I’ve made no secret here over the years, I have many friends and acquaintances in various parts of Russia. It is a fascinating culture with great art, literature, and music. I am watching with growing concern, the level of Russian demonization from seemingly every quarter being aimed at Russian people and businesses here. It seems that a great number of people have lost perspective. It also shows the power of propaganda. Theirs and ours.
To be sure, watching the situation unfold in Ukraine on social media is disconcerting. No one in their right mind can look at those images and say “Oh, that is normal.” It is greatly disturbing. It is also war. All wars are like this and have been like this since the beginning of time. The images of dead civilians, bombed-out cities, mass graves, and so on are broadcast to the world on social media in almost real-time. That is the difference this time.
This situation in Ukraine is complicated. It is a war of gas and ambition. There are many questions, good questions which can be asked; Why is NATO a concern? Why does Putin feel threatened by the EU? What is the Azov regiment? What did the natural gas fields discovered in 2010 have to do with the 2014 overthrow of Viktor Yanukovych? How much corruption is there with the Zelenskyy government? How did the US know that there was to be an invasion? What, if any, does the Bo Biden/Berisma thing have to do with this?
I mentioned in a previous post about Radio Free Europe/Radio Liberty shortwave broadcasts during the cold war. I am heartened to see that there is a private effort to use the facilities of WRMI to broadcast information to that area of the world. The VOA has stated that they are not making plans to make broadcasts via shortwave because few people in that part of the world have shortwave receivers. I know firsthand, that is not true. There are many shortwave sets still in existence and there are people who remember how to hook them up. As Russia becomes more isolated from the world, those shortwave sets are going to get dusted off and put into service.
Novo-Rossiya
Currently, WRMI is transmitting Russian language broadcasts on 7730 KHz from 0200-0500 UTC and 9370 KHz from 1900-2000 UTC. They have funding to buy broadcast time into the summer months. They are also leasing time on 1395 KHz medium wave, which I think is the public broadcaster in Armenia:
Radio International Broadcasting Center, 1395 KHz 500 KW
On the downside, shortwave transmission facilities are expensive to build and run. Unlike internet distribution, there is no way to measure audience engagement or gather audience data. On the upside, it is very difficult to effectively jam HF signals across large areas. It is also very expensive and it would take a fair amount of time to rebuild the old soviet jamming networks. In the meantime, people will be looking for good sources of information about a number of topics.
The one thing that I do know, Putin is the aggressor and he cannot be allowed to win.
I have been watching and listening to the news from Ukraine. It is somewhat horrifying to see the wanton disregard for human life. It is especially concerning when combatants begin shelling a nuclear power plant. A breach of one of those reactor containment buildings might have contaminated a wide swath of eastern Europe. Such an act demonstrates that the Russians no longer seem to care about anyone, themselves included. A man can be very dangerous when he has nothing left to lose.
I have known many Russians over the years through email exchanges, video chats, and meetings in person. People seem to be celebrating with glee over the sanctions but it just makes me sad. Obviously, the war of aggression is wrong. However, you cannot conflate ordinary citizens with the terrible acts of their government, whether in Russia or anyplace else.
Roskomnadzor is has removed almost all outside sources of information from the Russian internet. As of this writing; CNN, BBC, Facebook, Twitter, and Google (YouTube) have all been banned. Radio Free Europe and Radio Liberty still exist, however, they are either on FM or use the internet for distribution.
Close up curtain array
I have to wonder if the VOA is going to step up with some shortwave broadcasts to the region. I know that the BBC has restored two frequencies so far. I believe that the European VOA relay sites have been shut down. That means either leasing time with someone or using Greenville. That is a long way away from eastern Europe, however, HF propagation is currently good and those old Continental 420As could use a little workout. Looks like they still have a row of curtain arrays aligned along 30-40 degrees true North.
As the Chief Engineer of Radio Australia once said, HF will get through when nothing else will.
In the meantime, it might be a wise idea to dust off those old cold war contingency plans and review them. It appears a new iron curtain has arisen, stretching from St. Petersburg to Odessa.
As some of you may have noticed, recently I have been writing some articles for Radio Guide. There are several good reasons for this, but the most important one is education. I believe that terrestrial radio will be around for a few more years. As others have noted, there are fewer and fewer broadcast engineers. Those that understand high-power RF and all its intricacies are fewer still. It is important that a cadre of knowledgeable broadcast engineers carry on.
The internet is a great thing. However, it depends on cables of some type to exist. As we know, cables can be damaged. In addition to cables, there are routers, core switches, servers, and so on. All of that equipment can fail for various reasons. People have been working hard to improve the resiliency of the internet. That is a good cause, to be sure. However small it may be, there is still a chance that the internet can fail. Worse still, this can happen during some type of natural disaster or other emergency. Thus, during such an emergency, Radio can and will function as a vital information source provided that the station is on the air and has a program feed. That is also a good reason to keep the current RF STL paths in place as much as possible.
The Radio Guide articles are a great way to pass along some of that hard-earned experience to others. I also want to put supplemental information here for those interested to download. Things like charts, forms, pictures, videos, etc.
