I have been tasked with installing one of these systems for a sixteen channel bi-directional STL. This system was first mentioned here: The 16 channel bi-directional STL system. As some of you pointed out, the unlicensed 5.8 GHz IP WLAN extension was the weak link in this system. It was not an interference issue, however, which was creating the problems. The problem was with layer two transparency in the TCP/IP stack. Something about those Cambium PTP-250s that the Wheatstone Blade hardware did not like and that created all sorts of noise issues in the audio. We installed the Wheatstone Edge Routers, which took care of the noise issue at the cost of latency. It was decided to go ahead and install a licensed link instead of the license free stuff as a permanent solution.
Thus, a Cambium PTP-820S point-to-point microwave system was purchased and licensed. The coordination and licensing took about three months to complete. We also had to make several changes to our network architecture to accommodate the new system. The PTP-820 series has a mast mounted radio head, which is the same as the PTP-250 gear. However, for the new system, we used three different ports on the radio to interface with our other equipment instead of the single port PTP-250 system. The first is the power port, which takes 48 VDC via a separate power cable instead of POE. Then there is the traffic port, which which uses Multi-Mode fiber. Finally, there is the management port, which is 1GB Ethernet and the only way to get into the web interface. The traffic port creates a completely transparent Ethernet bridge, thus eliminating all of the layer two problems previously encountered. We needed to install fiber tranceivers in the Cisco 2900 series switches and get those turned up by the IT wizards in the corporate IT department.
Andrew VHLP-2-11W 11 GHz microwave antenna
The radios mount directly to the back of the 24 inch 11 GHz Andrew antenna (VHLP2-11) with a UBR100 interface. The wave guide from the radios is a little bit deceptive looking, but I tried not to over think this too much. I was careful to use the O ring grease and conductive paste exactly where and when specified. In the end, it all seemed to be right.
Cambium PTP-820S mounted on Andrew antenna
Not wanting to waste time and money, I decided to do a back to back test in the conference room to make sure everything worked right and I had adequately familiarized myself with the ins and outs of the web interface on the Cambium PTP-820 radios. Once that was done, it was time to call the tower company.
Cambium PTP-820S on studio roof
One side of these are mounted on the studio building roof, which is a leased space. I posted RF warning signs around the antennas because the system ERP is 57.7 dBm, which translates to 590 watts at 11 GHz. I don’t want to fry anybody’s insides, that would be bad. The roof top installation involved pulling the MM fiber and power cable through a 1 1/4 inch EMT conduit to the roof. Some running back and forth, but not terrible work. I used the existing Ethernet cable for the management port. This will be left disconnected from the switch most of the time.
Cambium PTP-280S 11 GHz licensed microwave mounted on a skirted AM tower
The other side is mounted at about 85 feet AGL on a hot AM tower. I like the use of fiber here, even though the tower is skirted, the AM station runs 5,000 watts during the daytime. We made sure the power cables and Ethernet cables had lighting protectors at the top of the run near the dish and at the bottom of the tower as well as in the transmitter room rack. I know this tower gets struck by lightning often as it is the highest point around for miles.
PTP-820S RSL during aiming process
Aligning the two dishes was a degree of difficulty greater than the 5.8 GHz units. The path tolerances are very tight, so the dishes on each end needed to be adjusted in small increments until the best signal level was achieved. The tower crew was experienced with this and they started by panning the dish to the side until the first side lobe was found. This ensured that the dish was on the main lobe and we were not chasing our tails. In the end we achieved a -38 dBm RSL, the path predicted RSL was -36 dBm so close enough. This means the system has a 25 dB fade margin, which should be more than adequate. While were were aligning the transmitter site dish, a brief snow squall blew through causing a white out and the signal to drop by about 2 dB. It was kind of cool seeing this happen in real time, however, strangely enough, the tower crew was not impressed by this at all. Odd fellows, those are.
Currently brushing up on FCC part 101 rules, part C and H. It is always good to know the regulatory requirements of any system I am responsible for. As AOIP equipment becomes more main stream, I see many of these type installations happening for various clients.
Some pictures of the studio build out in progress.
Counter top mounted
This is the counter top, mounted on a riser with the wire way cut into it. These counter tops will have AudioArts Air4 consoles installed on them.
AudioArts Air4 console with microphones
Studio is taking shape. Console mounted with microphones. The rack mounted equipment goes in the Middle Atlantic rack under the counter top to the left of the console. That rack is on casters so it rolls out to get access to the back of the equipment. We have pretty much done away with cart pods or other counter top equipment housings. The automation and other computers will be mounted in the rack room and extended to the studio with IP KVM extenders.
