Trip of 2013.09.22

• Succeeded: Yes
• First-activation: No
• Propagation forecast on departure: 40 Fair, 20 Good, 17 Fair, SN=0-1, K=1, A=7, MUF=13.19
• Propagation forecast on return: 40 Fair, 20 Good, 17 Fair, SN=0-1, K=1, A=5, MUF=26.33

See my trip planning guide at: SOTA Guide: W4G/NG-014, Levelland Mountain

Commentary:

Levelland Mountain (W4G/NG-014) is an unremarkable hill, but the trailhead is interesting. Levelland is on the Appalachian Trail and the trailhead is the one spot on the entire trail where the trail passes through a building.

There was something large crashing around in the bushes. Dunno if it was a deer or a bear. I never saw it, but it loomed large in my mind while activation. (Long ago, I was harassed by 3 bears while on a solo backpack trip, so I have a “thing” about bears.) And it appears that I set up operations near a hive of yellow jackets, so there was plenty of QRN from Mother Nature.

Lady Propagation was very kind today. Signals were strong across the country and I heard from one ham in the UK. (It is always exciting to hear from someone on the other side of an ocean when I’m operating with 12 watts and a make-do antenna.) I made 17 SSB QSOs and one FM. (I know some of you make way more on a typical activation, but that’s a lot for me.)

I used an EFHW, vertical, hung from a tree for 20m. I used a dipole with a 1-1 balun for 40 meters, with one leg vertical (it was my 20m EFHW) and the other leg about 4-5’ AGL.

I’ve been activating for 11-1/2 months now, and I had my first forgot-something-important today. My battery holder holds 11 AA batteries. I’m in the middle of a quarrel with my XYL and that distracted me enough that I filled it with 10 batteries. Oops! Fortunately, I was able to scavenge an AA from my GPS.

Wire at AWG gauge 50 is 1 mil in diameter. That’s very tiny at 1/1000th of an inch. Every 6 gauges, the wire size doubles. i.e.

• 50 gauge = 1 mil
• 44 gauge = 2 mil
• 38 gauge = 4 mil
• 32 gauge = 8 mil

I don’t think that knowing the absolute sizes is terribly useful, except as a parlor trick. However, the next time you’re looking at some 14 gauge wire and thinking, “I need something about half that thick,” you know you can get it with 20 gauge.

At DC, electricity flows through the wire across its entire diameter. At high frequencies, electricity travels only on the outside of the wire – as if it were a hollow tube. At medium frequencies, some of the thickness of the wire is used. This is called skin effect.

For copper wire, at 60 Hz, the “skin” is about 1/3”. Consequently, unless you have VERY thick wire in your house, the entire diameter of the wire is used to conduct your house current. At 1 MHz, the skin is less than 0.003”.

The end of the skin isn’t a sudden thing. About 2/3 of the current flows in the skin. As you move farther from the edge of the wire, less and less current flows.

At the moment (2015.08.17), I’m carrying about 32’ of poly-stealth 26 AWG, 19 strand, copper clad steel with a PE jacket as my counterpoise. I did read that I should seal both ends to ensure the steel doesn’t corrode.

SOTA Activation Report: W4G/NG-021, Buzzard Knob and W4G/NG-032 Little Bald Knob

Trip of 2013.09.07

• Succeeded: Yes
• First-activation: No
• Propagation forecast on departure: 40=fair, 20=good, 17=fair, S/N=1-2, K=2, A=5
• Propagation forecast on return: 40=fair, 20=good, 17=fair, S/N=0-1, K=1, A=4

See my trip planning guide at: SOTA Guide: W4G/NG-021, Buzzard Knob or SOTA Guide: W4G/NG-032, Little Bald Knob

Commentary:

It was N.A. SOTA weekend 2013 and the weather held true to the forecast - 0% chance of rain. Buzzard Knob and Little Bald Knob are on a section of the Appalachian Trail just south of Hightower Bald (the toughest summit in Georgia, IMHO).

The AT is a pleasant walk. The bushwhacks from the trail to the summits were tough with the foliage in full greenery - particularly Little Bald Knob. I ‘ate’ a lot of cobwebs while bushwhacking! =:-o The next time I activate these summits will be in winter. Dense greenery on both summits made erecting my antenna a challenge. Summer activations of these summits is a good use case for an AlexLoop!

It wasn’t a major contest weekend, but Illinois Parks on the Air and Ohio Parks on the Air were almost wall-to-wall on 40 meters.

20 meters was virtually noise free at about noon. By 4:30 it was picking up some lighting noise from somewhere in the country. The mosquitos were out in full force at 4:30 too.

Unusual events:

I saw a large owl on the trail and a tiny hummingbird in the parking lot. I encountered a male backpacker hiking in a forest-style kilt (i.e. not tartan).

While bushwhacking back to the trail from Buzzard, I heard something moving. When I called “Hello,” someone answered (so I knew it wasn’t a bear). I asked him to say, “Hello,” again and I navigated toward the sound. I’d have reached the trail in a bit, but navigating by sound helped me chart a shortcut back to the trail.

