What's that noise?

A man of Polish descent went to the Pacific Northwest wanting to become a lumberjack. In purchasing a chain saw, he was told by a salesman that a particular model was guaranteed to cut down at least ten trees per day. So he purchased it and wandered off into the woods to ply his trade. About one week later, he reappeared in the store and loudly complained to the salesman that the best he could do with the saw was seven or eight trees. The salesman took the saw from him, unscrewed the gas cap and noted that it was full. He then pulled on the starter cord and heard the saw roar to life.

Whereupon, the Polish gentleman exclaimed, "What's that noise?"

~Courtesy of Steve Pearson, a dear, departed friend

As related in a previous post, I am on this quest because my MFJ 259 took a dump and I seek a replacement for the test bench. Before plunging into a narrative on the adventure replacing the MFJ in subsequent posts, I would share one of the wonderful things today is home brewing and kit building. Back in the halcyon days of yesteryear the field was dominated by Heathkit. with Heath's passing from the scene, we have what is now a world-wide "cottage industry" and those techs and hams who engage in kitting are of the nicest, most personable sort. Doug Hendricks of NorCal fame, Jim Kortge, the father of the 2N2/40 family, Eric Swartz and Wayne Burdick of Elecraft, etc.

No exception to this -- and certainly worthy of warm and cordial citation -- is Lou Destephano, VK3AQX, the progenitor of the RX1 and RX2 noise bridge kits. I stumbled across these back in November of last year and ordered the smaller, less expensive RX2 from Lou as a way to dip my toes in the water to test things out.

I want to tell you that it has been a wonderful experience. For the price of a test instrument kit, I received a veritable electronics classroom, an abundance of quality materials and finely crafted components, and a warm and wonderful friend from Down Under. I used to describe my Elecraft K-2 (good ol' #999) as a kit that was not only a well-engineered radio but also a well engineered kit. It was designed so as to enable electronic dummies like me to construct one of the finest QRP transceivers made. You could put together a rig that would rival (and exceed) many of the commercial models available. (In fact, the K-2 specs bear this out.)

Author's RX2 with the FT-817 used as adjudicator

Well, Lou's RX2 not only achieves this level, it also puts more of the creative element in your hand as you fabricate it. My words here may be imprecise and possibly misconstrued but should not be regarded as anything but high praise for Lou's contribution to our hobby. Allow me to elaborate.

I am sure many of you have started on a weekend project and, late Sunday afternoon, have completed something of a kluge that works well but was band-aided, chewing-gummed, and bailing-wired together. Sure the thing received, oscillated, measured, and otherwise worked up to your expectations. But it -- well -- looked like shit.

(An exception to this are actually some QST/ARRL projects that just flat out did not work. I would build these little beasts, get curious results and consult my friend, Dick, WB6JDH, only to be told, "Oh yeah, that thing's a dog! You gotta look up the four editions of corrections and even then it drifts around like a drunk at closing time.")

So, for the most part, I stuck to kits in my building efforts and only engaged in the ARRL stuff when I was absolutely sure of the pedigree. Ironically, one of these cases was my attempting to fabricate a noise bridge that appeared in the mid-90s ARRL handbook. It was a good circuit and Dick said he built and used one. So I tacked the circuit together and lashed it up to see how effective it was. While not disappointing, I found that the bridge generated this rasping in my radio that was easily confused with incoming RF static and that, while there was a null, it was almost indiscernible.

This led me to cast about on eBay and at swap meets for a commercial alternative. I scored an old but clean Palomar Engineers model and employed that to provide impedance/resistance measurements -- only to find out that it was only marginally better than the handbook circuit. (Actually, I had wonderful memories of these as my late father, N6ABV, used to come over Sunday afternoons and we'd work through resonance/impedance measurements with his Palomar. Being a good tech and an MIT graduate, he had greater success with his than I had with mine. Frankly, I considered the Palomar I have now to be useless. So, I continued my search.)

And that's when I stumbled upon Lou's You Tube videos.

At first, I thought them to be the product of some Aussie proudly showing off a new purchase and -- because of the care and thoroughness of the videos (you do well to watch all of them, noting how exacting Lou is at describing his methods and techniques) -- I wondered where I could purchase such a wonderful instrument. Imagine my surprise and joy when I discovered it was a kit and Lou was the originator/seller. Needless to say, a short (and courteous) e-mail response and a PayPal transfer later and I was in the waiting game for the RX2 kit to arrive. During that time and while the kit was being built (and indeed still) I would e-mail Lou questions and receive the most wonderful responses. They not only nailed the questions, he and I nattered on about life, politics, ham radio, and other topics. Bet you dollars to donuts you never had a similar experience with a Heath tech. But, this is one of the values of the RX1 and RX2: Lou's friendship and readiness to engage in a perfectly marvelous conversation with you. It is like having an Elmer electronically close at hand.

But I digress. A couple of more observations and I'll turn to doing the subsequent posts on my building and learning experiences.

When I unpacked the kit, I noted that there was not a strict conformance to the inventory. Instead, there was an abundance of parts and "extra bits" that Lou includes. Then there were the components like the project box and the nylon bushings he provides for the capacitor and resistor. There were also these most wonderful labels -- magnificently done artwork -- a selection that Lou provides for the outside of the box and yet another ingenious cut-away "test label" that allows you to align the bridge with the top off. I gather from Lou's other videos that he is a machinist and this becomes readily apparent in the precision of the bushings and the fact that the labels are especially tailored to the resistance of the variable pot included in the kit!

Close up of RX2 label showing accuracy

As can be seen from the pictures of the RX2 labels, the resulting instrument is much more accurate and precise than the Heath, MFJ, and Palomar bridges. Yet Lou calls attention tho the fact that the RX2 is the smaller, less exact bridge -- a student model -- and the RX1 is what one would call the lab grade model.

That said, with this surfeit of parts and the ready and rapid e-mail responses, one gets the feeling that one is over at Lou's workbench with him at one's elbow offering advice and alternatives to complete the mythical weekend project mentioned above. Only this time, it would work outstandingly well and look excruciatingly handsome!

I could gush much more like this but I wanted to register my total and complete satisfaction with the cottage industry down under that produces these noise bridges. A warm and cordial friendship thrown into the bargain make this one of the best deals in amateur radio, if not life.

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