Poor man's FT8 SOTA

[OE6DUG]

Today I tried to activate SOTA OE/ST-299 on VHF in data mode / FT8 the cheap way:

• Quansheng uv-k5(8) version 1 with IJV mod ver. 3.61. This firmware offers SSB receive/transmit, in reality only DSB, so you compromise a bit on power.
• Android mobile phone with https://qft8.com/ - a pretty nice app.
• Audio connection with the usual 2-pin Kenwood cable. Most recent phones are no longer equipped with an audio jack, so I use a USB-C adapter cable containing a soundcard chip. As there is no RX/TX control via this connection, I had to enable VOX operation on my Quansheng.
• Diamond antenna RH-770 with BNC/SMA adapter

There is not much FT8 activity on 2 meters here. After calling cq SOTA on 144.174 for a 15 minutes, I got at least one answer, OE6IWG. And I was heard by a monitor station in pskreporter.

SOTA-wise, only one QSO resulting in 0 points - not really a success. But that was not due to poor equipment, it’s just that FT8 is not very popular on VHF. This is a bit of a shame, as this mode works very well with low power.

After all, this combination of hand held transceiver and mobile phone is very lightweight, so perfect for SOTA! It would be desirable if ham radio amateurs were to discover FT8 mode on VHF!

73 de Edgar/OE6DUG

[JP3PPL]

Don’t get discouraged! Have you tried 70 cm? The Diamond antenna you have works really well on 70 cm. Another possible factor might have been the summit you activated. This year the same thing happened to me at JA/HG‑193, where I only brought antennas for 2 m/70 cm, and after almost two hours calling CQ in FT8 and CW I ended up making just one QSO in CW. Good luck with your next activations!
73 de JP3PPL

[VK3SQ]

…hi Edgar, thanks for your observations about your experiences with FT8. Well done; I would encourage you to keep going with your experimenting and telling us of what you find. Great to have you with this group and I welcome you to the fraternity; remember to enjoy what you do and have fun!

Geoff vk3sq

[E77Z]

2027 SOTA Challenge?

[JP3PPL]

I had forgotten about this! Last year, when I activated JA/HG‑028, I got a big surprise. It was my first DX on 144 MHz — a 1,800 km QSO in FT‑8 using an Icom IC‑705 and a Diamond RH‑770 antenna. Power was only 3 watts because I hadn’t brought an external battery. So don’t worry if there’s little activity in your country; depending on the summit you activate, you might end up with several surprises. I’d recommend studying the summits to increase your chances.

[EA4WT]

Gran DX en VHF, enhorabuena.

73

[JP3PPL]

Me olvidé de comentar algo al principio. En donde no pude hacer más que un QSO había llevado una Yagi de 3el para 144Mhz y otra Yagi de 5el para 430Mhz. Y en donde hice el DX (si no mal recuerdo fueron 3 QSOs con Taiwán) solamente fue con la Diamond RH-770

[EA4WT]

Cosas de la propa 144…y mucho mar de por medio… aquí pasa lo mismo desde la costa a Canarias, a Italia, a UK…el mar es el secreto.

73

[OE6DUG]

As mentioned, my FT8 SOTA activation about a month ago was only partially successful — there simply isn’t enough activity on this mode.

Yesterday, I gave it another try by participating in the FT8 Activity Contest https://ft8activity.eu/. The 2-meter section takes place on the first Wednesday of every month, from 17:00 to 21:00 UTC. The only disadvantage is that during the European winter months, it is already dark at that time, which is not particularly convenient for SOTA.

So instead, I walked up a nearby hill that offers good propagation with few obstacles in the way. Messendorfer Berg is 440 meters high and is not a SOTA summit, but it is perfectly adequate for testing.

As soon as I switched on the radio, a bunch of stations could be heard. Using the same equipment as during my previous SOTA attempt, I was able to complete QSOs with stations up to 200 km away. In addition, I copied stations more than 500 km away in Italy and Romania, but they were unable to receive my weak 5 W signal.

