Order Cart | Contact Us | Home | SIGs | Login

N4XI X1W-4 EMP Sensor Kit

The EMP sensor kit was developed as a cost effective alternative to more expensive lightning detectors on the market. It boasts a fast response time and also allows adding an experimental input filter (a low-pass LC circuit which is normally not populated). Compared with commercial sensors, this unit is more sensitive, and allows repairs using readily available parts.

The design employed is essentially a VLF broadband receiver. The heart of the circuit is a Darlington pair that provides an open-collector output capable of safely sinking several mA. When a stroke is detected the output momentarily shorts to ground. Designed to be used with the X1W-1 or X1W-2 EMP interface, the output is fed to a simple 1-Wire counter which is then read by the system periodically.

Other than the usual assembly tools for kits, you will also need a hacksaw, drill and a high-wattage soldering iron or gun. The latter will only be used to sweat solder the copper antenna pipe to the PC board. A small 15W-25W iron will still be required to solder all other components on the PC board.

Ordering Information

The price for the X1W-4 EMP Sensor Kit is:

  • $ 19 US for members of TAPR

  • $ 22 US for non-members

    + shipping/handling if applicable.
(Place Web Order)

Shipping and Handling

Shipping and Handling within the US will be by USPS Priority Mail.

International shipping costs are calculated as closely as possible. If the actual cost exceeds the estimate by more than $10.00, TAPR will contact you to get approval for the additional funds. TAPR uses insured Priority Mail International, unless the purchaser requires something else.

Assembly and Operations Manual

The assembly and operations manual can be found online at http://www.tapr.org/n4xi-tmp-html/x1w-4/


TAPR kits can be complex depending on the kitting experience of each builder. We don't think you will have trouble with the kit, but it does require some knowledge and experience to successfully go from a kit to a finished, usable unit, depending on the mode of operations.

The T-238 series and X1W series kits are discussed on the Weather Special Interest Group (WXSIG). You can join WXSIG via the web at:



View WXN: A Weather Server For Amateur Radio


The TAPR X1W-4 Kit was made possible by the efforts of:
John Bennett, N4XI - Conceptual and PCB Design
Steve Bible, N7HPR - Project Manager
John Koster, W9DDD - Assistant Project Manager
Joe Borovetz, WA5VMS - Parts Liaison
Dwight Hazen, WB9TLH - Beta Tester


1-Wire™ is a registered trademark of Dallas Semiconductor Corporation, a wholly owned subsidiary of Maxim Integrated Products

About Us | Privacy Policy | Contact Us | ©2005-2016 Tucson Amateur Packet Radio Corp unless otherwise noted.

facebook twitter utube

Accept Credit Cards