Twin Panadapters

Click above to enlarge.

This screenshot shows the simultaneous capture of panadapter views at WA5MLF and W4UOA this morning. A QSO at 3745 kHz had one station that was strong enough for Carl to hear as splatter in the 3740 pass band. See Carl's screenshots here for better views of the effects at his location.

The station was not strong enough to be heard at WA5MLF below 3742. John's screenshot (panadapter with waterfall) shows some other random noise below 3740 (we were not transmitting at that time). The wiggly line around 3742 on John's waterfall display is RFI from an APC UPS in the other room.

- John

Google Hangouts to W4BXI and W4UOA

This is a screen shot from my PC yesterday morning, showing simultaneous Hangouts -- one for the audio to/from W4BXI's rig and the other showing W4UOA's panadapter in operation. Each Hangout is in a separate web browser. I added labels in yellow italics to all windows. Click on the image for a full size view.

- John WA5MLF

Google Hangouts: Video + Phone

A recent update to the Hangouts app removed or lost the ability to add phone users to a video (computer-to-computer) hangout. Many Hangout users complained about this change, and a forum posting provided  a way to run the older Hangout app to regain the phone calling feature.

Here is a summary of the process:

1. In your web browser address (URL) box, type g.co/hangouts.

 

2. Add users by:

• email invite
• call a phone (use keypad icon)
• share hangout link (e.g. via chat session)

3. Enter a phone number (or a contact name)

 At any time after starting the Hangout using g.co/hangouts, computer or phone users can be added by clicking the "people+" icon to get the window shown in step 2 above.

Lightning damage to antenna

On July 14 my multi-band dipole antenna had a lightning encounter of some degree. Below are some photos showing damage to the feed point and the surge arrestor that is mounted on the outside wall of the garage.

 Here is a view of the feed point after I lowered it to eye level. The front part of the Ladder-Loc mount was blown away, but the electrical connections are intact.

Later I found two pieces of the front part and put them in place as shown in this photo. I have not found the other pieces.
The front part of a new unit might fit in place of the one that was damaged, if the dimensions have not changed much. I could simply secure the feed line and use the back part as is, without a front.

 This photo shows the inside of the balanced line surge arrestor, model AS-309H from Array Solutions. The referenced PDF file gives specs and explains the design features.
The feed from the antenna enters at the bottom, connected to the two long machine screws. At the top end of each screw a gas tube protector and a 1 Mohm resistor connect to a ground lug. The resistor provides a path for static charge to bleed off. A capacitor at the top of each screw connects to the balanced output lugs for the portion of feedline that enters the house.

Here is an annotated close-up of the area that shows the visible damage. Click on the photo for a better view. The two resistors have normal readings. I plan to replace both gas discharge tubes. The two capacitors are not shorted, based on ohmmeter readings, and don't appear to be open, based on transceiver operation and SWR readings. They may have changed somewhat in capacitance and should probably be replaced, too.

At the transceiver end of the feedline, I inspected the balun and found no visible damage. Ohmmeter readings revealed no shorts or grounds.







Update: In February of 2017, when adjusting the lengths of the dipole legs, I found additional evidence of the lightning hit at the southwest end of the dipole. See the two photos at the end of this posting.

John

LIGO

On June 18 I enjoyed a visit to the  Laser Interferometer Gravitational-Wave Observatory (LIGO) installation at Livingston, LA. You can see an aerial view of the facility at this page.
To learn about LIGO, see the links at this page.

I was part of a tour group arranged by the Baton Rouge Amateur Radio Club. Our tour started one hour ahead of the normal monthly public tours. Our tour guide was Dr. Amber Stuver, a research scientist who has been working at LIGO for the past 8 years. We started at the LIGO Science Education Center, viewing two video presentations and Dr. Stuver's presentation with Q and A. Then we walked over to the main building to visit the control center where staff members use a room full of computers and monitors to oversee and control the operation of the system.  The detection of a gravitational wave event is not recognized in real time by the system operators. Analysis of the collected data from this facility and the Hanford, Washington facility leads to the identification of events. Two have been announced as of this writing. This article in Science News includes an audio player (see "Chirp, Chirp") for hearing the waveforms associated with the two announced events.

Below are additional views from our visit to the control room. The observatory is not currently operating, since it and the Washington state companion installation are undergoing  modifications to boost their sensitivity, to enable detecting more events. They are scheduled to resume operation in the 4th quarter of 2016.

I labeled the top 3 monitors to match the small label seen on each. They represent 3 different frequency ranges, corresponding to the types of vibrations that each displays. The graphs move from right to left, with new data added to the right side at 1-minute intervals.

System diagram displayed on a large wall monitor.

While looking at the various monitors in the control room, I recognized the presence of Apple and Linux desktop user interfaces. Our guide confirmed that those are the operating systems in use for the system. In a later question from a club member we learned that Matlab and Python are the main software environments used for data analysis. It would have been interesting to see some of the laser, optical, and detector hardware, but I don't know if those are ever included on public tours.

We returned to the Science Education Center to explore more of the hands-on exhibits there. Many of them involved aspects of wave behavior in various media.

Here is a photo of a Giant Slinky that is probably 25 ft long. It is suspended from vertical wires, allowing it to flex horizontally when the visitor moves a lever connected via a vertical pivot. This photo was taken before our tour started. The education center had many visitors when we returned from our tour as lots of folks were waiting for their tours that started every 20 minutes or so.
Below are additional photos showing other exhibits and the many afternoon visitors.

On our way out I took this photo where you can just see part of the concrete structure (near center, between trees) that houses the evacuated steel tube comprising one of the two 4 km (2.5 mile) tubes that form the laser paths of the interferometer. Many photos, graphics and videos are available on this gallery page.







Our guide encouraged us to return for another visit when the facility is operating.

Digital TV Resources

These are some links I collected over the years to help with using over-the-air Digital TV:

Find local broadcast channels:

• Antennapoint 
• Antennaweb 
• TV Fool

Other sites of interest:

• DTV Reception Maps
• Program Listings
• Digital TV Facts
• HDTV Info
• Accessories
• Home Entertainment Supplies

 John

Windows 10 Upgrade Topics

There is much discussion now about recent changes in the Windows 10 upgrade notifications and behavior, and the scheduled July 29 end of the free upgrade availability. Below are some recent articles that address these topics.

• Windows 10 Hits 300 Million Active Devices, Free Upgrade Still Ends July 29
• Microsoft Will Turn Off Windows 10 Upgrade Nagware In July
• The Ability to Cancel or Schedule the Windows 10 Upgrade is Not New

An alternative to upgrading in-place is to perform a clean install. This requires more work, but results in better performance and reliability by virtue of not carrying forward the baggage and debris accumulated by years of running Windows 7 or 8. Below are some articles about clean installation.They cover much of the same ground, with some variation in wording. The first link gives important details about the overall process, including how to handle your programs, files and settings. Note: in order to use the media creation tool you must be logged in with an Administrator account.

• How to clean install Windows the right way
• Microsoft instructions for media creation and clean install
• How to do a Clean Install of Windows 10, the Easy Way
• Revive a Windows 7 system with a clean install
• How to Clean Install Windows 10 on a Solid State Drive

Windows 10 Guides:

• Complete Guide to Windows 10 
• Understand and Configure Privacy Settings

Also see these two Youtube videos:

• 5 Things You Should Do After Upgrading to Windows 10
• Windows 10 Beginners Guide