Work – SYMON MUTHEMBA

Quick Guide To Radio Broadcast Transmission

symonmk — Thu, 18 Jan 2018 04:22:05 +0000

Your studio is already set up and it’s now time to go LIVE! Right? Well, there is the issue of how to get that audio to your audience. In Kenya, FM radio is the most common, and profitable, form of broadcast. This is why most of the infrastructure to support it has been set up across the country. Installation might be a grueling task for a small team (such as ours about a month ago), but the outcome becomes far more rewarding than I expected. In this post I go over the technologies that make radio broadcast transmission possible. With a new studio seeking to have their first broadcast transmission or an existing one seeking to expand to other regions, the requirements to be installed remain largely the same as they have been for decades, only this time, we have IP on our side, making things much easier. Audio Link Now starting from your studio, that fresh audio has been captured by your state of the art audio console and you need the people to hear. Transmitting audio over IP is as simple as installing a PtP (point-to-point) microwave link to your transmitting site. Usually the studio site and transmitting site are not in the same location as the transmitting sites are commonly in isolated highland regions. The audio over IP network can be achieved using audio IP-STL (Internet Protocol – Studio Transmitter Link). In our use case, Sigmacom’s Digital IP-STL encoder/decoder system. We set up them using their first recommended configuration as in Figure 1. In our previous installation, the IP link was of about 35 kilometers from the studio to the transmission site. The link was achieved through a PtP microwave link using Ubiquiti’s Rocket M5 radios (TX and RX) attached to RocketDish antennas that we mounted on masts at the TX and RX sites. After the signal has been captured and decoded, it is fed to the exciter. In our example the EuroCaster DS2000 FM Transmitter can power an RF signal up to 2kW of power. This transmitter power (TPO) is adjustable as is the frequency range of transmission, in Kenya it ranges from 87.5 MHz to 108.0 MHz. From this point, the signal can be sent to the broadcast antenna system. Filters, Feeders and Splitters Try saying that three times. The signal from the transmitter has to be propagated to the antenna system somehow. In between comes in a connection of transmission line components. The filter is a factory calibrated FM band-pass filter, which is set to the exact desired frequency, example 98.00MHz. The filter is connected to the antenna system through a coaxial feeder cable. A large feeder cable, like in Figure 2 that can go up to 170mm diameter, carries the large amount of energy from the filter with minimum attenuation to a splitter which splits the signal, in our example 8 times, to the low power antenna elements. The low power antennas may be fed with smaller feeder cables of 20mm. At every connection point with the feeder cable, for example, connection with the filter and splitter, a waveguide rotary joint is used in connecting the RF waveguides. The feeder cable is also grounded to the mast tower. The signal has now reached the antenna system. Transmission Antenna For this application, a circularly polarized antenna was used to achieve omni-directional signal transmission. Figure 3 shows one bay of the antenna. The antenna achieves circular polarization by having the radiating components perpendicular to one another, thereby propagation of horizontal and vertical components occur simultaneously. A singular antenna as in Figure 3 has the following features: Impedance of 50 Ohm Omni-directional pattern, approx. +/- 3dB Band start 87.5MHz, band stop 108.0Mhz Lightning protected, all metal parts DC grounded The antenna is combined with 7 other antennas producing an 8-bay antenna as in Figure 4. Increasing the antenna bays improves several performance parameters such as the directionality and gain. How? Circular polarization splits the effective radiated power (ERP) between the horizontal and vertical components, adding antenna bays on top of each other leads to addition in gain per bay. ERP is used to calculate the range of the signal, mathematically defined as: ERP = [Antenna Power] X [Antenna Power Gain] A 2-bay system has a gain of approximately 4.1dBd/6.25dBi while an 8-bay system has a gain of 10.1dBd/12.25dBi. Since the gain is higher and losses minimized, the system requires less TPO. Additional bays, however, increase overall system weight as the main trade-off. These are the basic components one would require to achieve broadcast, in our example, a radiating diameter of 100km could be achieved with the above discussed configuration. When setting up such a system, it is important to capture the necessary requirements so as not to have conflicting components during set up. Hopefully this guide will bring you closer to understanding what goes on before you tune in to your favorite FM channel.

