Weather Satellite Receiver

R139 ts The Affordable WeSat Rcvr!

Join Ihe growing ranks of amateurs who get striking images directly from the weather satellites1 We used our 30+ years of experience in designing high-quality vhf receivers to bfing you a new enhanced version of our long-popular WeSat receivers The new R139 a very sensitive wdeband fm fecBiver optimized for a-rateur recepT^on of NOAA APT and Russian Meteor weather facsimile images on the 137 MHz band. Use with any popular demodulator and software Covers all fAj& popular satei.rte channels Scanner circuit and recorder control allow you to automatically search for and I ape signals as sateflites pass overhead, even while away from home.

* R139 Receiver Kit less case $159

* R139 Receiver Kit with case and 1iVdc power adapter, SfS9

* R139 Receiver Wired/tested in case with iZVdc power adapter „„,$239

hamLronics, mc

65-D IVIoul Rd; Hilton NY 14468-9535 Phone 716-392-9430 (fax 9420)

Number Sort your Feedback card

Private Ham Satellite_

Bob Bruninga WB4APR may become the first ham with his own amateur radio satellite in space The Glen Burnie, Maryland, ham hopes \o have the new amateur radio satellite In orbit by next summer

No: this is not a joke or a pipe dream, Bruninga is !he director oi the Satellite Education Laboratory at the Naval Academy in Annapolis and the satellite Is a departmental project. Its primary aim is to provide every school in the country with socket radio satellite access:

We try to participate in all the SAREX missions with our students. The only problem is probably only 1% of the orbital passes is operational in the packet mode on the SAREX and you never know in advance tt is very hard for the students to go to alf this effort and not be able to make a packet link to the spacecraft. So, we think that there ought to be a very low budget, low tech packet satellite up there that is always on. always operational And every lime it comes over any high school in the country the students will see somethingBruninga

Bruninga says he plans to fly a one-watt Picosat transponder operating on 2 meter FM packet at 7 200 baud/The system is specifically designed for d g peating posiiion reports.

"Once you get the satellite up there then we can track guys driving across the country in their recreations] vehicles, we can track guys in their boats Qui in the bay and up and down the Allanlic.. all over the worid realty That s why we think there \s tremendous poteni;a. for position reporting

I mean that's what amateur radio is. It's not sitting in your basement. As far as our ability to contribute to the stale of the art and to public service, our abilities are not sitting en out basements. Our abilities are mobile."—Bruninga

Bruninga says that he already has a tentative invitation from NASA for a free launch on an experimental booster. The earliest possible launch date is in May But WB4APR says that the date could easily slip A lot depends on when the satellite is ready to fty. The parts are within amis reach, says Bruninga, but construction has yet to begin. TNX Amateur Radio Newsline

Still with ham radio satellite news, Jim White WD0E reports lhat Ihe DOVE DO-17 ham satellite S-faand transmiiter is on Jim says that a recent software load allows better power control and controllers now expect to be able to keep the pesky transmitter in operation on 2,401.220 MHz. TNX Amateur Radio Newsline

RF Lights_

RF light bulbs are on their way and they could add to ihe QRN currently on the ham bands. This, after the Federal Communications Commission waives its rules to permit the General Electric Com* pany to begin marketing a new RF-powerea light bulb.

At GE's request, Pan 18 of the commissions regulations has been waived. Part 18 limits on the amount of RF energy that can be conducted into the electric power lines by RF lighting devices in the band 2.2 to 2 9 MHz, GE proposes marketing to consumers an unlimited number ol FtF light bulbs that comply with the conduction limits for noncons^mer RF lighting devices in this band.

Commission rules already permit RF lighting devices used in commercial environments to place this signal level on the AC power lines. The FCC says that ihere has been no record of significant interference problems from the use of these devices in commercial environments. It also says that radio operations in the range 2.2 to 2.6 MHz are not normally employed or intended for reception in residential environment. GE was granted a waiver for one year, and the FCC reserved the right to revoke the permft if it determines that RF fighting devices operating under the conditions of the waiver create severe interference problems.

