten out the sequence; otherwise, it is a very good setup as it stands.
Fire Extinguishers for Electronic Equipment
(reprinted from Worldradio News, May 1979)
Have you a fire extinguisher in your shack to protect against a loss from fire? What type extinguisher? Don't stop reading yet, because that extinguisher may cause more damage than the fire!
Most dry chemical extinguishers may leave you with more damage to your electronic gear than you'd suspect. Dry chemical agents generally fall into one of the following groups: sodium bicarbonate base, potassium chloride base, ammonium phosphate base.
These three are suitable for use on Class B and C fires (flammable liquids and electrical). The ammonium phosphate base is also known as "multipurpose", or "ABC-type." This type extinguisher is suitable for Class A, B, and C fires (ordinary combustibles, flammable liquids, and electrical).
The ammonium phosphate base agent forms a soft sticky mass when hot and clings to surfaces after cooling. It cannot be brushed or blown away. Also, in combination with moisture, it can corrode copper and copper-alloy materials. The potassium chloride base in combination with moisture can corrode many metallic materials.
All dry chemical agents may cause problems with electronic circuits, and any applications where points or contacts make and break, or where parts have close moving or electrical/electronic tolerances.
One point applicable here is normal atmospheric air contains moisture. Your gear doesn't need to be wet to have moisture problems as mentioned above. How well do dry chemicals penetrate? Start a large floor or window fan and toss a cup full of flour into it!
The best extinguisher to use: Carbon Dioxide, Halon l30l and Halon 1211. Water may be used safely and effectively after power has been killed. The recommended extinguishers aren't cheap, except the water, but then neither is most electronic gear.
Don't hesitate to use anything that will work if further property damage or life-loss possibilities exist, but if you have a choice, try to stay away from dry chemicals.
(This article was reviewed by Glenn Berry, K6GHJ. Below are his comments. Ed.)
Most "home type" extinguishers are of dry chemical type. CO 2 and Halon extinguishers are available from most safety equipment distributors. CO 2 is relatively inexpensive, Halon is very expensive to purchase and re-charge.
Help Sought for Planetary Citizen Cruise
Have you heard of World Game? Planetary Citizen Clubs? Do you know how ham radio fits in with either of these? If not, we'll tell you here.
World Game was originated fifteen years ago by Buckminister Fuller at the University of Chicago. Students everywhere can ask real questions of local interest concerning pollution, ecology, the use of resources, etc. Graduate students at the University try to provide the answers from information stored on computer files.
Planetary Citizen clubs are formed by groups of young people who are trying to promote recognition of individuals and nations as members of the world community, with the need to think and act on that basis.
Mary Duffield, WA6KFA, is tying these activities together. She will be with a group of teen-agers that will be taking a cruise to Mexico this spring in order to set up Planetary Citizen clubs below the border. Ham radio will provide the link for the young people playing World Game. Additionally, of course, it will allow those on the cruise to. keep in touch with the folks back home.
If you think you could help Mary with schedules, training, equipment, publicity, or whatever, write her c/o: Mary Duffield, 259 4th Ave., Santa Cruz, CA 95060.
ARRL Notes, by Jay Holladay, W6EJJ
WARC UPDATE - During the ARRL preparations for WARC-79, one of our goals has been to have someone on the U.S. delegation representing the Amateur Radio Service. I am happy to report that at the end of May the Department of State began naming the official delegation to Geneva, and the name of Merle Glunt, W3OKN, the ARRL's consultant for WARC preparation is on the list! Merle brings to this post an impressive background of conference participation, including a key role on the U.S. delegation for the 1959 WARC, at which time he was on the FCC staff. For more information on Merle's background, see "Behind the Diamond" on p. 60 of QST for May, 1979.
The first batch of proposals for the HF bands is analyzed in the "WARC Countdown" column in July QST. These represent the proposals of 43 countries as part of their WARC preparations. Incidentally, at last count proposals from 47 countries had been received at ARRL Hq., and not one other country has supported the U.S. proposal to share the 220-225 MHz band with the Maritime Mobile Service. It is reasonable to assume that the U.S. will have to propose another frequency band for this service if it is hoped to gain any support from other countries
ANAHEIM CONVENTION - Plans continue to progress for the 1979 Southwestern Division Convention at Anaheim on October 19-21. Among the speakers already confirmed is the ARRL's new Communications Manager, John Lindholm, W1XX. John will conduct a session on brainstorming CD activities to promote discussion of these operating activities. Also on the program will be Doug DeMaw, WJFB, manager of the ARRL Technical Department, so we will have outstanding Headquarters representation
HP9 CALLS ILLEGAL - A recent ARRL Bulletin states that ARRL/IARU Headquarters has confirmed with the government of Panama that HP9 calls have never been issued for use on the amateur bands. The prefix designates commercial maritime users, and the bearers of such calls are expressly prohibited from using the amateur frequencies. U.S. and Canadian amateurs are therefore advised that communications of any kind with HP9 callsigns, including third party traffic, is not legal. See part 97.89 of the FCC Rules and Regulations.
HOT DOGS AT THE JULY 7 PICNIC
As announced last month, JPLARC will sell hot dogs at the annual JPL picnic. If you are attending the picnic, plan to spend some time helping out in the booth. Volunteers (still in short supply) should contact John McKinney, N6AVW at x6610.
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