Comparison Chart

Feature group



Cableless systems with only shootblind capability

Cableless systems with some data return capability

Benefit of feature and related issues

GPS timing

Internal to ground unit

Mostly internal to ground unit

Some systems rely on distributed timing

GPS reception cannot be guaranteed everywhere. Alternatives may be essential.

Ground unit shape

Virtually impossible to tip over

Some systems easy to tip, may lose GPS signal

Some systems easy to tip, may lose GPS signal

High stability internal clock


Not usual

Not usual

VHF sync


Not possible

Not possible


International Seismic Co

9425 E Tower Rd.
Ponca City, OK 74604
Phone: (580) 762-8233
Fax: (580) 762-1785
email: This email address is being protected from spambots. You need JavaScript enabled to view it.