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Here’s How You Make Sound Decisions on Acoustics

symonmk — Wed, 06 Dec 2017 13:47:50 +0000

Pun obviously intended. The effects of sound in some industries has an important effect on the quality of work produced as well as in some key applications, especially in the field of broadcast that I currently work in. Sound is the perceived pressure produced by the propagation of energy through a medium released when matter vibrates, while acoustics is the branch of physics that deals with the production, control, transmission, reception, and effects of sound. Some of the areas of application that are dependent on sound are full/hemi anechoic chambers, radio and television studios, airports, nightclubs, torture chambers (just a guess, I’m not completely sure about this one), recording booths and many more. These are environments where sound needs to be well controlled. An example that I’ve dealt with was in radio studios. Imagine listening to your favorite radio show in the morning then you faintly hear the buzz of a helicopter or the bark of a dog within the show. Such interference would obviously dampen your experience of the show. So before you give them a bad rating, get to know what they should’ve done. Soundproofing and Isolation Soundproofing is the act of minimizing the entry of external noise into a room. Noise comes from many areas; outside noise from traffic, planes; from inside the building like chatter, walking and movement. Noise is captured by sensitive microphones typically used in these applications. It’s obvious measures have to be taken to mitigate the effects of noise in a lab or studio, since running tests or shows only at 3am, dead in the night, is not much of an option. Therefore, soundproofing isolates an area from effects of such noise For proper isolation, consider right from the very architectural plan of these rooms to cater for factors such as sound pressure, to ensure desired noise levels. The room should be ‘shielded’ from outside noise sources using several ways: Construction with heavy material such as thick concrete walls Use of double doors Heavy doors Closing off the studios from sources of noise within the building such as steps, chatter Sealing any and all air gaps on windows and doors Acoustic Treatment Acoustic treatment refers to measures taken to ensure good quality sound capture/recording within a room. In-room noise from echo, air conditioning systems and computer fans lead to poor sound capture and this can never be reduced through isolation as discussed earlier. Treating a room requires knowledge of the kind of sound to be captured but a few methods that we will discuss will greatly improve the sound quality compared to no treatment at all. When we’re discussing acoustic treatment, we refer to catering for the following scenarios: Reflection of low frequency sound off the room walls caused by the size and dimensions of the room. Reflection of mid to high frequency sound off hard surfaces within the room. To have the best sound, an investment in acoustic treatment material that absorbs and diffuses sound MUST be made. Sound absorption Sound that bounces off surfaces can be reduced by placing panels which absorb the sound before it reflects back to the capturing devices. You can easily check the acoustic properties of your room by walking to every point of the room and clapping your hands as loudly as you can. Check the reverberations that are produced, if you get audible echoes especially with a ringing sound, you need a great deal of treatment, if you have minimal reverberation, this is good though you still stand a chance to benefit from some acoustical treatment. The room can be treated using some of the following methods: Using bass traps to absorb low frequencies Using acoustic panels and foam boards to absorb the mid to high frequencies Using diffusers to scatter the other frequencies Use an acoustic carpet specially made to absorb sound In an-echoic chambers, use of large acoustic absorbers Such items could be found locally in Nairobi, like acoustic carpets are easily found at Tile & Carpet Center and other vendors of these products. Final considerations you could make are the equipment to be used in the room, like computers whose fans make noise, the air conditioning system may also bring in undesired noise. However, different people may want different noise levels in a room so plan and execute wisely with proper research and consult the experts. Fun fact: Microsoft broke the world record for constructing the quietest place ever and they have an interactive website to show you how they did it, sounds really interesting.

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5 Things to Consider When Choosing an Automation/Playout Software for Your TV or Radio Studio

