Engineering

 


Hello, my name is Mark Voris Chief Engineer for the Spirit Catholic Radio Network and welcome to Engineering!
On this page you will see the “technical” side of the network.
We are headquartered with our studios and main offices here in Omaha.
 
Omaha air studio        Production studio
We have 14 transmission sites scattered across Nebraska and one site in west-central Wisconsin. Five of those sites are currently full-power stations (1000 watts and up), two are translators (250 watt repeater stations) and eight Low Power FM – LPFM (100 watt stations) owned and operated by local groups.

My work here requires the use of many tools and test equipment in order to maintain our network of stations. Recently I had to deal with an antenna issue with one of our LPFM affiliates. The antenna is 75 feet above the ground and beings I don’t climb towers anymore a crane with basket was brought in to get me to the antenna.

The antenna shown in the second image is what is called a circular polarized antenna, both vertical and horizontal polarization. Most vehicles have vertical receive antennas and radios in the home usually have horizontal receive antennas. The problem was that the antenna was no longer tuned on frequency for the station at 104.3 MHz(Megahertz) therefore causing a problem with a large amount of reflected power shutting down the transmitter. When an antenna is tuned to the station’s resonant frequency power output of the transmitter(forward power) is at 100% with no power being reflected back to the transmitter however if the antenna is mis-tuned or loaded down with snow or ice some of the power will be reflected back into the transmitter. Most transmitters will handle reflected power to a limit and then will protect themselves by lowering power or shutting down. Referring to the third image of the antenna you will notice on the elements(red arrows) can be adjusted to tune.
To tune the antenna I use assorted pieces of test equipment to measure the adjustments made. The main instrument I use is a Vector Network Analyzer(image below) used to measure the characteristics of the antenna and coax that connects the antenna to the transmitter. The yellow line on the display is the is the main indicator I’m looking at. The dip at the bottom is the frequency 104.3 MHz that the antenna should be at. When the antenna was first measured it was showing a resonant frequency of 104.6 MHz.

 


This is the amplifier tube for the KVSS and KOLB transmitters. It has the ability to put out 20,000 Watts
of RF power.

KVSS 102.7
Location: Southwest of Omaha
Effective radiated power ERP: 46.1 kW
Antenna height above ground AGL: 1,270 feet
Transmitter: BE FM25T tube type
 
KOLB 88.3
Location: Northwest of Osmond NE
Effective radiated power ERP: 100 kW
Antenna height above ground AGL: 370 feet
Transmitter: BE FM25T tube type

KJWM 91.5
Location: South of Wood River NE
Effective radiated power ERP: 11.5 kW
Antenna height above ground AGL: 591 feet
Transmitter: BE FM5C solid state type

KFJS 90.1
Location: North of North Platte NE
Effective radiated power ERP: 1.35 kW
Antenna height above ground AGL: 335 feet
Transmitter: Elenos ETG2000 solid state type

KETT
99.3
Location: Mitchell NE
Effective radiated power ERP: 950 W
Antenna height above ground AGL: 164 feet
Transmitter: Elenos ETG2000 solid state type

K257FK 99.3
Location: Northwest of Columbus NE
Effective radiated power ERP: 250 W
Antenna height above ground AGL: 236 feet
Transmitter: Elenos ETG500 solid state type

K207BY 89.3
Location: Chadron NE
Effective radiated power ERP: 250 W
Antenna height above ground AGL: 85 feet
Transmitter: Crown FM250 solid state type

Our LPFM Affiliate Stations

KLPH-LP 103.9
Location: Alliance NE
Effective radiated power ERP: 100 W
Antenna height above ground AGL: 49 feet
Transmitter: Crown Ecreso FM350W solid state type

KJTJ-LP 107.5
Location: Sidney NE
Effective radiated power ERP: 100 W
Antenna height above ground AGL: 101 feet
Transmitter: Crown Ecreso FM350W solid state type

KNKP-LP 104.3
Location: Imperial NE
Effective radiated power ERP: 100 W
Antenna height above ground AGL: 75 feet
Transmitter: Crown Ecreso FM300W solid state type

KQPK-LP 96.9
Location: McCook NE
Effective radiated power ERP: 100 W
Antenna height above ground AGL: 52 feet
Transmitter: Crown Ecreso FM350W solid state type

KMKP-LP 106.5
Location: Holdrege NE
Effective radiated power ERP: 100 W
Antenna height above ground AGL: 49 feet
Transmitter: Crown Ecreso FM300W solid state type
 
KPKA-LP 100.1
Location: Beatrice NE
Effective radiated power ERP: 100 W
Antenna height above ground AGL: 78 feet
Transmitter: Crown Ecreso FM300W solid state type

KMAY-LP 102.5
Location: York NE
Effective radiated power ERP: 100 W
Antenna height above ground AGL: 39 feet
Transmitter: Crown Ecreso FM300W solid state type
 
WASB-LP 96.5
Location: Boyd WI
Effective radiated power ERP: 100 W
Antenna height above ground AGL: 59 feet
Transmitter: Crown Elenos ETG500 solid state type
WASB-LP also has a co-located studio and air their weekend Masses.