Sub Panel with manual transfer switch
We installed a small Square D sub panel and manual transfer switch. This is to prevent the “Space Heater” outages, you know, when the morning show guy plugs a space heater into the same circuit as the console or computer, trips the breaker, then calls you because they are off the air. Yeah, good times.
In addition, the manual transfer switch will allow them to use a good portable generator if there is a prolonged power outage. On the bottom of the switch I installed a 30 amp twist lock input receptacle.
Since the building is older, the grounding buss was installed and wired directly to the ground at the service entrance panel. The building sub panel for this floor is using conduit for the ground conductor back to the service entrance panel, which used to be code compliant but no longer.
5.8 GHz dish with non-penetrating roof mount
STL/LAN extension dish installed on roof top. I used an old non-penetrating roof mount for a four foot satellite dish. The building owner was very specific about not having anything puncture the new rubber membrane roof. Thus, the heavy rubber mats and sand bags instead of cinder blocks. These stations will be using a Cambium PTP-250 system for STL/TSL and LAN extension. This will haul program audio for five radio stations plus satellite backhaul and remote control. It is a relatively short path with the FM tower visible from the roof top.
5.8 GHz path to FM tower
It was kind of hazy when I took this picture, but if you look really close, you can see the FM tower out there on the hill top. The path is 3.37 miles (5.43 KM). With a 40 MHz channel width, that should net about 175 Mbps bi-directionally, which is more than enough to do what we want. This set up will require a pair of managed switches and some VLAN configuration, which I will post separately.
We are in the process of building a couple of new studios for one of our clients. This one involves a small market combo of one AM and four FM stations. These stations were formerly located at one of the transmitter sites, two miles outside of town on top of a large hill. That site could be difficult to get to during the winter and the building itself was not in the best of shape. Thus, plans were made to move the studios to a better location. Fortunately, we discovered that right in the village there are several suitable office buildings.
Any worthwhile project needs to be planned for. The first consideration is the Studio to Transmitter Link (STL) paths. Since this is a radio studio, it makes sense to located it where viable RF STL paths exist. One might be surprised by the number times the issue of bad or non-existent RF STL paths has come up during these types of projects.
Studio to transmitter site LAN extension
The next thing to check is the satellite path. The plan right now is to keep the satellite dishes at the transmitter site, however, at some point in the future we can relocated the satellite dish to the roof of the studio building if desired.
AMC-9 satellite path
The floor space was measured out and I drew out a floor plan:
Walton Studio floor plan
Before we started work, all of the walls were painted and new carpeting installed.
Almost nothing at the old studio is worth keeping. Thus, all of the furniture, consoles, racks, STLs, and other equipment needed to be ordered. A local kitchen company traded out the counter tops, which we picked up at their facility and delivered to the studio ourselves.
Studio counter top
We will build risers for these on site then mount the consoles and such.
New Studio Equipment
In the mean time, most of the new studio equipment has been ordered and delivered. There are still some outstanding items that have not arrived, but I am assured that those are in process and should be showing up shortly.
Used equipment racks
These equipment racks came from another market, but are in good shape.
I had a good meeting with the building owner regarding roof access, a sub panel for the racks and studios and other issues.
We get requests to install Isolated Ground outlets from time to time, especially with sensitive equipment. The TELCO likes to have isolated grounds on their fiber MUX’s. It can become an issue with branch circuits in split phase or three phase services that share the same ground and neutral conductor. This can lead to a ground loop between neutral and ground, which will create all sorts of havoc in a broadcast facility.
20 amp, 120 volt, Isolated Ground Outlet
The National Electrical Code covers Isolated Grounds (IG) and sensitive equipment in several sections. The first is section 250.146(D), which states that installation of isolated ground receptacles is permitted. The grounding conductor connected to such receptacles is permitted to pass through one or more panel boards, boxes, conduit bodies, etc without being bonded to them. However, said panel boards, metallic boxes, conduit bodies, raceway, etc must also be grounded separately. That means running two ground conductors, usually the isolated ground conductor is green with a yellow stripe or spiral.
Studio electrical diagram isolated ground
The second is section 640.9(A), which refers to separately derived power systems. This section deals specifically with balanced power; 60 volts AC to ground. In such cases, a separate ground conductor is allowed as outlined in section 250.146(D) and in 647.6(B), which states that the grounding buss should be connected to the grounded conductor on the line side of the separately derived systems disconnecting means.
