Since getting back on the HF bands of amateur radio almost exactly two months ago, the majority of my logged contacts have been with FT8, and to a lesser degree, FT4 — digital modes introduced years ago by Joe Taylor, et al, and that have become insanely popular for a wide range of reasons. These modes have their share of naysayers, and while I am still attracted to both CW (Morse code) and SSB (phone) for HF work, I’m really enjoying the relaxed nature of FT8/FT4. Why I like it, and why I think the naysayers should be more open-minded about it, is the subject of a future post. For this one, I wanted to share some of the things I’ve learned about these (nearly identical) modes that I wish someone had told me from the start.
The intent of this post is to be along the lines of something that I read early on in a blog post from DX Engineering’s blog, On All Bands, written by Anthony Luscre, K8ZT, and titled, Top 10 Tips for Succeeding in FT8 Mode. But I’m not out to duplicate Anthony’s points; I want to provide some thoughts on what’s worked for me as I try and make the most of these interesting modes.
Before I even dive into this, I’ll say one thing here: I am not an expert who’s been using these modes for years like many of you. If you think I’m off base with any of these suggestions, have other ideas, or if you think I’ve gotten something badly wrong, get in touch.
Let’s dive-in.
Understand periods
Here’s something I wish someone had explicitly pointed-out to me at the very start with FT8/FT4, and which is very simple, but not really what I’d call “immediately apparent” — the use of periods, as the documentation calls them, or sequences, as some of the software’s hover text tool tips call them — suggesting that even the software’s authors don’t really know how to refer to them.
Of those tuning their radios to a specific FT8 or FT4 frequency, some number transmit on an even period and some transmit on an odd period, and each group listens on the period opposite the one they’re transmitting on. There’s nothing necessarily intuitively obvious about this when you’re first getting into it. If you listen to the frequency, you just hear signals en masse cycling, but when, why, or how you jump-in isn’t really spelled out — in large part because to a degree, it doesn’t actually matter. What matters is that there are periods, and because of the way they work, you can’t visually see on the waterfall what’s happening when you’re transmitting (obviously).
The periods are also not explicitly identified in the user interface of the software, which I think is regrettable. The only way to control the period you’re transmitting on is the little “Tx even/1st” checkbox in the interface, which is set (or unset) automatically if you double-click someone calling CQ in the Band Activity window; you get set to the period that’s the opposite of them.
See that checkbox in the image? It’s unchecked, meaning I’d be transmitting on the odd (or second) period if I were to call CQ. This box would get auto-checked if I double-clicked on a station transmitting on the odd (or second) period; it would remain as-is if I double-clicked on a station transmitting on the even (or second) period.
I don’t think that Mr. Taylor and his colleagues really make much of this, primarily because they don’t really need to; for the most part, it just works. But I do think it’s important to have some awareness about the concept for reasons that’ll become more clear with the very next thought.
Don’t think you’re going to plant a flag
For those of us accustomed to working more traditional modes like CW or SSB, the idea is that you go to a clear frequency, take reasonable steps to ensure that the frequency is not already in-use, and start calling CQ. That doesn’t mean you “own” the frequency, but I would say it does mean you have a reasonable, “first come, first served” sort of basis to use it, and it customarily involves a certain amount of basic respect and courtesy to other operators.
Regardless of mode, it goes without saying that just because you can hear someone interfering with you doesn’t mean that they can hear you at all, so sometimes, QRM becomes an issue, completely innocently, and you have to move around a bit, and so forth. It comes with the ham radio territory, of course.
With FT8/FT4, the combination of the periods and the same “nature of the beast” behavior of radio waves can make things a little more challenging. While you can plant a flag, as it were, with SSB or CW and feel like you own the spot, that simply doesn’t work very well with FT8/FT4. It can for short spans of time, but I thought that once I’d tuned to the agreed frequency, and clicked my spot in the passband, I’d staked my claim, and that was that. Nope. There are two reasons why:
- Everything already mentioned. Just because you’re transmitting doesn’t mean someone else will hear you, so they can transmit right on top of you and not even be aware of it. It’s way easier for this to happen with FT8/FT4 than traditional modes.
- The other station doesn’t even see you (visually, in the waterfall). This is due to the periods; if you and another station are transmitting in the same period, you don’t hear (or see in the waterfall) one another. It’s that simple. That means that you, too, will not (and cannot) see or hear that you’re transmitting directly on top of each other if you are.
I have two specific recommendations here:
- Listen for at least two full periods before you transmit. When you jump onto an FT8 or FT4 frequency, listen for two full cycles before choosing a spot in which to transmit, just to get the lay of the land. You’re looking for an open spot, of course, but moreover, you’re looking for an open spot on your intended transmit period. When you find one, go for it; shift-click to choose the spot, and start your CQ (or start answering others). If you plan to call CQ, you may need to check (or uncheck) the “Tx even/1st” checkbox to ensure that your transmitter is keyed during the right period; if responding to someone else’s CQ, that’s automatic.
