In the fall of 2004 I clicked on a link to Scotty's Spectrum Analyzer and for the first time I saw the type of spectrum analyzer I could afford and looked like it had most of the performance parameters that I would need.

I also joined the Yahoo [spectrumanalyzer] group and quickly learned that there was a discussion about how to get boards done and what PCB design software to use if someone were wanting to take on that task, either individually or collectively. We each have our own ideas and I evaluated several of the low cost (or no cost) products available and in the end stayed with my own trusty, tried and true friend CIRCAD. I have added lots of new parts to the libraries since I began this effort and those libraries will be made available, as well as, the sources to the boards, all part of my public domain agreement with Scotty.

At first I worked on a few schematics and got lots of help from Scotty, then I actually laid out a couple of boards. Scotty patiently explained his philosophy of keeping the signals on one side so that the "bottom side", which is all copper ground plane, would become the sixth side of a shielded enclosure.

On or about New Years Day, 2005, I announced that I had boards available for sale. I also showed the boards to some of the local Hams and my Elmer and immediately sold three sets of kits when I could get them together. I made a small buy for the local group. That is when I ran into the first challenge. There is so much copper (very good RF technique) on the boards that I could not get a proper solder bead on the surface mount pads that go to ground, which is nearly half the pads. I knew that the chips could tolerate 100 degrees Centigrade all day long because that is significantly below there storage temperature. I put the boards on a hot plate and turned it on it's lowest setting. I experimented with a setting that would regulate my hot plate to the proper temperature and then discovered that that made all of the difference in the world, the parts could now be soldered properly. It still was a laborious job to solder the small surface mount parts, however.

I did some research and reading on reflow soldering techniques that are used to assemble modern circuit boards. This toaster oven article gave me enough courage to try to the hot air method that I now use and teach. In order to try some of these techniques, some solder paste was needed. It comes in a small tub the size of a cold cream jar. For the typical kit builder this 0.5kg jar is a life time buy, but the shelf life might be way less than that. There are commercially available pneumatically operated syringe dispensers but not within my budget. Again, I experimented with a variety of hypodermic needles and syringes and found that a small diabetic syringe with the needle cut very short will serve nicely to dispense paste onto the pads. A whole modular board can be done in a matter of minutes. The paste does not dry excessively fast and so you have several hours to complete the next few steps, although it should only take 15 minutes. You now place the individual components into the paste blobs which act as an adhesive to hold the part in place. Once all of the surface mounted parts are in place I use a Wagner hot air paint stripping tool to mass solder the parts in place. Much more information will be included on this website to help you with this technique, it really works.

All board products are made to very high standards, FR-4 board material with one ounce copper. All board products have top and bottom solder masks and silk screened legend. The bottom copper side is continuous ground plane and as much of the top side copper is ground plane, as well. The ground planes are connected by ample vias. Signal paths that are designed for high frequency RF approximate stripline technique. Miniature coaxial connectors include SMA and SMB types and can be either vertical or right angle types. Digital and power signals are bypassed to prevent radiation of RF through these signals paths. Boards are designed to be surrounded by shielding on the top side to prevent RF leakage. No signals are exposed on the bottom side.

While all of the following boards were specifically designed to be integrated into Scotty's Spectrum Analyzer the boards can be used to create all manor of other circuits related to RF experimentation and testing.