Other sections of the NEC that may apply to broadcast radio and television facilities:
- Article 455, Phase converters (rotary phase converters)
- Article 480, Storage batteries (UPS)
- Article 520, Theaters, Audience Areas of Motion picture and Television studios, Performance areas and similar locations
- Article 640, Audio signal processing, Amplification and Reproduction Equipment (Audio wiring)
- Article 645, Information Technology Equipment (computer equipment and network wiring)
- Article 647, Sensitive Electronics Equipment (balanced power 60 volts to ground)
- Article 702, Optional Standby systems (generators)
- Article 770, Fiber optic cables
- Article 810, Radio and Television Equipment (antennas, towers and grounding)
- Article 820, Cable TV (CATV)
- Article 830, Network-powered broadband communications systems (power over ethernet)
If interested, I can do articles on these sections as well.
The finished product:
SAS Rubicon console, WAJZ Albany, NY
This is the finished product from an earlier post. Currently, it it the studio for WAJZ in Albany, but that is not permanent. The SAS studio goes together fairly quickly, as most of the trunking between the TOC and studio is done over the SAS data channel.
The studio monitors (Tanoy Reveal) are set on little posts under the computer screens. I like this set up as the DJ’s are less likely to rock the house if they decide to crank up the volume on their favorite tune. I am also kind of digging the lack of a table top equipment pod. That takes up a lot of counter top space and always seems to be in the way. There are two CD players rack mounted below the counter (lower left), which are almost never used.
It is time, once again, to replace some very old Pacific Recorders BMXII consoles. The Pacific Recorders consoles were very expensive when new, but after 30 years of continuous use, have more than paid for themselves. The replacement console of choice for this installation is a SAS Rubicon. I have installed these units elsewhere and they are the modern equivalent of the PRE BMX.
The heart of the Rubicon system is the 32KD router. Routed audio systems can save a lot of time and effort in a large studio facility installation. Not having to run and terminate multiple analog and digital trunk cables between rack room and studio is a huge deal in a six or ten studio installation project.
The SAS 32KD router and Rubicon console system uses a serial TDM buss to communicate and transport audio around. This is a simpler system than packet switched IP data. Basically, the console surface is a very large, fancy computer control interface. Here are some pictures of the start of the project:
New Studio room, furniture installed
This is the view from the entry door. The furniture was placed last week and the counter top cut in for the console. The furniture is made by Studio Technology. The pile of yet to be installed equipment:
New studio equipment to be installed
For monitors, we are using the Tanoy 602p near field monitor placed on the table top above the computer screens. This studio will not have a turret. Turrets used to be necessary to hold things like cart machines and CD players. These days the CD players are used so infrequently that it was decided to put them in the side rack under the counter top. Turrets also take up a lot of counter top space that can be put to better use.
New studio punch blocks
Punch blocks and power connections. The red outlets are isolated ground UPS type, the back outlets are feed by the emergency generator power panel. All electric wiring is inside of metal conduit. The punch blocks are the inputs to the SAS RIO link unit, one 16 pair analog audio cable and ten category 5e shielded cables. The cat 5e is used for computer and TDM data buss to the router.
New Studio Rubicon console
The SAS Rubicon console cut into the counter top and protected by plastic sheets.
Rack room with 32KD routers. This facility has 9 studios total plus a news room with three work areas.
SAS 32KD router on line
The SAS 32KD router. All audio from the automation systems, satellite feeds and other sources is connected directly to these units. This unit is on line for other studios that have already been converted to the SAS gear.
You know those fancy new facilities pictures with the accompanying article you can normally find in the trades? The article usually expounds on how this guy made the decisions on purchase then these guys worked hard and pulled it all together. Here is the works hard and pulling it all together story.
WEBE and WICC have been in the same studio building for several decades. The Pacific Recorders and Engineering equipment, while great, is tired and worn out. On top of that, an F1 tornado ripped the AC units off the roof last June, ripping the membrane and doing extensive water damage to the facility.
The cleanup/water damage mitigation took some time. All of the carpet and ceiling tiles needed to be replaced. The walls needed to be resurfaced with new drywall. In some cases, modifications such as removing a storage closet from the engineering room, moving a door, building a new talk studio and WICC control room needed to take place. In short, lots of dust, dirt and disruption to the station equipment and staff. It has not been trouble free, as several times computers and consoles failed due to age and dirt.
Sometime about the beginning of December, new equipment and furniture began to show up and the project was underway.
Cumulus Bridgeport new equipment
All of the new equipment was stored in the program directors office. Heh, the program directors office.
Cumulus Bridgeport new rack room
A new rack room was designed around the old one. The old racks are out of the picture to the left. The original rack room had a door into the hall, that has been replaced by viewing windows, the door has been moved to the engineering office, next door. I kind of like the windows, it lets visitors see the fancy computers but keeps them out of the room itself.