Obviously, the equipment performed quite reasonably, especially considering that it costs only a fraction of the price of all those shiny Icoms.

Only one real shortcoming showed up, and it is something that only becomes apparent in contest situations with lots of signals on the band: the Quansheng’s VOX refuses to trigger transmission when there is an incoming signal from the receiver, i.e. when the squelch opens.

This behavior is typical of most handheld radios and makes perfect sense for FM operation. However, on SSB — and particularly with FT8 — there are often several signals within the filter bandwidth. So sometimes it takes quite a long time for a message to get out. qFT8 generates the audio output correctly, but the transceiver does not actually start transmitting until the frequency appears to be clear.I don’t know whether this could be mitigated by modifying the firmware. After all, IJV, the only firmware that offers DSB transmission, is not open source.

One possible solution might be to use a DigiLink Lite instead of a USB sound card between the radio and the mobile phone. This device can be controlled by the qFT8 app, either by acting as a VOX itself or through control lines from the simulated serial interface.

Maybe the next steps will be to try the DigiLink and perhaps a directional antenna, such as a SOTAbeams antenna, for the next activation.

It’s a pity that FT8 is still so uncommon in SOTA, because it allows you to operate quietly without disturbing other people who are out in nature looking for some peace and relaxation.

[F4LEK]

@OE6DUG

It’s a pity that FT8 is still so uncommon in SOTA, because it allows you to operate quietly without disturbing other people who are out in nature looking for some peace and relaxation.

Good effort! Remember, any contact counts for a SOTA activation, even if the other station isn’t a registered SOTA chaser.

I think the problem in this case is more the lack of FT8 activity on VHF in general.

CW is a great tool to add to your arsenal. It’s lightweight, silent, and much more rewarding than digital modes on an app

[OE6DUG]

You are absolutely right! I am quite passionate about CW, used it a lot for my HF activities. On VHF, unfortunately, there is not much CW activity except of contests. But I will keep trying!

[OE6DUG]

In my earlier post, I mentioned the possibility of using a DigiRig interface between my Android phone and the Quansheng transceiver to improve PTT control. A few days ago, I received this little device: Digirig Lite – digirig , and it has turned out to be a real game changer!

During the 433 MHz round of FT8 Activity, I was able to complete QSOs with stations whose received signals had SNRs as low as -10 dB, all within just a few minutes. The key advantage is that the DigiRig’s VOX control switches the transceiver to transmit, even when incoming signals are still audible within the receiver’s filter bandwidth. No more waiting around for several minutes!

A few side notes:

• During my very first transmit test, I discovered that the audio interface cable I initially used, the BTECH APRS-K1, was not compatible with the DigiRig because it lacks the PTT control line, as discussed here https://forum.digirig.net/t/btech-aprs-k1-audio-cable/2621/10. Rather than ordering the appropriate Baofeng HT Digirig Cable Set – digirig , I decided to make one myself. I cut the cable from an old Quansheng headset and soldered a TRRS plug onto the section with the radio connector. It was a rather tedious job, but perfectly doable—and much cheaper, too!
• Here is an in-depth description of digirig function: Digirig Lite Setup Manual – digirig
• One caveat: As far as I know, the only firmware modification that supports SSB transmission (actually, double-sideband transmission) is IJV firmware, version 3.61 in my case. However, this version is compatible with the original UV-K5 (hardware version 1), but not with the newer hardware version 3 or the UV-K1. So, I guess I was lucky to get my hands on an older Quansheng radio!
• Using DSB instead of SSB inevitably comes at a cost: half of the available transmit power is effectively wasted, resulting in a 3 dB loss. Unfortunately, there is no way around this due to the Quansheng’s hardware limitations. Nevertheless, my 2 W output on 433 MHz was enough to achieve quite respectable results in the activity, especially considering that most other stations were running between 10 and 100 W!

Finally, the only thing left is to test this setup during a SOTA activation. After all, this combination of a smartphone, an ultra-compact interface, and a handheld transceiver could be one of the lightest and most compact setups for operating digital modes on VHF/UHF!