Cardputing on Whernside

[M1BUU]

I’ve been itching to get out to do my first activation of 2026. I managed to find a window of time to do a quick raid on Whernside G/NP-004 today.

I’d seen info from Wei AG6AQ about using a Cardputer ADV for FT8 and it intrigued me. I’d never heard of a Cardputer before and it seems as though the latest version, the Cardputer ADV is the 3rd iteration and is a fairly new product. At around £40 delivered from Pi Hut, the Cardputer ADV isn’t mega expensive to play with. I ordered the device and it arrived a couple of days after placing the order. My son saw the device and immediately wanted one of his own, so he then ordered one! My son is having great fun playing retro games on his.

I’m not good with computers but I am quite stubborn and I don’t give up easily. With the help of Gemini AI I found out what software I needed to install on my computer to get the custom FT8 firmware on to the Cardputer ADV. It took me a few goes over a couple of days to get the firmware into the Cardputer ADV but I got there without having to ask a physical human for help (amazing and scary stuff this AI!).

Having got the Mini-FT8 system working with my QMX into a dummy load at home, I was just waiting for an opportunity to try it into a real antenna.

I really need to make a hard copy of the Mini-FT8 manual, but I managed to get the device talking to my QMX after a few button presses and magically the little screen starting filling up with call signs!

I called a station in Italy by accident but didn’t manage a full contact in the end. Calling CQ resulted in 2 QSOs logged automatically in the Mini-FT8 Cardputer log. I felt that the device was struggling to make QSOs, I had a feeling that it might be down to timing, although I had set the clock to the second using my phone as a time source. Maybe I should have stuck at it, but I’d call two QSOs on a new system a success. Hooking up my phone running FT8TW resulted in some more FT8 QSOs.

I finished my activation by having a quick session on CW. I hadn’t done CW since before Christmas but I was happy to copy Aleksander, S57S, passing on his thanks for the FT8 QSO earlier - I was rather pleased with myself.

It was great to get out on the hill for my first points of 2026, I hope to get out more in the coming weeks. Mountain Rescue Dogs are competing for my time, I’m really enjoying being involved. I will try to achieve a sensible balance!

Mini-FT8 appears to work!

Photos don’t really show how tiny the Cardputer ADV really is!

Calling CQ SOTA

73, and happy new year!

Colin (and my buddy, Goose)

[G7ADF]

Could you connect an GPS (either I2C or UART) module to the cardputer. This should resolve any timing issues with FT8.

Due to the relatively short time span needed for an activation, it wouldnt need to run constantly, just run at boot time, wait for the gps lock, set the time then close the utility.

Ian

[M1BUU]

Yes, there is a compatible GPS module which will plug straight into the Cardputer ADV.

GPS/BDS Unit v1.1 (AT6668)

I’d seen Wei’s suggestion of obtaining a GPS one the day after I’d ordered my Cardputer ADV. The firmware doesn’t support a GPS as yet (AFAIK) but I think this intended in the future.

73, Colin

[AG6AQ]

Hi Colin,

Thanks for the report — I’m glad it worked for you.

On timing: Mini-FT8 will sync to FT8 signals automatically. Whenever it decodes 3 or more FT8 messages, it takes the median (not the mean) of delta_t and adjusts the RTC accordingly. In my testing, the RTC is dead-on after 1–2 minutes.

I’m a bit reluctant to add GPS right now for two reasons:

• It increases the system cost by ~30%.

• GPS also takes time to get an accurate fix/time, so it’s not necessarily faster than setting time from a watch or phone.

That said, I do plan to add GPS once the higher-priority tasks are done.

Two ways to increase your QSO rate:

1. Actively manage the TX queue
   By default, each TX message repeats up to 5 times. If you have more than ~3 messages queued, you can delete entries (click the number in front of the message) once they’ve already been transmitted 2–3 times. If that station replies later, they’ll get added back to the queue automatically.

2. Try a different TX offset mode
   There are three options: Random / Cursor (fixed) / Rx, each with pros and cons. I’m not sure if other rigs use Random (randomly picking an offset between 500–2500 Hz each TX) to help avoid getting overpowered by QRO stations, but it’s my default mode.

The Mini-FT8 “usage model” is: get to the summit, set up antenna + QMX + Mini-FT8, let them do the FT8 work while you rest/snack/lunch… then switch to CW (which is sometimes the intense part).

73
Wei AG6AQ

[M9OMS]

Have you tried FT8 via your phone Colin (or anyone else)? How does it compare?

I’ve never tried digital modes, so whichever of those I try will be my ‘first’… hopefully not my last HI.

[EI3LH]

This is a great use of a Cardputer. I’ve been meaning to get one for ages - for a different use case though. The GPIO and LoRa add ons seem to be forever out of stock though but I will keep checking.

