Ham To Ham #14 - November 1996

73's Ham To Ham column

c/o Dave Miller, NZ9E

7462 Lawler Avenue

Niles, IL 60714-3108

Cleaning up your act!

Here's another tip for the Alinco DR-1200T 2 meter transceiver, for cleaner sounding transmit audio when using the supplied electret hand-mic. It's a situation that can occur in other models and brands of transceivers as well...so it should have broad application...though the particulars will vary with each individual radio.

Electret condenser microphone elements are inexpensive and have very "flat" response curves...but they do require an external source of low-voltage DC power to operate the built-in FET preamp...an electret element puts out so little energy that preamplification is needed immediately, and a FET preamp is built into the element as an integral part of the tiny package. The external voltage to power the preamp usually comes from the transceiver with which the microphone is being used, although a battery within the mic's case can also be used. When the transceiver supplies the mic power, it usually comes in on one of the unused mic connector pins, and generally from the transceiver's +5VDC Vcc line. If that line also feeds any digital IC's, and filtering of the Vcc line isn't close to perfect, the +5VDC line can sometimes introduce noticable "digital noise" superimposed on you mic audio.

Listen to your transmitted signal on another receiver - with the CTCSS encoder off and in a quiet room - to see if this might true in your own case. If no one has complained about your on-the-air audio quality, then you probably don't have the problem, but if it has been reported to you from time to time, make the quick test mentioned above.

If you find that there is digital noise or other unidentifiable pops and clicks from time to time on your transmitted audio, the cure may not be all that difficult...depending on the transceiver you're working with of course. You can try simply more filtering - right at the mic connector pin that supplies the DC to the mic element - in the form of an additional capacitor from that DC pin to ground (trying different values to see if any improvement is noticeable). If that doesn't work, which is quite often the case, then it's on to the next step...which is what I needed to do with my own DR-1200T.

Probing around with a little battery-operated, solid-state, high-gain audio amplifier (via a .1ufd disc cap), I "listened" to the various DC lines in the DR-1200T. Some points are much noisier than others, some lines very "clean". It's a situation that's often difficult to predict from the schematic alone, but a cinch with the little "noise tracer" amplifier! By the way, this idea works in many other troubleshooting areas as well (hum problems, cross-talk, noise spikes, etc. on the DC lines), and it can be a good one to keep in mind. In my own DR-1200T, I found that the output pin on the 7808, 8-volt regulator (IC-1) sounded very clean, so I set about changing the DR-1200T's mic voltage source from the +5VDC Vcc "noisy" line to the +8VDC "clean" line. In the DR-1200T it's something of a chore, but still do-able. The reason is that Alinco uses PC board traces to feed the mic connector, and the connector itself is physically part of the "display" PC board...so traces must be cut and re-routed. Other radios, with individual "actual wires" being fed to the mic connector, will be a good deal easier to convert.

To get you going, Figure 1A shows the rear-foil side of the display board, and the trace that must be cut...the two bold-line jumpers shown in Figure 1A will also need to be added to re-route the +5VDC line "around" the mic connector. Since the display board is a double sided PC board, the opposite "component" side must also have one trace cut as shown in Figure 1B...no jumpers need be added on this side of the board. You can trace the circuit out if you wish, but these steps should effectively isolate pin 5 of the mic connector; now "clean" +8VDC can be brought up to the connector - via a new "direct" wire - from the +8VDC regulator mounted on the rear wall of the transceiver's case. If you follow the diagrams in Figures 1A and 1B you should have no problem making the modification. The circuit board is crowded, the traces close together, but if you take plenty of time and common care, it should go smoothly.

de Dave, NZ9E

More

Another side to the "clean DC" issue is in the area of obtaining a reasonably noise-free mobile environment. Mobile noise can wear two hats, that which is only perceived in the mobile's own receiver, and that which may also be impressed upon the mobile's transmitted signal. Both can

be problematical to deal with, in the sense that their solution is often one of mostly "cut and try".

There are a few things, however, that every "good" mobile installation should automatically include, whether in a car, motor home, boat or private plane.