What I am planning on is to list the articles here, then put links to any supplemental information provided below that subheading.
My journey into home stereo speakers and high-quality audio continues…
This is not a broadcast-related post, but I find this type of thing interesting nonetheless. A few years ago, I began fiddling around with flat panel speakers or Distributed Mode Loudspeakers (DML). My first attempt was lackluster, although adequate and not very expensive.
I enjoy listening to all types of music. I notice that some music reproduces better than others. The piano is a particularly difficult instrument to record and faithfully reproduce because of the complexity of the instrument itself. It is a percussive string instrument. When one of the hammers strikes a sting, the string itself does not make a very loud noise. The string is connected to a soundboard through a bridge. The much larger soundboard vibrates and amplifies the initial sound. Thus, the wood itself imparts a noticeable quality to the sound. Several other instruments such as acoustic guitar, violin, etc also use tonewood to amplify sound. Thus, when listening to a piano being played back on a set of speakers, it lacks much of the original texture of the actual instrument. It sounds like a recording of a piano, not an actual piano.
This made me think of ways to improve that reproduction.
A DML uses a large flat surface to reproduce sound. The large surface area and the bi-directional nature of the panel means the sound will be defused and not directional as is the case with conventional speakers at higher frequencies.
The principal characteristics of the material used in a DML are stiffness and density. The less dense (lightweight) and the stiffer the better. All materials have internal resonances, some decay quickly and others, such as steel will ring for a long time. A ringing reverb sound would be undesirable in most cases. Tonewood has suitable stiffness and a relatively high sound radiation coefficient that varies in density according to species and generally dampens high-frequency harmonics. Pianos often use Sitka Spruce for soundboards.
I made two terminated transmission line speakers last summer. Those sound great, but using one driver to reproduce all sound from 20-20,000 Hz has a drawback; the high-end lacks detail and is very directional.
A bit of research shows that Poplar has good to very good tonewood qualities while being inexpensive and readily available at the local big box hardware store. Thus, I purchased several 1/4 x 6 x 48 inch (6 x 152 x 1220 mm) planks and a few pieces for bracing to make two 33 x 22 inch (838 x 559 mm) flat panels. The idea here is to gently cross over the transmission line speakers at 4,500 Hz with these flat panels.
The assembly process was pretty easy. It took perhaps two hours to cut all the pieces to the right size. I used a router to chamfer the edges of the back bracing, mostly to reduce the weight of the brace. Everything was glued up and allowed to dry for 24 hours.
Gluing the parts togetherBack bracing
The bracing is designed to keep the panel stiff and helps with structural integrity. I sanded the fronts and backs of the panels, then finished them with Tung Oil.
Dayton tactile exciters
Each panel uses two Dayton DAEX32QMB-4 tactile exciters wired in series. There is also a Zobel network which is important for a tube amp. Most drivers’ impedance will rise as the frequency increases. This rising impedance is mostly reactance from the driver coil. For solid-state amps, this is not much of a problem. However, tube amps, because of the output transformer, need a fairly constant impedance across their output range. This is because the output transformer is a ratio device. The primary impedance is derived from the impedance on the secondary (e.g. what the secondary is terminated with). For example, a certain tube has a 5,000-ohm plate impedance. The output transformer is chosen to match this design specification. The output transformer is designed to drive an 8-ohm loudspeaker. However, the driver impedance rises to 16 ohms at 15 KHz and 24 Ohms at 20 KHz. Under those conditions, the tube would be seeing a 10,000-ohm impedance at 15 KHz and a 15,000 Ohm impedance at 20 KHz. This will lead to added distortion. The Zobel network keeps the impedance fairly uniform across the entire audio range.
Rather than build a cross-over into the transmission line speakers, I made an external unit. This allows the speaker system components to operate independently if needed. I can easily change the cross-over components for a different crossover point. I can also mix and match things in the future. In other words, it gives me a great deal of flexibility for future projects and experimentation.
Crossover and HF attenuatorCrossover and attenuator components
I made these small boxes to match the speakers. These contain the crossover and HF attenuator. The attenuator is necessary because of the difference in efficiency between the transmission line driver and the tactile drivers on the DML.
The schematic looks like this:
Cross over diagram
I kept things as simple as possible. Yes, I could have made a 12 dB per octave crossover with a few additional components, however, I like the gentle blend of both drivers in the mid-ranges.
A basic sweep with Room EQ Wizard shows a fairly flat response. There is a room resonance of around 90 Hz which I intend to correct with some sound-deadening materials in the corners and possibly a bass trap.
Room EQ Wizard waterfall display
This shows that the speaker system is relatively flat from about 200 Hz to 10 KHz. Those bumps and dips from 88 to 250 Hz are all room due to room resonance.
Room EQ Wizard SPL graph
How does it sound? Pretty good! Here is some copyright-free music, recorded from youtube, then re-uploaded to youtube! It is not the best video, there is some background noise, etc. However, it gives a pretty good idea of how these sound.
