"note that 20dB of feedline loss on 40m probably does not
degrade the receive signal to noise ratio because even when external
noise is decreased by 20dB, it still swamps the receivers internal
noise, and signal to noise ratio is dominated by the (external) signal
and external noise (both attenuated). "
Yeah. This is the counter-argument to "if you can hear 'em you can
work 'em"
Mismatched line loss needs to be covered on the entry level tests.
Heck, I think they should give it two questions. It's a major issue in
setting up your first station because all the tuners have two or three
SO-239 jacks and one "random wire/balanced line" output. Same with the
radio, tuner inside, coax connection outside. Who knows better than
the engineers that built the stuff, you know?
Well, I don't know if I've converted anyone yet but I often point
people to this page:
http://www.n3ox.net/projects/servo
It's the electromechanical equivalent of having long arms, and it's
ALMOST cheap.. I hope to inspire a few folks who've dropped a bunch of
money on a nice tuner before they discovered the tuner-at-the-feedpoint
advantage, though there are a couple of snags to work out before it's a
tuner add-on that anyone can build. I need to figure out something
better than 10 turn pots because they're hard to get and kind of
pricey, and MFJ, who seems to sell all of the budget tuners, has
stopped selling switched-inductor high power tuners. You can still get
them in the "300W" class, but no more of the "1500W" ones.
I'm not even using the remote tuner at the moment. I've rolled my own
fixed L networks for matching my 20m delta loop on 20 and 17 and my 40
foot vertical on 80,60,40, and 30. The remote tuner served me well for
the apartment doublet but I like the faster bandswitching with the
switched networks. I thought about making fixed, switched networks for
the wire I had up at the apartment, but it was 30 gauge wire and broke
too often, and I couldn't really control the exact length of wire I was
putting up every time, so the tuner really was a better solution. I do
a lot of band hopping while I'm on the air (DXing, mostly) so retuning
all the time was something I wanted to avoid in the new installation.
Dan