Tuesday, February 23, 2021

WQ6X Wings 1st Dual-Remote ARRL DX Cw GiG from Alameda

Business commitments kept me in Alameda over the weekend, giving me an opportunity to join
up with NX6T from our Anza Super Station, while in between getting to put WQ6X on the air remotely
from Nashville; all controlled by the recently debugged Elecraft K3/0 Mini radio (plus the RRC-1258 interface box).  I opened the DX contest from Anza, eventually moving on to remoting into Nashville
in between Anza OP shifts.

Unlike remotely-run RTTY GiGs, the weekend being a simple CW contest allowed me to run the Elecraft audio out through the Stereo-CW system setup at the Alameda location; a near-exact recreation of the basic Stereo-CW setup in use at W7AYT's QTH in Concord.  One difference
added to the Alameda operation is the idea of using an old MFJ-751 Signal Enhancer in-between
the Left/Right Autek QF-1A units; in effect, a crude recreation of the "Center-channel" concept
known to stereo audio buffs.  Tuning the FREQUENCY control on the 751-unit in effect shifts
the balance between left/right, further pronouncing the stereo effect.

In between my long operating shifts @ NX6T (9:00Z -14:300z & 00:00z - 04:00z) I found time to activate WQ6X from the Fallbrook location that was not being used this weekend (NX6T operated
from WA6TQT's QTH).  Throughout the weekend, Dennis (N6KI) elmer'ed me on the fine art of working the hidden camera system in Fallbrook, all so I can see the colored louvers disappear, indicating the A/C has been successfully turned on in the amplifier den of the wiring morass in Fallbrook.  As weird as it looks, we win contests with it. 

Thanks to ROTTEN QRN (Low-SFI, High K-Index) I had to dance around the noise. The secret to making it all work on the high bands was to point the 3-el Stepp-IR to SA, open it up BI-directionally to include Asia and then just Call CQ. Occasionally KH6 or VK/ZL would creep in adding to the fun. 

Sunday morning, noticing that all 3 Russian Beacons were alive on ~7.039, pointing the antenna towards Asia, I put out a CQ on 7018.18, keeping things alive for the next 2.5 hours.  As it turns
out, this time period produced the highest run-rate EVER for WQ6X in the ARRL DX Cw contest.

Knowing that 40 was wide-open to Asia, when I took over the 09:00z shift at NX6T, after S&P'ing
on 80 & 160, I settled in on 7017.17 and more-or-less repeated the exercise from the Anza station, with even more/bigger signals.  When N6CY relieved me at 13:00z, he kept the pile-up going for nearly another hour.  

For me, the amazing surprise was the Northern Europeans and Ukraine who managed to creep thru from time to time, even tho the 40-m antenna stack was pointed directly at Asia.  I want to thank the pileups for standing by and letting their S-3 signals flutter across the pole into the Fallbrook location; quite south, when you think about it.

While I love the simplicity of the ARRL exchanges, I get frustrated by the clueless stations who BARREL THRU with their callsign. I send a proper exchange and he sends his callsign TWICE;
then, Nothing!   HuH?   It took 3 exchanges to make ONE 3-point QSO. This happened repeatedly. Remember: if you don't know the rules - READ 'EM. If you DO know the rules then: PAY ATTENTION!

Because we encountered horrible Space-WX during the contest, I was continuously AMAZED by
the number 0f 5-Watt Asian stations who made it into the WQ6X & NX6T logs; not just on 20 & 15, but on 40 & 80 as well.  On the low bands, many times the QRP stations were as loud (or louder) than the KW stations; you can be sure they were NoT running wimpy-dipoles only 5mh.


 

 

 

 

 

 

When it was all over, there were a BUNCH of STATs to sort out. 
The continental breakdown for NX6T was NoT surprising.  It may well be
that antennas had something to do with it.  Available at our disposal included:

  • a 160-Meter TRI-Square
  • an 80-Meter FOUR-Square
  • a 40-Meter Stacked Array
  • 20/15/10 Stacked arrays and Stepp-IR's

 

 

 

 

 

 

 Running as WQ6X from the Fallbrook location I had available to me:

  • a pair of Coaxial Inverted VEE's for 80/160 - 13 mh
  • a 2-el Shorty-40 for 40 Meters - 13 mh.
  • a 3-el Stepp-IR for the high-bands - 13mh.

