BLASTS from the Past: The WPX Weird Prefix Ssb Contest - Part 2

As we come up on the 2o25 WPX (Weird Prefix) Ssb contest, looking back, a lot of different flavors
of contest participation.  Here are some things that come to mind:

• [X] - (2o20) - BLASTS from the Past: The WPX Weird Prefix Ssb Contest
• [X] - (2021) - WQ6X Wanders Thru Another Weird Prefix Ssb Contest
• [X] - (2o22) - WQ6X Works another Wonky Weird Prefix (Ssb) Contest
• [X] - (2o23) - WQ6X Works the WEIRDEST Weird Prefix Contest - EVER
• [X] - (2o24) - WQ6X Wrangles another WPX (Weird Prefix) Ssb Contest

In the last couple of years, the emphasis has been on QRP operation and WPX Ssb
operation have been a not-insignificant part of that happening.  Last year brought a 2nd-place
for W6, 3rd-place for North America and #11 worldwide - NoT bad using limited resources.

There are rumors afloat that a KPA-500 amplifier will be added to the lineup at KN6NBT's
Ramona QTH, possibly just in time for WPX Ssb 2o25 - Stay Tuned for the results.

WQ6X leverages an off-contest SPRINT weekend to be station ready for WPX

It is a rare weekend that sports no significant radiosport activity.  Except for the 4-hour Ssb SPRINT GiG, this was one of those weekend.  (Note: While there was the FOC QSO party, because it is not listed on 3830Scores.com, I usually ignore it.)  This March brought us 5-weekends, with the 2025
WPX (Weird Prefix) Ssb contest happening on the 5th weekend.

Considering the SPRINT GiG begins at 00:00z (5pm) and I arrived in Concord after 23:00z (4:20 to be exact), the decision was made to revamp the audio setup Sunday afternoon when nothing significant is going on.  SPRINT-wise, while I wasn't super-motivated to run an Ssb contest (my least favorite contest mode), an even greater challenge is running a SPRINT contest using QRP power.

About 25 minutes into the 4-hour contest, I was finally able to synchronize with the NA SPRINT format.  Thanks to mediumly-annoying geomagnetic noise, 20-meters was spotty during the 1st
hour and 40-meters was late to open, relegating me to survive the struggle on 20-meters, longer
then I would've liked, until it was "safe" to finally move down to 40-meters.

Of course, when 40-meters opens up, the foreign broadcast stations (7.200+) are already there. 
This of course induces stations to operate below 7.210.  Because the Advanced/Extra phone band
is below 7.175, General class operators are at a distinct disadvantage; another reason to pass the Extra class license exam.

What began as a slow grind, quietly picked up at a TRoT pace.  Before I realized it, we were down
to the last hour and 80-meters hadn't yet happened in Ramona.  The online scoreboard listed me
as the only QRP entry.  However, afterwards, there were 3 QRP scores submitted, with WQ6X in
the middle taking 2nd place.

Being an overall off-contest weekend, the 4th weekend offered an opportunity to revamp the power cabling, along with the stereo audio lines.  Since the last revamp (2+ years ago), last minute ad-HOC cable changes have created a jumbled morass of wires behind the scenes.  Considering that there are 9+ filter devices making up the audio structure for WQ6X's [so-called] portable setup @W7AYT's Concord QTH, it's relatively easy to confuse Left/Right channel audio, generating unintended ground loops between the similar yet disparate electronic devices.

There was a day ("back in the day") when the use of computer software during radiosport contests was somewhat frowned upon - some OPs considered it CHEATing.  Fast forward 20 - 40 years and
it is easily said, without using computer software, you have only a minute chance of turning in a high score.  Browsing the Ssb Sprint website, I happened onto a page detailing the different software apps compatible with the SPRINT Contest approach.  

