streaming audio – Page 2 – Engineering Radio

The neighborhood Mesh Network

Wireless IP Ethernet (802.11) technology has been around for a while. Many know it as “WIFI” but you could also call it “WLAN” or something similar. Like many other Ethernet technologies, WLAN relies on a spoke and hub connection system. The hub being the wireless access point or router and the individual hosts (PC’s, tables, phones, etc) being the end point for each connection. In a wired network, it is usually some type of switch that forms the center of the network data distribution system.

With a wireless mesh network or ad hoc network (802.11s), each wireless device can connect to any other wireless device within range. In this type of peer to peer network, there is no central access point, although something can act as an internet gateway or there can be several gateways. This type of topology functions much like the public network (AKA the internet), where there are many different paths to any one (major) destination. If any one of those paths goes down, another route is quickly found.

This technology was developed by several vendors for military communications systems and for OLPC (One Laptop Per Child) programs in Africa and other places. Each link acts to extend the boundaries of the network, thus the more users there are, the more useful the network becomes.

Advantages of mesh networking:

Networks are self forming; once the nodes are configured and can see other network nodes, the the network automatically forms
Networks are self healing; if one node drops off line, traffic is automatically routed to other nodes. If the node comes back up, it is included back into the network
High fault tolerance; in areas where many nodes exist and can see each other, the failure of any single node does not effect the rest of the network
Low cost to deploy; mesh networks use standard off the shelf WLAN (802.11) devices. Choice of software will dictate which hardware will work the best
Crowd sourced infrastructure; as each network node is owned by an individual, the cost and responsibility is shared among the community

Several specific routing protocols have been developed for the network side of the system. Hazy Sighted Link State Routing Protocol (HSLS), BATMAN, OLSR HWMP and others. These work well with the existing 802.11 a/b/g wireless network hardware currently available.

On the host side, a good IBSS capable wireless network adapter is needed, which many of the newer ones are. Several of the software programs have lists of WLAN adapters that work with their software. Open Garden is a free App for Windows, Mac OSX, Android, and they are working on an iOS version. This leaves out certain devices like tablets and iPhones for now.

Since existing wireless adapter drivers do not yet support mesh networking, usually an additional piece of software is needed. There are several interesting ones, including HSMM-MESH, which was developed by Amateur Radio operators. Open source programs for Linux, Free BSD and other are available as well as commercial versions for Windows.

I was thinking that this might be useful for broadcast applications. For obvious reasons, this type of system would work best in densely populated urban and suburban areas, which is exactly the type of area that LPFM licenses might be hard to come by. For those who do not have the time or wherewithal to apply for an LPFM license, or for those that simply don’t get a license due to scarcity of available channels, this could be a great way to cover a neighborhood or section of a city. The more people that participate in the mesh network, the stronger the network becomes. Additionally, by using FCC type accepted part 15 FM and AM transmitters as broadcast nodes, carrier current transmitters and leaky coax systems, the presence of the mesh network can be advertized to potential listeners, including directions on how to take part.

Wireless mesh network example, courtesy of Meraka Institute

Wireless LAN bridges or broadband internet connections can act as a backbone between distant nodes.

For bandwidth efficiency sake, AOIP services should be limited to multicast addresses.

A good site with more wireless mesh network information is http://wirelessafrica.meraka.org.za/

Two sub-reddits on the subject: /r/meshnet and /r/darknetplan

Then there is project meshnet and the project meshnet wiki

Oh, by the way, go ahead and ask me what I have been learning about in school these days…

Cost of Starting a LPFM vs Cost of Internet Streaming

I have been watching the LPFM proceedings with some interest. The FCC has not exactly promised to have a filing window by end of 2012, but indicates that it might try to do that. In comparison to such evolutions in the past, this is moving pretty fast. Those that want an LPFM station need to start planing now. As in previous LPFM windows, the availability is for non-profit organizations only. This does not mean all hope is lost; NPR stations are all non-profits and most of them are very successful.

One of the biggest questions is: How much will it cost? Like all things, it varies greatly. If I were to put an LPFM or internet radio station on the air, there would be certain minimums, such as the use of professional audio equipment, a new antenna, and some type of redundancy.

Generally speaking, radio stations and internet stations both need some type of office/studio space. This can range from large and opulent to a closet. The costs for these would depend on the type and quantity of equipment installed, whether the equipment is new or used, the building, the area, etc. Those facilities also have monthly reoccurring costs such as rent, electric, telephone service, internet service, etc.