Three years ago, a California company, Intersource Technologies, promoted an RF-powered hght bulb that operated at 13.56 MHz. According to the manufacturer it was designed to keep unintentional radiation io a minimum. The company claimed that its 25-watt RF bulb could generate as much visible hght as a "00-wau conventional bufb but these lamps were never marketed.

And the ARRL says it has a definite interest in what kind of interference the GE RF bulb may generate. The League says that it will obtain samples of the GE bulbs for testing as soon as they are available. ARRL Laboratory Supervisor Ed Hare KAlCV says that the new bulbs should notr if properly designed, create any more interference to Amateur Radio operations than fluorescent bulbs, dimmer switches, or other similar devices found tn |he home. Other experts disagree. Tfiey point to the oroblems that a bad incandescent lamp dimmer can create for the average ham. TNX Amateur Radio Newsline

Airwave Auction

The Supreme Court has given the Federal Communications Commission approval to go ahead with ils planned December 1 nth aucl'On of 498 licenses for smal businesses, A company called Radiofone Inc. had challenged the commission s celfufar per-sonaf communications services cross-ownership rule, which limits cellular companies to 40 megahertz of spectrum in their cellular service areas.

But in vacating a stay issued by a Federal Appeals Court, Justice Stevens noted that allowing the national auction to go forward would not prevent the federal appeals court from granting Radiofone appropriate reliel if it later found thai the company's case has merit As a resu't, the multimiiion dolfar auction will proceed TNX Amateur Radio Newsline

1996 VE Test Fee_

The cost of getting a ham radio license is going up again in 1996. Effective January 1st. the maxb mum allowable reimbursement fee for an amateur operator license examination will be $6,07. The FCC

set this amount based on the Consumer Price Index between September 1994 and September 1995. It's an increase of 17 cents from the current $5 90 fee.

Actually, nobody really makes any profit from ham radio testing fees. Volunteer examiners and volunteer examiner coordinators are permitted to charge examinees for out-of-pocket expenses incurred in preparing, processing, administering, or coord nat-mg reexaminations for amateur operator licenses. The amount of any such reimbursement fee from any one examinee for any one examination session, regardless of the number of elements administered. must not exceed the maximum allowable fee TNX Amateur Radio Newsline

FCC Wireless Chief Moves

Regina Keeney. chief of the FCC s Wtreiess Tele* communications Bureau which oversees Amateur Radio, has been promoted to chief of the Commissions Common Carrier Bureau Keeney, who has been chief of the WTB since the bureau was formed last December replaces Kathleen Wallman at Common Carrier.

Regina Keeney is the daughter of John Markey W2AAW and Marge Markey N4XZD. When she was named as chief of the Wireless Telecommunications Bureau she is quoted as saying lhat she had grown up in an enthusiastic ham radio family.

The FCCT in announcing Keeney s move over to Common Carrier, said thai during her tenure at the WTB, she oversaw the commission s auctions of electromagnetic spectrum and worked to develop fair ruies of competition ¡n the wireless communications marketplace. Thanks to her leadership, says the FCCt the previous backlog in license application processing has been cut in half.

No successor to Keeney in the Wireless Telecommunications Bureau has yet been announces. TNX Amateur Radio Newsline

Paralyzed Assistance Needed_

Bill Farley WA5FLG has posted a packet message asking for help for a paralyzed ham. Bill says thai Lowell Richardson W5UBW an avid DX chaser has become para fy zed bu\ wants to be able to communicate.

Bill says that Lowell no Eonger can speak. Bill is looking for any device that would help his friend who has the use of one hand only.

If you have any ideas, send them by packet to WA5FLG*iK5WPH or call Biff at (505) 437-5508. He is in Alamagordo, New Mexico, and is on Mountain Standard Time. TNX Amateur Radio Newsline

Canada Adopts IARP__

On the international scene. Canada has announced thai it has agreed to adhere to the Region 2 International Amateur Radio Permit It's the fourth country to do so and has issued the first two permits These went to Radio Amateurs Canada

Continued on page H7

Number 9 on your Fecaback card

The SP-10 "Senior Spider"

You may have heard (or knov\ firsthand) that transmitter power levels of 1 wail or less can indeed "get out" and have accounted for some remarkable teats of DX+ It's true.

