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

Standard Summer fare through this session as noisy conditions continue; High latitude transcontinental path is open; Field day is nigh upon us!

– Posted in: 630 Meter Daily Reports, 630 Meters

More of the same during this session.  Summer noise is here and stations just have to fight through it and not get their expectations too high, welcoming whatever surprises might come their way.  Fortunately we have had a lot of those nice surprises recently, particularly on the path to VK from North America.  I hope the path to EU from North America can be equally successful at some point this Summer as it has been in the past.  Joe, VO1NA, has recently blazed a trail to Europe so the path is open, stations only have to be active.

Geomagnetic conditions continue to be somewhat unsettled.  The Bz has seen some variability through the session although it is currently pointing to the North.  Solar wind velocities continue above 400 km/s with a few excursions above 500 km/s.  Steve, VE7SL, noted that auroral activity was reported on 50 Mhz.

planetary-k-index 062416

 

Kyoto DST 062416

 

Australia 062416

 

Ken, K5DNL / WG2XXM, reports heavy QRN in Oklahoma where he decoded two WSPR stations and was decoded by eighteen unique stations.

Rick, W7RNB / WI2XJQ, reports improvements in his antenna system although rain during the session complicated performance.  John, VE7BDQ, reported reported Rick’s aural CW at RST 449 with occasional excursions to RST 549.  Neil, W0YSE/7 / WG2XSV, and Larry, W7IUV / WH2XGP, were unable to hear Rick during this session.  I’m willing to bet that wet conditions have caused absorption to increase significantly.

Roger, VK4YB, reports extremely high winds in his area with many trees and antennas down.  He will assess the damage when it is light.

Steve, VE7SL, reports that he decoded nine WSPR stations and was decoded by ten unique stations while operating at 25% transmit cycle.

Mike, WA3TTS, took advantage of the high latitude transcontinental path that was open for part of the session.  Mike was fortunate to have much of the storm QRN on the backside of the receive antenna.  He offers these comments and statistics:

WA3TTS 062416

Neil, W0YSE/7 / WG2XSV, reports that “business is a-booming'” in the Pacific Northwest and propagation is pretty good:

WG2XSV 062416

Regional and continental WSPR breakdowns follow:

NA 062416

North American 24-hour WSPR activity (note massive map pollution by a station in Ohio! due to band error)

 

EU 062416

European 24-hour WSPR activity

 

VK 062416

Australian 24-hour WSPR activity

 

JA 062416

Japanese 24-hour WSPR activity

 

There were no reports from the trans-Atlantic, trans-Equitorial, or trans-African paths.  UA0SNV was present but no  reports have been filed at this time.

In the Caribbean, Eden, ZF1EJ, reported WG2XXM, WH2XZO, and WG2XIQ:

ZF1EJ 062416

ZF1EJ 24-hour WSPR activity

 

Laurence, KL7L / WE2XPQ, was reported by VE7SL and WH2XCR.  Laurence reports that he has removed a few trees very close to the new transmit antenna location.

WE2XPQ 062416

WE2XPQ 24-hour WSPR activity

 

WE2XPQ WH2XCR 062416

WE2XPQ, as reported by WH2XCR

 

WE2XPQ VE7SL 062416

WE2XPQ, as reported by VE7SL

 

Merv, K9FD/KH6 / WH2XCR, was reported for what may be the first time by Glen, K5FX / WH2XGZ, near Austin, Texas.  This is a pretty good accomplishment given that neither I nor Ken, K5DNL / WG2XXM, have been able to hear Merv since earlier in the Spring.  I’m suspecting that Glen is far enough South that the impact of continental storm QRN is reduced.  In Australia, poor weather conditions have limited active stations but VK4YB and VK3ELV have somehow achieved two-way reports:

WH2XCR 062416

WH2XCR 24-hour WSPR activity

 

VK3ELV WH2XCR 062416

VK3ELV, as reported by WH2XCR

 

VK4YB WH2XCR 062416

VK4YB, as reported by WH2XCR

 

WH2XCR VK3ELV 062416

WH2XCR, as reported by VK3ELV

 

WH2XCR VK4YB 062416

WH2XCR, as reported by VK4YB

 

Jim, W5EST, presents, “INVESTIGATING ONE TABLET AND MF/LF SDR”:

“Yesterday’s blog discussed in concept a homebrew combo using a tablet and an SDR.  Today, I offer a preliminary case study investigating specific products on hand here to suggest what might be analogous ways of combining whatever particular tablet and SDR you would actually have.

