Audio Interface Unit in Action - WW1USA


The Santa Fe Trail Amateur Radio Club is undertaking a construction project to improve the Field Day and Special Event operating experience. This article will provide information on the our project without repeating the full source article. A link to the original article is provided at the end of this article.

Events such as WW1USA Special Event Station and Field Day can be a fun and yet challenging for operators, loggers and guests. The noisy surroundings and need to concentrate on the chaotic signals on the band requires the use of a headset by the operator. This leaves the logger or the guest with limited ability to hear the contacts. Communications between the operator and logger is also difficult. To solve this problem John Raydo K0IZ designed and published plans in a June 2008 QST article titled "An Audio Interface Unit for Field Day and Contesting".  

The K0IZ Audio Interface Unit enhances headset operation by providing the following:

  • Operator headphone interface to the radio
  • Logger headphone access to the contact audio
  • Intercom communications between the operator and logger
  • A speaker for visitors to hear the contacts
  • Provides individual level control for the operator and logger
  • Supports three types of microphones; dynamic, electret and aviation
  • Foot switch interface
Front View
K0IZ Contesting Audio Box

Rear View


A number of the components have been donated by Jeff Darby, Howard Cripe and Jim Andera. Joe Krout provide the circuit board that started the project and the the QST article. Howard has volunteered to 3D print the project, should be interesting to see the finished enclosure. The remaining parts will be ordered online and hopefully will be here in time to complete the project for the 2019 Field Day. This could be an interesting project for new hams or those interested in building projects to observe or participate in the assembly.

Source: QST June 2008

Author: John Raydo, K0IZ

Title: An Audio Interface Unit for Field Day and Contesting

Click the link above to view a copy of the full article.

The ARRL, QST, provided written permission to use article content (May 7, 2019).