As you can see the list is extensive.  To the left of the list are Space-WX screenshots during this
chaotic SPRINT weekend.  The Space-WX Tracker screens are from a Beta-test version of the upcoming WQ6X Space-WX Tracker.

DiD YOU manage to navigate the March NA Ssb SPRINT Contest?

Are YOU on of my 58 logged contacts?

WQ6X Weidles thru another QRP BARTG HF RTTY Contest

One of the CooL things about the British Amateur Radio Teleprinter Group (BARTG) contest is its 02:00z start (7Pm PDT), instead of the usual 00:00z beginning of most European-based radiosport contests.  Unfortunately, thanks to moving sheets of geomagnetic noise, 10 & 15 meters were already over for the day.  By the time I arrived in Concord (05:35z), 20-meters was barely functional (RTTY-wise).  While 40-meters was more-or-less open, the RTTY participation was sparse, even more-so
on 80-meters.

The decision was to re-evaluate the recently introduced ad-HOC RTY system which uses a RigExpert PLUS CAT-control unit to key the PTT of the onsite Yaesu FT-2000 transceiver which in turn keys the footswitch jack on the rear of the Elecraft K3/0-Mini control head.

Stereo-RTTY audio is intercepted from the 8-Codec drivers installed by the RigExpert installation.  Receive audio is fed thru a pair of analog Autek QF-1A filters enabling the operator to PEAK each RTTY tone separately, which subtlety improves MMTTY's decoding algorithms, reducing the number of repeats on the receive end.

Unfortunately, this was the weekend of frequent/annoying internet dropouts, requiring repeats on even the strongest of signals (Bummer Dewd).  For calling a lengthy CQ (w/o dropouts). the F1-CQ key RTTY tones were recorded into the radio's DVK (voice keyer) #1.  Pressing/holding Key-1 puts the transceiver in repeat mode, which can be interrupted by pressing F1, followed by the [ESC] Key.

Reflecting back on just this last weekend alone, I was amazed at the myriads of things that can create operator disruption, at nearly any moment during a radiosport contest event.  Included in this list are:

• - Internet Dropouts
• - Internet Stuttering
• - Remote radio Blatantly disconnecting
• - Poor internet latency on the remote end.
• - Space-WX storms littered throughout the weekend
• - Swarms of FT-8 stations moving in on the run frequency.
• - N1MM software going into random loops and then recovering
• - Other digital QRM, sounding like R2-D2, a data cranker or cake-mixing sound.
• - Stations who move up slowly on my run frequency, requiring me to move up, ad infinitum.

There were even moments when virtually all of the above situations were occurring simultaneously.

Nevertheless, a reasonable contest effort was obtained.  

One of my MAIN operating goals was to significantly surpass last year's 2nd-Place for North America.  It would seem that goal was not only accomplished, quite early in the weekend.

DiD YOU work the BARTG RTTY Contest?

Is WQ6X in YOUR LoG?

Some Mixed-Bag Comments about mixed-Bag contest weekends

This past weekend (2nd weekend in March) presented us with 7-HF radiosport contest events,
of which I put in op-time for six of them.  Every mode combination from Ssb, Cw and RTTY were represented at some time during the weekend, as our geomagnetosphere (Planet) hurtled thru
the effects of several medium (yet equally annoying) geomagnetic storms. 
([CLICK HERE] for Part 1 of this story.)

Things contributing to the character of this last weekend's 6/7 radiosport weekend include:

• Space-WX Anomalies
• Stereo Ssb and Stereo RTTY
• The current antenna directionality of the 160-meter "Tri-Square" vertical array.

Space-WX Anomalies

Looking at the above Space-WX stats from WQ6X Beacon Tracker demonstrates that while the SFI remained at 147, geomagnetic storms came and went throughout the weekend, making 10-meters nearly worthless on Sunday, with 15-meters not much better.  The REAL upside (if you can call it that) came at 00:00z (Sunday afternoon) when 40-meters opened just enough to the Midwest to work 4 WIQP stations before the QSO Party ended at 00:59:59z.  One of the reasons I chose to run the contest weekend from WA6TQT's QTH was the 40-Meter stacked-yagi array up on the hill in Anza.

