I wanted to build a combo TDOA and offset-attenuator board for use in Fox hunting.  There are a few classic designs from the 80s that I wanted to remix and use the latest available components.  So I decided to make a microcontroller-controlled version that could be programmable and use the latest available RF chips.  Interesting thing about new components: 1) they are really good, 2) they are really inexpensive, and 3) they are super small!  Take this RF switch chip, 6 pins, switches between antenna A or B, works from 10Mhz to 3 GHz, and is less than a dollar, but look at the size of it!  That’s the point of my 0.7mm mechanical pencil.

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Next to impossible to solder with a normal soldering iron.  I have other components with the pins on the bottom of the chip.  I decided to embark on an adventure into professional, hobby-grade surface-mount assembly.  Along with the PCB board, I ordered a stencil and a stencil printer.  I also have a reflow oven.  So rather than hand solder these little tidbits I thought I would try my hand at stencil printing solder paste on the board, hand placing the components with tweezers and then baking them in the oven.  This is my first attempt.

The stencil printing is pretty simple.  A thin sheet of metal is laser-cut with holes where the solder paste should be applied to the solder pads.

Attach the stencil to the stencil printer, and carefully align the PCB so the holes match up.

Close it, then smear the paste on with a spatula!  Ideally, if done right, the stencil height ensures just the right amount of solder paste is applied.  This being my first attempt, well, I smeared too much paste, but they say it is forgiving and that’s okay.  And if not, well, I did order 10 boards, so I can practise quite a bit, HI HI.  Next, the board goes into a reflow oven.  I bought this oven several years ago for about $100.  Its claim to fame was that it didn’t work, was dangerous, but it was cheap.  And the hacker community figured out how to make it safe with about $5 worth of parts and even engineered a new firmware that could be flashed to make it work.  Gotta love the hacker community!

The reflow oven is basically a PID controller.  It has a heater and a fan.  The PID controller sets the temperature by either turning on the heater or the fan.  The solder paste manufacture specifies a temperature over time chart to ensure perfect results.  First, the temperature goes to 150 C to set the paste for 2 minutes, then it goes to 215 C for 90 seconds to solder, and then cools down at a rate of 3 C/second.  Overall, soldering the board takes less than 6 minutes.

And six minutes later, all 27 components have been soldered!

A little heavy on the solder, but only had one small bridge between 2 pins on U1, which was easily removed with a dab of the soldering iron.  Next steps: hand-solder the components on the top side, and the board is done.

And again the bottom side that was reflowed in the oven.

Overall, it was pretty easy.  Took about 2 hours to build this from start to finish.  Most of the time spent was getting the components out of the packaging.  I’ll probably sort these beforehand when I build up the next batch of boards.  Placing the components with tweezers is not that difficult (I had a magnifying headset to see them) because it just has to be close enough; the reflow process naturally straightens the components out so they are perfectly aligned, and because of the solder mask, any excess paste flows back to the component and pad and avoids bridging.

I am generally pleased and look forward to new projects that use these ridiculously small, inexpensive, and modern components.

7:00pm Virtual Eyeball QSO – Setup, Social time & Coffee

7:30pm
1. Meeting Call to Order, Welcome – Frank VA3FJM
2. Roll Call & Quorum – Rod VA3MZD
3. Adopt Agenda – Rod VA3MZD
● Motion to adopt Agenda of May meeting
4. Presentations/Speakers/Workshop
● Radio Direction Finding: Foxhunting on the 70cm band – Hagen VE3QVY
5. Secretary’s Report Rod VA3MZD
● Motion to accept Minutes of May/AGM Meeting
6. Treasurer’s Report Ted VE3TRQ
● Monthly Financial Reports -Motion to accept Treasurer’s Report
7. President’s Report
● Frank VA3FJM
8. Committee Reports
● Repeater Technical Committee Tony VE3DWI
● EMCOMMS Group – Paul VA3PDC
● Field Day – Ken VE3KCY – Saturday, June 27-Sunday, june 28, 2026
● Hamfest Report – Ted VE3TRQ
● Youth – Stewart VE3HWS
● Other
9. Unfinished Business
● Lighthouse Weekend – Bob VE3IXX
10. New Business
● Field Day Logging- Ted VE3TRQ
● Club Web Site – Hagen VE3QVY / Ted VE3TRQ
11. Announcements
● Next meeting: September 22, 2026 7pm
● Wires-X Net – 4th Thursday of the month – Thursday, June 25, 2026!
● Field Day setup – Friday June 26
● Other Announcements?

Adjournment

Sunday June 7, 2026, Waterloo Regional Police Association Rec Facility

Paul VA3PDC, John VA3PT, Ted VE3TRQ, Rod VA3MZD, Curtis VE3EFI, Tony VE3DWI, Ken VE3KCY, Mark VA3AZH

Missing (but at the Hamfest): Jim VE3JMU, Mike VE3FE, Frank VA3FJM (may have forgotten some 🙂

7:00pm Virtual Eyeball QSO – Setup, Social time & Coffee

7:30pm

Voting:

Voting shall be done during the AGM and in the case of an unopposed slate, in which a nominee is the single candidate nominated for a particular office, the nominee is elected by ‘acclamation’.

Elmira Radio Club members nominated for executive positions:

● President Frank Monteith VA3FJM, John Linnert VA3PT
● Vice-President Hagen Kaye VE3QVY
● Trustee
● Secretary Rod Murray VA3MZD
● Treasurer Ted Rypma VE3TRQ