NJDTechnologies

Radio: it's not just a hobby, it's a way of life

Current Operating Frequency and Mode

QRT but I'll be back tonight, WX permitting

SCHEDULED ACTIVITY: CQ 474.5 kHz CW by 1000z through sunrise most days, WX permitting

VE7SL joins the WSPR action overnight as the band continues to perform consistently; Multiple PY stations ramping up for operation

– Posted in: 630 Meter Daily Reports, 630 Meters

The band was reported to be noisy around the world by stations that were actually on the air during this session but propagation appears to have been consistent with the norm for this time of year.  One bright spot was the appearance of VE7SL on WSPR while he is testing some hardware at his station.  Using 68-watts TPO, Steve had a nice first outing on the digital mode, including transcontinental reports from Mike, WA3TTS, in Pennsylvania on a noisy night.  Imagine what Steve might accomplish under quieter band conditions.

VE7SL 060316

VE7SL 24-hour WSPR activity

 

VE7SL WA3TTS2 060316

VE7SL, as reported by WA3TTS/2

 

Geomagnetic activity was quiet and the Bz is pointing to the North with calm solar wind velocity, averaging 320 km/s.

planetary-k-index 060316

 

Kyoto DST 060316

 

Australia 060316

 

Larry, W7IUV / WH2XGP, reports that he decoded three WSPR stations and was decoded by 14 unique stations during the session.

John, WA3ETD / WG2XKA, reported Larry on the transcontinental path as most of his reports were located in the North and East:

WG2XKA 060316a

 

WG2XKA 060316b

WG2XKA session WSPR activity

 

Neil, W0YSE/7 / WG2XSV, reports a better session than previous while operating at 14% TX cycles, much less than typical:

WG2XSV 060316

Several of the boys in Australia have reported flooding, stormy weather during this session so I expect reports will be very lean down under during this session.

There has been a significant up-tick in activity in Brazil recently as stations are gearing up for receive.  Last night PU3VRW/SWL and PY2TI were joined by PY2CAC.  Its my hope that a few strong signals in the southern hemisphere will be QRV to give these ops a reasonable chance of decoding a signal (FR5ZX where are you?).  After an email from PY2TI, it seems that they are working on improving antennas at locations that are probably very noisy.

Doug, K4LY / WH2XZO, has recently been testing his K6SE flag on 630-meters after he lost a loop-mounted preamp, likely due to high RF fields killing the front end (that’s a guess at this point).  The flag has been directed to the West where many of us that are normally active have been QRT due to stormy weather conditions.  Doug noted that he decoded WG2XKA in Vermont last night so the flag does not appear to be working out and he is working on the HI-Z vertical array to get it back on the air.

Regional and continental WSPR breakdowns follow:

NA 060316

North American 24-hour WSPR activity

 

EU 060316

European 24-hour WSPR activity

 

VK 060316

Australian 24-hour WSPR activity

 

JA 060316

Japanese 24-hour WSPR activity

 

There were no reports from the trans-Atlantic, trans-African, Caribbean, or trans-American paths during this session.  UA0SNV and ZS1JEN were present, in addition to the three stations in Brazil, but no reports have been filed at this time.

Laurence, KL7L / WE2XPQ, reported VE7SL, WH2XCR and WH2XGP and was reported by WH2XCR during this session:

WE2XPQ 060316

WE2XPQ 24-hour WSPR activity

 

WH2XGP WE2XPQ 060316

WH2XGP, as reported by WE2XPQ

 

WH2XCR WE2XPQ 060316

WH2XCR, as reported by WE2XPQ

 

VE7SL WE2XPQ 060316

VE7SL, as reported by WE2XPQ

 

As storms and flooding rage in Australia, Merv, K9FD/KH6 / WH2XCR, has what is likely a deceptively lean session where reports were focused on the western coast of North America and Alaska.  John, VK2XGJ was able to decode Merv’s WSPR’s and Merv was able to decode Roger, VK4YB.

WH2XCR 060316

WH2XCR 24-hour WSPR activity

 

VE7SL WH2XCR 060316

VE7SL, as reported by WH2XCR

 

WE2XPQ WH2XCR 060316

WE2XPQ, as reported by WH2XCR

 

WH2XCR VK2XGJ 060316

WH2XCR, as reported by VK2XGJ

 

VK4YB WH2XCR 060316

VK4YB, as reported by WH2XCR

 

Jim, W5EST, will “COMPARE QRSS AND WSPR POWER LEVELS: DIGGING STILL DEEPER” in today’s discussion:

“Yesterday’s June 1-2 blogs tell some 2015-16 season highlights and TX+RX frequency drift constraints when using ARGO to display QRSS.  For best image contrast, QRSS lines should slant up or down no more than 45° at the highest QRSS mode number in use.  To prepare for a receiving run, open ARGO five times to nine times, each instance corresponding to a different overlapping frequency range and with the instances collectively centered around the expected transmitter frequency.

Now let’s confront the question of what QRSS EIRP compared to WSPR EIRP can achieve particular relative levels of SNR.  Remarkably, this question involves neither propagation nor station antennas/equipment.  Both QRSS and WSPR are processed with audio software, so the path to the answer amounts to a comparison of the software results.

