NJDTechnologies

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

Current Operating Frequency and Mode

OFF AIR but will be QRV on CW somewhere between 472.5 kHz and 475 kHz after dark

SCHEDULED ACTIVITY: CQ 474.5 kHz CW by 1030z through sunrise most days, WX permitting

Noisy band in North America but good domestic propagation, particularly short skip; Eastern US stations see open trans-Atlantic path; High band activity

– Posted in: 630 Meter Daily Reports, 630 Meters

With all of the noise present in North America overnight, one might think that the band must be very poor.   High activity seems to make up for perceived poor band conditions, however, and last night was no exception.  94 MF WSPR stations were active for extended periods during the evening.  Europe had participation in an MF QSO party centering on JT9 and WSQ2.  There was quite a bit going on at 472 kHz around the world.

We continue to see elevated geomagnetic conditions with solar wind velocities above 400 km/s.  Still, openings exist and it continues to improve the further south that stations are located.

planetary-k-index 031916

 

Kyoto DST 031916

 

Australia 031916

 

Larry, W7IUV / WH2XGP, reports that he heard eleven stations last night but was only decoded by 28 unique stations.  The northern transcontinental path was non-existent and while the short-haul paths were good, the long haul paths were very poor.  Its easy to forget sometimes just how far North Larry is located!

Neil, W0YSE/7 / WG2XSV, and Joseph, NU6O / WI2XBQ, reported at 0336z that they were QSOing again with WSQ2 and were looking for reports.

Ken, K5DNL / WG2XXM, reports that he heard seven station and was decoded by 47 unique stations.  Five VE’s were decoded in Oklahoma.

Eric, NO3M / WG2XJM, experienced a good session for a noisy night, with west coast reports from N6SKM at 0447z and trans-Atlantic reports from DL4RAJ and DL4RAJ/2.

Doug, K4LY / WH2XZO, was impacted by noise during the session but success was still to be found.  Doug details the session below:

WH2XZO 031916

 

John, WA3ETD / WG2XKA, was the recipient of trans-Atlantic reports from Germany.  John details his session below:

WG2XKA 031916

 

WG2XKA map 031916

WG2XKA session WSPR activity

 

Regional and continental WSPR breakdowns follow:

NA 031916

North American 24-hour WSPR activity

 

EU 031916

European 24-hour WSPR activity

 

VK 031916

Australian 24-hour WSPR activity

 

JA 031916

Japanese 24-hour WSPR activity

 

There were no reports on the trans-African path, however, ZS1JEN was present during the session.  UA0SNV was also present but there were no reports from Vasily.

Several trans-Atlantic reports were received by a number of stations:

G0MRF WD2XSH17 031916

G0MRF, as reported by WD2XSH/17

 

WG2XJM DL4RAJ 031916

WG2XJM, as reported by DL4RAJ

 

WG2XJM DL4RAJ2 031916

WG2XJM, as reported by DL4RAJ/2

 

WG2XKA DJ0ABR 031916

WG2XKA, as reported by DJ0ABR

 

WG2XKA DL4RAJ 031916

WG2XKA, as reported by DL4RAJ

 

WG2XKA DL4RAJ2 031916

WG2XKA, as reported by DL4RAJ/2

 

WG2XPJ DL4RAJ 031916

WG2XPJ, as reported by DL4RAJ

 

EA8/DL9XJ, continues to provide reports for stations located in Europe:

EA8_DL9XJ 031916

EA8/DL9XJ 24-hour WSPR activity

 

F6GEX EA9_DL9XJ 031916

F6GEX, as reported by EA8/DL9XJ

 

F1AFJ EA8_DL9XJ 031916

F1AFJ, as reported by EA8/DL9XJ

 

EA5DOM EA8_DL9XJ 031916

EA5DOM, as reported by EA8/DL9XJ

 

Eden, ZF1EJ, successfully reported a number of stations  located in North America in spite of a wall of noise in the Gulf of Mexico.  Eden used two receivers once again during this session.  The antenna is a log periodic array.

ZF1EJ 031916

ZF1EJ 24-hour WSPR activity

 

ZF1EJ1 031916

ZF1EJ/1 24-hour WSPR activity

 

In Alaska, Laurence, KL7L / WE2XPQ, is currently in receive-only mode, providing reports to stations along the west coast of North America and Hawaii:

WE2XPQ 031916

WE2XPQ, 24-hour WSPR activity

 

In Hawaii, Merv, K9FD/KH6 / WH2XCR, received reports from the mainland North America but the path to Japan and Australia were missing.