I use a software defined WinRadio® G33DDC Excalibur Pro because it has MF/LF performance with good stability and waterfall frequency magnification drilling down to 10Hz/inch making WSPR lines plainly visible.  Datasheet: http://www.winradio.com/home/g33ddc.htm . Software downloads to run this SDR are operating system specific—Windows, Mac, and Linux.

Plainly, the tablet and SDR can benefit from software suites that play with each other.  Samsung Galaxy Tab™ S2 tablet runs on the Android™ operating system. Software compatibility is an important checkoff criterion for your tablet vis-à-vis the SDR.

Is there a driver to software-connect the tablet and the SDR?   I don’t know of one for my SDR. If you do find a driver and you go outside trusted web sites to get it, scrutinize the site very carefully and be ready to manage virus risk regardless.

OK, then how can the related G31DDC SDR play on the S2 tablet? See: https://www.youtube.com/watch?v=h6lhfKIqmkM .The above YouTube video’s “Show More” option indicates Wi-Fi remote control on the Galaxy S2 tablet to control a G31DDC SDR, with a VNC connection by Wi-Fi. https://www.realvnc.com/products/viewerplus/1.0/docs/ae1052032.html . Audio streaming as in the YouTube video employed VLC, see http://www.videolan.org/vlc/index.html . I’ll not go into details since your equipment will be different.

My tablet noise check was informative: On battery power alone, the tablet delivered 630m rushing-river noise when placed near a 100uH inductor on a ferrite rod in my local-noise canceller here at W5EST 6/21/16. The noise emanated from the lower right corner of the rear of that tablet (as viewed with the portrait-oriented tablet with main homescreen button at bottom).

With the tablet’s charger connected to AC power and plugged into the tablet, 630m RF noise increased considerably in my noise pickup inductor. In a homebrew tablet/SDR combo, the charger would best be replaced with a non-noisy charger or power supply with same voltage and at least as much current capacity.  The 630m power switching noise is current-based and not capacitive coupled because no noise occurs when the disconnected microUSB charger cord end is put very near the 100uH noise-pickup inductor.

To reduce the noise, the usual HF-oriented common mode chokes were unavailing when applied to the microUSB charging cord. No surprise, this is 630m! Neither snap-on ferrite nor 5 turns of the USB cable when wound a on large rectangular core stopped the switching PS (power supply) noise coupling into the inductor on 630m. Physical separation, toroids, or more robust measures are among the appropriate noise rejection techniques.

Visual projection for visitors on a shack wall: HDMI facilitates coupling to a projector or TV. http://www.pcadvisor.co.uk/how-to/google-android/how-connect-android-tv-summary-3533870/ I experimentally connected a small HDMI converter to the tablet’s USB port while running the tablet on battery power, and did not notice more noise. Oops, one web site says the S2 tablet doesn’t work with either a MHL or Slimport cable adapter: http://forums.androidcentral.com/ask-question/594761-there-hdmi-cable-adapter-samsung-galaxy-tab-s2.html I was indeed unable to get the tablet via this MHL HDMI converter to communicate to my projector.  So what to do?

Fortunately, you can plug a wireless display receiver (adapter) to the projector’s HDMI socket, as I did with the Actiontec® ScreenBeamTMMini 2 adapter plugged into the Vivitek® projector here. I believe short range Wi-Fi is used. (Some projectors don’t self-power the adapter via that HDMI port, so plug in its wall wart & microUSB cable to the adapter to power it. The projector shows a default image provided by the adapter until the tablet takes over.)

To software-connect the HDMI adapter to the tablet, down-swipe the S2 tablet’s homescreen pulldown menu and click on “Quick connect.” Then click on “Audio path,” and select: 1) HDMI via the adapter, 2) tablet speaker, or 3) USB headphones. That way, you mirror the tablet screen to the projector and send tablet audio to a better sound system via the projector if you wish.

You can use a USB flash drive (thumb drive) with the S2 tablet through a short USB-to-microUSB cable. But if you want to connect a USB flash drive to the tablet and have the SDR connected by USB as well, then a powered USB hub is probably needed. Some tablets do not power a USB hub.

If you know other good tips for combining a tablet with an SDR, let us know. I did not have any other company’s tablet nor any other SDR products to compare.  GL with this topic–and with Field Day, 2016, Saturday and Sunday!”

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