NJDTechnologies

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

Current Operating Frequency and Mode

OFF AIR; QRT Thursday night but back Friday morning by 1100z

Transcontinental band openings continue as stations dodge storms and wait for relief; New part-5 application issued call sign in record time ; DL0IL/p final redux with pictures; Field day 2016 activity?

– Posted in: 630 Meter Daily Reports, 630 Meters

All indications are that the band was OK last night but many transmitting stations continue to be stuck in dry dock as unpredictable and inaccurate forecasts rule the night.  For the stations that continue to receive and transmit through this difficult period, thank you.

Geomagnetic conditions have been a little more active but the storm levels that were expected have not yet manifested beyond elevated solar wind velocities with persistent speeds above 500 km/s.  The North-pointing Bz appears to be contributing to the inability to reach storm levels.

planetary-k-index 051816

 

Kyoto 051816

 

Australia 051816

 

Phil, VE3CIQ, reports that he decoded four stations and was decoded by eleven unique stations during this session.  Transcontinental reports from WH2XGP in Washington state were also noted.

Ken, SWL/EN61, in Indiana was a victim of the low activity during this session, reporting only 80 decodes for the overnight session.

Neil, W0YSE/7 / WG2XSV, reports that he made  it to Alaska over night in spite of recent, interesting band conditions:

WG2XSV 051816

 

John, WG2XKA / WA3ETD, reports good two-way transcontinental reports with Larry, W7IUV / WH2XGP, have returned after a hiatus:

WG2XKA 051816a

 

WG2XKA 051816b

WG2XKA session WSPR activity

 

With Field Day 2016 approaching rapidly, I asked the question on the 600-meter research group about whether any others in the group wanted to participate in another Field Day activity this year.  Here is an except of that post:

FD 051816

 

I heard from Frank, K3DZ / WH2XHA, who indicates he will operate QRSS3 on 476.7 kHz during field day if the weather cooperates and can be trusted over night.  If there are other interested parties, please let me know.  I will be putting together a press release on or near June 1 and will post an updated page on this website with any additional participating operators.

Jim, K9JWV, of Utah, filed his Part-5 application yesterday and has been issued the call sign WI2XJG as of this morning in record time.  Hopefully his time-to-grant will also be short.  This may also be a clear sign that we are making progress with ET15-99.

Vinny, DL0IL, posted details and pictures of his portable operation from his team’s field day site:

DL0IL 051816a

 

DL0IL 051816b

DL0IL/p 630-meter vertical

 

DL0IL 051816c

DL0IL/p 630-meter variometer

 

Vinny notes that Wolf, DF2PY, was the last QSO for the event and every one returned home safely after packing up the site.  Additional pictures of the event can be seen at https://www.facebook.com/media/set/?set=a.1071290752918939.1073741837.181587651889258&type=3

Wolf, DF2PY, reminds operators worldwide that the ON4KST chat/logger is a great place to make schedules for QSO’s when the band is in the summer doldrums.  All are welcome!  Thanks to Alain, ON4KST, for making this tool available.

Regional and continental WSPR breakdowns follow:

NA 051816

North American 24-hour WSPR activity

 

EU 051816

European 24-hour WSPR activity

 

VK 051816

Australian 24-hour WSPR activity

 

JA 051816

Japanese 24-hour WSPR activity

 

There were no WSPR reports from the trans-Atlantic or trans-African paths.  UA0SNV and ZF1EJ were present but no reports were found in the WSPRnet database.

Laurence, KL7L / WE2XPQ, had a reasonable session for this time of year under the current propagation conditions.  It wont be long until it won’t actually get dark at his QTH.  In years past the path between Texas and Alaska has found some consistency during the North American summer.

WE2XPQ 051816

WE2XPQ 24-hour WSPR activity

 

WE2XPQ WH2XCR 051816

WE2XPQ, as reported by WH2XCR

Under the circumstances, Merv, K9FD/KH6 / WH2XCR, had a pretty good session, with continued two-way reports with VK4YB.  John, VK2XGJ, wrote early this morning to say that the path was not looking good but managed to achieve a near-detection limit reception during the session.  The path to the Pacific Northwest and southwestern Canada in addition to Alaska remain in tact.  Given the recent return of the transcontinental path on the mainland I am curious to see if the path between Hawaii and the central US has returned.

