Every now and then someone asks about the possibility of making a satellite QSO when the bird is below the horizon. Once in while it happens as it did with Adrian, AA5UK/KH6, on FO-29 this morning at 0849utc.
Adrian has been operating from KH6 and trying to give out WAS to the deserving. Many have made their first Hawaii QSO thanks to his efforts. I had a 0.8 degree pass this morning on FO-29 but when Adrian was at 3 degrees, I was at 0.0 degrees. There was a short window of opportunity after that point.
As I was waiting for FO-29 to come up over the horizon I started hearing Adrian at -0.9 degrees. At -0.5 I called him and we had a qso that ended about 2 seconds after my AOS. My recorder is configured to start recording at AOS and it only captured a few seconds of my last transmission. Doug KD8CAO had his recorder running so you can hear my qso that took place below the horizon. I have my ground elevation in the setup so the calculations should be accurate.
The best opportunity for a below the horizon contact occurs when the satellite is skimming the horizon rather than going away from you. If it is skimming there is much more time at the critical -1.5 to 0.0 degree elevation and that is what happened this morning. Recordings are on my website. http://www.papays.com/sat/general.html
A big thank you to Adrian for making the effort to work the difficult passes and stretch the limits. If it were easy, everyone would be doing it.
73, John K8YSE
Hi John,K8YSE
When AO40 was alive and well I had many QSO's with the East coast of USA in Mode L/S with the satellite down up to - 2.5 degrees belove the horizon for me and for the station in contact with me.
The keplerian elements were the same for me and for the stations in contact with me using both the same tracking program InstantTrack.
We supposed that in particular situations of temperature and humidity a duct is created over the surface of the see permitting the contact belove the horizon
We can't investigate more deeply into the above phenomenon because AO40 died.
I do not remember the call letter of many stations in USA in contact with me under such circumstances but if someone from the Est coast read this letter and remember,........please replay.
73" de
i8CVS Domenico
----- Original Message ----- From: "John Papay" john@papays.com To: amsat-bb@amsat.org Sent: Monday, March 26, 2012 4:45 PM Subject: [amsat-bb] FO-29 QSO Below the Horizon
Every now and then someone asks about the possibility of making a satellite QSO when the bird is below the horizon. Once in while it happens as it did with Adrian, AA5UK/KH6, on FO-29 this morning at 0849utc.
Adrian has been operating from KH6 and trying to give out WAS to the deserving. Many have made their first Hawaii QSO thanks to his efforts. I had a 0.8 degree pass this morning on FO-29 but when Adrian was at 3 degrees, I was at 0.0 degrees. There was a short window of opportunity after that point.
As I was waiting for FO-29 to come up over the horizon I started hearing Adrian at -0.9 degrees. At -0.5 I called him and we had a qso that ended about 2 seconds after my AOS. My recorder is configured to start recording at AOS and it only captured a few seconds of my last transmission. Doug KD8CAO had his recorder running so you can hear my qso that took place below the horizon. I have my ground elevation in the setup so the calculations should be accurate.
The best opportunity for a below the horizon contact occurs when the satellite is skimming the horizon rather than going away from you. If it is skimming there is much more time at the critical -1.5 to 0.0 degree elevation and that is what happened this morning. Recordings are on my website. http://www.papays.com/sat/general.html
A big thank you to Adrian for making the effort to work the difficult passes and stretch the limits. If it were easy, everyone would be doing it.
73, John K8YSE
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i8cvs -
John Papay