More of a Shout than a Whisper

The key to converting your treasured and incredibly versatile FT-817 or similar into a digital powerhouse seems to be an A. computer and B. a sound card interface.
So, armed with a tidy little Signalink USB interface, I’ve been attacking digital modes with vigour, starting with WSPR (Weak Signal Propagation Reporting). The Signalink USB is basically a remote sound card in a box, powered by your computer’s USB. This solution allows controlled audio isolation between your rig and transceiver. Level adjustment is available on the front panel too which means you don’t have to navigate clumsily through several windows on your PC and adjust sliders with your mouse to optimise levels.
 2013-02-04 15.47.14
FT-817 and Signalink USB Interface
The interface connects directly to the data port of my FT-817 and provides a PTT function, if required. However, I’m also using a CAT interface which provides PTT (Push To Talk) as well as frequency configuration from the WSPR program that I’ve started with.
So, straightforward then? Nearly but not quite. There are a few small pitfalls to be aware of. Firstly, the ‘817 needs to be put into DIG mode as opposed to USB mode. This routes the input and output signal to the data port on the rear panel. The data port is inactive in SSB modes. Secondly, the correct data mode needs to be selected in the second-level menu, namely USER-U. This means that it will be operating in USB mode and the passband will be adequate. If this were to be set to RTTY or PSK, then the filtering for WSPR would be too narrow. WSPR signals are individually narrow, but several occupy the given passband. Finally you need to follow the instructions on Windows setup that comes with the Signalink box to the letter. One unchecked box or misplaced slider will drive you to madness.
WSPR Control Software
Apart from that, it seems to be ‘plug and play’! My first play on 40m with a random wire of some 20m in the back garden pulled in a VK straight away. I was heard up in the Norwegian Arctic Circle with 1W. Elation. Simply tuning to 472kHz pulled in a Dutch station with absolutely no special equipment.
For one whole day I exercised near-military discipline. I stayed on the 30m band all day long without jumping to other bands. 1W into my rear-garden wire antenna reached Israel and the Arctic Circle again. East Coast US stations starting to come in at 20.00 GMT and I was reaching the Mid-West by late evening. Within ten minutes this morning on 17m I was heard in new South Wales and Iceland.


10 mins on 17m!



10 mins on 20m!


I finally unleashed my single Watt on the 20m band for the first time this afternoon, immediately yielding a nice path to the Philippines as well as Europe and the East US.
No wonder this aspect of the hobby is so absorbing. I’m absolutely addicted. Did the developer, Joe Taylor, K1JT, realise what he was unleashing on us? A ‘big shout’ goes out to the man who invented WSPR!


Rob Law, MW0DNK, is a regular contributor to and writes from Anglesey, Wales. Contact him at [email protected].

2 Responses to “More of a Shout than a Whisper”

  • Mike VE3WDM:

    Good morning Rob, I had the Signal link unit for a short time but ended up selling it. Not because it did not work or I could not get it to work…I have the Elecraft K3 and it has it’s own on board line in line out with isolation transformers and so on. I was told that no sound card was needed. I do have the Elecraft K2 as well so wanted to keep it for that. The reason it went on the selling block was the frustration I had with the digi modes!! At this point I only have WSPR (as the other modes were just a pain to set up) and now for some reason 80m just does not want to work, but all other bands are just fine!! So to keep my sanity in check WSPR is now on hold as well.

  • Hi Mike, I’ve also noticed the noise floor on the lower bands increases dramatically as soon as any USB from the computer is connected. I’ve tried toroidal chokes, but they have no effect at all.

    I agree with you about digi modes. The most frustrating aspect for me seems to be the sound setup in Windows XP which is very difficult to get right – especially for FreeDV, which uses both the Signalink AND the computer’s internal sound card.

    Computer and radio – oil and water? 🙂

    73, Rob.

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