The difference in receiving antennas on 40-meters between NX6T and WQ6X was noticeably different.  While a DOZEN 5-watt JA's stations made it into NX6T's 40-meter log, only FOUR QRP-stations were heard in Fallbrook (2-elements in Fallbrook versus a 40-meter STACK in Anza)..

While our scores were WILDLY divergent, I had a LoT of fun putting the Elecraft K3/0-Mini thru
all of it's paces into Anza and Fallbrook.  Altho there was an occasional 1.5-minute internet outage
(in Fallbrook) and the pulsing internet-breakups were frequent, overall it was a successful operation from Alameda.  The K3/0-Mini FINALLY redeemed itself.

DiD YOU participate in the ARRL DX Cw contest?

Is WQ6X or NX6T in YOUR LoG?


Tuesday, February 16, 2021

WQ6X Wanders thru another WEIRD CQ Weird Prefix Contest

There's no doubt about it, Weird Prefix contests seem to get weirder every year.  Last year there was no lock-down to deal with; this year I was hoping for an increased turnout because of it; we won't of course know until the results are published.

There's a REASON it's called a WEIRD prefix contest, LoTsa weird things happen as well as the Weird callsigns. Nevertheless, working around shack heat problems in Fallbrook (as I ran ~1350 watts much of the time), on Sunday I dialed it back to a mere KW - Oh the sacrifices we make.

For this weekend, a recent change in Ethernet connections all but eliminated dropouts on the W7AYT end of the remote connection. If I disappeared on you it was due to the occasional 1.5-minute internet dropout that sometimes occurs in Fallbrook.  

Saturday AND Sunday I put out CQ calls several times on 10-meters and had no takers; altho somehow I had
a feeling the band was open. With the recent SFI = 71, it ain't no easy thing, but I gopherit anyway. The RBN showed no 10-meter spots; then again it showed no activity on 80-m altho I was running frequencies more-or-less all evening. 

You'll notice I send "5NN" instead of
599 in a contest requiring a serial # afterwards. It's easy to confuse 599
with the serial # as happened when I received: WQ6X TU UR 599 599 599.
HuH? 

 

Overall it was an enjoyable RTTY GiG. I enjoyed all the extra RTTY activity from 14.101 to 14.145
and 21.100 - 21.40. The room is there - use it and enjoy relatively QRM-free contesting.  The biggest problem was the demodulator software (MMTTY) being able to decode signals during periods
of low Signal-to-JUNK ratio.

In years past WQ6X has been the ONLY WQ6 call in RTTY contests.  This year, I was joined by WQ6K, which was probably a bit confusing.  Then again, VE3KTB didn't hesitate to work WQ6K
first followed immediately by WQ6X on 20-meters.

Last weekend in the XE-RTTY contest, the 14.100 beacon corridor was completely QUIET.
This weekend in the WPX GiG I was APPALLED at how it was JAMMED with signals
OBLITERATING the beacon copy - no WONDER non-contesters HATE us.

Beacon-wise, listening around 7.039 during Saturday/Sunday mornings found the "F" and "M" beacons beeping away, and again, the "K" beacon is on the AWOL list.  This is giving me more "data" to complete my next installment on the Russian military propagation beacons - Stay Tuned.

LooKing back to last year's Single-OP event, it would seem that 2020 produced a much bigger score; but then, as I recall, I put more hours in the chair during that event.  While WQ6X hardly set any records for 2021, the time spent was a LoT of fun and gave me the opportunity to test-drive the
"new" remote access facility.

DiD YOU work the CQ WPX RTTY Contest?

Is WQ6X in YOUR LoG?


Sunday, February 7, 2021

WQ6X Wings another Wild Multi-contest Weekend

This last week was actually quite a busy one, between seeing clients and learning to program
C# for Unity in order that I take my design skills to the 2-D and (eventually) 3-D level.  As such,
it seemed too complicated to make my way to Concord, so instead, I managed to run the weekend's assortment of radios[port contests from Fallbrook's STN-1 remotely from Alameda by way of RCForb (to run the K3 Xcvr) and VNC Viewer (a VPN allowing me complete control of the station computer).  

