OzarkCon QRP Conference
2015

Kit Building Workshop

Friday Evening, April 10, 2015
    
The Midwest Homebrewers QRP Club coordinates and supervises the OzarkCon Friday Night Build Session.  Never built a kit or have questions about building ham projects?  Here's your opportunity to learn from the experts.

This year's build session kit is the

4S-Low Pass Filter

This year's kit is an inexpensive, but effective, low pass filter.
The FCC requires all spurious emissions below 30Mc to be attenuated by 43 dB or more.  The second harmonic usually needs the most effective filtering to meet that specification, and this little filter will allow your transmitter to easily meet that spec.  Simple homebrew transmitters such as the Michigan Mighty Mite and similar absolutely require an LPF between it and the antenna.  So if you enjoy building and experimenting with transmitters, this is the perfect filter project for you.  It will be available in both an 80M or 40M version.

NOTE: this isn't a QRP only design. You can put it behind any rig that you own, because it will easily handle well over 100 watts!

This is a "None Simpler" design.  That is, there are NO TOROIDS to wind, the kit features the NMØS famous spiral coil inductors as seen in the NS-40 transmitter.  It also includes a beautiful jet black pcb enclosure - another NM0S trademark.  At 2"x2"x3" it will fit easily on your operating desk or workbench.

The cost of the build session is $15, and you must attend to buy it at this price.  After the conference It will be available in the stable of Four State kits, but will be at a slightly higher price since the build session prices are always at or below Four State's cost.

 

This year's session will follow this general format.

  • 1. Short Power Point presentation (~10 minutes) on HF LC filters.
    • Short review of the FCC requirement for spurious emissions
    • No technical stuff or calculations, just general info and pictures, including:
      Types of filters with response curves, to show the differences between them.
      Response curve of the 4S-LPF and what makes it good.
  • 2. Build the kit.
  • 3. Test it.
    • Each of the builders can then check the performance of their own filter on the output of a test transmitter (Michigan Mighty Mite or similar) on an oscilloscope and a spectrum analyzer (if we can round one up).


The build session is limited to 40 participants.  So register early to assure yourself of a kit and a place at the workbench.
The price is $15. Which is good only during pre-registration, and availability is limited to one kit per person.  You must build the kit during the build session, no buying the kit and taking it home at this price. . The instructors for the evening workshop will be Dar Piatt W9HZC and Darrel Swenson KØAWB.  Dar and Darrel will guide you through the building process, starting with the "bag of parts" to the finished project.  First time builders welcome!

A large room is reserved so that seating will not be a problem.  Each session is limited to 20 persons (40 total)so that the instructors can provide plenty of 1 on 1 help.   They may however specify one large group rather than 2 smaller ones and stagger the starts by 15 minutes, depending on the project and the number of attendees.  Please check with them at the conference before the banquet.

Pre-register now and save
We are prepared for a large group this year, and we hope to see you in the Build Session.
For the workshop, you will need to bring your own hand tools for the session:
  • Soldering iron with a stand. A small tip on the iron is suggested. This could be a simple 25 watt iron with a bent coat hanger stand.
  • Damp sponge to clean the soldering iron tip
  • Rosin core solder - Kester "44" or similar. Note that we will have some spare solder available.
  • Small wire cutters
  • Needle nose pliers
  • Magnifier and/or light
  • Cookie sheet with upturned lip to catch stray parts, to reduce static discharge damage to components and to protect the table surface


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