Stereo Ssb and Stereo RTTY

Running QSO parties and the SA-10 GiG mixed mode offered the opportunity to explore the Stereo Ssb adjunct to the already ubiquitous Stereo Cw approach.  The different South American dialects
in the SA-10 contest can be difficult to comprehend w/o the ability to adjust the Left and Right ear passband characteristics provided by the pair of analog Autek QF-1A audio filters.

For RTTY operation MMTTY decoding success can be markedly improved by using the QF-1A controls to PEAK the individual RTTY tones (170 Hz apart).  The frequency knob on the QF-1A
filters declares the FREQUENCY for each tone, while selectivity knobs enable separate amplitude adjustment for each RTTY tone individually, accounting for any gain differences between the individual channels.

The current 160-meter "Tri-Square" antenna directionality.

For this season's Stew Perry TBC contest, my only goal was to say I wuz there and attempt to map
out which directions the stations worked actually are versus the 3-direction switch on the so-called
Tri-Square array at WA6TQT's hilltop QTH in Anza.  Allegedly, the phasing cable for S-E has one side disconnected/dangling in free space.  

Notice the near-random distribution of GRID Squares of these 4 QSOs

• ZP9CW (FK09) - with antenna pointed S-E
• W1RCR (EL96) - with antenna pointed West
• KM6FWT (DM04) - with antenna pointed West
• K7GK (CM87) - with antenna pointed West

Evidently, the ends of the Tri-Square are not on a pulley system, otherwise this 3-yr old
problem woulda been fixed long ago.  LooKs like more signal correlation research is in order. 
Just another of the never-ending challenges in radiosport.

DiD YOU work the March 8/9 contest weekend?

Is WQ6X in YOUR LoGs?

WQ6X Operates a MIXED-BaG of Radiosport Contests

This year's 2nd WeeKend in March has turned into a 7-event Extravaganza, except that somehow,
I missed one.  Depending on how I refresh the WA7BNM contest calendar, the Tesla Memorial does
or does not show up on the list - W E I R D fer sure.

There couldn't be a greater disparity of radiosport events than the 2nd contest weekend of March.
The commonality is that all of these GiG were run from Anza using QRP power into the antenna stacks.  Chronologically, the seven events were as follows:

1. [X] (12:00z) - The Argentinian SA-10 mixed-mode 10-Meter Contest
2. [X] (14:00z) - The Oklahoma QSO Party - OKQP
3. [X] (12:00z) - Stew Perry 160-Meter Contest
4. [X] (12:00z) - Tesla Memorial Cw Contest
5. [X] (14:00z) - The Idaho QSO Party - IDQP
6. [X] (00:00z) - The NA SPRINT RTTY
7. [X] (18:00z) - The Sunday Wisconsin QSO Party - WIQP

The Argentinian SA-10 10-Meter Contest

While the Solar Flux Index (SFI) dropped to its lowest point in weeks, Solar Cycle 25 is still
well under way.  Unfortunately, this weekend was littered with Space-WX storms, just enough to shutdown 10-meters earlier than it did just the weekend before during the ARRL DX Ssb contest.

The Oklahoma QSO Party - OKQP

The Oklahoma QSO Party turned out to be a mixed experience.  Due to poor band conditions,
no OKQP stations were copied or spotted in the band map on Saturday.  Beginning Sunday morning signals were finally heard.  Unfortunately, this QSO party ended at 22:00z - too early for a second chance at 40-meters to make up for nothing on Saturday.  Were it not for several rover stations,
the OKQP GiG would have been a complete DuD.