This weekend, we shared airspace with an FOC GiG (wherein they talk to each other and ignore us non-FOC operators).  There were five events that I focused on this weekend, listed in calendar order:

  • [x] - The Vermont QSO Party (VTQP)
  • [x] - The Mexico RTTY Contest
  • [x] - The Minnesota QSO Party (MNQP)
  • [x] - The British Columbia QSO Party (BCQP)
  • [x] - The North American CW SPRINT Contest

The BiGGest problems this weekend were heat in the shack and incessant internet dropouts.
If I seemed to disappear all of a sudden, it was because either the VPN connection or connection
to the radio would drop out. Nothing more frustrating than hearing you calling me while the VPN won't allow me to type or press function keys.  Nevertheless, somehow I got thru this weekend.

While local filters accomplish nothing in a remotely-run RTTY contest, the above setup works extremely well for CW contests.  Very similar to my setup in Concord, the filters here allow splitting audio between the ears, with low frequencies favoring the left ear and higher frequencies favoring the right.  In an attempt to simulate the 3rd-channel stereo-effect, you will notice a small MFJ-751 in between the QF-1A filters for each ear.  This will be written up in the next installment on Stereo-CW.

The weekend began with the Vermont QSO party, altho you would never know it because no VT stations were to be found on Friday evening.  Assuring myself we had 48 hours to find Vermont, when it was all over on 3 VT stations made it to the log - NoT that they couldn't hear me; there were virtually NONE in Vermont to be heard.  This echoes my BEEF with most QSO parties (Except CQP, 7QP & NEQP) - not enough stations play in their own QSO party - they put on an operating event and then don't participate in their own event.  HuH?

The Minnesota MNQP fared much better - ROVER stations were even worked.  Unfortunately again, the in-state turnout was abysmally low.  I guess I am spoiled by the HUGEness of CQP (followed by 7QP & NEQP) - we go out of our way to populate the bands (to the disdain of non contesters).

The same complaint can be made regarding the BC QSO party.  While there were more BC stations on than VT, they were largely on 40-m and that's it.  None were heard on 80 and none were heard on 15 (even tho the band was open).  I would think pointing the Stepp-IR DEAD north should've filled my receiver with BC stations - NoT So.

Running remote from Alameda, I was too lazy to run SSB. 
Who nose, maybe that was where the REAL operations were being held.  It certainly didn't help matters that Saturday evening was blanketed with a K-Index of 5; altho band noise was the least of our problems.  I would've traded noisy band conditions for the incessant internet dropouts.

The Mexico RTTY contest was the main GiG to play in this weekend.  Being careful NoT to overheat the shack, most of the RTTY time was spent running about 1150 watts by way of a KPA-1500 amplifer.  I purposely chose to run the 3-el Stepp-IR for the high bands allowing me to point the antenna towards South America and later in the afternoon to open it up BI-directionally for adding
Japan to the log.  

Both mornings, anticipating JA activity I looked for the Russian Asian beacons (~7.039) for indicators of propagation.  While the "F" beacon came through loud and clear both mornings, the "M" beacon was weak on Saturday and disappeared altogether on Sunday, just like its K-Beacon sibling which has been AWOL for months.

I was so wrapped up in running RTTY and looking for QSO party stations I  all but forgot about
the NA CW Sprint event.  For this month's running the event began at 23:00z instead of 00:00z
(giving E. Coast stations more of a shot at 20 meters).  My 1st QSO was on 20-meters at: 01:27z,
just in time for the Fallbrook internet to fail.  When things came back online 20 minutes later, 20 was gone and I took refuge on 40-meters until contest ended an hour later.  It was a kick bouncing around the band (instead of hogging a run frequency).

At 00:00z, when it was all over I had 5 logs to create and submit and 5 scores to post on the 3830 Scores website.  Barely 5 weeks into the new year and WQ6X already has 15 radiosport events posted on 3830 Scores.

What about YOU?

DiD YOU play radiosport this weekend?

Is WQ6X in one of YOUR LoGs?


Friday, February 5, 2021

WQ6X Dual-OPs 1st-Ever CQ-160 Cw Contest

wOw!  As I write this, January is Already OVER.  Because they gave us 5-weekends last month,
the CQ-160 Cw contest managed to be tucked right into the last two days (Daze?).  Dual-OP'ing certain contest events (usually Cw & RTTY) has become a new sub-hobby within the HOBBY Amateur Radio.

