Most Popular Articles
The birth of a radio station
Like the start of anything, there has to be a motivation. In this case, it was a man with a dream to build and run a radio station. His motivation stems from being raised in the area. Now he is a lawyer and partner at a law firm in Las Vegas. His name is Will Kemp and he is a man with vision, drive and the resources to build from the ground up; a combination that proved ideal for this project. The true genius behind the concept of designing the RF facility is Rich Green of Rich Green and Associates.
The KVEG control room is at the center of the fully digital facility.
Looking up at the Apex Communications site, which serves as the middle point of the STL path.
The rack room houses the automation system and serves as the central wiring point for the facility.
A typical installation using the JRBE Inter-Tie Panel, which serves as a high-density rack or wall-mounted cable termination.
The production studio is also equipped with a Logitek control surface.
Kemp and Green started working on the concept of a new station in Mesquite, NV, in 1997. Green, armed with a huge amount of antenna modeling and mapping software, came up with several sites. Even with all the best software, he likes to see things for himself. Because most of the proposed sites were in the middle of the desert with no road access, it became necessary to rent a helicopter and visit the sites by air. After the two looked at all the sites on Green's list, they chose a site that is next to an area called the California Bowl. Rich then returned to Cameron Park, CA, and started the long process to get a construction permit (CP) from the FCC.
Once the CP was issued, Green designed a 1,380-foot tall tower. This would be the tallest man-made structure in Nevada. He soon realized that this height would allow a booster to cover downtown Las Vegas.
My involvement in the project started while attending NAB2000. I was asked by Green to have lunch with him and Will Kemp. I had no idea that I was being considered to lead a large build-out. We talked about digital audio, appropriate STL systems and other elements of quality audio. I was intrigued by Kemp's eagerness to provide the best possible audio to listeners. Later that evening, I was told about the pending studio project and that I was going to build the facilities.
The following day, we visited the proposed transmitter site. My first thought was about the STL path. We wanted to send an uncompressed digital audio signal 47 miles northeast to the main transmitter site, through an area surrounded by mountains and without any utilities. Further complicating matters is the Apex Summit, which lies just north of Las Vegas. This land mass creates a giant curtain that blocks RF in or out of Las Vegas.
The transmitter site, located about three miles east of I-15 near Mesquite, was being carved out of the desert — as was the road to get to the site. Working without power, telecommunications, roads and security proved to be a nearly overwhelming challenge.
Constructing a building with enough cooling for a 35kW transmitter in 125-degree heat and a 1,380-foot tower is a major undertaking. After a few days working in this environment, it becomes business as usual. P&R Tower built the tower.
Because the site lacks all utilities, two Caterpillar 100kW diesel generators were brought in to supply the power needed. The first generator runs for 21 days, after which the second generator starts and switches over automatically. Near the end of the second 21 days, a local service company arrives to service the first generator, then switches generators and services the second. The above ground, 10,000-gallon fuel storage tank is filled as needed during each service visit. A 100-gallon back up tank is part of the system.
Green designed an air conditioner system with a custom built pre-cooler that works with great efficiency. The pre-cooler air is only on when the outside temperature is lower than the transmitter exhaust. It uses isolated outside air blowing across an air exchange then back outside. This keeps the outside air from contaminating the transmitter building's closed air-cooling system.
The STL path length was about 47 miles from end to end. I envisioned a double hop, but did not know where the middle point would be. I soon discovered a site on the west side of the freeway while driving north on I-15. While it was not easily accessible, I determined the position with GPS and turned it over to Kemp. This large peak with existing radio towers is called the Apex Communications site.
In short order I had a name and phone number to coordinate a site visit with a representative. I used my spectrum analyzer to check for available microwave frequencies and sent my findings to Green.
