[TowerTalk] Mosley Antenna Question

[Jim Lux]

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.