- Pause periodically. If you’re not in an active exchange, skip a full cycle from time to time, and listen. Did someone pop into the passband at the same spot as you, and is transmitting during your transmit cycle? Then you’re (potentially) limiting each other. Look for an open spot, do NOT change your transmit cycle, move your transmit audio frequency to that open location, and keep going.
Making sure that you’re on, and remain on a spot in the passband that’s open during your transmit period will help ensure that your signal will actually be heard.
And another tip: Is nobody hearing you when you call CQ? Try again. Just because a spot in the passband looks open on your end doesn’t mean it’s open to stations a few thousand miles away. If you’re not getting any responses to your CQs, there could be any number of things going on. But being sure you’re transmitting at a spot in the passband that’s actually open is certainly one of them.
Endless repeats? Try moving!
It can be extremely frustrating with these modes when you start an exchange with someone — someone who no doubt sent a great signal report — and all of a sudden, there’s a lot of evidence that they stopped hearing you, by repeating their last exchange two, three, or four times or more. This is a very good sign that another station started transmitting on top of you in the passband, on your transmit period. As I explained above, you have no way of knowing this without stopping to listen… so, stop and listen. If the station you’re talking to is engaged, they’ll still be there.
When I do this, invariably, I hear that indeed, someone is right on top of me and blocking my other station from hearing me. When this occurs, I turn-off Enable TX, listen, I very quickly look for a spot that appears to be open in the waterfall. Then I shift-click at that spot in the passband, and immediately re-enable the Enable TX button. With FT8, the delayed transmit won’t generally be an issue with your full message being transmitted or received; with FT4 and its much shorter period lengths, it might be, but it’ll always retransmit.
Jumping around too much is probably ill-advised, but you do not have to stick in the same spot, even during an active exchange. If the person you’re exchanging with has the software set-up at or close to defaults, they will very clearly see your message despite the audio frequency jump. Quite often, this has allowed me to complete contacts and log them in a very crowded passband.
Another note: If you jump spots during an active exchange, try to aim for one close to the location in the passband as the station you’re working. Why? Their radio’s passband width may not be wide enough to hear you, especially if you jump to the high end of the passband. Which brings me to the next thought.
Understand your radio’s passbands
The waterfall view of WSJT-X displays the upper sideband audio passband of the frequency you’re on, as heard by the software. It’s possible to pack a lot of operators in that space, given the dual-period nature of these protocols. But what you see (in the waterfall) isn’t necessarily what you get, nor is what you’re getting necessarily what you should see.
Your transceiver actually has two passbands: receive and transmit. For many hams, this is already understood and obvious, but I’m afraid it wasn’t for me — at least at the beginning. My Icom IC-7000 was a new-to-me radio, and I’d been away from this for 20 years, so I’ve experienced some brain rot with the stuff I used to understand. I’d also never used a mode that could take advantage of the audible bandwidth in the innovative way that FT8/FT4 can, and does.
The objective is to set the radio to the maximum passband width it’s capable of for both transmit and receive. Newer radios have digital-specific modes that maximize this automatically. But for the IC-7000, as one example, on receive it depends the setting of the IF filter, which has a maximum setting of 3,600 Hz for SSB mode. On transmit, it’s the SSB Transmit Bandwidth (SSB TBW), which needs to be set to Wide, but moreover, there are separate configurations that need to be set-up for how low the low-end is, and how high the high-end is, and the IC-7000 happens to default to the widest values: 100 Hz on the low-end, and 2,900 Hz on the high-end. Your transceiver no doubt has other options and values and defaults.
Your radio will vary (unless you happen to use an IC-7000 as well), but for me, this means that I can hear the majority of the passband that WSJT-X displays, but I can’t transmit across all of it. This manifested itself as “flaky output” when I set the transmit audio frequency much above 2,800 Hz. The power meter on the rig just bounced weirdly, and I thought perhaps RF was getting into the audio or something. Nope; I was just at the very edge of the transmit passband of my radio. This is where newer radios are going to have a distinct advantage with FT8/FT4.
Conclusions
I enjoy these modes, and the majority of the contacts I’ve logged in my two months back in ham radio have been made with them. FT8 and FT4 both seem to enable people like me, with low power and marginal antenna systems, to work DX that otherwise would be an impossibility because my set-up simply cannot compete with passionate hams running amplifiers and beams with rotors or multiple antennas optimized for different bands. I have one radio, one antenna, and not a great one at that. And yet, thanks for these digital modes, I’m nearing 100 DXCC entities worked.
But like any other aspect of ham radio, a little extra focus on understanding some important details can make the experience a heck of a lot more enjoyable — and successful.