symonmk — Wed, 08 Nov 2017 09:26:02 +0000

Broadcast automation is a crucial part of any modern radio or TV studio. A playout software is an application whose main function is to allow you to schedule and transmit media from your studio to your audience. For TV and radio studios this is a major component of the overall broadcast system and needs to be chosen very carefully. Typically, playout softwares are located in the master control room of a studio where all the feeds available are directed to it. These may include audio and video feeds from other sources such as live content from video switchers, media files located locally in the computer or a networked storage, incoming OB content e.t.c. One needs to understand what a particular brand of playout software offers to avoid certain mistakes and to meet your particular requirements. Radio and TV Automation While it might be a simple assumption that the only difference in automation for radio and TV is the type of media used, audio and video, there are a great deal of practical differences. The complexities of their automation are also increased by the fact that radio and TV are first and foremost businesses and require a smart, reliable way of tracking the ads and sponsored contents they get paid to do. A complete radio automation system may involve the following: Song scheduler/playlist editor Crossover editor Live-assist module Spots/commercials programmer (different commercials for different regions and commercials going to multiple stations) Integrated RDS (radio data system) Playout to defined formats Other possible features are a clock system, rules and programming commands for your music in their respective categories, practical templates, rotation and an audit feature that checks the users and their activities. In television, a playout software will include other features in addition to some mentioned above (especially the scheduler and the spots programmer), to support the video content going on air. The features of a TV automation system are such as: Output in multiple formats i.e. SD (576i), HD (720p and 1080i/p) and some up to 4K! (2160p) Output in physical SDI or network stream as H.264 or MPEG-2 Electronic program guide (EPG) generation Graphic insertion for logos , animations, scrolls and other elements Multiple client configuration for traffic, program and admin control Simultaneous outputs in different formats (SD, HD, 4K) Support of most popular and used codecs Real time graphics control and updating Other possible features include a teleprompter, a simple video editor and GPIO control. To a novice, the above information may sound cryptic but with good understanding of your requirements, you can apply the following five factors in choosing one for your studio: Reliability and stability of the system – Running a TV or radio studio requires 24 hour non-stop coverage every single day. It is one of the ways to ensure audience retention. Therefore, the playout software should be stable enough to be active throughout the lifetime of the studio, which is years. This means also providing the right hardware and operating system and conditions (ALWAYS disable Windows updates!), these are usually recommended by the creator. Technical Support – So much might go wrong during operation of the system. Ensuring the product you are purchasing guarantees technical support, either from the software creators or the contracted engineers you hired (such as the company I work for), might come in handy especially during the early stages of deployment. The technical support team may also offer training to the users within your station. Level of automation – While shopping for the software to pic, you would want to pic the one with the highest level of automation at your price point. This is to increase the overall efficiency of the system, reduce manual steps as well as labor costs. A high level of automation reduces the potential for errors in the system, especially when sponsored contents and advertisements are involved. Ease of usability and user experience – Ultimately, the main users of the system may never be users with technical backgrounds. This is important to consider as I have witnessed how complicated software becomes a pain to the point users reject going through a steep learning curve and most features of the software ends up unused. A friendly layout, comprehensive manual and easy-to-reach points are essential for such an important piece of your studio. Price and budget – This now depends on the studio’s ability to get the best product in the market or compromise for a cheaper solution and lose some above mention features or consideration factors. Whatever you decide on, keep your requirements at the top of your mind and let some of these factors guide your decision. While this is a simplification of sorts, other factors may come in to place depending on your unique situation but I hope I’ve shed some light on the aspects I consider important. I have personally worked with several playout systems including Cinegy AIR, AVRA, VPlay and Imedia, involving installation and configuration at a client site.

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Getting to know Visual Radio: The Future of Radio Broadcast

