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      G3PLX Project
        G0TJZ system



  G3PLX system

  G0TJZ system

Passive Ionospheric Sounding and Ranging - The G0TJZ System

What you need to use ChirpView


The diagram above shows how a typical ChirpView system is configured. The circuit diagram of the "attenuator" for the pulse-per-second signal is shown here.

Receiver Delay Calibration

For accurate work, it is necessary to know the delay time through your HF receiver. This is the time delay between a RF signal arriving at the receiver input and the corresponding audio signal leaving its output. The delay will usually be very short, perhaps 1-2 ms, and is not noticeable for most purposes. In measuring propagation delays however, 1-2 ms corresponds to a distance of 300-600 km, so correcting for this delay is important. A separate program, RxDelay, is supplied with ChirpView to perform this calibration.

RxDelay works by applying a pulse to the input of your receiver and to the soundcard and measuring the time taken for the pulse to travel through the receiver. The pulse-per-second output of a GPS receiver can be used for this purpose, though since the repetition period of the pulse is not too critical, other signal sources may be used.

This diagram below shows how hardware is connected for use with RxDelay.

Here is a screenshot of RxDelay in operation.

Copyright Andrew Senior, 1999 - 2003 mail