 Stew Perry 160-Meter Contest

This was one of the WORST SP-160 contests I've ever run.  Between lousy Space-WX conditions,
a crippled Tri-Square array and running QRP, I was lucky to contact stations outside of California. 
The big surprise was being heard by ZF9CW.  Unfortunately, PJ2T (Curacao) was just outside of
signal range.  Bottom line is at least I could say "I WuZ THERE!".

The Idaho QSO Party - IDQP

This year's Idaho QSO Party shoulda been call the IDA-Hose QSO Party as it was a complete DuD.
Like the OKQP, nothing materialized on Saturday leaving only Sunday morning to make ID QSOs.

The NA SPRINT RTTY

SPRINT contests are always a challenge; RTTY SPRINT contests are even more so.
Some software glitches found me starting 40-minutes late.  When it was all over, a whopping
73 QSOs made it into the LoG.

The Wisconsin QSO Party - WIQP

The WIQP is a unique state QSO party in that it begins at 18:00z on Sunday.
Like the other QSO parties for this weekend, 10-meters was a no-show.  In its place,
the last hour of operation found WQ6X scouting 40-meters, pointing the 40-meter stacked
Yagi's to 70-degrees, while praying for enough greyline activity to slip 4 QSOs into the WIQP Log.

As mentioned earlier, horrible Space-WX littered the entire contest weekend.
I will have more to say about that in Part 2 of this Blog post.

Perusing the Online Scoreboard results for this weekend produced some surprising results.

1. WQ6X took 1st-Place in the QRP category for IDQP, OKQP and SPRINT RTTY
2. WQ6X took 2nd-place for SA-10, SP-160 and WIQP

This was all possible thanks to a comprehensive system of organization behind the scenes.

DiD YOU work any of the above six radiosport GiGs?

Is WQ6X in YOUR Log?

([CLICK HERE] for Part 2 of this story.)

BLAST from the Past: CQ W.W. RTTY Contest - Part 2

Seeing as how it has been 4 1/2 years since I wrote a Blast from the past Blog about the CQ W.W. RTTY, it makes sense to write up a Part 2 from 2020 to 2024.  ([CLICK HERE] to read Part 1.)

For Part 2 we have a look back to the following 5 Blog entries about this contest.

1. [X] 2020 - WQ6X Runs a Raucous but Riske' CQ W.W. RTTY Contest
2. [X] 2021 - WQ6X Works a WEIRD W.W. RTTY Contest
3. [X] 2022 - WQ6X Wanders thru a Wicked World-wide RTTY Contest
4. [X] 2023 - WQ6X Survives another CQ Weird Wide DX RTTY Contest
5. [X] 2024 - WQ6X wRangles a Remote QRP CQ W.W. RTTY Contest

1. WQ6X Runs a Raucous but Riske' CQ W.W. RTTY Contest
   
   
   While Solar Cycle 25 was in its initial throes of waking up from a lengthy Solar-Snooze,
   there were a number of surprisingly AWEsome band openings.  While WQ6X made an impressive 1250+ contacts, the multiplier count was a fraction of the number made by
   my competitors, hence, the 4th place standing.
   
   
2.  WQ6X Works a WEIRD W.W. RTTY Contest
   
   
   This RTTY contest suffered from a low SFI (80) reducing the openings (especially to EU) available.  In the end it became a RTTY training exercise.  I summed up the weekend by saying "Because this was my 1st CQ WW RTTY GiG from the Concord location in quite awhile, we could easily say Miss Addams, that this was indeed another weekend of learning.
   
   
   
3. WQ6X Wanders thru a Wicked World-wide RTTY Contest
   
   
   What a difference a YEAR makes.  The Solar Flux (SFI) has jumped to 145 (from last
   year's 80).  Also different is the addition of a Yaesu FT-2000 to the Concord equipment lineup.  Like the FT-1000mp, the FT-2000 runs 100-watt FULL-Duty RTTY, without the chassis feeling even a bit warm to the touch.  Unfortunately, the weekend was littered with BLUE Screens - it never happened before - never occurred after that weekend.  (WEIRD!)
   