A year ago, about 9:30pm CDT on June 2, 2015, I monitored 50mw QRSS60 from WG2XIQ on the north Texas to Little Rock, Arkansas, path and got an acceptably visible trace on ARGO—not faint and not boldly bright. See illustration, center, compared to WSPR at right.* Think about it—50 milliwatts of QRSS60 gave visibility on ARGO when it took 5 watts of WSPR to deliver a modest -22dB SNR under similar band conditions to one same RX and its antenna.  Yes, the data rate of QRSS60 is less than WSPR2, but the QRPPP QRSS60 signal was visibly readable!

John’s 50mw (17dBm) flea power was 20dB down from his 5 watt (37dBm) WSPR power that yielded -22dB SNR. That -22dB SNR is well above the WSPR threshold, with lots of room above it for stronger signals too.  So I took these power levels—17dBm QRSS60 and 37dBm WSPR–as corresponding to each other in some sense for practical experimental purposes to power-wise relate a given QRSS mode number to WSPR. This information allowed me to fit a constant C60 = 42dB for QRSS60 in the below formula that in general depends on mode number # of QRSS:

SNRwspr= PTXwspr – PTXqrss# – C#                            (1)

With that constant -22dB = 37dBm – 17dBm -42dB, showing that Formula (1) works with C#=42dB at QRSS60.

The above formula (1) makes sense because WSPR SNR should increase with WSPR transmit power. Moreover, formula (1) also makes sense because it rearranges to give an equivalent formula (2) that finds the QRSS TX Power PTXqrss# that corresponds to such WSPR TX power PTXwspr.

PTXqrss# = PTXwspr – SNRwspr – C#                           (2)

Inspection of formula (2) shows that if band conditions changed so that more WSPR power were needed to get the same SNR, then correspondingly more QRSS# power would be needed to maintain visibility on ARGO.   (Remember when using formula (2) that –SNRwspr is positive when SNRwspr itself is negative.)  Likewise, if band conditions similarly changed so the same WSPR transmit power would get less SNR, then correspondingly more QRSS# power is still needed to maintain visibility on ARGO.

Today’s TABLE shows values of constants C# that I’ve estimated to apply in the formulas.  To interpret them, imagine that one might use the same QRSS# transmit power as for WSPR (and not go QRPPP).  Then SNRwspr = – C#.  In words, the TABLE indicates the visualizing power of a given QRSS# to probe deep into noise: -42dB at QRSS60!

If, say, 5 watts WSPR delivered a WSPR-undecodable -42dB actual SNR, the TABLE suggests 5 watts of QRSS60 could nevertheless deliver a visible ARGO image. And higher QRSS modes could probe even deeper into noise and penetrate exceedingly challenging propagation conditions.

To obtain the constants C#, I assumed that the QRSS power needed to get the same visibility is proportional to the QRSS bandwidth, which is inversely proportional to the QRSS mode number #.  The TABLE converts that concept to dB, using the observed 42dB at QRSS60 as reference.  The TABLE assumes apples-to-apples comparison of each QRSS# to have its pixels distributed on the screen the same way.

From another viewpoint, the TABLE imagines that the number of signal pixels increases with the QRSS#. Apples-to-apples, if the pixels are distributed the same way on the display screen, then they get brighter with increasing QRSS#. The eye sees their brightness in a way related to dB, I presume.  Since my observation of XIQ at QRSS60 is subject to some error and the psychometric properties of human vision are involved, the TABLE can only be approximate and subject to improvement. But it’s a start.

Thanks for noodling about QRSS with me.  GL!           

TABLE : QRSS MODE-SPECIFIC CONSTANTS FOR POWER AND SNR FORMULAS

QRSS MODE  C#

     3        C3 = 30dB

   10      C10 = 34dB

   20      C20 = 37dB

   30      C30 = 39dB

   60      C60 = 42dB

 120    C120 = 45dB

  600   C600 = 52dB

1200  C1200=55dB

* Composite screen shot shows WG2XIQ QRSS60 at left with some chopping and fading, probably due to propagation variations and the considerable lightning static from east coast and Nebraska. G33DDC dial was set to 473.000 KHz, so ARGO 1500 Hz delivers 474.500 KHz.
For this run, ARGO display gain was set to 35 with Visual Gain button set to “AGC.”  WSPR decoder has its volume slider set at 55% (just over halfway up). The RX audio output was set to make the WSPR decoder’s green volume-bar indicator just reach 100% of its bar-slot.
G33DDC dial was then reset to 474.109 KHz to center XIQ’s 6 Hertz wide 475.609 KHz WSPR signal around 1500 Hz on ARGO.  At right in the screen shot, ARGO imaged the WG2XIQ 5W WSPR signal.  XIQ 5W WSPR shows comparable ARGO image contrast to earlier 50mw QRSS.  The signal curvature indicates TX and/or RX frequency is settling after the QSY to WSPR.”
W5EST 060316

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Additions, corrections, clarifications, etc? Send me a message on the Contact page or directly to KB5NJD gmail dot (com)!