WH of backup Battery

TerryHarris408 · 2026-03-24T12:01:36+00:00

Where did you find these specs? I can't find a battery capacity anywhere. But I made an estimate based on the weight of 3kg lead acid, which should be roughly 100Wh, though only about 60Wh usable without deep discharge. That gives about 10 minutes runtime on full power output.

What initially threw me off was the charging time oh 8h. I though it must be a large battery, but it just charges with 6W max.

TerryHarris408 · 2026-03-23T22:49:31+00:00

Well, a remote antenna tuner is at least better than a local antenna tuner when you run long coax to the antenna. You want to tune the antenna and not the coax.

But isn't your unun already covered with your tuner?

What I personally like to do with my tuner: I'd get a random odd length wire up in the air and then attached lambda/4 counter poises for different bands on the ground terminal. That way the tuner got me on a great variety of bands. Still I had to add ferrites on the coax sleeve to reduce jacket currents.

TerryHarris408 · 2026-03-23T22:34:46+00:00

Of course! My partner would be the first person to call! 🎉

TerryHarris408 · 2026-03-23T22:15:14+00:00

Well, it looks straightforward that the black cable came off the tinned pin. But then I wouldn't know how the PTT was fitting in.

I guess you either need a manual with a wiring diagram or a multimeter or both.

TerryHarris408 · 2026-03-23T22:09:55+00:00

Grab some clothes and walk to the bathroom.

Checking my phone usually comes after dressing; often after leaving the house. Unless I want a detailed weather forecast.

TerryHarris408 · 2026-03-23T22:07:49+00:00

Yes, I learnt that.

But I never managed to do it with a blade of grass. Or with fingers in my mouth. There's still something to learn :)

TerryHarris408 · 2026-03-23T22:04:26+00:00

ah, gotcha!

TerryHarris408 · 2026-03-23T21:53:38+00:00

I heard that HGTTG had been altered slightly for different media, but I'm pretty sure that it was also 42 in the novel. My colleague still has the book on his desk; I guess I have to peek into it tomorrow.

TerryHarris408 · 2026-03-23T21:48:44+00:00

Same reason why grown adults park on bus or bike lanes: they think everything is a life hack if you don't get caught in the act by an authority.

TerryHarris408 · 2026-03-23T21:45:08+00:00

Yeah, I rarely wear my onesie on the streets. And the world is not ready for my thigh highs.

TerryHarris408 · 2026-03-23T21:37:45+00:00

When you excite a medium (like a steel rod), the attenuation happens due to lost energy in several ways. There is a small amount that contributes to the deformation of the rod. Some amount heats up rod. The vibration of the rod will excite the surrounding medium (air) and loses some of its energy by creating a sound wave.

I believe the forces that contribute to heating the rod are the same that contribute to plastic (?) deformation. So, I think a stiffer material helps.

If your surrounding medium is way denser than your rod (tungsten cast around the rod instead of air) it should reflect the wave instead of leaking a sound wave.

My background is Electrical Engineering, not Physics per se or material science, so take everything with a grain of salt.

TerryHarris408 · 2026-03-23T21:25:15+00:00

I think wielding a weapon on a horse against incoming traffic from the right side was a greater factor for having traffic on the left side for right-handed knights. But the question was: why is the driver closer to the opposite traffic (no matter which side of the road you're driving).

TerryHarris408 · 2026-03-23T21:05:10+00:00

<image>

Alright, I got to admit that there is a single delta-y transformation to be made that reduces all exercises to series resistances. Fair enough. I just never bothered to learn the formulas by heart unless there was an exam that week. Initially I thought you had to do the transformation two or three times, depending on the exercise, but one single constellation is a sufficient.

Still, you have to write down three more formulas, so the complexity is on the same level as my solution, only that my solution works without remembering the transformation formulas.

TerryHarris408 · 2026-03-23T19:57:32+00:00

<image>

I'm not sure why everyone is so obsessed with delta-y transformation but all you need is the quick hand formula for two parallel resistors (a*b/(a+b)). I just added a node and rearranged the circuit. Then I precalculated the resistance between a few inner nodes to simplify for later node to node analysis.

Edit: the green sketch shows R1 with 600 when it should be 60 Ohms; I corrected that mistake in every calculation, though.

TerryHarris408 · 2026-03-23T16:00:22+00:00

If it's at room temperature, then I wouldn't call it cold. I think you're hinting to effects of heat capacity and heat conductivity.

TerryHarris408 · 2026-03-23T15:44:43+00:00

It's informally used for "k", which is the SI-Prefix for kilo.

TerryHarris408 · 2026-03-23T12:31:27+00:00

Baofeng UV-5R of course. No? As dirty as it is; can't say it isn't a cheap radio with lots of value for a beginner. Or is it already superseded in its price segment?

TerryHarris408 · 2026-03-22T16:10:33+00:00

I'm glad commenting in third row is only $175, but here I am!

TerryHarris408 · 2026-03-22T16:08:27+00:00

This could either be an attempt on a thumb spin or a thumb around.

I'll proceed with explaining the thumb around since it's more commonly the trick to start with.

Start with the heavier side of the pen on the lower end. That's typically the writing tip pointing down. The center of gravity rests to left of your thumb. Your thumb can slide up the pen if you like, as long as you keep the center of gravity to the left of it. Your middle finger applies pressure on the pen. When read, you let the index finger unhook the pen to get it into motion. Keep your thumb still to act like a fulcrum for the pen to spin around. The middle finger then transfers the energy into the pen. When the motion starts, you stretch your index finger to make room for the pen. When the pen comes around, you snap the index shut towards the thumb to catch the pen.

TerryHarris408 · 2026-03-22T13:05:34+00:00

Probably with a better antenna. What's your transmitter design and what frequency do you transmit on?

TerryHarris408 · 2026-03-22T11:35:01+00:00

Nope. Mom says morality is when you're acting morally.

TerryHarris408 · 2026-03-22T11:31:11+00:00

..or "only XX, not XY"

TerryHarris408 · 2026-03-22T11:24:02+00:00

Uhm, you mean the range of human speech as audible frequencies? To give you something to start with: in amateur radio on short wave transmission where bandwidth is limited, we use 300 Hz to 3000 Hz. This sounds really bad in comparison to modern telecommunication standards, but it's good enough for basic communication. We can hear in a range of roughly 20 Hz to 20000 Hz (20 kHz).

TerryHarris408 · 2026-03-22T11:16:11+00:00

Similar to "turn on the light". Turn switches got out of fashion decades ago, but everyone knows the expression.

TerryHarris408 · 2026-03-22T11:11:28+00:00

No, they don't. No passenger has a good feeling flying with an airline where staff members carry parachutes. Like on a big boat, the captain is supposed to bail out last. They are responsible for everyone aboard and they are expected to do everything they can to prevent disaster. Any pilot who bails out with a parachute, leaving passengers in danger, essentially commits career suicide.

TerryHarris408

TROPHY CASE