First, and probably foremost (as touched upon in John Ayers, AA1IC's tip in last month's column) is running a separate "clean" battery feed - one that only feeds the ham transceiver, directly from the vehicle's battery. Hopefully, such a "dedicated" feed will be relatively free of switching noises generated by computers, the ignition system, vehicluar sensors, etc. The feed should consist of a separately fused battery run made with a gauge of wire heavy enough so that the voltage drop across the wire's resistance is insignificant at full transmitter power drain. Often, this alone will solve many mobile noise problems. But if it doesn't, here's a simple test you can perform to see if the noise is from radiated energy or if it's coming in via the DC power feed. Simply disconnect the radio's antenna. Does the noise disappear? If so, then it's radiated noise being picked up by your antenna - that's generally more difficult to troubleshoot. If it doesn't disappear - or if enough still exists to be a problem - then it's likely to be coming in via the radio's DC power feed.

What if you've run a separate power feed, directly from the battery, of heavy gauge wire, and a significant amount of noise still persists with the antenna removed from the set? You can try shielding the feed cable from the battery to the radio, using the shield and jacket from a length of RG-8 coax from which the center conductor has been removed. It shouldn't be necessary for most installations, but it's worth trying (and inexpensive enough) when the noise is persistent. If shielding the feed cable doesn't do it, then a choke in series with the DC power to the transceiver may help. Parts Express (1-800-338-0531) lists commercially made chokes up to 4.7mH, made of #14 wire, and exhibiting 0.52 ohm of resistance or less. They also carry computer grade very high capacitance power capacitors (one farad!) that will not only help filter noise, but will also smooth out any voltage variations from peak-surges during SSB voice operation - the next best thing to having the battery itself right behind the radio.

If most of the noise you hear in your mobile transceiver is coming in via the antenna, then you'll have to settle-in for some real "fox hunting". Ignition system wiring is usually the best place to begin - either installing new resistance ignition wires or going full tilt into a specially-made shielded system - it mainly depends upon how much noise you can comfortably "live with". Today's cars also can have one or more computers controlling various vehicular parameters. Computers generate squarewaves by the score, and squarewaves have lots and lots of harmonics; many of these harmonics will appear within the ham bands. Some of the slip-on, thread-through, clamp-over ferrites available today will often tame computer generated noise and harmonics without having the slightest ill-effect on the computer control system itself (they only absorb unwanted RF energy). Where they're needed and how many will be necessary is the "cut and try" part mentioned earlier...it's anyone's guess. Usually, it' s best to start at the computer's input and output leads, installing the ferrite cores as close as possible to the shielded computer case itself. From there, it's the sensors on the various parts of the engine that can be given attention, again, as close as possible to the sensor-body itself. A shop manual for the vehicle is almost a must at this point. Avoid any by-passing that requires electrical contact with the vehicle electronics directly; try to stick to non-invasive ferrite absorptive devices and you'll not run the risk of inadvertently compromising your vehicle's control circuitry. Perhaps most importantly, take your time and attack the problem systematically and in small chunks, and thoroughly check-out each advancement made, to make sure that no ill-effect is noticed.

de Dave, NZ9E

A spicey DIP chip

Here's an innovative idea from J. Frank Brumbaugh, KB4ZGC/ W4LJD, of Salinas, Puerto Rico:

"I've found this wiring technique to very helpful at times, so I'm passing it on to others who may want to give it a try. Many times Dual Inline Pin (DIP) chips, particularly those in the 7400 family or even the venerable NE-555, require a number of jumper connections between several of their pins to make everything operate correctly. This can often result in a jumble of wires or unnecessarily complicated PC board trace layout in order to accomplish the task. But here's another approach...carefully solder very fine wires - taken from an untwisted short length of ordinary stranded hook-up wire - and make some of those jumper connections right on the bottom of the chip itself. Care must be taken to avoid any shorts, and the connections themselves made high on the IC's "legs", but pre-wiring some chips like this can save a lot of under-board cross-wiring later on. This jumper pre-wiring could be done on the IC sockets instead, before installation, if your intended project uses sockets instead of the chips themselves soldered directly to the board. Even if it isn't practical to pre-wire every jumper needed, the more you can eliminate using this technique, the neater the finished board will appear. Take a quick look at Figure 2 for a couple of real-life examples of this technique."

Moderator's note: Frank has a clever idea here...it might also be a good idea to note on the project's schematic which jumpers are "hidden"...perhaps showing them in dotted outline.