symonmk — Wed, 20 Sep 2017 13:00:56 +0000

There comes a time when a concept that has been in use for decades is suddenly challenged by modern ideas. Such an idea is visual radio and, since its conception, has been widely adopted in Europe and America. This technological advancement is now creeping into Kenya. Will it have an impact? My recent experience setting up a visual radio studio has led me to believe it is an investment worth paying attention to. Let’s review and explore this technology and what we could expect from it. What is visual radio? Visual radio is the amalgamation of existing radio presentation of audio production with another layer of video production normally done with automatic camera control within the studio as well as playing video content. This results into a synchronized radio and visual production, what is heard on radio can also be visually consumed whether on digital TV or through live streaming. This modern solution on radio enriches the audience’s experience of live shows as well as provide a competitive reach for the broadcasters to newer markets such as the tech savvy youth through live streaming. Benefits of Visual Radio Should your radio studio upgrade to a visual radio one? Here are some of the reason why you should consider this shift: 1. Multi-platform reach With the rapid pace at which consumer technology is moving, visual radio seeks a new way to reach new audiences through streaming and social media platforms. Streaming services like YouTube and social sites like Facebook allow for live shows which radio presenters can take advantage of to create new ways of interaction with their audiences. This is done while still broadcasting via the usual FM channels. Now, listeners have more options to choose from depending on their preferences and access to supporting technology. In many parts of the country, 3G connectivity as well as digital TV migration is already a reality. This allows for such stations to provide richer content while still being the familiar radio their fans are used to. 2. More ways to generate revenue Setting up a radio studio to also produce video is not a complicated procedure as setting up a television studio might be, but it provides a way to present video advertisements just as television. This means that a simple visual radio studio may broadcast the same ads as a TV studio. Moreover, other creative ways of advertising may be achieved including overlays while a presenter is running a show, promotional items within the studio as well as special guests who may come in to promote their brands. 3. Simple equipment Radio presenters who are used to radio equipment will still the same type of equipment, such as audio consoles (maybe newer due to a few required functionalities) and their shows largely remain the same. The video production unit is an automated system that is linked with the audio mixer to facilitate automatic switching of the cameras such that when a mic is live, the output from camera corresponding to that source is what is displayed on the screen. Challenges This concept has been met with some challenges which include in most part for the users to determine what video content will be on air. This may require having all the previously only audio music as video. The presenters should also get comfortable with the idea of video presentation as opposed to audio only. In a quote from Radio World magazine special issue on Visual Radio (Jan 2017) visual radio content can be grounded in the spoken word narrative style that is at the heart of radio story-telling, rather than the “visuals come first” approach of broadcast TV What we set up In my previous article, I mentioned I worked for a broadcast systems integrator. The company was contracted to upgrade a popular radio station to have visual capabilites. The solutions we settled for were: LAWO Crystal audio mixing console – This the audio unit of the system that accepts a number of audio sources (mics and lines) as well as provide the camera control signaling for the video unit. LAWO Crystal console is a modern audio console with advanced capabilities on its fader panel, Surface, as well as its control center, the Compact Engine. HDVMixer – This serves as the video control unit. The HDVMixer is a modified tower workstation which accepts video inputs from cameras, audio input (from the Crystal console), embeds the video and audio and outputs the combined AV signal. Avipas PTZ cameras – These pan, tilt and zoom cameras function to capture video to the HDVMixer and additionally have the capability to be controlled remotely via an IP connection. Visual radio promises to be an amazing avenue for fresh, impactful content and I can’t wait to see what our clients will do with it.

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Working as a Broadcast Systems Engineer

symonmk — Tue, 22 Aug 2017 16:32:54 +0000

It is mid-August 2017 and I have been working as a broadcast engineering intern at Byce Broadcast and Technologies Kenya Limited, a system integrator company that offers turn-key solutions for TV and radio broadcasting. This business has a steep learning curve and I am required to learn real fast. Thankfully, the work is interesting and the fast changing technologies in this industry means that I’ll never stop learning. This post is just to simply provide an overview of the skills and competencies that are required in broadcast engineering and the work involved as a systems integrator. Broadcast Stations TV and Radio stations require solutions that facilitate their ability to deliver content to their audience. Satellite uplink – This refers to setting up a signal link from a TV/radio station to a satellite uplink provider who will send the signal to a satellite in space that will perform a broadcast downlink to users. You can read more about this on my previous post here. Teleport services – This is connecting a link from a TV/radio to a center that offers regional transmission of signals from the stations and has gateways to national networks. Budget – TV and radio stations are required to pay certain fees in order to access infrastructure for transmission and broadcast. Also, licensing of an allocation of the frequency spectrum to the Communications Authority of Kenya, CA. An understanding of satellite communication with reference to broadcast is required to provide the solutions stated above. In the last few decades, a set of international standards for digital television has popular. This is the Digital Video Broadcasting (DVB) standards. They are internationally recognized and supported by over 270 members. DVB standards are implemented for a variety of modes, the two of most importance are: Satellite: DVB-S, DVB-S2 Television: DVB-T, DVB-T2 Another way of broadcasting media that has been rapidly rising in adoption is the OTT (Over-the-top) distribution which allows for transmission of audio and video content straight to the Internet without any requirement of a satellite operator. Users can access this content directly on the Internet without the need to subscribe to a satellite TV provider. TV and Radio Studios Although TV and radio studios have different equipment set up in them, much of the underlying principles of design and setup is largely similar. Some of the technical considerations that are handled here are: Studio size and design Sound acoustics and material considerations Room temperature and air conditioning Choice of studio equipment Lighting considerations Choice of transmitting equipment Desk size and design Inventory Safety measures These considerations and equipment may be detailed further in later posts. Roles and Responsibilities Some of the organizational key activities include understanding client needs and budget, design of the proposed solutions, configuring, supplying and installing equipment at client site. For most clients, the four major initial service processes are to supply, install, commission and train users on the equipment. Thereafter, a SLA (service-level agreement) is defined between the system integrator company and the client to agree on terms of after-sales support such as troubleshooting and repairs. This is handled through official phone calls or email ticketing and could be handled either remotely or on site. So far I am involved in two ongoing projects for major clients in the country, as well as having successfully performed a small project involving the coverage of a recent graduation ceremony in the biggest university in Kenya. This is only the beginning and I anticipate exciting times ahead. Broadcast is a field of electrical engineering I formerly was not much aware of but my experience in the past few weeks has opened me up to a broader world.

