Sound Settings

Well, it's come round to that time again, when the shack laptop had to be replaced with a modern unit. The old HP notebook has done very well for about seven years but is now just a little too slow for comfort.

Inevitably, a lot of software installed over the years is no longer really in use. FLdigi, which I used a lot at one time with keyboard-keyboard modes like OLIVIA, hasn't been opened since the FT8 revolution and the consequent collapse in anyone much to exchange messages with. So I guess that won't be replaced for the time being.

New laptop! It's not much of a shack, as we don't plan on staying at this location very long.

 

WSJT-X, of course, had to be installed on the new machine. Whilst this was easy, I did encounter a strange glitch at the end of a FT8 transmission, where the laptop would key the rig off at the correct moment, but then momentarily key it on again. The messages weren't affected, but it was irritating

I thought the system sounds might be involved, but it was in fact down to the sound level setting on the computer for the USB soundcard output (I'm still using the excellent ZLP Electronics units, though my newer interfaces are Digilink Nano) was too high. Reducing this to around 20% of maximum output solved the problem entirely.

No power-hungry laptops for /p!  Raspberry Pi is the solution here.

 

And there we go!  Back to normal on the laptop front, even though most of my activity is now /p from the car on the beach, or a backpack, which uses a Raspberry Pi. Sadly, with the current post-pandemic supply problems, you'll be hard-pressed to find much of any of the aforementioned items in stock!

 

Ham Radio: not always a nice place

There seem to be two main kinds of people who get involved in our hobby: those who want to peacefully enjoy a technical pastime - or simply talking in a civil manner to others - and those who want to vent their dissatisfaction with life in general through using and abusing radio.

I have to be honest and say that, in the past, when the 'Laughing Policeman Wireless Society' (simply someone's user name on Facebook and Twitter) used to criticise the RSGB, I sometimes found it mildly amusing. Well, let's face it, in years gone by, if not now, the RSGB had issues that fully justified fun being poked at them.

But this morning, out of nowhere, came a post from LPWS on Facebook that really was unacceptable:

LPWS Facebook post, accessed 08:29UT, 20/03/2023.

I suppose that the author and commenter may view this as simply 'innocent banter'. But I don't think that washes. It's the kind of prejudiced nonsense that used to be pervasive in UK society back in the 1970s - no doubt reflecting the age of the author of LPWS.

This kind of thing is clearly not good for our hobby. Luckily, LPWS seems to be operating at the bottom of some big, empty pit, where hardly anybody ever sees the puerile nonsense that more usually characterises that accout. The stand-alone website, meanwhile, suggests a degree of obsessive behaviour that can only be described as alarming. 

It's up to all of us to continually present a positive, inclusive image of our hobby; there is no place for this anachronistic and hurtful nonsense, spouted by people who ought to take a long walk, often.

Beach vs Lake at 10MHz

Because my 30m vertical is currently working 200mW WSPR at a lakeside location, I decided this week would be a good opporunity to compare with an identical antenna at the beach.

The beach 10MHz vertical.

At the time of the test, the tide was about 1km out, but the sand surrounding the antenna is wet, with seawater at only about 2 feet below ground (this is a sandflat, with an extremely shallow gradient; land further out is slightly higher than the antenna's position - which is why people often get surrounded by an incoming tide here).

So, let's delve into the results!

First, the DX I was interested in: short path to Australia - in this case, to top-WSPR receiver, VK5ARG.  No real surprises here, though the relatively small difference of 6dB in favour of the beach location is encouraging to those who can't get to the coast but can find a lake. I've thrown-in G0PKT, the top-performing coastal station, as a baseline. MW1CFN is the seaside antenna.

Reception at VK5ARG, short path.

Why does G0PKT not do especially well in relation to my coastal location?  Partly, it's because that club station's antenna, whilst extremely effective and always at the top of the beaconing list, is based over land and so doesn't benefit from the full ground loss reduction effect of being over water or damp sand. And partly it's because the shortpath to Australia is in the landward direction, where the environmental gain reduces significantly.

The lake vertical, with WSPRlite and battery in the bag.

 

Whilst the difference at any given moment between sea and lake is not constant, the median value works out as exactly 6dB in favour of the beach.

Perhaps more importantly, there were nine receptions of the beach transmissions at VK6PK (median of -27dB) in the roughly 100-minute test, whilst the lake vertical was not heard at all.  The same was true at VK7ZAB (one spot from the beach antenna, at -27dB, none from the lake). A QSO you can make is a lot better than one you can't!

Let's look at SA2LLL, a much closer station, but in the seaward direction from my beach location:

RX at SA2LLL

The beach antenna achieves a median received signal of -25dB, whereas the lake vertical is heard only once, at -28dB. Perhaps a surprising result for the relatively short distance of 1995km.

Over at SM7KHA, we obtained a more informative plot, where the median difference is only 2dB in favour of the beach vertical. At the end of the run, the situation seems to be reversing, probably reflecting the changing propagation after sunset:

RX at SM7KHA

Let's look at a much closer station: GB7BI, near Inverness (450km):

RX at GB7BI

This is more complex! Overall, as a median, the two locations come out within 0.5dB of each other (-7.5dB for the beach, -8dB for the lake). But, you can see the situation changes over time, with periods where there is both a much larger positive and negative difference for the lake antenna. This probably reflects changing propagation angle changes as sunset approaches (around 17:55UT).

In my landward direction, out towards the south and EA8/DF4UE (2854km), the result was again in favour of the beach vertical:

RX at EA8/DF4UE

There's a significant, 5dB benefit to the beach location in this case - noting that the difference is sometimes very much less, or even zero. The sharp drop in signal strength between roughly 17:45 and 18:05UT is interesting - and much more pronounced for the lake vertical. The dip is coincident with my sunset period.

Out at UA3245SWL (2695km), a seaward direction for my beach vertical, the result is again in favour of the beach:

RX at UA3245SWL

I don't draw connecting lines in the above plot, as there is a lot going on, and lines tend to give a false picture in this case. The median difference is more useful, but amounts to only 2dB in favour of the beach antenna.

Finally, at OZ4JJ, the difference turned out to be 6dB - equivalent to what we saw to VK-land, despite the distance being only 1013km - but the period of reception is shorter from the lake vertical, even when the signal from the beach is strongest:

RX at OZ4JJ

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.