[Helge Fykse (LA6NCA)] has a type, as they say. At least as far as radios are concerned, he seems to prefer elegant designs that keep the BOM to the minimum needed to get the job done. And Altoids tins — he really seems to like putting radios in Altoids tins.
This QRP transceiver for the 60-meter amateur radio band is a perfect example of that ethos. For the unfamiliar, QRP is Morse code shorthand for decreased power, and is generally used when hams are purposely building and operating radios that radiate very little power, typically below a watt. For this transceiver, [Helge] chose to use modern components, a marked but interesting departure from his recent tube-powered spy radios. The design is centered on a custom oscillator board he designed using an Arduino Pro Mini and an Si5351 oscillator chip. Other components include an ADE-1ASK frequency mixer, an antenna tuner module that can be swapped out for operating on different bands, a receiver that’s little more than a couple of op-amps, and a Darlington pair for an RF power amplifier. Everything fits neatly on a piece of copper-clad board inside the tin box.
As is his tradition, [Helge] was on the air in the field with this radio almost before the solder had time to cool. His first contact was a 240-km shot to a friend, who reported a fine signal from this little gem. And that’s with just powering it off a 9-volt battery when it’s designed to the typical 12-volt supplies hams favor; he estimates this resulted in a signal of about 200 mW. Not too shabby.
Honestly, we’d love to learn more about that oscillator board [Helge] used, and maybe get a schematic for it. We found a little bit about it on his web page, but not the juicy details. If you’re out there, [Helge], please share the wealth.
There are various Si51351 synthesizer boards out there. Here is one:
https://qrp-labs.com/synth.html
Another:
https://www.adafruit.com/product/2045?gclid=Cj0KCQjw06-oBhC6ARIsAGuzdw12NbRHz05I_5gfpfKVcmk4GhrsSM-eSDSOocrDICAdvlh85VTLGT8aAuCwEALw_wcB
Should be Si5351. Amazing we don’t have an edit capability.
The true test of a hacker is hacking Hackaday to edit comments.
– Confucius
That is pretty cool, I especially love the software side tone, and no bfo required.
If he used something like the Arduino nano, he could decode the Morse code and output text (and probably take in text and generated the Morse).
“For the unfamiliar, QRP is Morse code shorthand for decreased power, and is generally used when hams are purposely building and operating radios that radiate very little power, typically below a watt.”
For the unfamiliar, QRP is a sub hobby of amateur radio of people who either have an excellent antenna park on their own property or who’re operating portable from the wilderness. In both cases, there’s nothing getting in the way of sending/receiving radio signal on the otherwise very noisy shortwave.
People, err hams, participating this QRP hobby are usually being bored by just making connections the normal way, they’ve already done that so often. They love to find out how low they can go with the power and still be understood. It’s sports, really. And that’s okay. Perhaps a bit akin to the hobby of making miniatures or the retro community trying to run Windows on the most underpowered hardware.
Anyway, the poor souls living in the city or near a power plant won’t be so lucky working in QRP and shouldn’t rise their initial expectations too much. They will need to use a small antenna with a low effectivity due to space limitations. Maybe need a separate magnetic loop antenna or active antenna/receiver for reception, too, so that electric interference will not disturb their reception. Here, “QRP” in practice does rather mean about 5w or 10w, to get out of the local noise floor.
The power increase isn’t as drastic as it seems, though. Merely 1 or ~2 S-Meter points are being gained over the basic 1w (6dB are one S point, or 4x the power each are; but please keep in mind s-meters readings are often vague as well). QRP transceivers like the FT-818 or Heathkit HW-9 can do 5w, as well. Vy73/55s
Altoids tins are great for projects. I remember I made an Atari Punk Console in one as a kid. I keep a bunch around now to put screws in, and I 3d print dividers to put in them.
“Anyway, the poor souls living in the city or near a power plant won’t be so lucky working in QRP and shouldn’t rise their initial expectations too much.”
I have transmitted QRP into a metal flagpole at the park, daytime on 20m, and worked people two and three states over. I have done similar using a small inverted V with a fiberglass tent pole apex at 10 ft high. I worked Japan and Hawaii with QRP on 40m at night, transmitting into a random length of wire dangling out of a 2nd story window. Heck, I did a 2000 mile shot QRP on 40m transmitting into a kite. All urban settings.
While your remarks are not incorrect, the situation is not nearly so bleak as your post seems to imply. My suggestion to others… Don’t waste your time on voice comm. Learn morse or run PSK. You will be astounded how far a watt can carry.
Morse/CW is awesome and way “better” if you actually want to talk to people. Or even if you don’t and just want to do contest-style contacts.
I worked at a broadcast FM station in college 20 years ago- we could reach about a 60 mile footprint broadcasting from a mountain top with excellent line of sight. and i just learned it was about 650W.
It took me a long time to realize why HF and FM voice suck so bad, even with 100W. My antenna is “good” enough but I can’t even reach 60-100 miles to talk to my best ham-friend and my understanding of propagation isn’t good enough to do better. The old men talking about hip surgery that I listen to all seem to be rocking a kW just to be able to talk to people in the same state.
But 100W CW will get me across the country easy. It is way less frustrating.
Aye. You comment makes sense to me and has good recommendations, I think. 😎👍
My main concern simply was that newcomers would expect good QRP connections to be the norm and then be disappointed.
For beginners, it might be good to start with a bit more power first.
And that involves having a bit of a reserve. Most HF rigs like, say, an ICOM IC-718 will make 1 to 100w.
And these huge 100w aren’t QRO (high power) by any means.
The ancient FT-101, which was sort of a reference in ham radio, gave about 120w output (SSB/CW). AM was less, of course. Unless CBers were at work, overburdening the radio.. Without the finals, it still made 10w via driver tube.
100w are the upper limit of normal output. In practice, I mean. What hams thought about it. Regulations on paper may say different, not sure. It also depends on were someone lived on earth.
For example, back in the day, say 70s/80s, hams operated with tube based linears that could do 750w to 2500w, if fed by about 100w. That’s real QRO.
That’s quite a difference to 1w philosophy of modern QRP. That’s toy territory – in direct comparing. Not that it doesn’t work, whatsoever. Depending on the radio weather and in a sunspot maximum, a watt will travel around the globe.
But that’s not for beginners. At least not in my opinion, I mean. With enough experience, QRP can be fun, I won’t disagree here. Vy73/55s