Application Notes

Radio Direction Finding Basics

Using Doppler Systems Radio Direction Finders to GeoLocate Transmitters11 May 2015Tutorial on using radio direction finders to geolocate transmitters.  Examples using single mobile and networked fixed sites and mobiles are presented.
Site Location for Optimal Triangulation24 Oct 1998Error contours that result when 2 to 10 direction finders are optimally located in a square coverage area.
In-band Interference from a Nearby Transmitter30 Jun 2018Graphs that allow the separation to be calculated between the DF array and a nearby in-band transmitter in order avoid damage and/or desensitization.
Errors Due To Side Mounting DF Antenna on a Tower11 Apr 2016Graphs showing the error to be expected when side mounting the DF antenna array on a tower or mast. 

DDF700 Series Radio Direction Finder

Accuracy of Series 7000 (MPT) DF11 April 2012Measured bearing accuracy of all fixed site 7000 series antennas
RF Sensitivity of Series 7000 (MPT) DF8 July 2011Bearing stability, and probabilities of detection and false alarms for 7000 series DFs.
Wind Loading and Stresses on the Series 7000 (MPT) Antenna Arrays.pdf21 Nov 2011Wind loading and stress for single and stacked 7000 series antenna with and without ice loading.
Using the DDF7001 with a ICOM R8600 Receiver 17 January 2020Instructions on how to use ICOM’s R8600 receiver with the DDF7001 direction finder.
Using the DDF7001 with a AOR DV1 Receiver 17 January 2020Instructions on how to use AOR’s DV1 receiver with the DDF7001 direction finder.
Streaming DF Audio over an Internet Connection17 September 2013Instructions on how to set up your router and the direction finder software to gather bearing data and receive streaming audio from the direction finder over the Internet
A Simple Homing Direction Finder Using a DDF7001 and an Android Device 7 August 2013Instructions on how to set up and operate a DDF7001 mobile direction finder using our new Android app available from the Google Play Store
Using the AOR AR8600 Receiver with Doppler Direction Finders 13 June 2013Settings required to use the AOR AR8600 with our direction finders
Splitters and Preamps for Driving Multiple Receivers in Series 7000 DFs8 June 2013When using a single antenna and multiple DF processors to simultaneously direction find on mulitiple frequencies, in general, you are better off not to use a preamp.
Guide to Lightning Protection of Series 7000 DF Antennas27 Mar 2013Lightning rod placement around fixed site 7000 series antennas
Back Pressurization of DF Antennas13 Jun 2009How to connect a low pressure dry nitrogen supply to the DF antennas for protection in extreme environments.

DDF6000 Series Radio Direction Finder

Sensitivity of Series 6000-6100 Direction Finders  8 Apr 2003Discusses the difference in the algorithms used in firmware versions 4.18 and earlier and the latest version 4.19, and it provides test data showing the sensitivity for both continuous and pulsed signals. 
Using the Digi One SP to Network Doppler Systems DDF6001s using an Ethernet  6 Feb 2004How to use a Digi One at remote sites. This solution provides very economical remote internet connectivity for the DDF6001 fixed site direction finders.
Using a Barix Instreamer to Remotely Connect a Direction Finder via a Network Connection.pdf 18 Jan 2008How to set up and operate a remote connection using the Barix Instreamer to provide both data and audio from remote sites.
Stress Analysis of Fixed Site Series 6000 Antennas12 Apr 2002Stress calculations and safety factors for our fixed site antennas and antenna stacks subject to wind and ice loading.
Remote Display for Series 6000 Direction Finder30 May 2004How to modify a Series 6000 direction finder to connect the 5921 remote display at J2.
Wind Loading on Fixed Site Series 6000 Antennas  4 Dec 2001Calculates the wind loading on all of our fixed site antennas and antenna stacks.

Older Models

A Covert Tracking System Using the DDF593125 Apr 2004Construction, calibration and operation of a tracking system based on the use of the Series 5900 Direction Finding System.
Changing Baud Rate on the DDF4003 or DDF5003  1 Oct 1995Circuit board modification needed to make this change.
Product Identification and Compatibility of Obsolete Models24 Nov 2011Identify older models and compatibility of summers to processors

General Interest

AOR AR8600MKII RSSI Connection .pdf10 Nov 2008How to modify this receiver for an RSSI connection on the Accessory connector.
ICOM R10 Receiver Modification to Provide S-Meter Output.pdf21 Apr 2001Directions for adding RSSI output to this receiver for use with any of the Doppler direction finders. 
Assigning COM Port Numbers to the Serial Ports of a USB-to-Serial Adapter.pdf 6 May 2008 Step by step method to configure multiple com ports assigned using a USB to serial adapter.