Since internet radio stations and traditional terrestrial over the air radio would use the same type of studio equipment, those costs will be similar. Here is a breakdown of the studio equipment:

Nomenclature	Cost new (USD)	Cost used (USD)	Comments
12 Channel professional audio console	$6,000.00	$2,500.00	Analog, 4 buss, telephone mix minus
Studio Furniture	$5,500.00	$1,000.00	Can also be fabricated locally
Microphones, RE-20 or SM-7B	$250-350	$100-150	Per unit, several required
Monitor Amp	$250.00	$100.00	Can also use consumer version
Monitor speakers	$500.00	$200.00	Can also use consumer version
CD Player	$500.00	$200.00	Professional unit with balanced outs
Computer w/ professional sound card	$1,500.00	$500.00	For automation and sound file storage
Computer, general use	$700.00	$300.00	General information web browsing
Computer, Streaming w/sound card	$900.00	$400.00	Sound card should be good quality
Studio Telephone system	$1,900.00	$300.00	Used for call in/on air
Barix remote box	$240.00 (x2)	N/A	Used for IP remote broadcasts
Comrex Matrix POTS codec	$3,200.00	$700.00	Used for telephone line remote broadcasts
Misc wiring, hardware, ect	$1,000.00	$800.00	Connectors, mic booms, wire, etc
Total	$21,780.00	$7,930.00

Some equipment is not available used such as Barix boxes. Of course, not all of this is required for a radio station, however, most local radio stations would want the capability to do remote broadcasts, take phone callers on the air, have multiple guests in the studio, etc.

For a traditional LPFM station, the transmitting equipment would entail:

Nomenclature	Cost New (USD)	Cost Used (USD)	Comments
300 watt transmitter and exciter	4,400.00	2,000.00	Smaller transmitters with higher gain antennas can also be used
2 Bay ½ wave spaced antenna	$1,900.00	$700.00
125 feet ½ inch coax	$350.00	N/A
100 foot guyed tower and installation	$4,000.00	$3,500.00	Not needed if station is on tall building or leased site
STL; IP radio w/ barix boxes	$850.00		In lieu of standard 950 MHz STL
STL standard 950 MHZ	$6,500.00	$3,500.00	Used in lieu of IP STL
STL antennas, transmission line	$2,500.00	$1,500.00
FM Processor	$10,000.00	$1,200.00	Can also use software such as Breakaway Broadcast
Misc connectors, grounding kits, etc	$1,100.00	N/A
EAS unit	$1,900.00	N/A	Fully operational CAP compliant
Processing software, Breakway broadcast	$200.00	N/A	In lieu of standard FM processor
Total	$12-24K	$8-12K

This is a generic station, most will be somewhat different due to antenna supporting structures, transmitter powers and antenna types. For the best possible signal, a circularly polarized antenna should be used. A two bay, 1/2 wave spaced antenna will give the maximum signal density, while minimizing downward and upward radiation. The upward radiation is simply wasted energy, as no one in space is listening to FM radio. The downward radiation reduction is key if located in congested areas.

For internet radio station, the following would be required:

Nomenclature	Cost New IUSD)	Cost Used (USD)	Comments
Streaming Server	2,100.00	1,100.00	Includes professional sound card
Audio processing software	200.00	N/A	Recommend software such as Breakaway Broadcast
Audio Processing, outboard hardware	650.00	400.00	In lieu of software
Audio Streaming aggregator	1,200 to 2,400	N/A	Annually

While LPFM’s are much more expensive than internet only stations, LPFM’s have the advantage of built in marketing, which is the on air signal. If it is broadcasting on the air, word will get out. On the internet, some other type of marketing will be needed to spread the word. Also, LPFM’s should also be streaming, which would incur the same costs above.

The long and short of it is, to put a technically viable LPFM on the air is not an inexpensive proposition. It is worth the effort, however, because the advantages of an LPFM over an internet only station are great.

All those servers do not run cheaply

As Google can verify. According to the NYT piece: Google Details Electricity Usage, Google said its operations draw approximately 260 million watts continuously to run their online services and office buildings. That figure includes all of the e-mail applications, Youtube videos, Google searches, Google documents, etc. That works out to be about 6.24 million KWh per day or 21,292,752,000 BTU per day. Here are some of the amounts and costs for other fuels:

Fuel	Unit	Amount	Average cost $	Cost per day
Electricity	KWh	6,240,000	0.05	312,000
Gasoline	Gallon	185,963	3.61	671,326
Diesel	Gallon	170,342	4.05	689.885
Coal	Ton	819	156.40	128,091
Natural Gas	CCF	211,868	2.335	494,712
Propane	Gallon	231,443	3.02	698,957

Those figures do not take into account the efficiency of the generation process. For example, the average coal fired power plant is 32% efficient, thus the actual tonnage of coal needed to produce 6.24 million KWh is 1,376 at a cost of $215,194. Other fuels have similar electrical conversion efficiency, with the internal combustion engine being about 19% efficiency for any given fuel.

