Last time, I said I would tell you what the secret ingredient is for the peanut butter jar dummy load, and so I shall. Are you ready?

It’s water. Yep, plain ol’ H2O. Well, actually, there are some other ingredients, which I will get to, shortly.

To finish the dummy load, remove the lid and fill the jar with water to within about three-quarters of an inch of the rim. Remember the two "extra" electrodes? Place them on opposite sides of the jar, as shown in Figure 1.

Connect each lead from your VOM to one of the electrode, red to one electrode and black to the other. I get a reading of about 50k Ohms using Ventura tap water. The exact reading depends on the mineral content of your water. While giving a demonstration of this dummy load at the Ventura County Amateur Radio Club a few weeks ago, in Oxnard, CA, I got a reading of only 20k Ohms. Evidently the water over there has more "stuff" in it than we have here in Ventura. In any event, what you want is about 5k Ohms. You reduce the resistance to 5k by adding salt. Yes, ordinary table salt does the trick. Using a non-metallic instrument, stir the water as you SLOWLY add the salt. I use a piece of bamboo about a foot long for stirring; a plastic fork or knife will do the job. Watch the meter as you add a pinch of salt. "A pinch?!" you might ask. Yes, a pinch may be all you need. If you don’t know what a pinch is, consult a cookbook. If you don’t have a cookbook, a pinch is equal to half a shake from a salt shaker. If one pinch doesn’t do it, try two, watching the Ohm meter while gently stirring the solution to be sure all the salt is dissolved.

OK, now that you are reading about 5k Ohms ("about", in this case, means anything from 4k to 6k) you are ready for a live test.

Alert readers, such as yourself, may be thinking: "Wait a minute, my transceiver requires a 50 Ohm load, or it shuts itself down. 5k is not going to hack it !"

Not to worry!! What your transceiver r-e-a-l-l-y wants to see at the antenna terminal is a low Standing Wave Ratio (SWR). This dummy load will deliver just that, trust me.

Now that I’ve cured your paranoia about the 5k dummy load (You are cured, aren’t you?) remove the two test electrodes, insert the "real" electrodes that are connected to the coax connector in the lid, and connect a coaxial line from your transceiver to the dummy load. If you like, you can insert an SWR indicator between your transceiver and the dummy load, just to be sure I’m not cheating.

If you suffer from lingering paranoia, start with very low power for initial testing, and feed some RF into the dummy load.

Guess what, RF is going into the dummy load, and the SWR is way down there where your transceiver likes it. See, I told you it was going to work ! "How/why does it work?" you might want to know. You have a transceiver happily feeding RF into a dummy load, so don’t worry about it. These articles are about tinkering, not scientific research.

In case you are wondering who came up with this idea for a dummy load, I haven’t the slightest idea. It is one of those things that’s been handed down from one generation of Ham Radio operators to the next, and I doubt of anyone knows, for sure, where the idea originated. I got the idea from a Military Affiliate Radio System (MARS) buddy of mine, Lasalle, AAR9RAR. My MARS call is AAR9EV, and I also carry the billeted call of AAM9TCS. I’m also a member of the National Communications System (SHARES). I do lots of radio stuff !

Speaking of MARS, it occurs to me that radio junkies, such as yourself, might be interested in this fine organization. No, this is not a recruitment pitch for you to join MARS. I realize that MARS is not everybody’s cup of tea. This is simply my way of showing (or reminding) you that there is more to Ham Radio than tinkering, chasing DX, or collecting QSL cards. For those who are so inclined, emergency communications in general, and MARS in particular, can be a rewarding adjunct to your Ham Radio activities. 

First of all, I want to point out that you do NOT have to be a member of the military or a veteran to join MARS; many members have NEVER served in the military. There are, however, some requirements:

You must be 17 years of age, or older.

You must be a United States citizen, or resident alien.

You must hold a U.S. Amateur Radio station license (any class). If you hold a Novice class license, you must upgrade to Technician or higher class within one year. 

In addition to these prerequisites, MARS has certain eligibility and participation requirements that must be met, including a minimum of 12 hours participation in each calendar quarter. Six of those hours must be on the air. That’s only 2 hours per month of air time, which is easily attainable. MARS time is recorded in increments of 0.5 hour. One through forty-one minutes count as half an hour; forty-one through sixty minutes count as one hour.

If you decide to join MARS, there is a Basic Training Course that must be completed within six months. This training consists of on the air activities as well as self-study material that must be completed. This training includes terminology and definitions, fundamental MARS voice net operations, emergency communications procedures, and traffic handling. Of course, the time you spend in training counts toward meeting your participation requirements.

Most MARS traffic is handled via digital modes, including AMTOR, PACTOR, GTOR, and PACKET (both HF and VHF). Some administrative traffic is handled via e-mail. If you are not equipped to do digital modes, no problem; there is plenty of activity on SSB and FM (MARS does not use CW). There are MARS nets in every state, both VHF and HF. All MARS nets are operated OUTSIDE the Ham bands. Some of the MARS nets are near the Ham bands, so your equipment may not have to be modified immediately, but sooner or later you will want to modify your equipment (or have someone else modify it for you). 

Speaking of equipment, while getting "free" goodies should NOT be the primary reason for joining MARS, I must point out that there are, indeed, some fine goodies available to active MARS members. For example, a few weeks ago, I picked up a brand new RT-1446 / URC transceiver. No, this is NOT a WW II boat anchor. This is a very modern, solid state, computer controlled HF transceiver (2 MHz – 30 MHz). The rig is very conservatively rated at 100 Watts. The power source can be either 120 volts AC, 13.6 volts DC, or 28 volts, DC. The rig operates in several modes, including USB, LSB, CW, and AME (AME is SSB with the carrier re-inserted so that a receiving station with only AM capability can copy the signal). No documentation came with the rig, and it took me a while to get it up and running. I now have it going on SSB, CW, Packet, and AMTOR. 

Anyone wanting additional information can find more than you ever wanted to know about MARS by visiting any of several MARS web sites on the internet. I suggest you start with the MARS Headquarters site at

www.asc.army.mil/mars/Default.htm

This site has links to individual state MARS web sites in addition to details regarding just about every aspect of the MARS organization. 

That is more than enough about MARS.

Next time we’ll take a look at a new series of modules. ‘Til then …

73, Dick,,W6BKY
 

73, Dick, W6BKY