Bob, doesn’t this assume a perfectly resistive load presented by the antenna? If the
antenna presents a reactive load, it will be non-linear, so a peak on the fundamental may
well result in spurious emissions. No?
73, art…..
W4ART Arlington VA
On 2-Oct-2017, at 04:27 PM, Robert McGwier
<rwmcgwier(a)gmail.com> wrote:
Yes
On Thu, Sep 28, 2017 at 5:02 PM, Franklin Antonio <antonio(a)qti.qualcomm.com>
wrote:
Can't you just tune for maximum signal level
received, and bypass
measuring SWR?
________________________________________
From: AMSAT-BB <amsat-bb-bounces(a)amsat.org> on behalf of Robert Bruninga <
bruninga(a)usna.edu>
Sent: Thursday, September 28, 2017 1:25 PM
To: amsat-bb(a)amsat.org
Cc: Jin Kang
Subject: [amsat-bb] TUning the antennas on a Cubesat
Someone asked me how to tune the antennas on a cubesat without the
instrumentation totally becoming part of the antenna system itself?
I said you have to put the SWR instrument inside the cubesat as we did
here:
http://aprs.org/PSAT2/SWR-testing-0160x.jpg
But that only works on a 1.5U cubesat where and MFJ Antenna Analyzer will
fit!
The other method is to just put in a bidirectional coupler chip, and then
feed the forward and reflected voltage taps to the internal cubesat
telemetry system and then compute the SWR from these two Forward and
Reflected power telemetry channels.
Bob, WB4APR
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--
Bob McGwier
Founder, Federated Wireless, Inc
Founder and Technical Advisor, HawkEye 360, Inc
Research Professor Virginia Tech
Chief Scientist: The Ted and Karyn Hume Center for National Security and
Technology
Senior Member IEEE, Facebook: N4HYBob, ARS: N4HY
Faculty Advisor Virginia Tech Amateur Radio Assn. (K4KDJ)
Director of AMSAT
Member of PVRC (Roanoke-Blacksburg), TAPR, life member of ARRL and AMSAT,
NRVR.ORG (Rocketry)
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