Wednesday, 11 January 2017

Shut Up and Transmit!

If you're fairly new to amateur radio - or even if you're not - then it's a fair bet that you'll spend a lot of time surfing the internet and reading books with titles like '600 More Vertical Antennas for Attics'.

What always happens with looking around for advice and tips on antennas is: total contradiction.  This leads to a feeling of frustration.  One guy will tell you his magnetic loop bust an antipodan pile-up on 5W, whilst others will happily argue for their entire given lifetimes that magnetic loops only emit feeder radiation (which isn't true, by the way!)

Now, the title of today's post is inspired by those who work on quantum physics.  Whilst the maths is worked out fairly nicely, nobody understands what quantum physics tells us about the true nature of reality.  A very recent survey found most still hang on to ideas formulated in the 1920s and that are almost certainly wrong. 

As a result, some physicists decided to tell others to stop pondering over the interpretation of quantum events, and simply 'shut up and calculate!' 

So, 'shut up and transmit!' is not a bad conclusion for us ham radio people.  I started out with little knowledge and therefore even less prejudice about what would - and what wouldn't - work as a good antenna.  As a result, I think in some ways, I have a better idea about antennas than those who figure out ways to spend ever more money on ever bigger towers, multi-element arrays, and those terrible things called amplifiers.

Here are my pearls of semi-wisdom after some years of keeping it simple:

(1) You have to work really hard to find sensible, objective views about antennas.  This is as true of printed books as it is of the internet and its endless bun-fights.

(2) It's the environment, stupid!  Stick a vertical in a housing complex, and it will probably work infinitely worse than if you stuck it in a n open field atop a rural hillside overlooking the sea.  If you realise that the most ham operators are based in highly-urbanised western nations, then most of those people saying that verticals 'radiate poorly in all directions' are almost certainly basing their simplistic - and wrong - opinion on their limited experience of trying to get radio waves through dense brick and concrete.  The nature of your ground is also hugely important.  Not all of us live on dry, sandy desert soils!

(3) An antenna does not need to be hundreds of feet in the air, nor does it have to have a 1:1 match.  At low frequencies, especially when using twin line feeder rather than coax, line losses in imperfect antenna systems are utterly insignificant.  If you have an open environment, and especially if there is some somewhat higher ground available, then a low antenna can work just as well - or even better than - an antenna placed much higher up.  A simple horizontal or sloper from my QTH shows the best low angle gain (which is very high) when a dipole is as low as 10 feet off the ground.  Almost everybody will shout at you that this is impossible and stupid.  But it isn't.

(4) What works for you is what works for you.  You aren't setting up a station for someone else.  Whilst some might dismiss digital modes as somehow not really radio as they think of it, the fact is that digimodes have opened up the world of DX to those of us who have less than £50,000 to spend on equipment, and a garden that's less than 100 acres in size.  Simple and less-than-ideal antennas will bring in the DX, believe me!

(5) Work the long path!  When the terminator lines up between you and an interesting DX country, it's time to work DX.  A simple antenna with low power can easily work the other side of the world with a good signal for about 20 minutes at local sunrise and/or sunset.  There are an awful lot of people who, despite years of operating, still don't really grasp this concept, so make sure you're not one of them and work the opportunity that this period brings almost every day.

(6) Keep trying new ideas!  That way, you might find some nice surprises with antenna performance! 

(7) You definitely don't need a tower and a Yagi!  They are nice to have but, with digital modes today, can be a hindrance, rather than a help in many cases (because the direction you are pointing your Yagi in is often not the direction from which an interesting signal might come.)

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