It s also true thai I watt, in HF sky wave service, has little endurance to spare. You get lucky and snag a good one when the band is optimum and two minutes later, you're talking to yourself because of QSB or QRM at the oiher end! Clearly, some extra holding power is called for if you want to chew the rag or make 5-WPM Novice QSOs that, of necessity, take longer to complete. The question is, how much will it lake to do the job?

When n comes 10 irons mi iter power, the sk\ *s the limit of course, up to the legal limit for your license class, but here wc alsn want easy construction and minimal cost to encourage beginners so we'll just split the difference between a measly I watt and the widely effective 100 watt levels. And the answer is.+.IO watts! That's right. To judge the effect of a power change, you must think in terms of dB (decibels) and nut be mislead b> the watts. Ten w atts is 10 dB better than I watt and 10 dB worse than one hundred. placing it on middle ground theoretical!) and in terms of on-the-air readability.

The rig to follow is a simple 10-watt, crystal-controlled CW transceiver that may be built for 80, 40, or 30 Meters. You can build it and learn a little about how it works. Should it ever malfunction Just fix it yourself. There's no need to rel> on the service of a distant repair facility. That's independence!

The SP-10

The SP-10 presented here is functionally very similar to its predecessor the SP-I (Jan, 1993 issue of 73) which has enjoyed popularity in the QRP world,

The receiver front end is triple-tuned to improve in-band sensitivity and out-of-band rejection. The dual-gate MOSFET receive mixer has been retired and its job turned over lo a multifunction 1C that also includes an op amp for audio bandpass filtering and a very effective audio muting switch. A low-noise audio preamp stage for increased gain rounds out the receiver improvements.

The transmitter section is pretty much the same as the original "Spider" except here it drives a power MOSFET ^afterburner" producing 8 to 12 watts of RF output. Physically, the highh successful SP-I layout has been retained wherever possible. The additional circuitry requires a larger circuit hoard which His comfortably in the next size up enclosure, an RS #270-232 measuring about 8* w by 4" d by V h.

"Your brain needs a change of pace and here you get it whenever you close the key /"

The net effect of these changes is a quantum leap in overall transceiver per-fonnance and just a modest increase in cosi and complexity. By strictly avoiding "dinosaur" and one-of-a-kind components in the design, easy duplication and maintenance for years lo come is almost assured. So gel with it and, ne\l lime, youT! be the one to say "Rig here is home-brew!"

Circuit Description

The heart of this radioteiegraph trans-cciver is continuous wave oscillator Q! (refer lo the schematic, Fig. I). You plug a quanz crystal (more on crystals later* lor the desired operating frequency into the top panel socket and Q1 circuitry provides the needed gain and feedback to sustain crystal vibration and supply

Mike Agsten WA8TXT 405 W. Bogart Rd. Sandusky OH 44870

RF drive to other circuits via the secondary link on TI,

During receive, incoming signals pass Lhrough L5, L4, L3 and scries resonant C23/L6 to receiver input circuits T2/C32 and T3/C33 (which are top coupled by C34.i and onward to the receive mixer at U3 pin IK. 1 here, in conjunction with oscillator signal via CI8 lo U3 pin 1, they arc converted directly to audio at U3-3* filtered by C59 to remove unwanted RF byproducts and then audio bandpass filtered by the op amp at U3-12 and U3-13. which provides a distinct peak at about 400 Hz. In receive, the audio muting transistor at U3-16 is off (open) allowing signal passage to AF preamp Qfi. volume control R47 and AF power amplifier U1 (pin 2 in, pin 5 out U1 employs a small amount of negative feedback (C52) to roll off unnecessary high-frequency components in the AF output.

