[amsat-bb] TUning the antennas on a Cubesat

[Robert Bruninga]

This might be possible, but then EMI testing should reveal any increase in
spurs in radiated emissions...
bob

-----Original Message-----
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 at gmail.com> wrote:
>
> Yes
>
> On Thu, Sep 28, 2017 at 5:02 PM, Franklin Antonio
> <antonio at qti.qualcomm.com>
> wrote:
>
>> Can't you just tune for maximum signal level received, and bypass
>> measuring SWR?
>>
>> ________________________________________
>> From: AMSAT-BB <amsat-bb-bounces at amsat.org> on behalf of Robert
>> Bruninga < bruninga at usna.edu>
>> Sent: Thursday, September 28, 2017 1:25 PM
>> To: amsat-bb at 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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>> _______________________________________________
>> Sent via AMSAT-BB at amsat.org. AMSAT-NA makes this open forum available
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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)
> _______________________________________________
> Sent via AMSAT-BB at amsat.org. AMSAT-NA makes this open forum available
> to all interested persons worldwide without requiring membership.
> Opinions expressed are solely those of the author, and do not reflect the
> official views of AMSAT-NA.
> Not an AMSAT-NA member? Join now to support the amateur satellite program!
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_______________________________________________
Sent via AMSAT-BB at amsat.org. AMSAT-NA makes this open forum available to all
interested persons worldwide without requiring membership. Opinions
expressed are solely those of the author, and do not reflect the official
views of AMSAT-NA.
Not an AMSAT-NA member? Join now to support the amateur satellite program!
Subscription settings: http://www.amsat.org/mailman/listinfo/amsat-bb