For this 160 GiG, remote operating came in two flavors: ANZA-based (as NO6T) and Fallbrook-based (as WQ6X); "officially" NX6T was dark, off the air.  Additionally, I put in a reservation for the W6C callsign, creating a Concord signal-vortex investigation; more on that later.

Equipment-wise this weekend opened with some subtle (but not-insignificant) changes to the
audio-line.  Thanks to the newly added Radio Shaft A/V switch box (4-channels of stereo audio & mono audio) it is now possible to switch either the FT-1000mp, ICOM-7000 or Elecraft K3/0 into the main audio filter line.  I've never been impressed with the K3's APF (Audio Peak Filter); with the external audio filters we get the best of both modalities.

Being able to combine the already AWEsome DSP in the ICOM-7000 with the AUTEK, NIR & MFJ filters in the audio line makes for some amazing receive capabilities; more on that later.

-----------------------------------

While I've been utilizing the "Stereo-CW" modality in WQ6X operations for years, this CQ-160 GiG (being a Cw contest) allowed me to knob-twiddle, looking for the EXACT Left/Right adjustment of the Autek QF-1A filter pair.  You may remember, for me the idea is for lower-pitched signals to appear
in the left-side of my Experience, while the higher-pitched signals appear in the right-side of my Experience.  The Stereo-CW concept must be Experienced to really GROK the jist of what I am saying.  All you need is a pair of identical filters intercepting the audio-line to Experience it.
I circled the frequency-settings demonstrating how "subtle" these settings really are for
a TRUE Stereo-CW Experience.

I've written a LoT about this idea, the most recent being AUGUST of 2020.  Based on this weekend's experiment, another BLOG-installment should be forth-coming.  When running a Cw pile-up, having different signals appear at different "locations" in my experience allows me to mentally-focus more-easily on that specific signal.  Used in conjunction with the R-i-T, allows me to position signals around in my listening-Experience.  During the CQ-160 contest (both from Anza and from Fallbrook) having Stereo-CW capability with the K3 made for an AWEsome operating Experience.

DISCLAIMER:
WARNING!: Stereo-CW should NoT be undertaken when seriously under the influence.

As weird as it may seem, the W6C Experiment was a marginal success, although the W6C callsign confused nearly everyone I worked; I had to reassure them that I was for real (because I was).  What
I unfortunately confirmed was the FACT that Concord California (at least locations near the creek) is indeed a signal-vortex.  As to what I should DO about it, that is fodder for a future BLOG entry.

When it was all over, it would seem that NO6T took 47th-place W.W., 10-place for USA, 2nd-place for the Southwest Division and 1st-place for California - GO Figure.  At #284, WQ6X was in the REAR of the Single-OP Assisted (HP) category.  As for W6C's 9 QSOs, we have to get the magnifying glass out to find them.

DiD YOU work the CQ-160 Cw contest?

Is NO6T, WQ6X and/or W6C in YOUR LoG?


Thursday, February 4, 2021

WQ6X Reconfigures Radios amidst the BARTG Sprint

Life has kept me so involved in SO many things, I've not found the time to BLOG Post, although
I operated radiosport GiGs every weekend in January.  Being a 5-weekend month a LoT of radiosport happenings happened to happen giving me opportunities to not only operate, but work on the equipment configuration at the Concord location.

Since my Dual-OP of the NAQP Ssb GiG (with NO6T and as WQ6X), the equipment configuration underwent a dramatic shift as the Elecraft K3/0 was moved to the top shelf and the MFJ filter-Trio
was moved directly below the FT-1000mp, enabling it to look "logically correct" - filters for the left
ear appear to the left-side of the operation while filters for the right-ear appear more to the right.

While unfortunately, the wonderful filter settings maximize the local audio (for the FT-1000mp and ICOM-7000) they (as yet) are not inline with the K3/0.  For the next trip to Concord, a plan is being devised allowing the K3/0 to be switched into the filtered audio chain.  For this trip I was just happy
to have the K3/0 more at eye-level.

Filter-wise adding in a Radio Shaft audio switch box allows two kinds of filtering for the FT-1000mp.  Above the keyboard sits a pair of Classic MFJ 752 "Signal Enhancer II" units; the "C" model for the left ear and a modified "B" model which allows switching in an old CWF-1 filter for Cw, as the right ear (Sub-RX) by choice lacks any CW filters.

