Roger Hayter wrote:
Stephen Thomas Cole wrote:

Jeff Liebermann wrote:
On Tue, 16 Oct 2018 07:44:53 +0000, Spike
wrote:

Very interesting, but I'd have to say that none of what you say refutes
my original contention that the distant station, which after all is the
one we are trying to communicate with, will notice any difference to the
received signal whether the sending station's antenna was tuned with a
20c torch bulb or a $300 VNA. You touched on the main vagaries of the
system when you said "What I've found is that such side by side
comparisons do not account for variations in propagation, path,
interference, local noise, time of day, position of the moon, and other
factors beyond the operators control".

Perhaps an analogy might be useful. Instead of an HF radio, you're
dealing with your automobile. Under normal circumstances, it will get
you to work and back fairly efficiently. However, you notice that
your gasoline (petrol) mileage is not quite what you might expect. So,
you have a choice of mechanics. The first mechanic tunes the engine
with a light bulb, divining rod, magic incantations, and offers a
rather bizarre description of what work was done on the vehicle. The
second mechanic uses proper computerized test equipment to analyze the
situation, uses factory parts, and delivers the car with a detailed
printout of what was done, what changes were made, what parts were
used, and a before-after gas mileage comparison performed on a
dynamometer.

Now, which mechanic would you prefer? Your car will still go to work
and back in some manner. The second mechanic will cost more, because
he has to pay for all the expensive equipment and genuine parts. If
you're impoverished, obviously the first mechanic will be the only
available choice, but assuming you plan to keep the vehicle, one might
suspect it is a bad long term solution.

From my perspective, both professional and as a ham, I deal in
numbers. I can tell by looking at the numbers what is happening and
what needs to be done. I have a small collection of aging test
equipment to help me generate the numbers. Light bulbs do not
generate numbers and are therefore (in my never humble opinion)
useless and worthless.

However, I will concede that if your intent is "to be able to transmit
signals intended to be received by another station", a light bulb is
sufficient to determine that your transmitter is spewing RF, spurs,
harmonics, and noise into an antenna-like device that is either
radiating the RF, absorbing it into heat, or reflecting it back to the
transmitter (because the light bulb indicates the same in both
directions).

Burt won't appreciate being given an absolute schooling from Jeff here.

I don't appreciate an interesting discussion being interpreted as a
schoolyard fight by ignorant troublemakers like you and Gareth.


I couldn’t give a **** what you don’t appreciate, Rog. HTH.

Vote Steve!

--
STC / M0TEY /
http://twitter.com/ukradioamateur