[SI-LIST] : Re: microwave radiation due to network analyzers

CHIN-SOON_TEOH@HP-Malaysia-om1.om.hp.com
Fri, 22 May 1998 17:06:41 +0800


Eric, Tan Hin,

The 8719C VNA has -65dBm<Pwr<+10dBm, or 0.32nW<Pwr<10mW. The usual
mode of operation when testing passive devices is to fix the power
level at a certain value while sweeping the frequency over a range
(e.g. 1700->1900MHz). It is not usual to use the VNA at +10dBm.
Something like -20dBm (=0.01mW) is more likely.

DCS1800 Phase 1 has 1mW<Pwr<1W, Phase 2 (newer std) has 1mW<Pwr<4W.
All PCN/Digi1800 phones must meet these criteria. I suspect in
Malaysia we are still using Phase 1 std. The pwr level output by the
phone varies between these limits depending on how far it is from the
Base Station. So the average power (burst) by the handphone is about
50mW. As this burst occurs 1/8th of the time, an RMS-averaged
equivalent is about 6mW.

So Eric is correct that on average the VNA outputs LESS power than the
handphone.

The standard safety limit for microwave radiation exposure is
10mW-per-unit-area (I think area=cm squared, but not definite about
it). So for Tan Hin's concern about radiation from the VNA, I would
say that:

1. Unless you connect a properly-matched antenna to the output port of
the VNA, the radiation from it will be <<0.01mW (for -20dBm setting)

2. Therefore I would rather spend 24hrs-a-day in front of the HP8719C
than 20mins-a-day talking on any handphone (or living near the top
floor of a building which has Base station antennas on top!)

So the UNAVOIDABLE radiation from handphones and base stations (and
you are always surrounded by MANY) is FAR GREATER than any you will
get from an HP instrument. You are right, Eric.

Cheers,
Chin Soon
______________________________ Reply Separator _________________________________
Subject: Re: microwave radiation due to network analyzers
Author: ERIC-CS CHOW at HP-Malaysia,om1
Date: 22/05/98 16:06

Hi Tan Hin,
Hem..I don't think the VNA's power is higher than my Ericsson GSM
phone (1.8GHz, > +20dBm). You could check it out how much power you
are using by going into the source power control menu of the 8719C.

So far no one complain about this, even in HPM. Anyway, let consult
my AE.

Chin Soon,
Any comments?

Regards,
Eric Chow


______________________________ Reply Separator _________________________________
Subject: microwave radiation due to network analyzers
Author: Non-HP-tat.hin.tan (tat.hin.tan@intel.com) at HP-Malaysia,mimegwklmail
Date: 5/21/98 5:17 PM


Hi Eric,
I'm just wondering if there is any safety hazard due to any
radiation emission from microwave probes connected to the network
analyzer? I've been using an HP8719C and usually operate it in the
50MHz-8GHz frequency range.
If I'm not wrong, microwave oven freq is ~2GHz. Does that mean
that when I'm doing frequency characterization work on the VNA, I'm
slowly being cooked? What is the usual power range for the HP8719C? Is
there any safety qualification for these microwave instruments?


rgrds,
Tat Hin
Intel Test Tooling Operations Penang

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