   
   
4. WQ6X Survives another CQ Weird Wide DX RTTY Contest
   
   
   For the second year in a row, the Solar FLUX was certainly a PLUS for this worldwide contest weekend.  As a result, when it was all over, the decision was made to submit the log as SO(A) SB-10 LP - a low power, single band entry.  According to the 3830 Scores, WQ6X took a 2nd-place overall and 1st-place for USA/NA - who woulda thunk it?
   
   
   
5. WQ6X wRangles a Remote QRP CQ W.W. RTTY Contest

This contest operation was loaded with operator nonsense and a wild JUMP of the SFI from 172 (with solar storms) to 275 (nice and quiet).  When it was all over it would seem that WQ6X took 3rd-place worldwide and 1st-place for USA/NA - again, who woulda thunk it?

According to predictions by the "Experts", Solar Cycle 25 has finally PEAKED and is on its way down.  With 6 months to go before the next CQ W.W. RTTY GiG, in my opinion, virtually ANYTHING is possible.

Have YOU worked the CQ W.W. RTTY contest?

Is WQ6X in YOUR LoG?

WQ6X Blasts from the Past: a LooK back at a Look Back - Part 2

Posting Blast from the Past Blogs from time to time makes it easier to look back years later recollecting about past experiences with upcoming radiosport event.  In Sept. of 2019, for the helluvit, I published a compendium of all the Blast From the Past Blogs up to that point.  ([CLICK HERE]
to read that.)  Over a period of 7 years, only 8 B-F-P Blog entries were written.

As a research project, it was determined that since 2019 19 B-F-P Blogs have been posted
on all manner of differing topics. Check out this list:

• [X] Blast from the Past: California QSO Party (CQP)
• [X] WQ6X Blast from the Past: ARRL Dx Phone Contest
• [X] WQ6X Blast from the Past: ARRL Dx Phone Contest => Part 2
• [X] WQ6X Blast from the Past: CQ WPX RTTY
• [X] WQ6X Blast from the Past: CQ WPX RTTY - Part 2
• [X] BLASTS from the Past: The WPX Weird Prefix Cw Contest
• [X] BLASTS from the Past: The WPX Weird Prefix Ssb Contest
• [X] BLAST from the Past: External Audio Filters I have Known
• [X] BLAST from the Past: Memories of Marconi Memorial
• [X] BLAST from the Past: NAQP Ssb Contest
• [X] BLAST from the Past: CQ W.W. RTTY Contest
• [X] BLAST from the Past: CQ W.W. RTTY Contest - Part 2
• [X] BLAST from the PAST: QRP Reconsidered
• [X] A WQ6X as W6J Retrospective
• [X] Blasts from the PAST: Worked All Europe (WAE) Cw contest
• [X] Blasts from the PAST: End of August Contests
• [X] BLASTs From the Past: Cinco de Contest
• [X] BLASTS from the PAST: Stereo CW and it's many Variants.
• [X] Blast from the Past: California QSO Party (CQP) - Part 2
• [X] BLAST from the PAST: 2024 Radiosport in Review

wOw!  Whatta buncha STUFF?!!

1. Blast from the Past: California QSO Party (CQP) - Parts 1 and 2
   
   
   Next to the ARRL November Sweepstakes (SS) GiGs, the California QSO Party (CQP)
   is my favorite domestic radiosport event.  Since 2000 I have NoT missed somehow participating during the 1st weekend of October event.  For county hunters, it is realistic
   and feasible that you can work all 58 California counties in ONE (count 'em "1") WeeKEnd;
   one state done with 49 to go towards your USA-CA (Worked All U.S. Counties) Award.
   CQP is so much one of my favorite events that 2 Blast from the Past Blogs have been
   written about this event.  Before long, it will be time for Part 3.
   