WH2XCR 051816

WH2XCR 24-hour WSPR activity

 

WH2XCR VK2XGJ 051816

WH2XCR, as reported by VK2XGJ

 

WH2XCR WE2XPQ 051816

WH2XCR, as reported by WE2XPQ

 

WH2XCR VK4YB 051816

VK4YB, as reported by WH2XCR

 

WH2XCr VK4YB 051816

WH2XCR, as reported by VK4YB

 

Jim, W5EST, presents a topic that is of particular interest to me as a fanboy of the GW3UEP amplifier design, with this offering on the topic of non-linear amplifiers entitled, “630M CLASS C/D/E AMPLIFIERS”:

On HF, hams often use a linear amplifier because nonlinear amplification would distort single sideband (SSB). Then digital modes are handled by supplying them in audio form as if they were audio input for transmission as SSB.  Unfortunately, linear amplifiers inefficiently dissipate power.

By contrast on 630m, especially in the 7 KHz 472-479 KHz band awaiting FCC approval for Part 97 hams, the 2-3 KHz bandwidth of SSB occupies too much space and demands about +0 dB SNR in a 2.5KHz noise bandwidth.

Consequently, digital modes and CW are likely to rule 630m.  Most of these modes can be generated by efficient nonlinear amplifiers without distorting the modulation.  Practical 630m antenna systems are necessarily less efficient than HF antennas, so why sacrifice 630m transmitter efficiency in the shack?

Instead, says this train of thought, drive a good 630m transmitting antenna system with a nonlinear amplifier.  Get more transmitter power output (TPO) from the power supply’s input to the final. Put up the best 630m  receiving antenna system you can, too.

What types of nonlinear amplifiers are there, in terms of the principle of operation? Several! Their efficiency is high at two levels. First, when a power amplifier (PA) device is off (current I =~0), dissipation P = V I = (V x 0) = 0.  When a power amplifier (PA) device is on, it’s full on so the voltage across it is near zero (voltage V=~0).  P = (0 x I) = 0 when the PA is on.

Class C amplification feeds a 630m sine wave to a power amplifier that is sufficiently biased that it delivers a pulse once per 630m cycle.  Since a pulse contains lots of harmonic content, a tank circuit or filter tunes the output to keep unwanted frequencies away from your antenna system.  Your outdoor 630m antenna tuning unit (ATU) further rejects them.

Class D (see endnote*) switches the analog input signal to create pulse width modulation (PWM) or pulse density modulation that’s more fully at work than Class C throughout each 475KHz 2 microsecond cycle. Then a PA-LPF (PA low pass filter) passes signal and rejects switching frequency and harmonics.

Class D uses a smaller heatsink because its PA is even more nearly full off or full on.  Unlike Class C that effectively switches on once per cycle, Class D switching frequency is much higher (like 10x the 475 KHz signal frequency). That makes output filtering simpler and smaller.

Class E ** amplifier design even more fully confronts the challenge of getting PA voltage down to zero by each time the PA conducts.  Class E artisans determine the right drive circuit and PA circuit inductances and capacitances so that economical FETs devices achieve remarkably low power dissipation in class E throughout the start, middle and end of transmission.

Do you have experiences you’d like to add, beyond what’s said in the cited web sites?  Let us know!”

*https://en.wikipedia.org/wiki/Amplifier#Class_E (Scroll down 60%.)

http://www.gw3uep.ukfsn.org/100W_QTX/100WTX/PA_cmos.gif  (472-479KHz)

http://www.gw3uep.ukfsn.org/100W_QTX/100WTX/100WTX_2july11.htm (Scroll halfway.)

** http://www.classeradio.com/theory.htm

http://ve7sl.blogspot.com/2014/09/gw3uep-630m-tx-complete.html

VK1SV class-E design class for beginners. http://people.physics.anu.edu.au/~dxt103/class-e/

Sokal, N.O. WA1HQC. (2001)  Class-E  RF Power Amplifiers.  QEX, Jan/Feb 2001:9-20.

http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=12&ved=0ahUKEwjx8tP-4OHMAhVKSSYKHbw2DggQFgheMAs&url=http%3A%2F%2Fpeople.physics.anu.edu.au%2F~dxt103%2F160m%2Fclass_E_amp_design.pdf&usg=AFQjCNEVu5gz7gsdmT5xwWtIpd8hbGx0rw

 

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