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Comment by mikewarot | Hacker News Reader

I had to look around to find a datasheet[1] for the BK4819 which is the heart of this rig, but it appears that there are I/Q outputs on receive, and possibly I/Q inputs on transmit internally, so it's an SDR, and not limited to FM only. The low output power will likely restrict it to line of site, but it's an interesting substrate on which to work.

[1] https://touchardinforeseau.servehttp.com/f4kmn/f4kmn/FRANCAI...

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I really wish someone would use one of these chips to make computer-controlled SDR radio. Basically, USB-C port on one side and antenna connector on the other.

There are lots of interesting things that could do on VHF/UHF bands with computer radio. Good example is APRS repeater. Or packet data. Receive can be done with SDR but transmit requires a radio that use audio that is flaky. I would love full I/Q but FM data would be fine.

Yeah, maybe couple of USB-C ports, one for control another for power, would make sense for using a smartphone as the controller.

This is my holy grail. All band all mode would be ideal. The Xiegu X6100 is a pretty decent close strike, and the Q900 looks solid as well, but I know I'm paying for more than just the components I would want which is a clean amp and tuner+maybe an antenna matcher in a box, just like you said, USB-C + power + transceiver + antenna out. Would be a game changer for POTA/SOTA as well as just sitting on the desk, even something small like 5 or 10 watts. I use a (tr)uSDX for my POTA/SOTA stuff on CW and SSB, and it's dinky but it definitely gets the job done -- surely something more PC-reliant wouldn't be too hard.

Looks like someone is working on this for the UV-K5: https://github.com/nicsure/QuanshengDock

There is some work involved but looks pretty fun.

Isn't UHF/VHF (edit: pretty much) always line-of-sight?

Edit: Can the downvotes please explain where I'm wrong? It's a genuine question!

Tropospheric ducting is a thing... [1]

[1] https://en.wikipedia.org/wiki/Tropospheric_propagation

Sure, but is that a thing you'd be able to (and want to) do using a small handheld radio?

It's not like HF where ionospheric reflections are pretty much the biggest appeal of the band.

Plenty of use-cases, unsure what you're arguing against.

https://www.youtube.com/watch?v=PmNo1TX1E3Q

https://www.youtube.com/watch?v=Hn7_CZurV7Y

https://www.reddit.com/r/amateurradio/comments/jcvv5g/did_so...

Who's arguing?

I was under the impression UHF/VHF is mostly used for line-of-sight communications, unlike HF, and NLOS usually needs much stronger transmitters than would be practicable in a handheld radio.

Curious to learn about other applications.

> […] and NLOS usually needs much stronger transmitters than would be practicable in a handheld radio.

While not typically thought of as a "handheld radio", Elecraft's KX-line are pretty compact and portable:

* https://elecraft.com/collections/kx-line/products/kx2-ssb-cw...

* https://elecraft.com/collections/kx-line/products/kx3-all-mo...

The KX3 can run on eight AA batteries.

There are people who use SSB on VHF to talk over long distances. There is always some bending and they can get weak signal. On rare times, troposphere ducting means they can reach hundreds of miles.

This wouldn't be useful for that since, like most handhelds, it doesn't have SSB, just FM.

Radio line of sight also includes repeaters on a mountain 100mi away (radio line of sight is somewhat further than optical) and satellites 250 miles above.

Tropo does occasionally get intentionally used by HT users though most weak signal operation is on SSB (and not on HT's, which don't do SSB for frequency stability reasons that no longer apply and amplifier linearity issues that only somewhat apply).

That I was aware of, and I'm not saying that LOS can't achieve impressive things. Quite the contrary, I think it's amazing that it's possible to sometimes reach the ISS with a small and affordable Baofeng handheld!

I just wasn't aware which applications could benefit from a (much) larger transmission power in a handheld UHF/VHF radio.

It's only I/Q on the receive side. The TX side is FM only.

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