KZSU Technical Info

Our studios are in Memorial Hall on the Stanford campus. There are two control rooms, both using Broadcast Audio Series IV consoles; the consoles were purchased around 1988 and 1991. Other studio equipment includes Technics SL1200, SP10 and SP25 turntables, Marantz PMD340 CD players, Scott Studios digital "cart" machines, Otari open reel tape decks, Tascam DAT and cassette decks, and telephone interface gear from Comrex and Symmetrix. Audio production is on small digital (PC-based) workstations.

Our air chain includes a dbx Professional Products Model 1066 performing dynamic compression, as well as an Optimod 8000A stereo generator, which has a limiter to prevent overmodulation.

FACTOID: The cable run from our studios to the transmitter uses 10,687 feet of 22 AWG twisted pair telephone cable (50 pair). Other KZSU cables run from Memorial Hall to various major venues on campus, to facilitate coverage of events at those locations. We installed most ofthese lines ourselves. In addition, a Pacific Bell line runs to Palo Alto City Hall and carries our weekly City Council broadcasts.

Up at the transmitter shack, an equalizer compensates for the cable's frequency response and feeds the Optimod stereo generator, which drives a Continental 802B exciter (installed in 1995), which drives a 250W power amplifier. The power amplifier is part of a Gates FM250H3 transmitter (the original exciter is no longer used). Although the transmitter site is normally unattended, with equipment controlled from the studio, it has a mini-studio so it can be used to originate our programming in an emergency if the Memorial Hall facility is unusable.

A Jampro JCP-4 four-bay circularly polarized antenna is mounted on a 65-foot wooden pole; antenna height is about 520 feet MSL [heightabove Mean Sea Level]. It is located in the foothills behind the campus near the Big Dish. The existing antenna was installed in 1971; the transmitter was purchased at the same time, but was run at 10 watts (exciter only) until we obtained our power increase in 1978. The wooden pole was replaced in Spring 2000.

We have an effective radiated power of 500 watts with both horizontal and vertical polarization. That's actually 500W vertical, 500W horizontal. Note that ERP is the amount of power you'd need to feed into a simple dipole antenna to produce the samefield strength, and is rated for the horizontal plane. Stations are permitted to radiate the same energy, or less, on the vertical plane. So KZSU's "500 watts" is figured by

transmitter power = 250W
1/2 power to horizontal = 125W
antenna gain of 4 x 125W = 500W

Like other radio stations, KZSU employs the Emergency Alert System (EAS). EAS uses multiple redundant paths to receive emergency information; KZSU's EAS system monitors KCBS, (740 AM), KQED(88.5 FM), and the National Weather Service.

In case of power failure, the studio and the transmitter site are each equipped with uninterruptible power supplies(UPS) and a standby generator. Additionally, we have a secondary hookup at Stanford's Emergency Operations Center to help disseminate important information in the event of a campus-wide (or larger) emergency. We installed the cabling and equipment for the EOC facility in 1994.