General – Page 49 – Engineering Radio

The World Turned Upside Down

I have been watching the events unfold in Japan. It is truly astounding the power of Mother Nature. While several US networks seem to be tempering their coverage of the nuclear fuel melt, and yes, there are multiple reactor fuel melts in progress, other sources are forthright. The BBC seems to be on top of things, as well as Russia Today.

Thus far:

No fewer than four hydrogen explosions have taken place in all four reactors at the Fukushima-1 Power plant. The after the third explosion yesterday in unit 2, there are two major concerns; breach of the reactor vessel(s) and runaway nuclear fission. After that explosion, the pressure in the unit 2 reactor suppression chamber dropped from three atmospheres to one atmosphere, indicating the suppression ring had breached. Currently, the nuclear disaster is categorized as a 6/7, surpassing Three Mile Island. The worst case scenario: Reactor Unit #2 completely breaches, this unit contains Mox fuel Note: unit #3 contains the Mox fuel. (mixed plutonium/uranium oxide), which is far more dangerous than the fuels in the other reactor vessels. Mox fuel has a lower melting point and could potentially melt into a pool at the bottom of the reactor vessel resuming fission. Criticality? Yes, but not the high-order type as seen in a nuclear weapon.
The root cause of the disaster is the loss of cooling after the reactors were shut down. The nuclear fuel cores require cooling for at least two to four weeks after shutdown. The backup diesel generators went offline approximately one hour after the units were automatically shut down during the earthquake. Three probable causes for this have been proposed; the electrical switch gear for the generators was in the basement of the generator building, which was flooded by the tsunami, fuel contamination/fuel loss, and submergence of the GENSETs by seawater. All three of these scenarios point to a design flaw.
Radiation levels have varied but are elevated, peaking at various times before and after each explosion. Until this morning, the major radiation plumes were being blown offshore. The wind has become variable, causing the downwind zones to shift.
Prevailing east winds could blow some of the contamination to the west coast of the US within 36-48 hours, the east coast by 48-72 hours, and in 7-10 days there will likely be a band of radioactive particles in the jet stream that circles the globe in the northern high latitudes.

Good explanations: MIT NSE Nuclear Information Hub

I never thought I’d recommend a Russian News media source, but they seem to be nailing it. There is also some coverage on NHK shortwave frequencies:

All times UTC / target areas: af (Africa) as (Asia) EU (Europe) na (North America) pa (Pacific)

0500-0530: 5, 975 KHz (eu) 6,110 KHz (na) 9,770 KHz (af) 15,205 KHz (as) 17,810 KHz (as)
1000-1030: 9,605 KHz (as) 9,625 KHz (pa) 9,840 KHz (pa) 11,780 KHz (as)
1200-1230: 6,120 KHz (na) 9,625 KHz (pa) 9,790 KHz (eu)
1200-1300: 9,695 KHz (as)
1300-1330: 9,875 KHz (as)
1400-1430: 5,955 KHz (as) 9,875 KHz (as) 21,560 KHz (af)

But not to worry, everything is okay. There will be no detrimental effects of this, whatsoever.

Regardless, I have headed down to the basement and dug up my CD V-700 RAD meter. I salvaged this from the dumpster at WPTR after one of the contract engineers threw it away in the early 1990’s. I believe I used this meter to measure the radiation from the tubes in the BT-25A and the MW50B transmitters.

According to the “Operational Check Source” on the side of the meter, it still works and is pretty close to the calibration level. Even if it is not totally accurate, it will still indicate an increase in radiation.

This is an Anton Model 6, which is the most sensitive of the V-700 series meters. It can be used to check background radiation levels and/or contamination of food or clothing. The best plan is not to ingest radioactive particles in food and water. Why wonder about it, when you can know?

