Re: [amsat-bb] Be kind to our old lady AO-7
Lately, AO-7 has spontaneously switched out of Mode B during passes over the US and probably other places. >...
My understanding is that this is not uncommon. The first question that comes to my mind: Are there stations that consistently work AO-7 on Mode A shortly after the satellite resets?
73, Ryan AI6DO
Are there many stations doing Mode A at all? I haven't worked too many people on that mode before, but it is a lot of fun. Once it switches to Mode A, what causes it to eventually go back to Mode B?
73 John AF5CC
On Thu, Jun 1, 2017 at 12:04 AM, Ryan Noguchi via AMSAT-BB < amsat-bb@amsat.org> wrote:
Lately, AO-7 has spontaneously switched out of Mode B during passes over
the US and probably other places. >...
My understanding is that this is not uncommon. The first question that comes to my mind: Are there stations that consistently work AO-7 on Mode A shortly after the satellite resets?
73, Ryan AI6DO
Sent via AMSAT-BB@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
It nearly always wakes up into mode B after each eclipse. So since it is currently (and for the foreseeable future) eclipsing every orbit, it will reset once every orbit after re-entering sunlight from eclipse.
73, Gabe NJ7H
On May 31, 2017, at 8:16 PM, John Geiger af5cc2@gmail.com wrote:
Are there many stations doing Mode A at all? I haven't worked too many people on that mode before, but it is a lot of fun. Once it switches to Mode A, what causes it to eventually go back to Mode B?
73 John AF5CC
On Thu, Jun 1, 2017 at 12:04 AM, Ryan Noguchi via AMSAT-BB < amsat-bb@amsat.org> wrote:
Lately, AO-7 has spontaneously switched out of Mode B during passes over
the US and probably other places. >...
My understanding is that this is not uncommon. The first question that comes to my mind: Are there stations that consistently work AO-7 on Mode A shortly after the satellite resets?
73, Ryan AI6DO
Sent via AMSAT-BB@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
Sent via AMSAT-BB@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
On 05/31/17 20:16, John Geiger wrote:
Are there many stations doing Mode A at all? I haven't worked too many people on that mode before, but it is a lot of fun. Once it switches to Mode A, what causes it to eventually go back to Mode B?
Perhaps a novice question: Is there any reason not to work it in Mode A when it switches?
--- Zach N0ZGO
Why does Mode A have a normal transponder, whereas Mode B uses an inverting transponder?
73 John AF5CC
On Thu, Jun 1, 2017 at 2:09 AM, Zach Metzinger zmetzing@pobox.com wrote:
On 05/31/17 20:16, John Geiger wrote:
Are there many stations doing Mode A at all? I haven't worked too many people on that mode before, but it is a lot of fun. Once it switches to Mode A, what causes it to eventually go back to Mode B?
Perhaps a novice question: Is there any reason not to work it in Mode A when it switches?
--- Zach N0ZGO
Sent via AMSAT-BB@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
Inverting transponders exist to reduce the total Doppler shift. Since the Doppler shift on 10 meters is so low, there's no real need to invert the passband.
73,
Paul, N8HM
On Wed, May 31, 2017 at 22:22 John Geiger af5cc2@gmail.com wrote:
Why does Mode A have a normal transponder, whereas Mode B uses an inverting transponder?
73 John AF5CC
On Thu, Jun 1, 2017 at 2:09 AM, Zach Metzinger zmetzing@pobox.com wrote:
On 05/31/17 20:16, John Geiger wrote:
Are there many stations doing Mode A at all? I haven't worked too many people on that mode before, but it is a lot of fun. Once it switches to Mode A, what causes it to eventually go back to Mode B?
Perhaps a novice question: Is there any reason not to work it in Mode A when it switches?
--- Zach N0ZGO
Sent via AMSAT-BB@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
Sent via AMSAT-BB@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
Hi John,
It's a bit involved without having a white board or the use of hands to wave around but maybe I can state the principle in 25 words or less ...
A transponder is pretty much an RF mixer where a local oscillator (LO) frequency is mixed with an input signal. The resulting output of the mixer is a combination of ... 1. the LO frequency (call it F1) 2. the originating input frequency (call it F2) 3. a resultant output of LO-input freq (F1-F2) 4. a resultant output of LO+input freq (F1+F2)
Depending on which resultant mixer output you transmit you'll be inverted or not inverted. Perhaps that is too simple of an explanation to make sense. More details thanks to google like this one: http://www.radio-electronics.com/info/rf-technology-design/mixers/rf-mixers- mixing-basics-tutorial.php
More experts around here will tell better :-)
-- 73 de JoAnne K9JKM k9jkm@amsat.org
Thanks for the information, that clears up one question I have always had.
73 John AF5CC
On Wed, May 31, 2017 at 9:41 PM, JoAnne Maenpaa k9jkm@comcast.net wrote:
Hi John,
It's a bit involved without having a white board or the use of hands to wave around but maybe I can state the principle in 25 words or less ...