We quickly learned that a microwave channel would not be available in a timely fashion. An alternative was needed. I chose Harris TM-2400 Aurora 2.5GHz spread-spectrum radios for the primary link and the TM-5800 5.8GHz Aurora spread spectrum radio for the secondary link. Many consider spread-spectrum to be unreliable, but both systems have worked perfectly with no down time in three years. Both radio systems interface directly with Harris Intraplex T-1 multiplexers, which provide an uncompressed bidirectional link. Program audio is sent to the transmitter site and an air monitor is returned. The system also carries the transmitter remote control data. The primary Intraplex system uses digital input cards, while the backup system uses analog cards. At the transmitter site, the two outputs feed the TFT 999 Digital Insertion unit. This accepts the analog and digital signals and automatically switches to the analog feed if the digital signal fails.
Inside the studios
Kemp wanted a facility that could handle several stations, including radio, TV and webcasting. He wanted four studios, starting with an on-air studio and production studio. The other two studios would be built for future expansion. Kemp wanted an impressive facility to demonstrate his commitment to his new industry.
We planned on building the station in one of his existing properties on the Las Vegas strip, which was next to a large parking lot that is often used for bus traffic. Buses would sit in the lot idling for long periods of time, providing a constant noise source that needed to be addressed. I designed the studios with the usual construction techniques: double walls, three layers of insulation and double sheetrock. Although the cost of specifying an NC-20 standard in this case was impractical, all efforts were made to make it as quiet as possible. Even with good communication between the contractor and me it still took several inspections during construction to prevent sometimes almost hidden breaches of the isolated walls. We decided to spend the money on backup power and studio equipment. This turned out to be the right move.
Kemp also wanted the best possible audio to crush the competition. We wanted the perfect digital chain: CD quality with absolute linearity all the way through to the exciter. I started with a product that I knew well; I needed a hard-drive media delivery system with truly linear capabilities at 44.1kHz. It needed to handle all the latest nuances, such as CD ripping, importable music scheduling, ease of use and plenty of backup infrastructure including a backup server and separate play-to-air machine for each room. I also wanted to remotely locate the machines in the rack room to keep the studio as quiet as possible. Luckily for us, my last responsibilities at KMEL were to purchase and install just such a system to replace the station's aging ITC cart machines. I knew which system I wanted. We purchased a Mediatouch system.
For the audio console, I chose a product that I think offers a lot of bang for the buck; the Logitek audio engine with the Numix control surface. Its mix-minus capabilities and ease of use makes it a real winner and it looks great. We used these consoles in the on-air and production rooms.
The telephone hybrids are from Telos, complete with talk-show options. The Inter-Tie system was my own design that I first used at KSTE in Sacramento, CA, in 1993. I have always felt that if engineers had more options, they wouldn't use 66-style punch blocks with their knife blade's width connections. After all, most phones and data circuits develop problems because of bad punch connections. My system uses a series of Molex, BNC and F-type connectors and can be fitted with any other connector as well.
These connectors are mounted on a custom-built JRBE Inter-Tie panel that I have improved over the years. Every type of cable is run and terminated to both ends. It is considered permanent and even if the room is rebuilt, these connections need never be removed. The user end can be used as needed or changed completely. With every wire numbered it was easy to trace any wire. I believe that full documentation is always appropriate, if not for your benefit, for whoever follows you. It is a real challenge to explain it to management, but they can be made to realize that it will cost them more in the long run for engineers to try to figure out the wiring every time a change or connection is needed.
The air chain
Content (music) is ripped into the Mediatouch system from CD in straight PCM 44.1kHz format at eight times speed or faster. Content is reproduced on the Mediatouch play-to-air machine (PTA) for studio A (on-air control room), which is equipped with Digigram digital audio cards. The system features a second play-to-air machine running off the redundant server simultaneously playing the same content for the back up. In case of a failure, the secondary can be brought in immediately. The AES digital audio from the PTA machine is routed to the air studio and feeds one of the Logitek audio engine digital inputs. Mixed program audio leaves the control and returns to the rack room, feeding the TFT program interrupter. The digital output of the interrupter feeds a Ward-Beck Systems POD digital distribution amplifier. Digital output-1 goes to the main transmitter Intraplex digital input and the second digital audio output-2 goes to the booster transmitter Intraplex digital input. The main transmitter audio is sent to the Apex site. The main transmitter Intraplex digital audio output fed an Orban 8200, which then fed the input of the Broadcast Electronics Predator Exciter. (We have since changed the processor and exciter.) The entire path maintains a digital signal throughout at 44.1kHz sampling rate.