Never "assume"

Last year I made a "lights on" alarm (a buzzer sounds when the lights are left on without the engine running) for one of my cars that was missing this feature from the factory. The circuit worked like a charm on the bench and ditto when I installed in my car in the fall. Then the cold weather came. When the temperature dropped below freezing, the circuit still worked, but the buzzer would sound for a few seconds, even when it wasn't supposed to, that is, when the lights were on but also the car was running. The colder it became outside, the longer the circuit would take to operate correctly. My wife Sue, KA9UCK is very patient, but it even started to get to her!

To make a long story short, the problem turned out to be in the relay I had chosen to use to key the buzzer on & off...it was a small, sealed, good-quality relay, but it was also very temperature sensitive. Apparently, the contact arms in it deformed enough in the sub-freezing temperatures to cause it to make contact when it shouldn't have, but after heating up just a bit (from current flowing through its coil), it then operated correctly. Here's the point, we should never assume that any electronic circuit - even a simple one like this one - will behave "exactly" as we would like it to behave under all climatic conditions. I thoroughly tested the replacement relay in my lights-on circuit for temperature sensitivity (by putting it in the freezer for a while) before committing it back to the under-dash of my car again! Case closed, lesson learned.

We've all run into these types of problems, equipment that doesn't operate as expected under all extremes of temperature - extremes of either hot or cold - and it might be a worthwhile effort if you were to jot down some of the more interesting ones you've encountered and I'll include them in the column at some point in the future.

Cold testing a piece of mobile gear is relatively easy, just put it in the freezer for a while. Heat testing is a bit more tricky. The inside of a closed vehicle can reach very high temperatures during the summer months, but testing for extreme heat - by putting the item into an oven - is often a bit more dangerous. You don't want to damage your gear with the test! Has anyone devised a reasonably "safe" heat-test-setup, for subjecting mobile ham equipment to expected summer heat extremes, without too great a risk of permanent damage to the equipment itself? You folks in the desert areas should be experts on this one!

Dig-out your mobile vertical!

Back to the cold weather, here's another "environmental" tip. With winter coming, this piece from William Thim, N1QVQ, of Broad Brook, Connecticut, that we ran last April, bears repeating again now: "While you're in the process of cleaning that snow and ice off of your car windows, don't forget to dig-out your mobile antenna! A build-up of snow and ice around the base of your VHF or UHF mobile whip antenna can significantly raise your SWR, even to the point of forcing your transmitter to cut back on its power output. Check it with a good SWR bridge and you'll see what I mean. 2" to 3" of snow built-up around the lower "active" portion of the antenna will often result in a very noticable SWR change."

Moderator's note - Bill brings up a good point, even though the bottom part of a 1/4-wave vertical is the high-current, low-impedance end of the antenna, depending upon the amount of snow and ice, its conductivity and - to a great extent - the operating frequency involved, the tuning of the antenna - and its losses - can be changed quite a bit. It's something we may not always think of when we're not hitting the repeater quite as well as we used to during rough winter weather!

Mood lighting

From R. Gary Bartlett, VE1RGB, come these thoughts on lighting ideas within your amateur station: "To me, there is something very calming and perhaps a bit romantic (in the old-fashioned sense of the word), about a ham radio station that makes use of the built-in panel and edge lighting that comes fitted in most ham gear, as the primary radio room lighting. It's sometimes necessary to supplement the equipment lamps with some sort of external "spot" lighting, to illuminate a work surface or control panel, but the use of dimmer - rather than brighter -lighting is often the better choice. Having spent some time as an electronics systems operator on a Canadian military subhunter aircraft, often at night, I suppose that I feel most comfortable under the dim light of an operations area, but I've a hunch that many other hams feel the same way. I still enjoy listening on 3.4793KHz, late in the evening, as the Gander and Shanwick Oceanic Air Traffic Controllers are trading position reports back and forth and vectoring their flights across the Atlantic. I try forming a mental picture of where all of those airplanes are, and what they're doing, where they're going and all the many countries and companies they might represent.

How can you replicate this mood in your own shack? In our aircraft, we used what was known as a "Grimes" light, which had a selectable clear and red front lens. It also had a dimming "pot" and a focusing adjustment on it. It came with a helical coil-cord (like a telephone handset cord) and a quick-disconnect mount, so that the light could be easily removed for viewing some deep, dark recess if needed. In an aircraft, that's usually down near your left foot, where a dropped pencil could easily jam the mic foot-switch, HI. If you have any military surplus stores in your area, it might be worth checking with them to see if they have anything resembling what I've just described. You might also peruse any RV or camper supply catalogs, and/or dealers in your area, since lights of a similar type can sometimes be found in recreational vehicles. Even if you can't locate the exact "Grimes" light, you might be able to modify a light that is readily available, putting a little of your "ham ingenuity" to work.

