Fluke 85RF Instruction Sheet

®
Instruction Sheet
85RF

INTRODUCTION

The 85RF High Frequency Probe is designed to convert a dc
voltmeter into a high frequency (100 kHz to 500 MHz) ac
voltmeter. Conversion from ac to dc is accomplished on a
one-to-one basis and includes a range of 0.25 to 30V rms.
The probe's dc output is calibrated to be equivalent to the
rms value of a sine wave input.

SPECIFICATIONS

AC to DC RATIO: 1:1
RATIO ACCURACY: (At 25 MHz and loaded with 10 M e )
Above 0.5V: ± 0.5 dB
Below 0.5V: ± 1.0 dB
Add ± 0.2 dB in RF fields of 1 to 3 V/m
FREQUENCY RESPONSE: (Relative to 25 MHz)
100 kHz to 100 MHz ± 0.5 dB
*100 MHz to 200 MHz ± 2.0 dB
*200 MHz to 500 MHz ± 3.0 dB
*Referred to high and low inputs at probe tip.
EXTENDED FREQUENCY RESPONSE:
Useful for relative readings from 20 kHz to 700 MHz.
RESPONSE:
Responds to the peak value of an input and is calibrated to
read rms value of a sine wave.
VOLTAGE RANGE: 0.25 to 30V rms
MAXIMUM INPUT VOLTAGE: 30V rms, 200V dc
INPUT CAPACITANCE: Approximately 3 pF
TEMPERATURE RANGE:
Operating: +10°C to +35°C
Storage: -40°C to +75°C
HUMIDITY: <90% R.H.
OUTPUT CONNECTOR: Fits standard 0.75-inch dual
banana connectors
ACCESSORY: BNC to Probe Adapter, P/N 574756

VOLTMETER COMPATIBILITY

The 85RF is compatible with any dc voltmeter that has an
input resistance of 10 megohms, ±10%. Voltmeters with
higher input resistances can be used if an external shunt is
placed across their input terminals. The shunt value is
selected to reduce the input resistance to 10 megohms.
PN 630376
July 1981, Rev.6, 6/09
©1981-2009 Fluke Corporation, All rights reserved.
Printed in the U.S.A.
All product names are trademarks of their respective companies.
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