A transponder is pretty much an RF mixer where a local oscillator (LO) frequency is mixed with an input signal. The resulting output of the mixer is a combination of ...
- the LO frequency (call it F1)
- the originating input frequency (call it F2)
- a resultant output of LO-input freq (F1-F2)
- a resultant output of LO+input freq (F1+F2)
Depending on which resultant mixer output you transmit you'll be inverted or not inverted. Perhaps that is too simple of an explanation to make sense. More details thanks to google like this one: http://www.radio-electronics.com/info/rf-technology-design/ mixers/rf-mixers- mixing-basics-tutorial.php
More experts around here will tell better :-)
-- 73 de JoAnne K9JKM k9jkm@amsat.org
No reason, except it's a little more difficult to carry around a 10m antenna than it is to carry an Arrow or Elk :-)
- Matthew kk4fem
Sent from my iPhone
On May 31, 2017, at 22:09, Zach Metzinger zmetzing@pobox.com wrote:
On 05/31/17 20:16, John Geiger wrote: Are there many stations doing Mode A at all? I haven't worked too many people on that mode before, but it is a lot of fun. Once it switches to Mode A, what causes it to eventually go back to Mode B?
Perhaps a novice question: Is there any reason not to work it in Mode A when it switches?
--- Zach N0ZGO
Sent via AMSAT-BB@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
Nope! By all means, work it in Mode A if you're equipped!
73,
Paul, N8HM
On Wed, May 31, 2017 at 22:09 Zach Metzinger zmetzing@pobox.com wrote:
On 05/31/17 20:16, John Geiger wrote:
Are there many stations doing Mode A at all? I haven't worked too many people on that mode before, but it is a lot of fun. Once it switches to Mode A, what causes it to eventually go back to Mode B?
Perhaps a novice question: Is there any reason not to work it in Mode A when it switches?
--- Zach N0ZGO
Sent via AMSAT-BB@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
I agree,
I Love Mode A
And even more basic equipment can be used to make a contact on Mode A. No expensive all mode VHF/UHF rigs needed. Joe Sig The Original Rolling Ball Clock Idle Tyme Idle-Tyme.com http://www.idle-tyme.com On 5/31/2017 9:09 PM, Zach Metzinger wrote:
On 05/31/17 20:16, John Geiger wrote:
Are there many stations doing Mode A at all? I haven't worked too many people on that mode before, but it is a lot of fun. Once it switches to Mode A, what causes it to eventually go back to Mode B?
Perhaps a novice question: Is there any reason not to work it in Mode A when it switches?
--- Zach N0ZGO
Sent via AMSAT-BB@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
That was true in the 1970s, but today working VHF/UHF linear transponders can be done quite inexpensively. Certainly for no more than an average HF station.
73,
Paul, N8HM
On Wed, May 31, 2017 at 23:09 Joe nss@mwt.net wrote:
I agree,
I Love Mode A
And even more basic equipment can be used to make a contact on Mode A. No expensive all mode VHF/UHF rigs needed. Joe Sig The Original Rolling Ball Clock Idle Tyme Idle-Tyme.com http://www.idle-tyme.com On 5/31/2017 9:09 PM, Zach Metzinger wrote:
On 05/31/17 20:16, John Geiger wrote:
Are there many stations doing Mode A at all? I haven't worked too many people on that mode before, but it is a lot of fun. Once it switches to Mode A, what causes it to eventually go back to Mode B?
Perhaps a novice question: Is there any reason not to work it in Mode A when it switches?
--- Zach N0ZGO
Sent via AMSAT-BB@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
Sent via AMSAT-BB@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
who says HF is inexpensive? Joe WB9SBD Sig The Original Rolling Ball Clock Idle Tyme Idle-Tyme.com http://www.idle-tyme.com On 5/31/2017 10:19 PM, Paul Stoetzer wrote:
That was true in the 1970s, but today working VHF/UHF linear transponders can be done quite inexpensively. Certainly for no more than an average HF station.
73,
Paul, N8HM
On Wed, May 31, 2017 at 23:09 Joe nss@mwt.net wrote:
I agree,
I Love Mode A
And even more basic equipment can be used to make a contact on Mode A. No expensive all mode VHF/UHF rigs needed. Joe Sig The Original Rolling Ball Clock Idle Tyme Idle-Tyme.com http://www.idle-tyme.com On 5/31/2017 9:09 PM, Zach Metzinger wrote:
On 05/31/17 20:16, John Geiger wrote:
Are there many stations doing Mode A at all? I haven't worked too many people on that mode before, but it is a lot of fun. Once it switches to Mode A, what causes it to eventually go back to Mode B?
Perhaps a novice question: Is there any reason not to work it in Mode A when it switches?
--- Zach N0ZGO
Sent via AMSAT-BB@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
Sent via AMSAT-BB@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
Sent via AMSAT-BB@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
participants (8)
-
Gabriel Zeifman -
JoAnne Maenpaa -
Joe -
John Geiger -
Matthew Stevens -
Paul Stoetzer -
Ryan Noguchi -
Zach Metzinger