Receiver line-tuning is accomplished by using RIT control R23 to vary the tuning voltage (via RI) to DL This special tuning diode transforms RIT rotation into variable capacitance which, in conjunction with LI and YK alters the oscillator frequency. Normally, ihis receiver is properl\ tuned when there is a 400-Hz difference between signal and oscillator. The resulting beat note provides peak output because it is centered in the audio bandpass response. Frequencies higher and lower receive less amplification. This is how selectivity is provided; I he desired signal is louder unless interference is overpowering.

Automatic receive-transmil switching (QSK) is initiated bv closing the key, Q8 switches on, rapidly energizing the 12T bus which, in turn, accomplishes the changeover to transmit by switching several circuits, 12T via D8 mutes receive audio by placing a short circuit at U3-16, h turns on sidetonc generator Q7 (a unijunction transistor or UJT) via R38 and R39, Sidetone allows you to monitor your telegraph sending quality by providing a nice, tight feedback ioop that includes ear, brain, fist, and key The sidetone in ihts rig also provides an important secondary function, Us complex, harmonic-rich output soothes your brain by dispersing all those headache-forming neural knots that ma\ come from excessive sine wave exposure during receive. Your brain needs a change of pace and here you get it whenever you close the key!

Moving onward, 12T via R25 and Qfi grounds D1 tuning voltage to provide transmit off set which allows same-frequency transmit-receive with other stations. It switches Q3 on, enhancing oscillator output level \ia R5 and assisting transmit offset with C3. Finally, 12T keys Q4. which permits Q2 to amplify the incoming oscillator signal. Q2 output via low-pass filter L2 and resistive pad R14-17 then drives final RF power amplifier Q9 to full output of 8 to 12 watts, depending on hand, power supply and transistor grade.

Harmonics present in this raw power are attenuated to insignificance by low-pass filter L3-L4-L5 and associated capacitors. Since the receiver input is tied directly to transmitter output aL C23, D4-D7 are included to protect the receiver. Transmit RF turns them on andH while in conduction, ihe> place a near-short at the junction of C23 and L6, breaking up the scries resonance and forcing C23 and C22, because of their relatively low capacitance, to look like a high impedance during transmit, thus blocking most of the RF. This technique was actually developed for radar equipment where a sensitive receiver and high-power transmitter had to share a common waveguide, What you sec here is [he same principle in u less pure but still adequate form,

10 73 Amateur Radio Today * January 1996

Photo H Bottom view of ¡he 5P-W


In the top ^ iew photograph ot the SP-10, >ou can see the octal-type crystal socket in the left-rear corner. Since this socket holds two FT-243 or similar crystals, DPDT switch S2 is provided just in from lo select one or the other. TBI, a four-lug terminal board, mounts along the rear edge of the top panel, near the right-rear corner. Its terminals are numbered ! to 4 going from left lo right. Connections to TBI are DC power to 1 ( + } and 2 <-) and antenna svstem to 3 (coax shield) and 4 icenter}. Along the right edge are 3.5-mm jacks for speaker/ headphones (J2;-rear) and external telegraph key (J 1-front).

The built-in telegraph key is just left of the jacks. Its arm. a 3' strip of .025' thick brass or aluminum, is mounted on 1/4" spacers and grounded to the top panel by its two mounting screws. The ke> knob, a rubber or plastic equipment foot, is fitted or gtued to the hex nut attached with machine screw, up through the arm. The head of this screw is the upper contact. The key contact beneath the arm is a 6-32 brass machine sercw with head filed flat. This screw is insulated from the top panel with a shoulder washer above and fiber washer below, and secured with Hat washer, solder lug (for connecting to) and hex nut.

The two knobs front and center on the top panel are Volume control R47 on the right and receiver incremental tuning (RIT) R23 on the left, Just left of RIT is slide switch S3, unused here but available for extra audio filtering (to improve selectivity) or other contingencies. Left of S3, in the left-front corner is DC powTer control sw itch SI,

Running front to rear between RIT and Volume, and below the top panel, is a T wide by 3" long by 3/8" thick solid aluminum slab thai pro\ides heat sink and mounting platform for RF power amp Q9. This slab, to further increase heal dissipation, is attached directly to the aluminum top panel with three machine screw s, heads \isible in the photograph.

