All these things

These are a few notes and links about NVIS propagation and antennas. This is in the context of setting up reliable-ish NVIS connections for regular morse QSOs for practice.

NVIS Propagation

Reflections at high angles (near 90 degrees) to the ionosphere only happen when below the critical frequency, known as f0F2.

For the UK, looks like f0F2 in daylight can be over 10MHz, but at night is likely to sit at 4MHz or possibly lower. So in terms of useful ham bands, 80m at night, 40m in the day are probably what will work best.

Maps of f0F2, both derived from

• Global f0F2 Map (BOM Australia)
• KC2G f0F2 Map

So, worth considering antennas for 80 and 40.

Antennas

Needs to cover 80m and 40m, with 60m as a bonus and possibly 160m if it can be done.

For me, I need an end fed wires for NVIS: https://practicalantennas.com/applications/nvis/end-fed/

One note from “The NVIS Illusion that is interesting:

Ground waves are transmitted by just about every antenna and extend to the local horizon. In the area close to the transmitting station it is likely that the ground wave will interfere with the received NVIS signal to produce fading (QSB) or other effects. It is a good idea to keep transmitted power low to mitigate this effect.

So low power might be sensible here, or experimenting with lowering power might be useful to stop ground wave propagation interfering with NVIS.

References and reading

• NVIS (wikipedia)
• Rohde & Schwartz “Understanding NVIS” paper
• The NVIS Illusion

I always have to look up how to wire an iambic paddle to a 3.5mm or 6.5mm TRS (tip, ring, sleeve) jack and which paddle is which. I’m left handed and have over time taught myself different left handed and right handed paddling so what I’ wiring to what is easy to get backwards.

You want the dits on the thumb, and the dahs on the fingers. And on the connector, the tip pulled to ground makes dist, the ring pulled to ground makes dahs, and the sleeve is the ground.

Here’s the table to explain this:

Symbol	Left handed	Right handed	TRS Connector
dits	right paddle	left paddle	tip
dahs	left paddle	right paddle	ring
ground	–	–	sleeve

Ideally I’d wire all my paddles the same, and that should be to use the right-handed setup — more common, then adjust to reverse the paddles in software. This to allow swapping paddles and avoiding confusion.

Link to another good reference on this from AD6DM

Something I’m experimenting with… consciously slowing my thoughts and speech — for a couple of reasons or occasions:

• In the late evening, close to bedtime I slow my speaking and slow my thinking to prepare for sleep. I don’t mean zoning out, I mean just slowing down thinking and speech — and thus breath as well. It also is nice and helpful to sit in front of a fire, or turn the lighting more yellow/red, or turn the lights off or down. Very relaxing and leads naturally into sleepiness.

• In the early morning before stuff kicks off, and at spots later in the day, slowing thinking helps to bring me back down from the stressy speed of full on work or life. Again, this is not stopping thinking or zoning out. Keep at it, but slow down. There’s a quality improvement here in thinking too, when done a bit more slowly. And it feels great.

New Normal (RadioLab podcast)

Stories around the possibility of change — temporary and permanent. Listen in the player below or see the website above.

Operant Conditioning Chamber aka Skinner Box (Wikipedia)

Slot machines and online games are sometimes cited as examples of human devices that use sophisticated operant schedules of reinforcement to reward repetitive actions.

Wikipedia

Roblox sounds awful for young kids (twitter thread by @Arumi_kai)

It appears that many all-ages games have dodgy content and programming. Not really surprising, but it is easy for parents to just assume that somebody is actually trying to moderate content. Doesn’t look like moderation is fit for purpose.