Try to stick to 12 or 24 volt lighting if you can...it's much safer and easier to impliment than the much higher "line voltage" systems. A husky 12 volt transformer, properly fused, is all that's need for an AC low-voltage lighting setup, or your station 12 volt DC power supply can be used to power some lamps, as long as the supply's current limitations and adaquate fusing precautions are observed.

Dimming the lamps on an AC system requires a rheostat capable of dissipating the correct amount of wattage, whereas a DC system is able to use some of the modern adjustable regulator chips and a simple pot to vary the light output from your low-voltage lamps...an LM-317T is a good one to look into for this purpose (see the drawing in Figure 3).

External wiring to the lamp fixtures themselves should match the fuse rating and current drain of each lamp in a leg, and the use of insulated and adaquately marked terminal strips makes changing or expanding the system a breeze. Low voltage wiring is much easier to work with than its line voltage counterpart, but care still must be exercised to ensure that all wiring and connections are safe and low resistance. Keeping an up- to-date diagram is very desirable and not at all difficult to maintain.

By the way, if you happen to run across some particularly good hardware (fixtures, connectors, extensions, etc.) in implimenting this idea, please send them to this column's moderator so that we can all share in your discovery."

Moderator's note: Good observations, Gary, indoor lighting can often create the mood that you want more easily than just about any other easily accomplished project.

Super table

Here's another good workbench pin-up, this time from John Mc Dermott, N4YIC of Manassas, VA: "Here's a reference table of popular coaxial cable line-loss data that you can add to your Ham To Ham 'pin-ups'! It's certainly not 'original', but it does provide a fair amount of information in one, easily posted piece...see Table 1. It lists 32 coaxial cables, along with the normal loss-data, from 10MHz all the way to 3,000 MHz (3GHz) in an easy-to-read format. I hope it's as useful to others as it has been in my ham station."

TRANSMISSION LINE LOSS TABLE FOR COAXIAL LINE

(all values are in DB of loss per 100 feet)

Cable ------------------------- Frequency in MHZ -----------------------

RG/U Type 10 50 100 200 400 1000 3000

6A 0.04 1.90 2.70 4.10 5.90 9.80 23.00

8, 8A, 213 0.551 .30 1.90 2.70 4.10 8.00 16.00

Belden 9913 0.41 .64 1.00 1.60 2.50 4.50 **

Belden 9914 ** 1.10 1.60 2.40 3.50 6.00 **

Belden 9888 0.60 1.20 1.70 2.70 4.20 7.80 14.20

Belden 8214 0.60 1.20 1.70 2.70 4.20 7.70 14.20

8X 1.10 2.50 3.70 5.40 8.00 13.50 26.00

9, 9A, 9B, 214 0.66 1.50 2.30 3.30 5.00 8.80 18.00

11, 11A 0.66 1.60 2.30 3.30 4.80 7.80 16.50

14, 14A, 217 0.41 1.00 1.40 2.00 3.10 5.50 12.40

218, 219 0.24 0.62 0.95 1.50 2.40 4.40 9.50

Belden 9915 ** 0.60 0.80 1.20 1.90 3.50 **

34, 34B 0.32 0.85 1.40 2.10 3.30 5.80 16.00

55B, 223 1.20 3.20 4.80 7.00 10.00 16.50 30.50

58 1.25 3.15 4.60 6.90 10.50 17.50 37.50

58A, 58C 1.40 3.30 4.90 7.40 12.00 24.00 54.00

59, 59B 1.10 2.40 3.40 4.90 7.00 12.00 26.50

62, 62A 0.85 1.90 2.70 3.80 5.30 8.70 8.50

** No data available

Table 1

A charge slip

Here's a tip for those of you who might own the Yeasu FT-209RH or FT-709RH hand-held transceivers specifically, but may well have applicability to other models of portable hand-helds as well.

There are usually two choices for recharging a hand-held's battery pack: 1) using the optional drop-in charging stand via the charging contacts on the bottom of the battery pack, or 2) charging the pack with the small wall-cube-transformer/rectifier via a little charging jack on the bottom or back of the pack. But wait, here's a third alternative, and one that allows you to customize a bit as well.

