Stay tuned, 1994 redux

In case you haven’t heard, May 21, 2011, will mark the beginning of the end of the world. It is on this date, according to Harold Camping, the rapture will begin. For those not versed in bible lore, this is when God will take all of the saved souls directly to heaven, body, and all. Further research reveals that it will begin at 6 pm local time, in every time zone.

I’d imagine you can listen for updates on Family Radio stations or shortwave if there aren’t any local stations to listen to.  Those on the west coast may want to tune into the shortwave broadcast (transmitters are in Okeechobee, Florida) for a preview of coming events.  You can try:

  • 5950 KHz 22:00 through 0100 UT (6 pm through 11 pm EDT)
  • 11470 KHz 22:00 through 23:45 UT
  • 15440 KHz 22:00 through 23:59 UT

The full shortwave schedule is available here.  I am setting my clock so I can tune in and see what happens because I am curious; dead air? Does the station sign off?  I really want to know how a station plans for the end of the world.  Hopefully, it will be marked by some program, announcement, or something special.  Operations as usual would be very boring, as most Family Radio programming is mundane and predictable.

Frankly, Camping has made these predictions before, the last was September 6, 1994, when the faithful gathered in the Alameda’s Veterans Memorial Building, bibles open, hands outstretched, awaiting the moment.  After a while, it became clear that something was amiss and everyone went home, wondering what went wrong.  There have been many religious-based predictions for the world ending: 1806; October 1844; December 21, 1956; November 1982; January 1, 2000: etc.   The Jehovah’s Witnesses alone have predicted the end coming in 1914, 1915, 1918, 1920, 1925, 1941, 1975, and 1994.

It’s either a really good radio stunt, which would go down as one of the greats of all time or they actually believe it’s the end of the world.  In the case of the latter, does this mean they will be selling their radio stations?  There are several around here that I’d be interested in getting my hands on.  I’d even give a fair price, considering the circumstances and all.

Update: How do radio stations prepare for the end of the world?  T -40 minutes and the answer appears to be play canned programming, or in other words, business as usual.

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:

  1. 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.
  2. 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.
  3. 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.
  4. 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.

Anton Model 6 CD V-700 radiation meter
Anton Model 6 CD V-700 radiation meter

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?

The K9AY receiving loop antenna

Not to take anything away from Gary Breed, K9AY, who makes and sells these things under the corporate name AYTechnologies, I decided to make my own K9AY antenna system and controller.  Basically, after looking at the currently available commercial version, I figured I could make a better unit for less money and be happy.

The basis for the K9AY antenna is that it has a steerable null.  The gain around the antenna is close to unity, except for the terminated side of the loop, which has a deep null.  This can be switched around using a combination of relays that change the loops and termination.  This comes in very handy for MW and SW listening when co-channel stations can create annoying interference and heterodynes.  I have had good success pulling many stations out of the muck, especially in the AM band using this antenna.

This antenna requires a good ground to work against.  For optimum installations, I would recommend placing two radials under each side of the loops.  This will keep the ground conductivity below the antenna fairly constant, thus the value of Rterm will remain consistent for each band.

My other idea is to add a preamp right at the antenna to overcome transmission line loss and the loss from a 4 port passive receiver coupler.  Something around 10 dB, low noise (obviously), low parts count, and rugged.  I decided that a Norton preamp was a good design, with only one active device, a common 2N5109 BJT.  Most of the time, this preamp is switched off and out of the circuit.  There have been several occasions, however, where an extra 10 dB made the difference between no copy and good copy.

This is the schematic of the relay board and preamp combined:

K9AY antenna controller with preamp
K9AY antenna controller with preamp

The parts list is as follows:

C1 – C5Ceramic 0.1 uf capacitorR12 Kohm ¼ watt
FB-1Ferrite bead, Amidon FB-43-101R28.2 Kohm ¼ watt
K1 – K3Omron G6K-2F-Y small signal relayR3100 ohm ¼ watt
L122 uH ¼ wattR451 ohm ¼ watt
L2100 uH ¼ wattT-19:1 balun
Q12N5109 w/heat sinkT-2Norton feedback trans

The 2N5109 transistor is a CATV unit and it has a 50 input and output, that reduces the number of impedance transformers required. The value of Rterm is determined by which band one wants to operate on.  I used Omron G6K series low signal relays.  Again, because this is a receive only antenna, those relays will work well.

Terminal board connections, TB1:

1SW loop
2SE loop
3NW loop
4NE loop

Wire loops go between Terminals 1-4 and 2-3.

Control terminal board connections, TB2:

1Preamp power
3Rterm ground
5Relay 2
6Relay 3

To create a low noise preamp, I decided to use surface mount devices and to try and make all the traces as close to 50 ohm impedance as possible.  I created this SMT-printed circuit board:

SMT K9AY board, not to scale
SMT K9AY board, not to scale

From this, I ordered 6 boards from PCB express:


This is the board with all passive components installed:

K9AY loop antenna control board partial
K9AY loop antenna control board partial

This is the board completed:

K9AY antenna control board completed
K9AY antenna control board completed

My current K9AY is an amalgamation of parts removed from various equipment.  The relays are large, 12 VDC units which do not have the best contacts.  It works well enough, but I’d love to get one of these units into the control box at the base of the antenna.  Unfortunately, my antenna field is still in about 18 inches of snow, so it will have to wait until some of the snow melts off.

I would position this antenna as far away from transmit antennas as possible to avoid overloading the preamp and or causing problems with the switching relays.  For the average amateur set up, 75 to 100 feet separation should be more than enough.

ABC turns to HF during tropical Cyclone

Super Tropical Cyclone Yasi, a category 5 storm, came ashore this morning between Cairns (pronounced Cans) and Townsville, Queensland around midnight Thursday (9 am Wednesday, NY time).

Tropical Cyclone Yasi, February 2, 2011
Tropical Cyclone Yasi, February 2, 2011

Radio Australia carried Australian Broadcasting Company (ABC) Queensland coverage of the storm, which was extraordinary.  Spot coverage, emergency information, sheltering information, updates, and calls from listeners in the midst of the storm.  Some of it is pretty intense.  One fellow, John, out in the country all by himself in the height of the storm sounded somewhat forlorn, I hope he makes it.

Due to the size of the storm, widespread power outages are expected and may last for weeks or months.  As a part of this, there are numerous outages and potential outages in their AM and FM broadcasting chain.  To that end, ABC has two shortwave frequencies available for their Queensland service; daytime (8 am to 8:30 pm local time, 2100 – 0830 GMT) on 9710 KHz and night time (8:30 pm to 8 am local, 0830 – 2100 GMT)  is 6080 KHz.

Once again, HF (shortwave) radio gets the job done when local stations, cell towers, and internet connections to dead.  Sometimes it is the low-tech answer.