Some other interesting tidbits from the article:

Each Google search uses about 0.3 Watt-hours of electric
The average user uses 180 Watt-hours per month
Approximately 12.5 million Watts or 30,000 KWh per day are used by search engine traffic
25% of Google’s energy is supplied from renewables
Google designs and builds it’s own data centers using energy efficient technology

One can assume that other data centers are not as efficient as Google’s. It would be interesting to do a comparison between the electrical use by AM and FM broadcast transmitter sites and the energy used by data centers that stream radio content. Right now the data center’s electrical costs are still relatively low because over the air radio listenership far out strips on line listenership. Eventually, those numbers will flip and I’d think the increased costs associated with greater streaming will be paid by somebody, likely the content generator.

All those webstreams, videos, search engine queries are not free.

VOA to end HF broadcasting

Several places have reported that The Voice of America will sunset it’s shortwave broadcasts in the not too distant future. Boing Boing reported yesterday, based on a paper titled “Broadcast Board of Governors 2010-2012 BBG Technology Strategic Plan and BBG Technology Update – 2009” received via FOIA last January.

The 2009 study notes that the weekly audience for radio is 101.9 million listeners, TV is 81.5 million and the Internet 2.4 million weekly listeners. I don’t know how much that has changed in the last two years, but I’d imagine some shift towards the internet has taken place in light of recent shortwave transmitter site closings.

There are several interesting aspects of this report, notably the disparity between what is termed “Classic Engineering” and “Classic IT” fields. This is the concept that radio engineers toil on RF and transmitters, while the IT guys work with computers.

As the dependence on shortwave continues to wane and the distribution focus shifts to third party operations, satellite and other direct-to-consumer methodologies, the skill sets of some engineering personnel become less and less relevant to the agency.

This issue is further compounded by the relatively difficult transition from a traditional RF, antenna, transmitter design, and maintenance knowledge base to the technologies involved in digital satellite and IP-based networking systems.

Perhaps that is how it is done in government circles, but I have found in private sector, most radio engineers know at least the computer automation systems that run the stations. Of course, everyone has preferences and we tend to gravitate toward things we like to do, especially in a field as diverse as broadcast engineering. When I was in the military, somebody posted the “Eleven Rules of Success.” The only one that I can remember now is this: “Pick the thing that you hate and become proficient at it.”

In order to stay relevant, broadcast engineers have to keep up with the technology while remaining proficient with RF and audio skills. Computers and automation programs are not terribly hard to understand, but each one is different and operates differently. Most, if not all automation companies offer some type of training, which is fine. Nothing can beat hands on installation and trouble shooting for learning the important details, however.

The report also mentions that morale is an issue for several reasons. First, it is noted that:

Despite several recent high profile station closings, the organization continues to employ shortwave as the most important transmission mechanism to many of the target areas around the globe. Often surge activities are enabled byvadditional shortwave transmissions that end up as an integral part of the ongoing schedule. Effectively, this diminution of transmission resources accompanied by no reduction or even an increase of reliance on this transmission methodology creates overburdened schedules and often the deployment of less than optimal assets for transmission into target areas.

This additional operational burden likely extends to other disciplines within the agency where programming staff must expend substantial additional effort to produce or adapt content for a multiplicity of transmission methods.

In essence, the decision process for station closing does not appear to follow an overt decision and stated plan to reduce shortwave usage.

That is known as the “more with less” paradox. In the private sector, more with less has been going great guns since the first loosening of the FCC’s ownership rules in 1994. For those that are used to working in optimum conditions, anything less is a shock to the system.

The issue of low morale is palpable and often present in conversations that address historical perspectives on a particular station closing, transfer of technologies around the network and any other such topics. Precipitated by the long periods of employment that are relatively standard in the Engineering area and perfectly understandable, this grieving process is a natural consequence of the pride involved in creating a state-of-the-art technical facility only to see it being dissected piece by piece as technology continues its relentless creative destruction.

An interesting statement and it shines a light on several things heretofore unsaid in broadcast engineering. We love our transmitters, as strange as that may seem. We love our towers and antennas. Parting with something that has become an integral part of our working environment is difficult to say the least. Watching something be signed off for the last time and then hauled to the scrap heap is very disheartening, especially if there is no replacement.

On the IT side, things are not so good either. The main concern is the infrastructure of the IT backbone. Several deficiencies are noted in the cabling and router; the cabling is in serious disarray and there is only one router for the facility. There is also other problems noted with personnel and lack of project management experience and/or IT department goals.

Overall, moving into new media fields makes sense. There are, however, many places where new media is unknown or at best, mostly unavailable. Moving content delivery from over the air broadcast to IP based distribution may be far less expensive to operate, that is true. It is also far more susceptible to being disrupted by accident or design. In those areas where the internet is spotty, shortwave radios are abundant and relied upon. If the VOA is not on the air, then some other station will be.