Most of the project is contained on the PC board depicted by ihe etching pattern in Fig, 2 and the parts overlay. Fig. 3. Of special note on PC board assembly, voltage regulator IC U2 needs 2 to 3 square inchcs of heat radiator coupled to its mounting flange. 1 cut and bent a piece of .025" aluminum sheet as shown in photo B (inside view) and on the parts overlay, and installed it between IJ2 and the PC board.

T4, the tri(liar-wound matching transformer, uses two oi" the specified core placed side-by-side. The wire winding holds them together no problem. Don't be intimidated b> "tritliar winding/ All you do is cut three equal length wires and twist them into a bundle. Thread the bundle onto the core until you have the specified turns count. It should look like an octopus w iih si\ tentacles coming off the bottom- Trim excess wire but allow enough for connections and installation. Now you have three wires on the core, arbitrarily designated A, B and C, and color-coded or tagged for easy identification. Connect the end of A to the beginning of Connect the end of B to the beginning of C. The beginning of A and the end of C remain single and go to "Com" and "Out" at T4 on the PC board. The two cross-connections go to "X" and In/'Voila!

Because Q9 is the (asi part installed, even after the PC hoard is mounted to the top panel, provision must be made for connecting it to the top side of the board. 1 used short "Ilea clips" as mounting posts at holes Ci, D, and S. An> thing snug enough to remain tight when reheated will do the trick here, In other words, you don't want the mounting posts to come loose from the PC board when you're attempting to solder the leads of QV!

With the PC board complete, use it as a template to mark its corner mounting holes on the inside of the top panel as shown in Photo B, The heat sink slab mentioned earlier runs from beneath the rectangular Q9 cutout to the area between Volume and RIT. Drill and tap a 632 mounting hole for Q9\ flange in ihe heatsink, positioned so QL) leads will bend and reach the PCB mounting posts.

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The MFJ-989C is not for everyone.

However if you make the ins esurient, you'll get the finest 3 KW antenna tuner money can buy.

Massive Thinsmittinn Capacitors

You get I wo massive 250 pf transmitting variable capacitors with detailed logging scales rhey can handle amps of RF current and vs ithstand 6000 RF volts because the plates are smoothed and polished and have extra wide spacing.

Precision Roller Inductor

A precision roller inductor, 3 digit turns counter and spirmcrknob ives you exact inductance control or absolute minimum SWR.

Hall bearings on sleel shafts ive you a velvet smooth vernier eel and long term durability. Yqu won't have arcing problems


with this roller inductor, Firm springs put high

Cross-Needle Meter s349

ign MFJ-9S9C You get a lighted peak and ressure on a plated contact wheel average reaciiii» C ross-Needle

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For excellent electrical contact.

Wide, low inductance straps are used for high currents and a new core minimizes RF loss.

Cross-Needle Meter

Super Heavy Ihity Balun

You get a super heavy duty current balun for balanced lines, It has two giant 2yh inch powder iron toroid cores and is wound with Teflon* wire connected to high voltage ceramic feedthiu insulators, it lets you operate high power into balanced feedlines without core saturation or voltage breakdown.

Ceramic Antenna Switch

A two wafer 6 position ceramic antenna switch with extra large contacts gives you trouble free switching.

Plus much, much more

You also get a 300 watt dummy toad, l ull one year unconditional

SWRAVatlmeter with 200 and 2000 watt ranges. Its new directional coupler pives you accurate guarantee, ilip stand, alt aluminum m baked on pi compound on all nuts and cabinet, tough baked on paint, locking compound on alf nuts ; upier gives you accurate bolts. 3 KW PER JOVjx^/zx 15 in, readings from K8 to 30 MHz» Don V settle for less, get yours today 1

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