Broadband for First Responders Act of 2011

I found this bit of proposed legislation by Peter King (R-NY) interesting:

Not later than 10 years after the date of enactment of this Act, the paired electromagnetic spectrum bands of 420–440 megahertz and 450–470 megahertz recovered as a result of the report and order required under subsection (c) shall be auctioned off by the Federal Communications Commission through a system of competitive bidding meeting the requirements of section 309 of the Communications Act of 1934.

Will this mean broadcasters be losing their Part 74 Broadcast Auxiliary RPU licenses? Section 74.402(4)(b)(4) lists those frequencies as 450.03125 through 450.950 and 455.03125 through 455.950 MHz in various channel configurations. These frequencies are used mostly for RPU but are also used for TSL systems. This is the NITA frequency allocation chart. The RPU frequencies are shared but I doubt an entity that has paid through the nose for exclusive use of a frequency band would be interested in that. Further, according to Part 97.301(a), the 70 cm Amateur Radio frequencies are from 420 to 450 MHz. That has the Amateur Radio users quite upset, and rightly so. I don’t know if this has filtered down to broadcasters yet, but losing RPU and TSL frequencies would likely be an inconvenience, to say the least.

What gives? Reading through the bill, it seems there would be a multi-part shuffle over several years to move the “first responders” to a nationwide system on the 758-768 and 788-798 MHz frequencies. The then “empty” frequencies would be auctioned off, except some of them aren’t so empty.

Does this mean that all the existing police, fire, and ambulance radios will be phased out in favor of the 700 MHz units? Didn’t they just install a bunch of trunked 800 MHz systems recently? Wasn’t that an expensive boondoggle that still has yet to be sorted out in some locations? Ah well, it’s only $2 billion or so taxpayers dollars, which, to fight terrorism, anything goes.

The LED work light

As is often the case when doing studio wiring, some type of work light is needed, especially when working inside studio furniture. Having a good work light makes it easier to see wire colors and usually means fewer mistakes, thus the installation work goes faster. I remember being questioned by the CFO of the last company I worked for when making purchases like this in the past:

CFO “Fifty-nine dollars for a work light? Did we really need that?”

Myself: “Yes.”

CFO:

Myself:

CFO: “Uh, care to expound on that at all?”

Myself: “No.”

The studio I was working in yesterday didn’t even have its overhead lights installed yet, so work lights were a must.

Normally, some type of halogen or incandescent light is used. The downside to these types of work lights is excess heat, especially inside studio furniture cabinets. I have often felt like the side of my face was getting sunburned when working in close quarters with one of these units.

Fortunately, we bought this light:

Say or think what you will about global warming, environmentalists and so on. The high-efficiency LED light works very well and kept me from boiling when punching down wires. As with most LED lights, it has a high blue content, which most people find a little harsh. I like this light temperature for detail wiring work. It has an internal battery plus a plug-in wall wart for recharging and using as a wired light.

Not that I have any loyalty to that particular brand, but the light worked very well. I am not sure how durable it is, it seems a little light duty. That being said, I’d recommend it.

Solar flare may disrupt radio systems

Update: What? Nothing Happened! Something I think any radio engineer can appreciate, the incoming magnetic field from the flare was not polarized for maximum effect. According to NOAA Space Weather Prediction Center, the incoming particles were parallel to the earth’s magnetic field, and thus blocked. In order for storms to have major effects, they need to be cross-polarized with the earth’s magnetic field. Learn something new every day.

On February 15 at 01:50 UTC, a massive flare erupted from the sun. Classified as an X2.2 storm, it is the largest since December 2006. The 2006 storm disrupted GPS, and some satellite signals and caused 950 mHz STLs to burp occasionally. With all of the cellphone systems synced to GPS, not to mention things like HD Radio exciters, it could be an interesting day. Or not. Already, some reports are trickling in from southern China of communications disruptions.

According to NOAA Space Weather, there is a 45% chance of geomagnetic activity starting on Thursday, February 17th. It is noted that Geomagnetic storms reaching the G1 level and radio blackouts reaching the R1 level are to be expected. Mid to high-level latitudes may see extensive aurora borealis, which will be visible in spite of the full moon.