I am not a fan of omni antennas for the current LEO satellites. The
eggbeater or moxons are marginal performers at best.
Short, quality feedlines and RX preamps are good ways to minimize
ineffectiveness of omnis but there's no silver bullet.
If you have no other choice but omnis, you may find yourself limited to
certain satellites and certain passes. SO-50, for example, is not going to
be favorable. Compensating for lack of hearing ability by running full
power won't make you many friends.
Working satellites on an almost daily basis, one can often identify an
eggbeater or omni user by their inability to hear a very strong signal from
As previously mentioned, a set of small yagis at a fixed elevation with an
azimuth rotor will yield far better results. The trick is not using
longer, high-gain yagis. You'll have more beam width with smaller ones.
Considering what many stations achieve with an Arrow or Elk antenna (7,000+
km contacts,) bigger isn't always better.
Omnis are okay as long as you understand the shortcomings.