Friday, May 3, 2019

WHY I Do Radiosport - PT. 3 - Learning Technology Improvement

Many people (radio amateurs & "civilians") often ask why I spend so much time engaging in radiosport.  This series of posts in the WQ6X Contest BLOG is an attempt to answer that question.
Click [HERE] for Part 1 and [HERE] for Part 2.

The 3rd installment in this series is about taking the understanding of our equipment and antennas
to the next level.  Over the years, the main transceiver in my operation(s) have grown in ability from
a Kenwood TS-50 & loaded TS-450s to an ICOM 7000 & Yaesu FT-900 and then to a Yaesu FT-920, eventually "trading up" to the current Yaesu FT-1000mp (with the IC-7000 as backup radio).

Despite the radio upgrades,  WQ6X operations have kept the same audio filters; either an MFJ-752 + JPS  NIR-12 combo (in past years) to the more recent Autek QF1-A and JPS NIR-12 combinations. 

It might surprise you that I go to the trouble of adding external filtering to radios (like the FT-1000mp & ICOM-7000) that already have their own DSP filtering.  In truth, no DSP or interference filtering is a panacea. 

It has been said that we don't get something for nothing. Example: many noise blanking circuits either add their own distortion (at high[er] signal levels) or make the receiver more susceptible to "AGC-pumping" in the vicinity of STRONG signals.

When the Collins 75-A4 was introduced, the noise blanking circuitry sampled the noise-blanking signal OUTSIDE the amateur bands (usually BELOW the Cw band segments); doing it this way reduces the likelihood of strong signals keying the noise blanker.

In recent months, I have added an Elecraft K3/0 to lineup allowing more effective remote of the facilities @ NX6T.  While K3 radios (in Fallbrook) have built-in IF-based DSP, no DSP is perfect.  Sometimes the K3's NB and/or DNR circuits seem to have no effect.  Other times - WoW - the
effect is DRAMATIC.  Nevertheless, the K3/0 audio is fed into one or more QF-1A filters.

Whether or not I make even a single QSO in a radiosport event, the GiGs offer the opportunity to learn the intricacies of the equipment configurations.  Listening to signals under QRM-ridden or QRM-free conditions allows experimenting with the built-in DSP and external audio-filter combinations.

In particular, the Autek QF-1A filter
can produce subtle (yet powerful) audio peaking; rivaling if not exceeding the APF knobs found on radios like the Kenwood TS-930 / TS-940.

I am always amazed how well the
QF-1A can boost a signal right out of
the noise or above other signals inside
the audio passband.

While the FT-1000mp possesses an audio-based "contour" control and DNF (Digital Notch Filter), those features work ONLY with the Main-RX, not the Sub-RX.  Inserting the QF-1A / NIR-12 pair in the sub-audio line offers up DNR & DNF functionally equivalent to those features present with the Main-RX.  Learning to leverage the entirety of these controls is what radiosport is all about.
And then, it's practice, practice, practice.

When I discovered the world of "Stereo Cw", these filter combinations took on new possibilities.  (CLICK [HERE] & [HERE] to read about that.  With an understanding of stereo-Cw, "playing around" with the various filter combinations & settings has transformed my radiosport operating enjoyment, and as a result, made a considerable improvement in scores WQ6X submits to the contest committees.

Put simply - a MAJOR reason I do radiosport, is because, for me, it's just FUN.

What about YOU?
Why do YOU do radiosport?

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