[TowerTalk] Measuring DX Performance of Verticals

Ward Silver hwardsil at centurytel.net
Wed May 7 14:15:07 EDT 2003

> >The bottom line is that trying to make any kind of an A/B comparison over
> >sky-wave path is pretty much an exercise in futility.  [snip]
> One could probably approach this statistically using something like the
> NCDXF beacons.  Log beacon strengths 5 minutes on antenna A, then 5
> on antenna B, etc, for a suitably long test period (>24 hrs).  Yes, you'd
> need to rig up some sort of electrical antenna switch, but that doesn't
> strike me as particularly complex (one bit from a printer port).  A
> like BeaconSEE can log the signals quite nicely, and, once synchronized to
> UT, will separate out the various beacons.
> Another approach is to use more than one receiver simultaneously..
> Something like the Icom PCR1000, while not as wonderful a receiver as you
> might have in your contesting rig, does have a reasonably well calibrated
> signal strength indication, and is completely controllable over an RS232
> The real point is that you don't need sophisticated test gear... what you
> need is sophisticated measurement design.
> Jim, W6RMK

What you describe would take a lot of time and energy to set up and verify
as a test system, thus my remark about sophisticated test gear. The end
result would be very good data...at your location and under the ionospheric
conditions present during the tests.  What, exactly, could sky-wave testing
tell us that the far more controllable range tests can not?  Not much and
certainly not with the degree of repeatability that range testing provides.

Our goal is to create tests that give general results and under conditions
that can be easily reproduced by others - both for validation of our results
and for the general utility of the ham community.  The specific tests that
you describe are certainly of interest, but of limited applicability.  The
individual user must build an in-depth understanding of the local variables
that affect his or her purchasing decisions and then extrapolate from
general information based on experience.

73, Ward N0AX

More information about the TowerTalk mailing list