The Yaesu FT-209RH uses a "slip-on" battery pack, slipping on from the side of the transceiver, and then locking into place...many others use a similar scheme. My wife and I have two of the Yaesu hand-helds, and a couple of the FBA-5 alkaline cell cases too. These are the battery cases made by Yaesu to house throw-away alkaline cells, but instead, I've opted to install AA Ni-Cad rechargables into the FBA-5's...this gives me the ability to put in new Ni-Cads with ease (or throw-away alkalines), any time I wish (ever try to open a "normal" sealed Ni-Cad pack...ugh?). The down-side is that the FBA-5 doesn't have the familiar charging contacts on the bottom...not being meant to house rechargables and also so that the user doesn't accidentally drop it into a desk charger with non-rechargable alkaline cells installed. In order to use Ni-Cads with it then, the cells must be physically removed each time recharging is needed...not the handiest of methods.

Necessity being the mother of invention, I wrote to Yaesu's Parts Department and inquired about the possibility of purchasing the battery mounting track and the battery contact plate assembly for the FT-209RH. These are the two pieces that are normally mounted on the bottom of the hand-held itself for holding the battery pack in place and to make electrical contact with the pack's output pins. My reasoning was that if I had these two essential parts, I could build a "slip-on" charger housing for my FBA-5 packs, making recharging them a snap (pun intended). Yaesu quoted a very affordable price for the two parts that I needed...their R3800630A and R3501270 (which are shown roughly drawn in Figure 4)...so I went ahead and ordered them, completing the job with the addition of the simple input jack and charge indicator circuit shown in Figure 5. I'm now able to use the standard Yaesu NC-18B wall-cube, along with the new slip-on adapter, for charging the Ni-Cads in my FBA-5 packs - while at the same time providing a visual indication that the batteries are taking a charge via the LED "continuity" indicator. Overall, a nice additional accessory to the battery line-up for these hand-held transceivers. Of course, the "slip-on" charger can also be utilized with the "normal" non-openable Ni-Cad packs too, providing you with a good "low-profile" travel-option.

de Dave, NZ9E

Gobs of mods

More on the topic of equipment modifications...there are a number of BBS's (bulletin board systems) around the country that have copious quantities of interesting modification files for commercially made ham equipment...all for downloading by interested individuals. And you don't necessarily have to have a packet station to access these files, though many full service packet BBS's also support a number of equipment modification file downloads. But if you're not yet into packet, all that you really need is a computer with a fairly modern telephone modem...and a terminal program that permits uploading and downloading of files. With just that minimum, you can make contact with many amateur radio oriented telephone BBS's who welcome fellow ham callers from outside the group of normal users. Check around with local club members, or on your local 2-meter repeater, to find out the phone number of the popular ham telephone BBS's in your own area.

One such system that I've personally explored is run by Bill Cohn, N9MHT in Schaumburg, Illinois

and operates under the name "The Precision Board". Bill encourages any ham, from anywhere,

to call up his system at (847) 985-9544, 24-hours-a-day. When you first sign-on, you'll be guided

through a few easy-to-answer questions...just to get acquainted. Then, as with many such

telephone BBS's, you can fairly quickly download Bill's ALLFILES.ZIP file, sign-off, un-zip the

downloaded file, then browse through the listing off-line...to see exactly what specific program files

might be of interest to you (the shareware file for un-zipping the ZIP file is even available if you

don't already have it). You can then call back later to download just those files of specific interest

(many are in the zipped format)...keeping your telephone charges to a minimum and not

occupying the board any longer than needed. The Precision Board is affiliated with the Arlington

Communications League (ACL) - a local suburban-Chicago ham radio club - and has hundreds

and hundreds of files (programs) dealing with both amateur radio as well as general computing

utilities and games. Some of the programs are Freeware (no strings attached), others are

Shareware (where the user is encouraged to pay for the use of the program after a free trial

period...if you like the program and plan to continue to use it regularly).

It's also a good idea not to just "take" from any BBS, but also to "give" a bit back...in the form of

uploading interesting programs that you might have that are also of a Freeware or Shareware

nature - don't upload commercially purchased software that isn't intended for secondary users.

Like a repeater system that you regularly chat on, a telephone BBS SYSOP can always use an

extra dollar or two to help with line charges, equipment operating costs and system upgrades.

