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
Can't you just tune for maximum signal level received, and bypass measuring SWR?
________________________________________ From: AMSAT-BB [email protected] on behalf of Robert Bruninga [email protected] Sent: Thursday, September 28, 2017 1:25 PM To: [email protected] 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 _______________________________________________ Sent via [email protected] 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
Yes
On Thu, Sep 28, 2017 at 5:02 PM, Franklin Antonio [email protected] wrote:
Can't you just tune for maximum signal level received, and bypass measuring SWR?
From: AMSAT-BB [email protected] on behalf of Robert Bruninga < [email protected]> Sent: Thursday, September 28, 2017 1:25 PM To: [email protected] 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 _______________________________________________ Sent via [email protected] 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 _______________________________________________ Sent via [email protected] 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
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 [email protected] wrote:
Yes
On Thu, Sep 28, 2017 at 5:02 PM, Franklin Antonio [email protected] wrote:
Can't you just tune for maximum signal level received, and bypass measuring SWR?
From: AMSAT-BB [email protected] on behalf of Robert Bruninga < [email protected]> Sent: Thursday, September 28, 2017 1:25 PM To: [email protected] 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 _______________________________________________ Sent via [email protected] 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 _______________________________________________ Sent via [email protected] 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
-- 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 [email protected] 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
To thrive in life, you need three bones: a wish bone, a back bone, and a funny bone. - Reba McEntire
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 [email protected] wrote:
Yes
On Thu, Sep 28, 2017 at 5:02 PM, Franklin Antonio [email protected] wrote:
Can't you just tune for maximum signal level received, and bypass measuring SWR?
From: AMSAT-BB [email protected] on behalf of Robert Bruninga < [email protected]> Sent: Thursday, September 28, 2017 1:25 PM To: [email protected] 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 _______________________________________________ Sent via [email protected] 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 _______________________________________________ Sent via [email protected] 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
-- 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 [email protected] 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
To thrive in life, you need three bones: a wish bone, a back bone, and a funny bone. - Reba McEntire
http://afeller.us http://afeller.us/
_______________________________________________ Sent via [email protected] 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
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Arthur Feller, W4ART -
Franklin Antonio -
Robert Bruninga -
Robert McGwier