My VX-8GR APRS radio battery died just before I returned to the car. Looks like it is good for 4.5 to 5 hours of actual beaconing. This was the standard-capacity battery. Sadly, no beacons were picked up at any point along the trail, nor was I able to send an APRS text message from the trail.

=====

Trip of 2014.01.12

• Succeeded: Yes
• First-activation: No

See my trip planning guide at: SOTA Guide: W4G/NG-021, Buzzard Knob or SOTA Guide: W4G/NG-032, Little Bald Knob

This was my second trip to Buzzard Knob and Little Bald Knob. Although the trail passes near both summits, there are significant bushwhacks from the trail to each summit. The bushwhack was easier in January (this trip) than in September (last trip). Georgia bushwhacks are easier when the vegetation has died off (assuming it hasn’t snowed recently).

It was a beautiful winter’s day in north Georgia – temperature ranged from 35 up to about 45, with a cloudless sky and about a 10 MPH wind. I encountered no one on the trail.

There was a good turn-out of chasers on both summits. On Buzzard, I didn’t manage the pile-up so well on 20m. Perhaps because of this, many chasers I normally talk with on 20 showed up on 40. On 40m, I use a 1/4 wave with a single radial, so I’m pleased with any contacts I can make. I had contacts with KB1RJC and KB1RJD in New Hampshire and K0LAF in Missouri, which is better than I can usually manage on 40.

On the hike in, I lost a fight with some trees. There was a small branch across the trail. I figured, “I don’t want to have to deal with this on the way out, when I’ll be tired,” so I grabbed it and tossed it off the trail. But I didn’t pay enough attention and I tossed it into some trees and it bounced right back into my face.

After cursing a bit, I notice a bright read stream of blood. I’m thinking, “Oh great. Not yet 300 yards from the car and I’m going to have to call the trip off due to a stupid injury.” A little patience and a big wad of TP stopped the bleeding.

Next time, I’m gently placing any branches I remove, rather than haphazardly flinging them!

For some reason, this double-header felt more strenuous than my recent double-header to Double Spring Knob and Round Top. I’m thinking, “Two hills means two hikes up and two hikes down. Why am I so darn tired?” Then I had an astute perception of the obvious. When you park between two hills, it is up and down and up and down. But when you park at the end of a trail with two hills on it, it’s up and down hill 1 and up and down hill 2, and then you have to go up and down hill 1 again in order to get back to the parking lot. Duh! (Subtitle this trip, “Maps are flat and the terrain isn’t.”

Need to write this up…

Need to write this up…

Need to write this up…

This is my eBook/eMagazine on doing SOTA. I’ll be posting a chapter each month. This content will also be appearing in the newsletters of some Atlanta-area ham radio clubs.

• Chapter: What is SOTA?
• Chapter: Your First Chase
• Chapter: Your First Activation
• Chapter: Things You Do NOT Need
• Chapter: Beginner Summits Near Atlanta
• Chapter: Reasons to Learn CW
• Chapter: Sisyphus the Activator
• Chapter: SOTA Web Resources
• Chapter: Finding Your Way to Nowhere
• Chapter: Portable Power
• Chapter: Winter Activations
• Chapter: Antennas for Summits
• Chapter: Travelling Light
• Chapter: Special Events

“Resistance is useless.” – Daleks; Doctor Who

Resistors in series: \( R_{1} + R_{2} + R_{3} \)

Resistors in parallel: \( \left ( \frac{1}{R_{1}} + \frac{1}{R_{2}} + \frac{1}{R_{3}} \right )^{-1} \)

Voltage divider (using resistors in series): \( v_1=\frac{R_1}{R_1+R_2}v \)

• \( v_1 \) = The voltage across the first resistor
• v = The voltage across both resistors

Current divider (using resistors in parallel): \( i_1=\frac{R_2}{R_1+R_2}i \)

• \( i_1 \) = The current through the first resistor.

At RF, all resistors act like a resistor, an inductor, and a capacitor. For the three major types of resistors:

• Carbon composition resistors - act a lot like a capacitor, due to the capacitance between the granules.
• Wirewound resistors - act a lot like an inductor, because the wire looks a lot like a coil.
• Metal film resistors - act closer to an ideal resistor (but not perfectly so) than the other types. “Thin film” surface mount are the best of the best.

A “linear” system must exhibit both homogeneity and superposition. Linear systems are interesting because they are easier to analyze than non-linear systems.

Superposition holds true if: \( f(x_1+x_2)=f(x_1) + f(x_2) \)

Homogeneity holds true if: \( f(Kx)=Kf(x) \)

Ohm’s law is normally written as v = iR. But you could also write it where voltage is a function of current. e.g. f(i) = iR.

\( f(i_1+i+2) = f(i_1) + f(i_2) \)

Superposition applies to Ohm’s law. It doesn’t matter whether you add currents and then compute voltage, or compute both voltages and add them.

Also, doubling current doubles voltage (2 is your constant), so homogeneity applies too.

Using Superposition to Understand Linear Circuits

• Zero-out all independent sources (i.e. short your voltage sources and open your current sources).
• Return each source, one at a time, and solve for values of interest.
• Sum the values of your results.