This item is from ARRL Propagation Bulletin ARLP031 is pretty good stuff: "David Mays, W8UI of St. Mary's, West Virginia sent some big beacon lists for HF and six meters, put together by G3USF.
See them at www.keele.ac.uk/depts/por/28.htm and www.keele.ac.uk/depts/por/50.htm "
-Diamonds are a ham's best friend - L.B. Cebik, W4RNL has a short article about rhombics on his web page www.cebik.com/radio.html in the series Antennas From The Ground Up. L.B. has also started a new series on Long Wire Antennas www.cebik.com/wire/lwl.html) which will eventually have a detailed analysis of the V-beam and rhombic. (Thanks, Henry K4TMC)
-Does the rumble of distant thunder make you nervous? Thomas KN4LF contributed a couple of Web URLs for information about lightning protection http://groups.yahoo.com/group.LightningProtection and www.lightningsafety.com
-There are a lot of times when we'd like to find out whether two locations are line-of-sight. With the availability of highly detailed, accurate mapping data in electronic form, the answer to this and other similar questions isn't that far away. Kevan NS4T recommends MicroDEM by Dr. Peter Guth of USNA. It can do terrain mapping, overlay road maps, and similar useful tricks. And the price is right - free! Get the program at http://tinyurl.com/lche
-Fans of "hollow state" technology (i.e. - vacuum tubes) will enjoy the Fun With Tubes site www.funwithtubes.net There are quite a few schematics, tutorials, projects, old parts catalogs and more. In addition, Cardwell Condensers now owns the E.F. Johnson capacitor line with information posted at www.cardwellcondenser.com/PAGES/jcd.html (Thanks, Mike AE6WA and Jim WA7DUY)
-Several folks in the construction business remind tower builders to keep the surface of a concrete base wet during the first week of the curing period. This prevents cracks due to the surface hardening faster than the inside. Either keep the surface misted with water or place old rugs or cloth on top of the concrete and keep them wet. Don't be hasty - it takes 28 days for concrete to cure to 90% strength!
-Trying to get stuck hardware apart? Dino K6RIX gives this wholehearted endorsement to PB Blaster. "Some products are rust removers and others are penetrants and lubricants. PB Blaster is BOTH! No need to climb twice. Take it up with you and get the job done!" http://tinycurl.com/bnxsm
-Today we usually think "DSP" or "op amps" when figuring out how to get rid of noise and other "stuff" that we don't want to hear in our audio. Well, 'twas not always so! Passive audio filters still do a fine job in many areas and you never have to change the batteries. One classic reference about these filters is Ed Wetherold W3NQN's article "Passive Audio Filter for SSB" in the Technical Correspondence section of Dec 1979 QST, page 50. Another is "The Crud-O-Ject" by Bob Myers, now W1XT, in the Feb 1972 QST, page 11. (Thanks, John W0UN)
-If you wish your noise-cancelling Bose headphones came with a boom mike, Doug K1DG shows you how to "make it so" at http://tinyurl.com/mx16c A bit of work with a drill and little, tiny screws and there you are!
-Here's a really nice toroid/coil calculator plus more: "Mini Core Calculator" by Colin G3VMU is freeware from www.dl5swb.de It makes lots of calculations for a wide range of iron powder and ferrite cores and other coils. (Thanks, Chuck W5USJ)
-Here's a new grid-dip meter by two Peters, DK1HE and DL2MI
www.qrpproject.de/UK/DipItUk.html . It covers 1-42 MHz with a 5-digit display. The meter has several significant improvements over other widely used meters. This is not your Elmer's grid-dip meter! (Thanks, Chuck W5USJ)
-Here is an interseting item from Mike K5UO on climbing belts, somewhat edited. "At HamCom in Plano Texas; a representative of Pinkerton Sales www.pinkertonsales.com), representing the "Ultra-Safe" fall-arrest climbing belt, gave an excellent demo outside of the convention hall. He would winch up a 220-pound weight and let it fall in different situations. The message was that different lanyards (position or fall-arrest) exert dramatic differences in force to the user when a fall occurs. As I recall (approximately):
- Six-foot conventional lanyard: 2500 pounds (ouch!)
- Six-foot lanyard w/ sewn fold-out layers (shock absorbing): 700 pounds (still "ouch")
- Six-foot lanyard, now get this, WITH A KNOT IN IT: "0" force; it broke instantly! (Big ouch!)
At least on two of the ouch's, the user survived. He demonstrated two types of climbing harnesses:
- Conventional with nylon straps.
- A nylon harness with straps that have some very slight stretch to them. I liked that harness.
He added that any and all harnesses must be tightened "firmly"; not loose and, of course, not uncomfortably too-tight. Any extreme slack or sloppiness can be harmful in the event of a fall. He mentioned that always someone should be present while the climber is working on the tower and have a plan in the event of a fall. He also demo'd one little gadget, like a reeled-up harness (see next item) hooked above your climb that catches you immediately with no drop at all; much, I think, as a vehicle safety belt does. Gradual movement around the tower or climbing does not set it off; but "instant thrust" (my words) does." Food for thought, Mike!
The catching harness is actually a Self Retracting Lifeline (an example can be seen at http://tinyurl.com/jnrpj). You can install one at the top of your tower below the guy points, attach a line to the hook, then pull it down when you need to climb. You wouldn't want to leave your lifeline exposed to the elements all the time, hence the attached line to retrieve it. Granted, these aren't cheap, but they're less expensive than a week in the hospital or your funeral. More samples are shown at www.rjsafety.com/CS5. (Thanks, Jason KC0ERG)
Steve K7LXC notes that the correct place for a fall-arrest lanyard is the D-ring between your shoulder blades. That will catch you and hold you in a benign posture. The D-ring in the front is for when you use a safety climb cable and slider system with a climbing ladder or pegs.
A text reference on tower safety is "Tower Climbing Safety and Rescue." This professionally written book is full of accurate, useful information and is available through the ARRL Products Web site at www.arrl.org.
That's it for January.
de W6IGK Elmer
New Color Bandplan Chart - HambandsColor.pdf (Adobe Acrobat File)