Overall, I've never been a foot pedal operator.

I've not managed to connect with transmitting using my feet. 
Most foot pedals are either too small, move around under the
table or always seem to be at the wrong "angle" relative to my feet.  Rummaging around the storage shed I happened across this unit that was "shelved" when it didn't make it into a CQP operation
from Twain Harte years ago.

The downside of this unit (the reason it was sidelined) had everything to do with the super-mini plug on the end that doesn't mate with any of the audio adapters available from the junk box.  There was nothing to be lost by hacking the plug and replacing
it with something more contemporarily functional.

For my operating-style, BiGGER is indeed Better.  Now I actually find foot-pedaling to be fun.  The old saying ("If it feels GooD Doit") certainly applies here.  While I still love VoX, Foot-to-Talk can certainly be a very effective modality.

Remembering that the REAL goal was to run the BARTG RTTY Sprint contest remotely, once the K3/0 and audio filter swap was complete it was time to shift into radiosport mode.


What I LIKE about the BARTG Sprint contest is the rules specifically stating that it is UNNECESSARY to send "599" (or "5NN") as part of the exchange.  What I DISLIKE about
this contest is that over 50% of the participants either didn't read the rules (or didn't care),
or, were too lazy to clean up their software keyboard macros eliminating the USELESS
signal report (which never really was a REAL signal report anyway).

This seems like a minor beef until you realize that not only is sending "599" a waste of time,
when medium-fading surrounds the signals, after sending "599" the signal fades and the Serial-# does not decode.  My response is to send "UR NR AGN?", to which I would often receive "WQ6X UR 599 599 #8@2#0"  HuH?  JUST SEND ME THE NUMBER DAMMIT!

In a way, it could be said that the "significant" happenings occurred outside of the BARTG RTTY contest/context.  With no advance warning the Russian K-Beacon was back in action, after a lengthy absence, return and then absence again.  The "K" beacon (on ~7.038) is rather useful for predicting 40-meter propagation openings to Asia.  

Unfortunately, at 13:26z our "friend" the WooDPecker made a NASTY appearance off and on for about 30 minutes.  I dunno what is worse, being intentionally swarmed by FT-8 signals (forcing me to move) or the WooDPecker.  What is frustrating is having a "Moscow Muffler" sitting in the equipment stack which is worthless for remote operating.  Even IF there were a WB-1C in Fallbrook, the technology is too old to allow remote adjustment.  When are the SDR manufacturers going to
offer a Software Defined Receiver (SDR) with a WooDPecker blanker DSP in the front-end?

Other than the incessant internet dropout problem I encounter in Concord when remoting-in by way
of the RRC-1258 unit, the BARTG GiG ran rather smoothly, once I got started.  A plethora of ZOOM meetings made it impossible to conduct both simultaneously with any amount of coherency, costing me juicy QSOs from the 1st four hours of operation.

When it was all over, according to 3830 Scores, WQ6X took 37th place across USA, 4th-place for California, 2nd-Place for the SW Division and 1st-place for the San Diego section; not bad for just screwing around.

DiD YOU work the BARTG RTTY Sprint contest?

Is WQ6X in YOUR LoG?



Tuesday, January 19, 2021

WQ6X joins up with NO6T for another NAQP-Ssb Contest 1st-Place

Last weekend for various reasons I joined NX6T remotely from Alameda for the NAQP Cw contest. 
([CLICK HERE] to read about that.)  While we could've done better (we can ALWAYS do better),
we DiD take 2nd-place for California and 1st-place for San Diego and the Southwest Division. 
For this immediate-last weekend we had a larger more robust bunch of team players, running remotely as NO6T from our ANZA Super Station.  

While I was on-shift for only 2 hours (22:00z to 24:00z), my contribution included our contacts on
10 meters before firing things up on an already wide open 40 meters.  Online Zoom meetings kept
me out of the WQ6X operating chair until nearly 21:30z, altho I DiD manage to put Zoom in the background and snag a handful of multipliers during the Zoom session.

