On 2/20/15 7:28 AM, Ed Sawyer wrote:
It seems to me quite clear as to what Mosley's strategy is. "Make my HF amp
happy and let me crack most pileups in a reasonable amount of time and I am
a happy DXer". That means the lowest SWR at the output of the amp for the 3
bands - period (think dummy load). All of their trap design materials are
design to be lossy and inexpensive and to balance with the lack of matching
network at the feedpoint (again inexpensive). The gain claims are legendary
and ridiculous to the point of the strategy being that if someone really
knows the theory - they will know this isn't real as a free space gain and
waive it off anyway. But a good portion of the market won't know any
better, like the match, and as long as they get through to the DX will be
happy.
It might also be that the perceived advantages are not so much in
forward gain, but in the "shape" of the pattern in terms of side/back
lobes.
When trying to make marginal contacts, or be louder than everyone else
in a pileup, a few dB might be useful. Operating technique might
actually be a bigger effect. Timing (when to make the call, either
during the pileup, or with respect to propagation path availability) has
a huge effect.
Suppressing undesired signals might also be very useful. An antenna
with good directivity and poor gain (e.g. lossy) might work really well,
especially if you're in an area where that would help.
Imagine a couple scenarios:
1) You're the only ham for 1000 miles and there's no thunderstorm
activity anywhere near you, etc.
2) You've got a lot of other hams around, and there's thunderstorms
everywhere, particularly in the direction opposite your desired DX.
The ability to suppress the extra signals in scenario 2 might be more
useful than a few dB of absolute radiated signal strength.
Lots of people claim that 0.5 dB makes a difference when you're close to
the noise floor, and I believe it, and that's where skill and experience
helps. BUT.. to make the QSO, you need BOTH ends of the link to work.
Are you presuming that the ham on the other end is also working against
a 0dB SNR and is very skilled, so that boosting your Tx power (and their
received signal) by 0.5 dB makes a difference? Are they optimizing the
passband of their IF, listening to SSB through a 1kHz wide signal to
double the SNR over a 2kHz filter.
Or, are they receiving you with 10-15 dB SNR with a wide open receiver,
because they're out in a RF quiet area, and 2 or 3 dB signal strength
one way or the other makes almost no difference.
Hams focus a lot on gain and VSWR claims.. They're single numbers, so
it's easy to rank performance. They're also not necessarily indicative
of actual operating performance.
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