Doppler Systems Blog One of the often overlooked features of the Doppler DDF7000 series direction finders is the ability to direction find on several frequencies simultaneously using a single antenna. This is most often used in a fixed site system. All that is required is a DF processor and receiver Read more…
Doppler Systems Blog Recently one of our customers requested that we include the AOR DV1 as a receiver option. We are always happy to support as many receivers as possible, so we gladly agreed. Our customer sent us a DV1 and we proceeded to add the firmware to control the Read more…
Doppler Systems Blog In our specifications we call out a sensitivity specification of -123 dBm. A detailed explanation of how we define sensitivity is given in our technical application note entitled RF Sensitivity of Series 7000 (MPT) DF but I thought I would hit the high points of the application Read more…
Doppler Systems Blog Occasionally we are asked about how we build and test our products. So, I thought I’d share a little about our design and manufacturing process. We design all our products locally using in house engineers and some outside consultants. This includes all the schematic design, printed wiring Read more…
Doppler Systems Blog We’ve just released version 2.34 of the firmware. This version fixes two recently discovered bugs. Bug 1 occasionally caused the DF processor to miss commands sent to it by the software. This occured when the commands were sent rapidly and the underlying Windows IP socket chose to Read more…
Doppler Systems Blog Some people insist that radio direction finders based on the Doppler principle suffer from low sensitivity. Recently I saw a claim from one of our competitors recently that their unit was 10 dB more sensistive than psuedo-Doppler based direction finders. This is simply not true and our Read more…
Doppler Systems Blog Last week I attended the NSREN conference in Orlando. A big thanks to Paul Coburn for inviting us. During the discussion times a number of good ideas were suggested for improving our software. Throughout our history our customers have made suggestions for new features and new applications Read more…
Doppler Systems Blog We added a feature to the MPT User Interface program to allow a user to save the direction finder settings to a file. Once you have the direction finder settings the way you like them you can save them. If someone changes the settings you can always Read more…
Doppler Systems Blog Recently someone made hoax calls to pilots, causing a passenger flight to abort landing as it approached Melbourne Airport in Australia. In total there were 15 unauthorized transmissions on aircraft frequencies in the Melbourne area (see article here). The Australian Communications and Media Authority deployed a Doppler Read more…
Doppler Systems Blog Frequently we are asked, “What antenna spacing should I use for my mobile antennas?” This is a good question because many people think that antenna spacing would be critical for good performance and people are surprised when our answer is, “Somewhere between an 1/8 and 1/4 wavelength.” Read more…