   
   
2. BLASTS from the Past: The WPX Weird Prefix Cw & Ssb Contests
   
   
   What I specifically LIKE about the CQ WPX (Weird Prefix) contest, is THAT - WEIRD Prefixes.  Of course, my "WQ6" callsign certainly qualifies as a WEIRD prefix.  Additionally, it is certainly No accident that I define the N1MM FK-12 Key to send out some form of "W-E-I-R-D" message when people do WEIRD things.
   
   
   
3. WQ6X Blast from the Past: CQ WPX RTTY - Parts 1 and 2
   
   
   The WPX RTTY Contest is one of my overall favorite events - I don't have to copy
   Morse code, nor do I have to strain my voice.  I can often experience the RTTY tones
   as synchronistically soothing.
   
   
   
4. WQ6X Blast from the Past: ARRL Dx Phone Contest - Parts 1 and 2
   
   
   Overall, for me, the ARRL DX Phone contest is usually, overall, a ho-Hummer.
   Then again, coming to each iteration of this event found me exploring new ideas to
   alleviate what I call Ssb-Boredumb.  It is from this, the Stereo-SSB concept was perfected. 
   40-plus year-old technology (the Autek QF-1A) still outperforms most DSP technology built-in
   to today's transceivers.  The proof of perfection came with setting a Southwest Division record
   in 2024.
   
   
5. BLAST from the Past: External Audio Filters I have Known
   
   
   Long before I began seriously working on the Stereo-CW concept, I added a number
   of different analog and DSP filters to the audio lines, experimenting with the different combinations that eventually became the Stereo Audio concept.
   
   
6. BLAST from the Past: Memories of Marconi Memorial
   
   
   Every year, the Marconi Memorial radiosport offers outstanding opportunities and every
   year, it becomes a Ho-Hummer.  Nevertheless, I find time in between the other GiGs that weekend to play around and submit a log.  At the very least, it adds another entry to the number of contests submitted to 3830Scores.com.
   
   
   
7. BLAST from the Past: NAQP Ssb Contest
   
   
   The North American QSO Party (NAQP) makes for a GREAT introduction to domestic
   radiosport contesting.  With the exchange of NAME and STATE, it is EASY and FUN. 
   Back in the day, I used to join the multi-OP crew live in Fallbrook.  In recent years the
   current crew has been running REMOTE from ANZA.
   
   
   
8. BLAST from the Past: CQ W.W. RTTY Contest
   
   
   My first introduction to serious RTTY came from the encouragement provided by N6GEO.
   It wasn't long before I found my groove and we began making high scores in RTTY contests, highlighted by our appearance on St. Croix for the Jan-2014 RTTY-RU contest, operating as WP2/WQ6X.  Around our 1st-Place (worldwide) win, I spent time running pileups from 80 to 10 meters (Ssb and Cw), including the WARC bands.  From an amateur radio standpoint, it was
   a complete success.
   
   
   
9. BLAST from the Past: CQ W.W. RTTY Contest - Part 2
   
   
   In recent years, running RTTY has largely been a remote running affair.
   Then again, because the FT-1000mp and FT-2000 can run FULL-Duty RTTY,
   running RTTY live is still a viable approach.  Even more recently is running the above transceivers by way of the RigExpert unit to accomplish PTT keying for running the K3/0
   and K3/0-Minit control units to make RTTY transmissions remotely, even though the tones
   are generated locally.
   
   
   
10. BLAST from the PAST: QRP Reconsidered
    
    
    Beginning in 2023, WQ6X found it more imaginative and exciting to run as many events using QRP as can be successfully accomplished.  Running remote from Ramona and Anza makes it possible to leverage hilltop QTH's as well as the antenna configurations that go with them.
    