Remember, these are volunteers who've put up their own gear for our benefit...don't be a rude

"guest" in their electronic den. The same courtesy should apply to SYSOP's within the

HF/VHF/UHF amateur digital network as well. They're giving of their time, energy and equipment

for our convenience...in the traditional ham not-for-profit spirit.

de Dave, NZ9E

Getting wired

Mike Hall, KE4GBE offers this worthwhile tip: "Next time you attend a hamfest or computerfest, keep an eye out for someone selling multi-colored computer ribbon cabling, it makes great hook-up wire for general electronic project construction use. Even the all grey ribbon cables can be utilized if you mark both ends of the individual wires with tiny dots...1, 2, 3 , 4, etc. dots, using a black fine-point felt tipped marker pen, but of course the multi-colored ribbon is much simpler to identify if it's available.

The flat computer ribbon cable I'm refering to is generally very good quality, stranded, easy to strip and tin, and will make your home-brew projects look much more professional. There is naturally some inter-wire capacitance, but it usually won't have any serious drawbacks in non-critical circuits. I've also seen twisted-pair computer interconnect-ribbons that have automatic resistance to inductive coupling from the outside due to their twisted format.

I'm sure that I'm not the first to 'discover' this tip, even Heathkit used to use sections of ribbon cables for some of the interchassis wiring in their kit designs, but I simply thought that I'd mention it again in case it's been forgotton or overlooked by some."

Moderators note: Good suggestion, Mike. Of course the multi-colored ribbon cable can also be separated into individual colors for use as regular single-circuit hook-up wire when distinctive colors will be helpful in troubleshooting later on. It's a good way to collect a wide variety of short hook-up wires of every color imaginable without having to buy the more costly long reels of each color.

That wraps up another month of Ham To Ham. As you've no doubt noticed, I'm still using too many of my own ideas and suggestions in the column...I need more input from all of you if we're to keep on exchanging ideas each month through the pages of 73 Magazine. I've mentioned it before, and it's true...this is your chance to express some of the neat and interesting ideas, solutions, tips or suggestions that you've found handy in your ham radio career. Jot them down and send 'em on to me at the address in the masthead...there's a very good chance you'll see them in print here in one of the future issues. You needn't be an "old timer" to have had very worthwhile experiences, I've received a number of very good ideas from relative newcomers to our hobby. Often techniques that can apply to ham radio are picked up from your professional experiences on the job, or sometimes they're just inspirational flashes that come when walking through a store or thumbing through a catalog and seeing something that has "good application for the ham shack" written all over it. Amateur radio touches on so many other areas of life's experiences...outdoor structural and wiring techniques, indoor shack and workshop ideas, computer conveniences, test equipment shortcuts, and on and on. Whatever you've experienced that you believe would be helpful to others is fair game...send it in and let me see what you've thought of. I'll be sitting out by the mailbox, and it's kind of cold this time of year, so don't let me down!

And as always, many thanks to those who've contributed to this month's column:

J. Frank Brumbaugh, KB4ZGC/ W4LJD

c/o Defendini

P.O. Box 30

Salinas, PR 00751

William Thim, Jr., N1QVQ

50 Miller Road

Broad Brook, CT 06016-9676

R. Gary Bartlett, VE1RGB

24 Lawrence Place

Wellington, NS

B2T 1A3

Canada

John E Mc Dermott, N4YIC

7977 Deward Ct

Manassas, VA 22110-3120

Mike Hall, KE4GBE

8131 Browning Circle

Acworth, GA 30101

Note: The ideas and suggestions contributed to this column by its readers have not necessarily been tested by the column's moderator nor by the staff of 73 Magazine, and thus no guarantee of operational success is implied. Always use your own best judgment before modifying any electronic item from the original equipment manufacturer's specifications. No responsibility is implied by the moderator or 73 Magazine for any equipment damage or malfunction

resulting from information supplied in this column.

Please send all correspondence relating to this column to 73 Magazine's Ham To Ham column, c/o Dave Miller, NZ9E, 7462 Lawler Avenue, Niles, IL 60714-3108, USA. All contributions used in this column will be reimbursed by a contributor's fee of $10, which includes its exclusive use by 73 Magazine. We will attempt to respond to all legitimate contributor's ideas in a timely manner, but be sure to send all specific questions on any particular tip to the originator of

the idea, not to this column's moderator nor to 73 Magazine.