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Ten Essential Skills for Electrical Engineers by Barry L. Dorr, Chapter 10 Part 1 Summary

symonmk — Tue, 09 May 2017 10:13:01 +0000

Ten Essential Skills for Electrical Engineers is a wonderful book and at the writing of this post I am summarizing the fifth chapter. However, I couldn’t resist skipping over to read the tenth chapter, GETTING A JOB – KEEPING A JOB – ENJOYING YOUR WORK. In this chapter, Dave a 74 year old friend of the author and successful engineer, joins in writing this chapter. Together with Dorr, they provide suggestions on getting and enjoying an engineering career in the following ways: Positively distinguishing yourself from other job applicants Distinguishing yourself in the workplace The chapter is divided into three parts: How to effectively market yourself to ccompanies as a candidate with strong technical and interpersonal skills How to quickly develop skills that will make you a valuable part of any engineering department How to ensure the nearly 100,000 hours of your working life be satisfying, rewarding and meaningful This chapter advises one to select the information that is right for you at the moment. For myself, I will focus on the first part. Part 1. Getting a Job First of all, familiarize yourself with the corporate hiring process. This is usually done in 4 steps: Step 1, Computer screening. Step 2, Review by Human Resource personnel. Step 3, Telephone screening. Step 4, Interviews at company. Tips for bypassing the above corporate hiring process: Avoid the computer screening process by taking advantage of all the job placement assistance available at your school Target companies carefully and send resumes to individuals within the company Getting an Interview Take and pass required engineering exams and certifications by these companies Get some experience, in form of internships or projects Attend job fairs Send resumes to a carefully chosen set of companies Send your resume to the right person Always accompany a resume with a cover letter Contact companies even if they are not hiring Preparing for an Interview Get your suit cleaned and pressed Prepare to discuss anything on your resume Mentally prepare to be interviewed by a team Be prepared for the interviewer to ask you to discuss a subject of your choice The Interview There might be an initial telephone screen. If you do well, you will be invited for an on site interview. At this stage, follow the following: Treat the telephone screen as you would a normal. serious interview Be prepared to work problems Be confident and enthusiastic Don’t worry about being nervous When asked something you don’t know, do not give up or panic If the interviewer is inexperienced (like in your particular expertise) help him/her out in understanding When doing problems, check your work When asked about team projects, make sire to credit your team members Be prepared to ask the interviewer questions Send a follow-up email immediately after the interview Selecting the Right Offer After going through the above stages and hopefully succeeding in getting an offer for a job, it might still be important to ask yourself these questions: Does the company offer job security? Did the company offer a high starting salary? Did you meet mentors you could learn from? Did you see women in engineering and management positions? (Relevant benefit to female candidates) Is the laboratory well equipped? The above is only a shallow summary. The complete book further elaborates each point stated. I will continuously internalize on these concepts as I continue with my studies and career search. The next two parts will become relevant to me as soon as I start working and I’ll be sure to capture that too!

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