Another Goal for this weekend was to relocate the Elecraft K3/0 unit, putting it more at eye level. 
Accomplishing this required moving the MFJ-784 and MFJ-752b boxes into the former K3/0 location, along with the audio switch and Rockville mixer unit.  For the next operation in Concord, I may bring back another MFJ-752C filter languishing in Alameda.

While I was taking-care-of-bizniss in Concord, KI6RRN (Axel) & WM6Y (Phil) were filling the 15 & 20 meter logs, somewhere around 650 contacts in 2.5 hours.  wOw!  While my 66 contacts were not a lot, they DiD give us a 10-meter presence (bringing more multipliers) and an early presence on 40-meters to work the easy-loud E-coast stations.

Being a 12-hour contest, in the NAQP there are no "do overs"; there is no "tomorrow" to start over and try again.  When the high bands are done, they are done.  The alternate band is of course 40. 
In recent months, 40 has been open domestically by 22:00z.  Of course having a great ASL location and above-average 40-meter antennas in ANZA helps out quite a LoT.

Having an exceptional crew of operators behind NO6T was the secret to running the show;
no operators were over-worked and everyone got the time in the chair they wanted.  I got to
put time in as WQ6X, altho the signal-vortex in Concord didn't make things easy.

When it was all over, it would seem that NO6T took 1st-place, but by only a slim margin. 
When the Log Checking Robot (LCR) scrutinizes our logs, the scores will be adjusted
accordingly, always downward.

What about YOU?

DiD YOU play around in the NAQP Ssb Contest?

Is WQ6X or NO6T in YOUR LoG?


Wednesday, January 13, 2021

WQ6X Helps navigate NX6T's NAQP Navigation

As I write this on Sunday morning, I am bemused by the process of establishing an anchor point around which to write this Blog entry.  A LoT of weird, disconnected occurrences occurred this weekend during this year's 2021 NAQP Cw contest.  To level the playing parameters, NAQP
contests have a 100-w max power limit (anything above that power-level becomes a checklog).

For this weekend's 12-hour GiG, we had plenty of operators for our Multi-2 operation which offered
me a LoT of flexibility in on-the-air time.  My assigned time slots were 21:00z to 23:00z followed by 01:0zz to 03:00z.  At 21:00z, STN-2 was knocking 'em out on 20-meters while N6KI was making a presence on 15-meters.  Literally minutes after my start time, I noticed that the band "seemed to be dead" and the radio was only putting out 25% of its rated 100-watts; a closer look showed the SWR to be 6.7:1 - some sort of failure seemed to have occurred with the 3-el Stepp-IR antenna.

After 20-minutes of wasted futzing, it was decided to forgo 15-meters and make an early appearance
on 40-meters.  Amazingly the east coast was already coming in; more amazingly, a European callsign (LZ1340B) was also heard in Fallbrook - Huh?  On 40-meters in the early afternoon?  wOw!

In recent months 40-meters has been remaining open later in the morning and opening earlier in the afternoon.  With the remaining 80 minutes of my 2 hour shift I managed 52 QSOs into the 40-meter log while the 20-meter crew kept things alive there.  Coming back at 01:00z 40-meters was WIDE OPEN and the 20-meter crew was already making 80-meters happen.  During the 5 - 7 dinner hour,
I managed 141 QSOs on 40-meters before turning things over to N6CY at 03:00z.

You've heard me talk about the intentional QRM I often encounter on 40-meters; that usually occurs after midnight (08:00z).  For this NAQP gig, other than crowded band segments it was too early for the QRM'ers to get out of bed and get started.  Tuning around 7047.5 (the W1AW Bulletin and Code practice frequency) I was proud to note that NAQP'ers completely avoided that segment; however in place of US, swarms of FT-8 signals riddled the W1AW area.  There is plenty of room on 40-meters for ALL of us to give W1AW an open frequency for transmissions that benefit us all.  Is it REALLY
that difficult to understand?

When it was all over it would seem that NX6T too 10th place overall, 2nd-place for California and 1st-place for San Diego and the Southwest Division; not bad considering what we had to work with.

DiD YOU play in January's NAQP CW contest?

Is NX6T in YOUR LoG?



Friday, January 8, 2021

Analog or Digital - Which shall we choose - Part 2

Sometime ago I wrote the original blog entry by this name.  ([CLICK HERE] to read that). 
This topic was introduced based on equipment configurations in use in many of my different contest operations from Concord, Ca.  Since then, a number of equipment reconfigurations have been made.

