[amsat-bb] Re: AO-40 Replacement

Bryce Salmi bstguitarist at gmail.com
Wed Sep 4 23:19:50 PDT 2013

The short answer to all these "why are we building FM satellites" comments
is that the #1 operatation reason to build and FM satellites is that they
provide an easy way for anyone to enjoy a satellite contact. Yes there is
field day, one day out of the year. Given several operating FM satellites
in orbit of AO-51 performance, it's feasible that at least one per day will
provide a nice, comfortable opportunity to talk. This is important to grow
the hobby and to provide an easy entry-point for people into satellite

However, the #1 technical reason to build any satellite right now,
regardless of FM or linear RF capabilities, is that the RF communications
part of the satellite is only one part of the satellite. Is the RF
down-link crucial, yes, but so are the solar panes and the Maximum Power
Point Tracker for example. Without those, a perfectly functioning linear
transponder is useless because we all know that you need electricity to
actually turn any of the electronics in the satellite on, including the
communications system. The Internal Housekeeping Unit (IHU) is also
extremely important from an operational standpoint. It allows health and
status telemetry to be obtained from  the satellite to best command and
configure it for optimal use as it ages or enters different periods of

Regardless of the form of communications package, on-orbit operation of
systems build heritage and with heritage comes confidence in the design and
with confidence in the design we get satellites that last a long... long..
time. That tends to keep satellite operators happy! While I'd be against
this, and I'm sure most of us would be... it would still be beneficial for
AMSAT to fly a telemetry only satellite to prove subsystems for a future
comms satellite from a purely technical viewpoint. There are many
subsystems that would be exactly the same on a telemetry only satellite as
a linear transponder satellite.

Point is, flying FM satellites is extremely beneficial to any future
satellite be in FM, Linear, etc. By standardizing with the CubeSat
standard, AMSAT can make incremental improvements on each satellite and
envelope more daring/complex missions as subsystems obtain flight heritage.


On Wed, Sep 4, 2013 at 10:36 PM, Daniel Schultz <n8fgv at usa.net> wrote:

> I know how much the FM satellites are loved by certain segments of the
> community, and FOX-1 will serve that community beginning late next year. In
> addition, many universities are building 2 meter FM satellites as part of
> their aerospace engineering curriculum.
> The problem with the FM satellites is that only one station at a time can
> access them, during field day I listened to several passes and I did not
> hear
> one complete field day exchange during any of them. They are just too
> limited
> to serve as a pathway for growth for AMSAT.
> I have also read many recent posts regarding the late, great AO-40 and how
> much the long distance DX that it provided is missed. The S-band downlink
> for
> AO-40 performed well and was quite inexpensive for hams to acquire. It is
> simply a myth that microwave equipment and antennas represents a difficult
> entry path to amateur radio.
> In the event that AMSAT should find an opportunity to place a Cubesat into
> HEO, it will not be able to replace the performance of AO-40, but it could
> provide the long distance DX opportunities for those stations that are
> willing
> to make a modest investment in equipment. I am sorry that we cannot
> provide a
> HEO DX satellite that anybody can work with an HT and an Arrow antenna,
> but we
> are limited by the laws of physics, the size of the solar arrays, the
> antenna
> gain and the link budget from HEO. We can only fit so much stuff into the
> tiny
> little satellites that will be available to us in the future.
> If we build a small HEO satellite some people will be excluded from using
> it.
> We are not trying to exclude anybody but those are the facts of life as I
> see
> them. If you want a HEO DX satellite it is going to cost you some money to
> equip yourself to work the satellite with its limited power output and link
> budget. This is not because we want to exclude anybody, this is doing what
> we
> can with the launches that are going to be available to us in the future. I
> don't see the value of bringing new hams into the satellite hobby if they
> make
> a few QSO's and then grow tired of the limited capability of the LEO FM
> satellites. To attract and keep these hams we must provide something more
> challenging and more useful for communications. That doesn't make us
> elitist,
> but until somebody writes a $10 million dollar check to AMSAT, that is
> what we
> can do and it is better than disbanding the organization and giving up
> because
> we can't do magic on our shoestring budget.
> Dan Schultz N8FGV
> ------------------------ Original Message ------------------------
> >What should a ham satellite program offer to the amateur community?
> >If bringing new hams into this aspect of the hobby is important,
> >then we need another AO-51 - which was probably the greatest marketing
> >tool ever seen in the amateur satellite community. Its ease of use
> >was the cause of scores of media alerts and publicity for amateur radio.
> >And most importantly, it got more people looking skyward and thinking
> >they could work amateur satellites than any other project.
> >Then there was the marvelous marketing surrounding ARISSat-1 ...
> >What else should an amateur satellite program offer? Many here want
> >satellites that are only accessible with an investment of many hundreds
> >of dollars' worth of antenna systems and equipment. (Some would actually
> >love it if Technicians weren't allowed - that's how extreme thinking is
> >on this topic.) Is THAT what will move the hobby forward for the masses?
> >IS there a "middle ground?" Sure is a polarized topic (pun intended). Some
> >want the hobby and sat use to grow ... others want to exclude as many
> fellow
> >hams as possible.
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