tomfanning

it's rare you hear one that heavy any more

With respect, this is nonsense.

In SSB there is no carrier transmitted. Two SSB stations on top of each other sounds exactly like two microphones mixed.

DIY: slim jim, J pole (https://m0ukd.com/calculators/slim-jim-and-j-pole-calculator...) or quarter wave ground plane (https://m0ukd.com/calculators/quarter-wave-ground-plane-ante...). A slim jim made from 450 ohm ladder line and rolled up for storage, hoisted into a tree by a cord, is a favourite. A NanoVNA will help a lot while building any of these.

Commercial portable: Nagoya NA-771 (beware clones)

Commercial fixed: Diamond X30, X50 or V2000 colinear.

With any upgraded antenna on a receiver with little filtering like the Baofeng, you may deafen it into hearing no wanted signals if operating it in an RF-hot environment.

Don't transmit without a licence.

That’s a pretty narrow perspective. From both the perspective of HF and VHF/UHF.

For HF there’s all sorts of digital stuff going on. Check out FreeDV for a Codec2-derived digital voice mode. We are also doing packet radio (yes, AX.25, still built into the Linux kernel) with BPSK/QPSK modems on HF replacing the 61 year old Bell tones- see https://wiki.oarc.uk/packet:ninotnc#experimental_new_modes_f...

I recently stood up this site to support and track the re-emergence of the / redevelopment UK packet radio network- which is utilising VHF, UHF, a geostationary satellite, as well as HF. https://ukpacketradio.network/

It’s not my bag but I see a lot of VARA going on too.

There’s a lot more going on than just WSJT-X.

Speak to a specialist about the Stretta procedure. Application of RF energy to the lower esophageal sphincter in a short outpatient procedure. More effective than PPIs, but less so than fundoplication, which is much more invasive and permanent.

Even ignoring the impedance mismatch, loss in typical 75 ohm coax at 2.4GHz is going to be something like 0.5dB per metre. Far worse again at 5GHz. That's going to add up quickly.

Someone once told me "Friends don't let friends use Fritzing".

An entirely sensible one which prohibits you from preventing an emergency call being made in case of fire, injury, crime etc.

Wheel successfully reinvented :)

Nothing stopping you setting up a whole AX.25 network between multiple machines using Dire Wolf [1] and the built-in AX.25 [2] (a derivation of X.25) support still in the Linux kernel. You get a proper network interface that shows up alongside eth0. Nice short instructions at [3]. Just don't hook it up to radios unless you're appropriately licensed. Speakers and mics only.

[1] https://github.com/wb2osz/direwolf

[2] https://en.wikipedia.org/wiki/AX.25

[3] https://g7vrd.co.uk/ax25-direwolf-linux

It would be better for everyone if this were deleted.

PSA: Pi 4 + M.2 SATA SSD + USB3 adapter is blisteringly fast. No micro SD card needed any more. Runs Ubuntu x64 and Docker.

Even better with a heat-dissipating case with an integrated M.2 SATA port in the bottom, like the Argon ONE M.2.

I use mine to run multiple .NET 6 microservices, and it's replaced an entire HP Microserver. The entire Pi setup will have paid for itself in under a year in energy savings alone.

Who specifically is "their"?

For every engineer on six figures there will be many many of them on five figures. We read about six-figure engineer salaries because people write about them. $100k is well above the US median. I don't think there should be an absolute expectation that every engineer position earns $100k even at 10 years experience. Some will, but many won't.

Yes but.

I'm looking right now at a mtr (traceroute) screen from a rural fibre-to-the-premises broadband connection in Lancashire, north-west UK, achieving 2.5ms RTT to Manchester (the nearest major city, ~60km) and 8.5ms RTT to London (~325km). Things are improving.

That's only ~10x and ~8x the light travel time, assuming straight lines which is best case. ~8.3x and ~5.3x respectively if you consider that light is much slower in fibre than air.

Trans-oceanic flights go far beyond the VHF radio horizon to land so routinely use HF radio. It's not a backup, it's the norm.

Example: https://www.iaa.ie/air-traffic-management/north-atlantic-com...

"Huge" is probably not that big vs VLF. Maybe on the order of ~50m width (~3MHz / ~100m wavelength for ~50m half-wave antennas). VLF is more like wires across entire valleys - kilometres.

Isn't this completely standard practice now?

Many of the red areas I see on the map, particularly in France, are fairly obviously where someone's been running a TomTom while on a train or a boat. Of course that's not going match OSM roads. I'm a little surprised this is not mentioned in the blog post - it seems a bit obvious.

Europe is a continent.

Not over licensed RF links in most countries, unless you publish the private key.

The experience operating sats is very different depending on where you are on the globe. Advice that's okay in one place may be bad advice in a different location.

One final heads-up, the vertical antennas typically fitted to vehicles make really poor satellite antennas because you can easily emit enough power to make it into the sat, but there isn't enough directional gain to hear the downlink, so you're back in the same situation. A dual band yagi antenna really is the way to go. You also don't want to use a mobile radio with a yagi unless it's turned down to low power, because of RF exposure limits at VHF/UHF. A typical portable station is a dual band yagi (e.g. Arrow II) with one FD or two HD handheld radios, a headset, and a voice recorder, and a typical fixed setup is az-el rotator with computer control, dual circularly polarised X-quad yagis, masthead preamplifiers, and Doppler control of uplink and downlink frequencies.

Fancy-pants cross-band full duplex can be achieved with two £15 Baofeng UV-5Rs and a DIY duplexer with about 2 components on it (or just two antennas on one boom).

That's my setup - I'm not better equipped than that.

A second-hand Kenwood TH-D7 is an alright choice.

Dual watch, or full duplex?

My decades-old FT-470 can do true full duplex too, but it's less common in current radios. Just dual watch now.

Kenwood TH-D7

Yes, you absolutely do need true full duplex to (a) know you're getting in, (b) not step on anyone else, (c) know when you're being stepped on, all of which are really required to operate effectively and courteously.

Yeah, it's a lightly modified Kenwood mobile VHF/UHF set typically used in a car. Model D710GA. Stock it's a 50W radio, though can be run at 5W. Cube sats have around the hundreds of milliwatts. So yes, much higher power than a cube sat.

Sounds like you're already on it, but anyone who is thinking of trying, (1) make sure you are correctly licensed, (2) make sure you only transmit while you can clearly hear the downlink, and (3) make sure you are listening to the downlink while transmitting (full duplex) to ensure you aren't stepping on other people.

For listening, a QFH antenna is ideal for LEO objects. It's typically made of copper pipe or the braid of stiff coax.

Short answer - by one or two of the smallest steps on a typical handheld, starting above the nominal frequency and ending below it. A bit more than that for UHF downlinks.

A 90 degree pass (overhead) is around 10 minutes. And obviously for radio, it doesn't need to be visible (reflecting sunlight), just ~above the horizon.