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RA8GA Tech Notes

RA8GA, PA5, or HTI3 behave erratically


Product: RA8GA, HTI3
Version: RA8GA serial numbers < 2066, HTI3 serial numbers < 1018
Date Added: 2009-06-02


Timing errors may occur when using the RA8GA, PA5, or HTI3 if the zBUS clock lines become overloaded. This happens most often when two RA8GA devices are placed in the same zBUS caddie but can also happen with any other combination of these devices. Symptoms of this issue include erratic behavior of the LEDs or buttons (i.e. LEDs flash erroneously when a button is pressed or unresponsiveness when a button is pressed)


If possible, rearrange the affected devices so that they are not located in the same zBUS caddie.


If you have experienced this problem, contact TDT for an RMA.

Preamplifier clipping indicators light when signal input voltage is below the input range


Product: RA16PA, RA8GA
Version: All
Date Added: 2007-03-05


When using the RA16PA and RA8GA preamplifiers, note that Clip indicators light when the input signal voltage is below the maximum voltage of the selected range. Clip indicators light to alert the user that the input signal voltage is approaching the clipping voltage. The input signal is not clipped until the selected range maximum voltage is reached.

Device Clip Range
RA8GA -6dB maximum voltage
RA16PA -3dB maximum voltage
Cross talk at low gain setting


Product: RA8GA
Version: Loggerhead Serial numbers < 4000
Date Added: 2003-10-21


When acquiring signals in the 10 Volt rage (lowest gain setting), the RA8GA may experience cross talk (> 40 dB) at frequencies of < 500 Hz.

Signals recorded using an RA8GA are inverted relative to the original signal


Product: RA8GA
Version: Loggerhead
Date Added: 2003-10-21


Signals recorded using an RA8GA will be inverted relative to the original signal.


Scale the signal by -1 in RPvdsEx to correct the polarity.