Return to the beach!

Here we are again. After the tumult of moving home, covid and the shifting sands of social media, I've returned to Blogger. I started this to remember all the things I've done in radio, and to act as a handy reference for those infrequently-done things.

Yesterday, I returned to the beach.

With two kids approaching university, the opportunity to do anything other than family duties is quite rare these days.

Luckily, I had a window of opportunity early this morning, so that I could set-up a 30m vertical at the coast whilst my identical lakeside vertical ran alongside.

How would the coastal antenna compare with the freshwater location? Well, let’s have a look at what WSPR said.

It’s important to properly frame the question you want to answer with comparisons like this. My aim this morning was to set-up on a NW-facing beach, so that the path to the US in the morning on 30m is a clear line-of-site, sea horizon aspect in that great circle direction. For that reason, I’m not really interested in any other direction for this test, and the long path, at very low angles, is anyway not favoured from this beach.

Now, let’s look at the detail. Here is how the two antennas turned out over the four hours I was active at the beach, as heard by N2HQI:

 And this, pretty much identical, is forWA2TP:

 

These two stations were selected because they have good receiving conditions and are always available. Whilst we can see that there are periods when the lake antenna does somewhat better than the coastal edition, for the 05-06:15UT period, the seaside antenna does very significantly better: the peak difference is around 16dB. The seaside antenna is also heard more frequently than the lakeside.

The changing fortunes are almost certainly the result of changing propagation paths. Additionally, there is some evidence of changing angles of propagation within these two plots, as revealed by what may be several points of anti-correlation.

Let’s look at how KD2OM heard the few other UK stations making it across during this period; I’ve included all but two or so, as I was so tired, I just couldn’t crunch any more numbers today!

 

The performance of the coastal antenna is outstanding, notably at the middle part of the period. Note that the long lines indicate periods of non-reception at KD2OM. The picture becomes more complex towards the end of the run, when propagation conditions are changing, post-sunrise. Note that the lakeside (MW6PYS) station is up there with the best of the UK stations as well (some of those may even have directional antennas; finding out from operators is painfully difficult).

Curiously, the signal to TF4M turned out stronger from the lake. Explaining this is probably straightforward, because the peak angle of radiation to Iceland, being fairly close, is higher, thus favouring the higher pattern of the lakeside antenna; the seaside antenna may simply be ‘firing too low’ for this path.

The signal to TF4M. The lake does better, although they both appear to peak at much the same level (no data for the seaside antenna after 08UT, sadly).

 

It’s also useful to look at the landward direction for the coastal antenna, in this case, to OH8GKP. The lakeside antenna has an open, watery foreground for this path and, again, a higher takeoff angle is probably preferred, given the fairly short distance involved:

Signals to OH8GKP, in the landward direction at the coast.

 

Overall, it’s clearly better to be at the coast than at the lake, and the difference can be very high - higher than the gain afforded by a multi-element Yagi - something that few of us could, or would want to, erect at 10MHz! But, in both cases, being near water, fresh or salty, puts you up there with the best of the best.