    
    
11. A WQ6X as W6J Retrospective
    
    
    
    Over the years, I have registered the W6J callsign, mainly for running variations on
    the Japanese JIDX DX contest, while also joining NX6T in one of our 1st-place finishes. 
    Last year the rules for JIDX were changed, no longer allowing me to do both.  Now, I
    either join NX6T or else run as a Single-OP station.  The JIDX Ssb contest in November
    runs concurrent with the WAE RTTY contest, to enable running BOTH during the same weekend.
    
    
    
12. Blasts from the PAST: Worked All Europe (WAE) Cw contest
    
    
    Due to the sending of QTC messages, the Worked All Europe is the most complex of all radiosport contests - even more than the November Sweepstakes.  Thanks to the Ctrl-Z
    capability built into the N1MM software, sending QTC messages is about as easy as it
    will ever get.
    
    
    
13. Blasts from the PAST: End of August Contests
    
    
    The last weekend in August presents us with a number of disparate events.  In some cases,
    I ran the same event as WQ6X (from EB section) and NX6T (in the SDG section).  In all cases,
    the goal was to up the number of 3830 Score events submitted.
    
    
    
14. BLASTs From the Past: Cinco de Contest
    
    
    The 1st weekend in May I call Cinco De Contest, running for State QSO Parties and the Italian ARI contest.  I have won two 1st-place plaques in the 7QP event, one for LP and more recently one for QRP.
    
    
    
15. BLASTS from the PAST: Stereo CW and it's many Variants.
    
    
    While I have written about Stereo-Cw and its variants, I finally got around to writing a BLAST Blog about my audio filter discoveries since the original Blogs, which now include Stereo-Ssb and Stereo-RTTY.  Despite the fact I am a Californian, it is no secret that CQP is the most populous state QSO Party of them all.  Running for 30 continuous hour
    
    
    
16. BLAST from the PAST: 2024 Radiosport in Review
    
    
    Ending 2024, I did something new by briefly reviewing the contest activity for the entire year, beginning with the RTTY-RU in January, followed by the NAQP GiGs during the 2nd and 3rd weekends.  The above graphic demonstrates contest activity from 2020 - 2024.
    
    

WQ6X Weasels another QRP ARRL DX Ssb Contest

In preparation for this weekend's ARRL DX Phone contest, I have been working on Blast from the Past Blogs regarding the ARRL DX Contest GiGs, truly bringing back operating memories from the last dozen years.

This weekend's goals included reprising last year's Southwest Division win running QRP (of course).  These daze, unless given a specific reason to do otherwise, most of my contest activity (outside of the EB session) is run at the QRP power level.  The major exception is RTTY contests that don't have a QRP power entry - I dial back the power to 50-watts and run it remotely.  (When running RTTY from W7AYT's QTH, the Yaesu FT-2000 and FT-1000mp transceivers can run FULL Duty AFSK w/o getting warm.)

For WQ6X it's: Filters, Filters and MORE Filters - Part 2

When I looked at the publication data of Part 1 (Sept. 08, 2023), the most noticeable thing in the
lead photo is how much the same external filter configuration units have found new locations on
the operating table, and in some cases are positioned differently in the WQ6X Stereo Audio lines.

Then again, some units found an immediate home in the audio line 5+ years ago and have remained 
in that position - case in point being the Radio Shaft stereo equalizer.  Because we only need to hear
a "small" frequency range (~600hz to ~3000hz), the equalizer deemphasizes all frequencies outside of that range, BEFORE sending the resultant audio to the splitter for redirection to the various filter
audio lines.

One of the secrets to all of the above filter combinations are the Input mixer and the Output mixer units.  The 4-channel input mixer receives its power via a basic USB connection (for the power only). The Rockville output mixer blends the different types of filter outputs into a common stereo output
for the stereo amplifier block, receiving its power from a common SAMLEX 20a power supply. 
An A-B-C-D switch directs the output to wireless headphones, or one of 3 different speaker sets,
most importantly a pair of LEKATO JA-o2 mini guitar amp speakers (8).