Because WQ6X operations use cascading filters, back in 2014 I asked the QST Dr. about the ramifications of a given order of devices in each audio chain.  Joel's comments about device
linearity and overload were very prescient.  ([CLICK HERE] to read that).

Recent audio filter re-cabling @W7AYT brought his comments back to life. 
Several questions come to mind

  • How many devices can be practically cascaded on each audio line?
    (Left ear and Right ear)
  • What order should those devices be?
  • Can we intermingle Analog and Digital circuits?

Because noise (QRN) is always a problem, it was discovered that
overall there are 5 types of noise limiting/processing circuits:

  • Peak Limiters
  • Trough Limiters
  • Noise Silencers
  • Noise Blankers
  • DSP (surgical) Noise limiting

Realize that the above categories are approximate.  Different manufacturers use different names
for their NR circuitry, in the same way that the terms "IF-Shift" and "Passband Tuning" (PBT)
are often interchanged.  The classic MFJ-752c ("Signal Enhancer II") utilizes both Peak and
Trough noise filtering.






PEAK LIMITERS
Peak limiters are essentially 2 (or more) diodes across the audio line to clip the +/- noise peaks. 
An adjustable potentiometer (between the diodes and ground) allows adjustment of the depth of clipping.  Early ANL (Automatic Noise Limiter) circuits were tube diode circuits; often using the
stubby 6H6 (and later 6AL5) dual-diode tubes to accomplish the clipping.  Not surprising,
the results were not that spectacular.  In my mind, most <NL> switches on all the classic
shortwave receivers were nothing more than a JOKE; add a DEPTH potentiometer and
they become useful.


TROUGH LIMITERS
Trough limiters are essentially 2 or more (reversed) diodes "biased" to NoT conduct unless the signal components exceeds a (pot-adjusted) threshold.  The advantage of this approach is that low-level noise is not allowed to pass while signals above that level come right through.

NOISE SILENCERS
Noise silencers are essentially all based/influenced by the 1936 work by James Lamb and are often called Lamb silencers.  The idea of this approach is to remove the excess noise pulses from the IF signal path before they have a chance to key the AGC line.  Collins used this approach by including
a separate 40-mc receive circuit; capturing JUST the "noise", the output can be allowed to influence the AGC line.

NOISE BLANKERS
As we moved into the 70's various adaptations of the Collins Radio adaptation of the Lamb circuit began to appear.  In the Collins approach the blanking signal was usually made outside of the amateur band being received.  The more economical/common approach takes the blanking signal right at the IF frequency.  The downside to this approach is that with the blanker circuit inline and no noise present, strong signals on nearby frequencies can trigger the blanking circuit, creating a form of static/distortion; another name for this is artifact.

DIGITAL SIGNAL PROCESSING
With Digital Signal Processing, the idea is to digitize an analog signal in order that it be
"dissected" on a Bit-by-Bit and Byte-by-Byte basis.  At least theoretically, the extreme PEAKS
can be completely removed; as well as signals below a minimum threshold.  Once all this "JUNK"
is removed, the digital is transformed back into analog, as if nothing had happened.  Unfortunately most DSP-algorithms are not flawless and can [theoretically] contribute their own artifact.

I use the above DSP units for the Right Channel (NIR-12) and Left Channel (MFJ-784) audio coming from the Yaesu FT-1000mp.  Because the Sub-RX lacks any kind of notch facility, the NIR-12 gives the equivalent of the Main-RX eDSP.  They both can auto-notch carriers and can shape the audio passband.  The NIR-12 also offers a DYN PEAK (essentially a trough limiter).  For practical use,
the signal threshold of this circuit is set WaY too high; however when it works, the effect is AWEsome.  LooK for me to devise a circuit modification introducing a threshold adjustment PoT.

Because Noise Reduction (NR) is needed MORE for the Main-RX, the MFJ-784 does an AWEsome job.  While the Yaesu's eDSP NR clips the noise-heads off rather nicely, the MFJ-784 actually seems to "root out" the noise from underneath - what a great combination.  The FILTERs selection knob produces effects quite similar to the eDSP Contour control; the pair used in cascade produces
some unusually interesting listening effects.

