Toshiba RF Project

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Toshiba RF Project

• Presentation 12 02/17/2005

Team Josue Caballero, Brett DiCio, Daniel
Hooper, Efosa Ojomo, George Sewell
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Last week

• Met with Professor Cook
• Sought sources of material for building an RF
  Transformer
• Obtained copies of the Amateur Radio Handbook
• Researched air-core coupling transformers

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Planned for Last Week

• Meet with Professor Cook tomorrow
• Research more on RF transformers
• Possibly build an RF transformer
• Test the RF transformer (dependent)

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RF Transformers

• Devices that transfer energy from one circuit to
  another by electromagnetic induction
• Very short range
• Used for impedance matching to achieve maximum
  power transfer
• Used to suppress undesired signal reflection

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Transformer
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Meeting with Professor Cook

• Discussed why an antenna was not good for our
  situation with Toshiba
• High bandwidth and variety of frequencies
• Distance between transmitter and receiver under
  one wavelength
• Determined that Toshibas current solution works
  more like a transformer than an antenna

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Meeting with Professor Cook contd

• Air cored transformers do not wrap around a piece
  of ferrite material
• Simple coils floating in space
• Lower gauge wire beneficial, maintains shape
  better
• If stability is a problem, the wire can be
  reinforced on top and bottom by some form of
  housing.
• Coupling is the process of both sides of the
  transformer meshing without touching
• Increases efficiency and reliability
• Decreases the necessary signal strength for good
  reception

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Meeting with Professor Cook contd

• Other design notes
• Parallel capacitance with the transformer can
  adjust reception for a specific frequency
• Transformer strength can be adjusted by moving
  the coupled parts closer and further apart
• May need two separate reciever transformers for
  VHF and UHF frequencies
• Need to use adjustable capacitors for best results

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News from Toshiba

• Toshiba will allow an easy means of switching
  between channels on the receiver
• We may include as many or few test per station
• Toshibas current solution uses copper wire with
  an extremely thin clear-coat insulation

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For Next Week

• Obtain a spool of copper wire
• Build a test-transformer (basic design)
• Design a coupling transformer
• Test coupling transformer
• Research equations and methods for performing
  calculations on bandwidth
• Learn about tuning capacitors

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References

• http//www.minicircuits.com/appnote/howxfmerwork.p
  dfsearch'rf20transformers
• Harris Electric Supply CO Inc