Cumulus Bridgeport Op-X servers
The existing automation system is being replaced by Op-X. This is the business end of the Op-X audio servers. All of the network connections are Gigabit using Belden Mediatwist (1872A) Category 6 cable.
Cumulus Bridgeport wire wall
All the wiring from the studios and racks are brought to this wall. The terminations are Krone LSA-PLUS blocks. AES/EBU digital and analog audio is run on Category 5e cable.
Cumulus bridgeport wire wall Krone block
Krone LSA-PLUS termination block with Belden Mediatwist cable. All rack and studio wire runs are terminated on this style block. Notice the wire labels, every run is labeled with both termination ends and use. Mediatwist cable is fairly easy to work with, the pairs are bonded, so a special tool is recommended to quickly separate the wires.
Cumulus Bridgeport wire tray
Wire tray between the racks and wire wall.
WICC new Axia console installation
The new WICC control room and talk studio. The Axia consoles are pretty slick. They are not a true mixing console in the traditional sense, they are more like a control surface. Most all of the audio inputs are in the rack room, however, the microphones are digitized in the studio and sent over an IP network to the rack room. All input and output channels are computer configurable and remote controllable. Console inputs also have onboard mic preamps and full processing.
Cumulus Axia console set up
Axia console control software.
New WICC talk studio furniture
The new talk studio set up. This is located where the news room used to be. In order to stay on the air and maintain the old studios, a sort of musical chairs system needs to be played. In the end, the WEBE studio and one production room will end up where they started, everyone else will be in a new space. The news room will end up where the current WICC control room is.
Cumulus Bridgeport network switches
Network audio switches.
Cumulus Bridgeport network patch pane
Network patch panel, notice the T568B markings.
Currently, the program directors are loading all there material in the Op-X system. The time schedule is to transfer WEBE into a temporary studio in about two weeks.
More updates as the project progresses.
Update: The new Axia equipment and Op-X automation is on line as of 2/24. More pictures to follow.
Update 2: For more information on how the Axia consoles are made, check out A broadcast console makers perspective.
Update 3: More pictures:
WICC new studio with Axia console
WICC studio is nearly done, just a few odds and ends here or there. This is located where the former talk studio was located.
WICC talk studio
WICC talk studio, host and four guest positions. This is located where the former news room is.
Former WICC air studio, gutted
This is the former WICC control room. It has been gutted and several walls are being removed. This will become the permanent WEBE control room when it is finished.
WEBE temporary control room
WEBE temporary control room.
WEBE old control room, gutted
The former WEBE control room, gutted. All the carpeting has been removed and 1/4 inch drywall is going over the old, glue encrusted drywall. This room will become a production room.
WEBE WICC rack room
WEBE WICC rack room viewed from the hallway, approximately where the door to the room used to be. The old racks to the left are being stripped out and removed. All of the stations are now on the air from the new racks.
The phone company came out and cut over the T-1 circuit on Wednesday, June 2nd. This really kicked things into high gear. By that afternoon we had moved the Prophet systems automation rack up to the new location and started broadcasting from there.
Unfortunately, the backup plan, which was to use the phone company DSL circuit to relay audio to the transmitter site, fell through at the very last minute. I think the phone company mistakenly turned off the DSL service to the old studio ahead of schedule. The net result was 2 hours off air in the middle of the day, which we were seriously trying to avoid. Once it was done, however, there was no going back, so we worked extra hard to get back on the air from the new location.
Naturally, while all this is going on, the electrical inspector shows up to do the final electrical inspection for the town building department.
Here is a nice progression on the equipment racks:
Equipment rack with automation system
After the T-1 circuit was cut over, we began broadcasting from the new location with the equipment rack automation system using the production room as a studio for live elements and voice tracking.
Equipment rack, wired to both studios
The wiring on the equipment rack is completed.
Completed with phone system and network switch
The equipment rack is completed, the phone system is installed, the computer network is wired and tested. The yellow light on the top of the rack is a silence sensor.
The old WKZE studio
The old WKZE studio was ripped out on Thursday. The console was removed and rebuilt with a new control surface
New WKZE air studio completed, console is a Radio System millennium 12
The production room was completed, speakers hung, etc.
The production room is long and narrow
All set and ready to be “customized” by the DJ’s. Monday morning, the staff will roll into their new digs, which is always fun. In comparison to most studio moves and builtouts these days, this one was relatively small and simple. Last studio consolidation project involved 5 radio stations and ten studios. That one took place in steps over several months.