The other units play different roles in the assistance of recovering sound intelligibility, altho individual units can occasionally contribute artifact to the output, at which time the mixer output for that device can be reduced.  A description of these individual units makes for better understanding of the system as a whole:

1. It ALL begins feed the output of the input mixer to a classic Radio Shaft 15-channel stereo equalizer (Model 32-2059).  While virtually any equalizer device can be utilized, I like the
   RS 2059 unit because it can either be rack mounted or used as a place to put other units,
   as in this configuration with the individual QF-1A filter and LEKATO speaker combinations.
   The Audio Passband for amateur radio is ideally set from ~400hz to more-or-less ~1600hz. 
   Setting the equalizer sliders to accomplish this also offers an immediate visual indication
   of the initial passband.
   
   
2. The original Stereo Cw article implemented a pair of fixed bandpass filters (800hz and 1200hz)
   to create the "stereo" effect.  Experimenting with different filters over the years, the vintage
   Autek QF-1A analog OP-amp filters allow using ANY pair of frequencies for the stereo effect.  Should fatigue set in from a particular setting, the individual settings can be altered to create
   a similar but different effect.  This is even more useful for peaking the individual tones during RTTY operation.
   
   
3. My first real exposure to external audio filters came by way of a pair of MFJ 752 filter units purchased at different times - a "C" model and a "B" model now setup for the Left and Right channels respectively.  The "B" model was modified to include a 2 setting (180hz and 80hz) repurposed MFJ Cw filter, which makes up for the the Sub receiver's lack of Cw filters in the FT-1000mp and FT-2000 Yaesu transceivers.  Currently, the MFJ filters with wider bandwidths have more application during Ssb contests.
   
   
4. At different times, I acquired a JPS NIR-12, and later a JPS NIR-10 external DSP filters.
   Currently, these filters run in cascade mode on the Right channel of the audio, providing DSP
   filtering for the Sub-receiver of the Yaesu transceivers which lack DSP for those receive lines.  The downside of these filters is that that their processing speed actually introduces about 120
   ms of audio delay, creating a sort-of echo when using stereo reception.  This was resolved by adding an external audio-delay device to the left channel, allowing the two outputs to properly synchronize.
   
   
5. I picked up an MFJ-784 "programmable" DSP unit at one point which currently processes the left audio line Channel 3 of the output mixer.  The MFJ-784 contains a crude form of DNR and several flavors of notch filtering.  For the most part, it simply gives me more knobs to twiddle.
   
   
6. All of the filter and DSP devices eventually send their audio to the appropriate channel
   of a classic Rockville 8-channel mixer, allowing a blend of the various filter effects, which
   can easily be turned to 0 should they not contribute to audio intelligibility.  This mixer has no built-in output amplification, requiring some sort of output amplification in order to properly drive the speakers, or even the wireless headphones.
   
   
7. Over the years, experimentation has been done with different forms of audio amplification
   for this multi-filter arrangement.  Some approaches have ended up in overloading feedback,
   while others have required a jumble of wires to make it all work.  The current solution is a $23 10-watt per-channel amplifier purchased on e-Bay.  The challenge with this setup is keeping hum-creating ground loops out of the final result.
   
   
8. While it is possible to switch in one of three speaker arrangements, the current favorite is a pair of LEKATO mini guitar amp speakers.  A pair is used by shorting both speaker channels
   of each unit and feeding them with the left/right amplifier channels.  Like the input mixer,
   these speakers are powered by way of a USB hub, providing the required 5V needed
   to produce adequate audio.

While this current audio filter arrangement seems to synchronize symphonically, it has come
to fruition over 15 years of cut-and-try of the various filter units, eventually landing themselves into
this reasonably practical arrangement.  Then again, at any time, I reserve the right to rip the cables out and restring the audio into a completely different configuration.  The above scribble sheet crudely documents how it currently flows.

Do YOU use any form of external audio filtering?

What unique ideas have YOU created?