[1000mp] Updated (3rd Time) QST Mark-V Field Numbers ...

[Billy Cox]

Just downloaded the latest QST review, looks like they went back
again and found a couple more errors to correct.

So ... again ... KUDOs to the ARRL Lab for striving to correct the data !

The first new correction I see is a "nit" ....

Blocking Dynamic Range 5 kHz spacing

Was     3.5 MHz  Preamp off/on
                                         106/107 dB
Now     3.5 MHz  Preamp off/on
                                         106/108 dB

The second correction ... well it's more of a concern. As when I looked
at the 2nd set of numbers, something did not seem right for when you
normally ADD a preamp, the 3rd order intercept numbers go DOWN ...

Third-Order Intercept

Was    3.5 MHz  Preamp  off/on
                                         -6.1/+2.0 dBm  <this number was ??

Now    3.5 MHz  Preamp off/on
                                         -6.1/-16.1 dBm < this number now OK

Why ? Most preamps are "roughly 10 dB" ... if you look at the other
numbers in the chart, there's roughly the 10 dB difference also ...

That lowers the new Mark-V Field down to about the same level of
receiver performance as the Icom 756Pro-II it might seem ...

For 3rd order numbers, normally higher (as in more positive) is
considered to be better ... as in +2.0 dBm is better than -16.1 dBm

Now ... while we may agree to disagree as to the 20 kHz verses the
5 kHz spacing ... the 5 kHz gives one a better idea of say in the middle
of 40m SSB in Europe, or 40m CW in the USA SS test. The better the
design (due to roofing filters, or <you fill in the blanks here>) the better
the 5 kHz numbers may be, and the better ultimate receiver performance.

As to will an average user notice the difference ... that's an individual
response that goes like "just depends". Some will, many won't. Key is
for the design to allow such performance benefits to actually be utilized.

Interesting ... as to how far receivers have come since my first National
NC-183 and old surplus BC-342 as a SWL ... simply amazing !

73 Billy AA4NU