WH2XCR 031916

WH2XCR 24-hour WSPR activity

 

WH2XCR WE2XPQ 031916a

WH2XCR WE2XPQ 031916b

WH2XCR, as reported by WE2XPQ

 

In Australia, Phil, VK3ELV, received reports from three stations in Japan:

VK3ELV JH1INM 031916

VK3ELV, as reported by JH1INM

 

VK3ELV TNUKJPM 031916

VK3ELV, as reported by TNUKJPM

 

VK3ELV JH3XCU 031916

VK3ELV, as reported by JH3XCU

Jim, W5EST, provided this very interesting multi-part discussion entitled, “EXTRAPOLATING ANTENNA RF CURRENT READINGS, PART 1”:

“Suppose you want to get a particular value of RF current like 1.50A to show on the RF ammeter at the base of your 630m or 2200m top-hatted transmit vertical.  You can adjust the power of the transmitter in the shack but you can’t be in two places at once to see the ammeter outdoors at the antenna. And, of course, you don’t want to spend unnecessary time at this task.  What to do? Here’s one way.  Tell us if you have a better way and let’s blog it.

Outdoors beforehand, an antenna analyzer can help you achieve an ATU input impedance near 50Ω resistive at the ATU. Resonate the antenna with TX off and achieve the lowest SWR you can tune on your ATU (outdoor antenna coupler box). Suppose your best impedance gets to 57+j9 Ω.  SWR is 57Ω/50Ω, about 1.1 : 1 SWR. So far so good.

If the meter isn’t there already, connect an RF ammeter in a way that will safely measure antenna base current. You can connect the RF ammeter between the antenna base and whatever feeds it, like a loading coil or ATU output. Remember: the ATU and overall antenna Q can multiply the coax voltage when you turn on even low 630m/2200m TX power–up to many KV (kilovolts) at the antenna base!

Go indoors, turn on the transmitter and set the transmitter power output (TPO) to some low-to-moderate level like 10 watts. Tweak to improve the match indoors if that’s possible.  A scope match or your favorite SWR equipment can help verify when you have the RF voltage and current in phase and aligned close to 50Ω. Leave TX running while you go back outdoors briefly, making sure nobody will be at risk in the shack and that the TX won’t overheat in the meantime.

Outdoors, fine tune the antenna coupler (ATU) now under power, if you can safely peak up the RF current at the antenna base at the low TX power level.  Don’t touch the antenna base, ATU output or anything connected to either of them.  If in doubt about your safety or TX resilience, omit ATU adjustment entirely at this point.

Record a first RF current measurement I1 from the RF ammeter connected to measure antenna base current. Suppose the meter shows 0.63A antenna base current with TPO nominally 10 watts. Close up the ATU box if it’s open.

Go back in the shack.  Recheck and record the actual TPO if it has changed somewhat—now, say to 11 watts.  Now adjust the TPO to four times as much power– 44 watts.

Return outdoors, don’t adjust the ATU, and do read an antenna base current value I2. If the meter is calibrated right, it should show 1.26A– double the earlier 0.63A.  Let’s take the harder, less calibrated case tomorrow.  For today keep it simple, at 1.26A.

The hypothetical goal in this example is 1.50A antenna base current.  So how much TPO should you set in the shack to get that 1.50A?

Already you probably have a hunch about what to do.  It’s based on P =  I2base  R.  TPO power P is the power needed to get RF current Ibase  to be 1.50A, so  P = (1.50A)2 R.

Resistance R is the total ohmic resistance of the antenna system, including its antenna conductors themselves and radials and earth grounding. Fortunately, you don’t need to know what R actually is, for this purpose.  Proceed this way:

Recall that 44 wt = (1.26A) 2 R.   Divide that into  P = (1.50A)2 R to cancel R out.   Get  P/44 = (1.50/1.26)2.

With a hand calculator or your smartphone, tablet or PC calculator app, calculate P = 62 watts.  You’re still in the shack, so set the transmitter at 62 watts.

When you happen to be outdoors some other time, you can satisfy yourself the RF meter reads 1.50A.  Later some night, check visually or with binoculars that there’s no corona or sparks off any part of the antenna system when it’s under full power.

Do you have better wisdom?  Let us know your experience and tips!”

 

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