I love reading about your projects. You always come up with titchy radios to test out on something the size of a single granule of sugar with a power output of minus 9999 milliwatts and a wavelength of a single Planck unit, housed in a Stradavarius that is only visible under an electron microscope and yet still getting 599 on EME and EVE QSO’s.

[DH2ID]

I got good results using my IC-705 and my Smartphone running SDR-mobile. No cables! GPS and log included. Works for FT8/4 and CW on all bands.

[GM4LLD]

I’ve toyed with FT8CN on a scrap Android phone, it works well. Is it better than this? Don’t know, but I do know I can actually see the phone and screen without taking my portable electron microscope up the hill with me. It’s hard to fit that in my bag along with an anvil or two.

[2E0FRU]

I’d suggest looking at FT8TW, a fork of -CN.

Chris

2E0FRU

[M6GYU]

‘Tis the work of the devil.. ( )

[EI3LH]

@GM4LLD

It’s hard to fit that in my bag along with an anvil or two.

Nearly choked on my Corn Flakes reading that!

[M1BUU]

I tried FT8TW for the first time yesterday after running FT8CN for some time. The FT8TW fork is even better than FT8CN.

Whilst on the Isle of Coll in August my venerable Samsung A52s had a charging port wobble and refused to charge. I’d had a few funny events before that whilst connecting the phone to my QMX with a USB C to C cable. I managed to keep my phone going by using every power saving means known to man, I’d just reached home on the Saturday afternoon, and sent a text to my wife saying I was safely back, when the phone when flat. I ordered a new charging port PCB via ebay and I couldn’t believe it when the postie knocked on the door the following morning - Sunday - with the new charging port!

I try to look after my phone and I hate plugging the QMX into the USB port, I try to avoid it. I thought the Cardputer would be something to replace the phone and I wouldn’t be too worried about it.

73, Colin

[M1BUU]

I did wonder if a programmable 433 LoRa module would be available. And could you run the GPS module at the same time? I’m guessing that you could use both units. All in one LoRa messaging unit?

I suppose it’s re-inventing the wheel to a certain extent, a Heltec board and a phone with Bluetooth could do the same thing.

[GM4LLD]

@M1BUU

I wouldn’t be too worried about it.

They’re expendable items Colin. You may not think that way if you’re mug enough to drop £1000 on a phone with a 1-2yr life. But for most people, you buy a phone and expect to get 4yrs before it starts showing age etc. It’s those older phones that make ideal FT8 devices… the one that’s sat in a drawer after you treated yourself to an upgrade.

[M1BUU]

Yes, I’ve used my phone, FT8TW/FT8CN works really well.

The Cardputer Mini-FT8 is just a novel and fun way of doing FT8. You should know that I like fun and simple ways of doing things.

Like Wei stated, I envisage using FT8 as a log filler whilst I’m looking at the view or eating a sandwich. I ate my lunch yesterday whilst Cardputer ADV was attempting to net me some QSOs. The phone apps are scarily good at filling the log with very little effort- they log everything automatically, you don’t even realise you’re working people if you don’t pay attention!

I wouldn’t say I’m a massive FT8 fan I just like the challenge of trying something new.

73, Colin

[M1BUU]

Ha! I’ve looked at a new phone many times and realised that I would be no better off. My A52s does everything I need and has done it well for 4 years. I do have a 1 inch scratch on the screen when I carelessly put my rucksack down on the cross shelter at Great Shunner Fell, my phone was in the front stretchy pocket of my bag, obviously with the screen to the outside. Doh! Oh well, it’s a scar with a tale!

[EI3LH]

@M1BUU

I did wonder if a programmable 433 LoRa module would be available

Chambourcy nouvelle!

M5Stack LoRa Module (433MHz)

[M1BUU]

I did look briefly, the info I saw was that it was fixed on a single frequency

[EI3LH]

This is entirely your fault. All of it.

Note: Use this code on the official M5Stack shop to get a discount: ARDUINO_FB_GROUP

[GM4LLD]

@M1BUU

would be no better off

Yes. In my case I’ve found there’s normally some event that causes a new phone to be worthwhile. My previous phone, due to many circumstances, didn’t have all the provisioning data in it. This meant that the switch to 4g voice wasn’t supported on most carriers. I had to change provider to get 4g voice and Wifi calling. It only supported 4g voice on EE and not on EE MVNOs. But it worked well, EE worked well and I acquired many loyalty bonuses (10% of account cost, 6.5GB bonus data etc.) However, after about 4 years you could see the battery flagging. I could have got a new battery for £40 (needs heat guns to melt the glue to take the old one out) or buy a newer 5g phone with more carrier support. New phone made sense in that case. Had I spent the money on a battery I would probably be looking for a new one now. And being a cheapskate I had a 5g phone on an account that only did 4g. Well until yesterday. Not a real issue, 4g data and 4g voice work more than well enough TBH. But I now get 5g when I go into the office “down the smoke”.

In your case Colin, your old phone is really quite modern so, yes, you wont see any real benefit for lashing out money on a new one.