[amsat-bb] Re: AO-10 Report On Sat Status

MM ka1rrw at yahoo.com
Mon Mar 9 05:49:05 PDT 2009

Q Chris Bloy wrote: 
> How strong would it be?  Would you pick it up with a 3-ele
> yagi?

Hi All:

In theory you can work a satellite such as AO-10 (in a Molnyia Orbit) with a Zero Gain antenna system.  You just need to be in the right place a the right time.
The orbit for AO-10 varies in altitude from 2,560 Miles (4,120 km) to 21,747 Miles (35,000 km ) every day (twice a day).

If the low orbit Dip is close to your House  then you will have a 15 –30 minute opening when a Zero Gain antenna system will work for a few minutes (assuming AO-10 is running that day).  However as soon as the satellite starts to climb in altitude, you will need to switch over to a higher gain antennas such as a 9-12 dBd system.

In the spring of 1994 I worked AO-13 many times with a pair of Zero Gain Ringo vertical antennas mounted to my Apartment Deck (on a hill, with 200-watt amps).  The Secret was timing.  I would plan ahead and then wait for the low altitude dip to take place near my apartment in Boston and set aside that time to work people on AO-13.  My window of access time was very limited to approximately 15-30 minutes of good access, before the satellite screamed up to higher altitude.

After my new house and tower were installed, I switched over to a full AZ/EL antenna system (22 elements CP on 2 meters (element gain ~10 dBd) and 40 elements (element gain ~14 dBd) on 440 CP, Amps and LMR-600).  At the higher altitude’s 21,747 Miles (35,000 km ) I could still work AO-13, however AO-10 was much more difficult. 

This Month March 2009 AO-10’s Low dip is in the South Pacific and in the South Indian oceans.  Has anyone heard AO-10 recently?  I would like to give it a try again.

73 Miles WF1F  Marexmg.org

Note:  I prefer to use the terms Element gain because it cuts out the Advertisement hype.
Most advertisers add an extra 3-6 points of gain to an antenna. If you ever see an antenna advertised with two letters “dB”, always subtract 3+ to convert it to “dBd”.  Or Just count how many Half-wave dipoles are in this antenna and use the chart.

Antenna power tips


--- On Sun, 3/8/09, Gordon JC Pearce <gordonjcp at gjcp.net> wrote:

> From: Gordon JC Pearce <gordonjcp at gjcp.net>
> Subject: [amsat-bb] Re: AO-10 Report On Sat Status
> To: amsat-bb at amsat.org
> Date: Sunday, March 8, 2009, 7:00 PM
> Chris Bloy wrote:
> > Hi All,
> > 
> > I see that IK2MKE has reported hearing AO-10, any idea
> if this is
> > possible?
> > 
> How strong would it be?  Would you pick it up with a 3-ele
> yagi?
>    I could hear *something* on 145.810MHz but I'm in
> the middle of a 
> city so it could be just about anything.  I'll try in
> an hour to see if 
> I can rule out local QRM.
> Gordon
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