Earlier on I raised the question of whether or NoT Analog and Digital can be intermingled.  Eventually it ALL becomes analog.  It seems to me that as long as we don't introduce undesirable artifact into the audio we are processing, we can/should give consideration to all manner of audio improvement.

Remember: IF You Can't Hear'Em, You Can't Work'Em.

What Do YOU use to accomplish signal-copy improvement?

Write me and let me know.


Wednesday, January 6, 2021

WQ6X Doubles Down for 2021 RTTY RU

 

 

 

 

 

 

Paraphrasing my latest FaceBilk post:

The "Official" 1st Radiosport contest of the new year was of course the ARRL RTTY Roundup
(RU). Seven years ago as WP2/WQ6X from St. Croix, N6GEO and WQ6X took 1st-place for the world.  I did not come anywhere near that this year due to  circumstances that relegated me to run Single-OP (solo) as W6R remotely from Fallbrook.  The modified goal became to run mainly as W6R (remoting into Fallbrook),  filling in the gaps by running as WQ6X from the Concord location; no remote - as direct as you can get.  However I'm getting ahead of myself.

For 2021, the new year being so close,
at the last minute I surprisingly realized that the Scandinavian SARTG Happy New Year RTTY GiG was well underway, explaining
why RTTY signals started appearing in my headphones around 7.055.  Hastily putting together an N1MM+ log and a set of run macros, I found time for the HNY RTTY GiG.
 
Band condx. being overall horrible, only K8YE, GW5NF, HB9MXY & MM9I made
it to the low power log.  At least I can say
I was there ("...It's Nice, to know, that you were there...").  Weird internet disruptions was a preview of what was to come throughout the entire weekend.

In order to run as a high power (over 500 watts) operation, the shack A/C needed to
be toggled on as soon as I could; otherwise,
I would have to monitor the KPA-1500 amp's TEMP, keeping it below 65-C.
 

 
Because the WEMO switch seems to be failing, until our tech-guy (N6KI) comes in on Wednesday
to replace the unit it's a keep-trying-until-it works operation.  Having an Accurite APP on my Galaxy cellphone allows me to track the individual amplifier temperatures; RTTY transmissions SURE generate a LoT of amplifier-heat.

You've heard me complain about the intentional QRM we get on 40-meters late[r] at night. 
In recent years, the QRM-Joker during RTTY contests has been some sort of Data Cranker. 
I guess the cranker got bored or died cuz I don't hear "him" anymore.  The NEW QRM-Joker
is the cluster of FT8 signals that love to swarm around me, or the FT8-IDIOT who parks himself
on my MARK frequency.  The frequency can be ABSOLUTELY Quiet; I make one CQ call and an FT-8 swarm immediately shows up; they probably spot my goal posts on the spectrum display.
 
Of course accompanying EVERY radiosport contest is your friend and mine, the "National
Tuneup Frequency" (N-T-F).  The N-T-F is whatever frequency I happen to be on at the time. 
At 16:39z on 70986.38 funny "popping" sounds began to appear.  I first I thought it had something
to do with distorted audio from the Rockville sound mixer until I "saw" the PoP sounds tickle the S-meter, realizing that they were coming in thru the antenna.
 
The time on/off calculation in the RTTY RU rules document seemed to confuse many a contest participant.  Because adequate sleep was important to me starting this new year, the rule-confusion didn't affect me.  As W6R 17:17 hours were spent in the remote chair.  The operating time for WQ6X from Concord was a mere 2:22 hours; in both cases, a LoT of productive fun, altho unfortunately the internet dropouts every 5 - 10 minutes were frustratingly frustrating.

Statistically, rather than give you a QSO x QSO breakdown, the above stats really tell us about
what really matters anyway.  Paying attention to the band/hours stats can give you an idea what propagation was like in the SDG section throughout the day.

What the statistics DON'T SHOW are the hundreds of internet dropouts occurring throughout the weekend.  Bottom-Line: If alluva sudden I seemed to have disappeared on you, it wasn't personal; most likely, either/both of the Radio/VNC (pair) took a dive.  I could probably HEAR You - I just couldn't respond.  VERY frustratingly Frustrating.

DiD YOU work the ARRL RTTY RU Contest?

IS W6R or WQ6X in YOUR LoG?