Hi John, great to read your post, thank you! I have a few comments on your observations. First about the antenna. The doublet and dipole should be exactly the same though it depends on the length as to gain and lobes. However, the height is most important, and if it is less than 10m above ground it's not likely to be directional but high angle and more omni-directional. Above 10m, especially at 15m above ground a 30m dipole or a doublet tuned on 30m would have the typical broadside pattern, unless it is bent. However, the ends are not important and can be bent sideways or downward and won't affect things as the current is mostly in the middle portion and gets less toward the ends. As for picking up noise, both the single band dipole and the doublet should in my experience be the same, as they are only resonant on the one band (and some harmonics). The doublet has to be matched/tuned, the 50 ohm dipole does not. However, it can be that if the doublet is shorter than 14m long that the top part of the feedline will form part of the antenna and thus also radiate (vertical) and pick up more noise than a 50 ohm coax feed. On all the above, if anyone knows better or otherwise or I'm wrong on any of this, be welcome to comment and/or correct me.
I think Will's experience of the difference between trap dipole and resonant single band dipole is also logical: there can or will be losses with traps, it is a sort of compromise, whereas a full half wave dipole without traps is not. But again for doublet vs dipole, I'd say there isn't any real difference other than if the doublet is short or very long. You did not say how high your doublet is. The general truth is get as much wire as high as you can. And with a horizontal dipole that means the middle part to be as high as possible. If however it is an inverted vee then even if the apex is at 15m or more above ground, the pattern will no longer be broadside but more omni-directional, and, a compromise on low angle radiation compared to a flat dipole. But again, great for regional communication.
Now about contacts over the Atlantic! These are possible and EASY every single night of every year on 30m, every season and at every point of the solar cycle, with modest antenna such as a dipole up 10-15m or more, or a vertical, when the path is mostly in darkness, that is to say, from shortly before sunset at the local USA or Canadian station. It is just that there are not always that many stations active in the early evening North America side as their XYL haven't gone to bed yet or they're watching the news, eating dinner etc, and also there are not many G that go onto 30m late in the evening G time since they have stopped watching TV or eating and are going to bed with the XYL. :-)
RBN are not necessarily switched on all the time, but you should normally find being picked up if you call CQ on 30m after the local sunset on the other side, even before it. And this open 30m band (and also 40m a little later and stopping sooner) continues ALL night right up until just after dawn on the G side but longer than it remains open on 40m. SO it is indeed just a question of activity and being on between mid to late evening and early morning.
Also, from just before local G sunset right up until the local sunrise in Asian locations, i.e. again when the path is mostly in darkness, 30m is open to ALL of Africa and Asia up to Australia. For South America is the same applies, thus when you get North America or even before, you will also be able to get South America. Into Europe 30m is open 24 hours a day.
A final observation comment: I have done a lot of listening on Twente Web SDR this year while I was off air and overseas and I've all too often observed that a station calls CQ on 30m several times then gives up, and minutes later someone else does the same. Most people calling CQ don't remain persistent long enough. How long is long enough? Of course if we call all day and night we'll get an answer but that's too long. I'd say you can get lucky first call, but generally 15 minutes of calling would be long enough to get a QSO. And let's not forget some are "callers" who almost always call CQ rather than look for CQ and some are only "listeners" who reply to CQ. We'll get the best results if we do both: e.g.. call CQ three times in a row, if no reply, tune around to see if there are other CQ and note any other QSO in progress and the frequencies, if not, back to the SAME frequency as before and call CQ again. I've also often noticed that when a CQer gives up too soon and doesn't come back to the same frequency a station that needed some time to get ready (a drink, tune up?) calls back and the other station has gone. This is the reality of 30m: always open to somewhere all day and night, the only band that NEVER closes in all situations (40m can be dead due to D layer absorption in middle of the day especially at lower latitudes and 20m can be dead due to lack of F layer at night especially at higher latitudes and low solar activity). The problem as you said is really the lack of activity much of the time, which is also the fact on even 40 or 20m in some parts of the world now.
Thank you for keeping active on 30m and I hope it continues to bring both of you much joy. Indeed, it is the optimal all-round QRP band, given that the antenna doesn't need to be as high as on 40m for the same result, and the better propagation overall, and also it is a great band for CW rag chew. The other day two thirds of the entire CW band, from 10110 to 10130 was wiped out with wall-to-wall CW calling a DX station operating unspecified "up" split. Not good for a number of reasons that is a different topic of discussion, but proof of the propagation. All of Europe and beyond could be heard with hundreds of stations callign simultaneously with no gap of more than 0.1 kHz over the entire 20kHz wide pile up!
I look forward to hearing more about your experiences!
77/73 de Ali G4OJW