The Predator is outfitted with the 10MHz time-base option, which is fed by an ESE GPS receiver. This works well to synchronize the main and booster carriers. The audio is carefully synchronized through another Intraplex card to add a small amount of delay. To give the station every edge possible, Kemp let me indulge in new and some old processors and exciters to make the station sound its best.
While digital audio has a natural advantage for maintaining audio purity, when it's all said and done the ear is still analog. We like certain types of distortion. We found that another processor and exciter combination sounded even better, and we incorporated a few new and old tricks that work nicely. I feel that in the end, an all-digital chain helps to provide excellent audio all the way to the transmitter and gives you a great platform to work some analog magic for our analog ears.
|ADC Pro Patch
Mark II patch bays
APC Smart UPS-3000
Auratone 5R3C-FG rack monitors
Belden 1192A Starquad, 1222B 16-pair cable, 1633A CAT5 cable, 1800B 22-gauge cable, 1806F 12-pair cable, 8240 RG-58, 8241 RG-59, 8325 25-pair control cable, 8444 22-gauge cable
CRL Stereo Automatic Gain Controller
Denon DN-951FA CD players
Denon DENTU1500RDP AM/FM receivers
Electro Voice RE-27 mics with shock-mount
ESE Master clock system
Eventide DSP4000-B Plus Ultra Harmonizer
Fostex D15 DAT
Furman PL-Pro power conditioners
Gepco 61801ECGP 22-gauge cable
Hafler P-3000 power amplifier
Harris DA-16000 audio distribution amplifier
Harris TM-2400 2.4GHz spread spectrum system
Harris DA-16000 audio distribution amplifier
Harris Pacific Prime Line studio furniture
Henry Engineering MB-II Matchboxes
HHB CDR850+ CDR-RW recorder
Harris Intraplex STL Plus
Harris Intraplex IX-4101DD TSL
|Jay Rose custom
Jay Rose Inter-Tie custom wire termination panels
JBL 4410A studio speaker monitor
Lea Dynatech line eliminators
Logitek Numix Audio console
Logitek Audio Engines
Logitek Supervisor control program
Mackie 1604VLZ-PRO mixer
Marantz PMD-501 cassette
Mark P9A120 microwave dishes
McFphilben MCP33E6200 warning lights
Mediatouch Imediatouch digital delivery system
Middle Atlantic rack shelves
Middle Atlantic MRK-44-31-LRD equipment rack
Moseley Starlink SL-9003Q
O.C. White mic booms
Omnimount 100WB mounts
Orban 8200 audio processor
Ortofon Night Club cartridge and stylus
Otari Mx5050BIII reel-to-reel
Presonus VXP microphone processors/preamp
RDL ST-PH phono preamplifiers
Symetrix 420 power amplifier
T.F.T. EAS 911
Tascam 302 cassette
Technics SL-1200-MKII turntable
Telos 1x6 hybrid talk-show system
Telos Assistant Producer software
Telos Zephyr 9202
Ward-Beck Systems POD-12 digital audio D.A.
West Penn 291 22-gauge wire
Yamaha SPX-990 multi-effects processor
Rose is chief engineer of Jay Rose Broadcast Engineering.
Acceptable Use Policy blog comments powered by Disqus
[an error occurred while processing this directive]
Today in Radio History
The history of radio broadcasting extends beyond the work of a few famous inventors.
EAS Information More on EAS
The feed provides feeds for all US states and territories.
Need a calendar for your computer desktop? Use one of ours.
Information from manufacturers and associations about industry news, products, technology and business announcements.
Browse Back Issues[an error occurred while processing this directive]
Also in the January Issue
- Trends in Technology: AES-X210, The "Missing Piece" of AES67?
- FCC Proposes Online Publc File Rules for Radio
- RF Engineering: Licensing AM Stations Using Method of Moments
- Field Report: Zoom H6