Bell Ringers on Skype Video

Here are two views that I captured during yesterday's Skype video conference, which included a walking tour of Dave's new QTH. Click on each image to see the full-size copy.

The image below shows a close-up of the SoftRock SDR transceiver that Jack is now building.

Happy New Year 2011 to all!

Frequency Analysis of On-Air Audio Recordings

I used the FFT frequency analysis feature in my audio editing software to produce some views of audio from several members' transmissions as received on my Heathkit SB-104A. The results are presented in this photo album. Click on the first thumbnail image to display it full size with its caption. You can use the two arrowheads above the image to go backward and forward to compare images. Or you can select the slide show mode and navigate using controls below the photo. All graphs were made with the same settings in the audio software. Two overlay images show a pair of curves on a single slide.

Here are some additional notes:

• All audio recordings are influenced by the receive passband and audio filtering of my SB-104A 
• A local peak appears around 3 kHz in all graphs. This is a birdie in my receiver and should be ignored.
• Each horizontal line represents a 3 dB amplitude step -- a factor of 2 power ratio
• Each graph is the result of FFT analysis of the speech sample that was recorded, and the frequency content varies according to what slice of time you choose to analyze. Speech is a complex, continuously changing waveform. Pure, steady tones would give more consistent results.
• My software can present a real-time FFT of the audio as it plays. In that case the frequency display varies continuously as expected for a complex, continuously changing waveform.
• Increasing the FFT size from the 1024 used in these graphs to higher numbers (2048, 4096, etc.) reveals increasingly fine details, but does not affect the overall shape of the response shown in the lowest (1024) setting. 

John

Antique Telephone

Here are some photos from George KW7GAM showing his antique phone. Click on the slide show thumbnail to view the photos full size. George said: 

The old Western Electric telephone needed a few drops of oil on the generator shaft. I had to open it up so I took a couple of pictures.

My Dad brought it up from South Alabama when we were kids in the 1950s. I'm sure it must have been when my future company, GTE, was converting to dial in its Alabama properties. My brother and I had it working back then, and I restored it in the 1970s.

See the little key hanging on a loop of the battery wire that the telephone man used to open the compartment with the secret electronics.

Ten-Tec Hamfest 2010

Phil KB4XX and Tim WA4PTZ attended the Ten-Tec Hamfest on 9/25/10. Here's an excerpt from Phil's email report:

"For those who have never been, this is  what I would consider an “old-fashioned” hamfest… free parking… free admission… free outdoor flea market (bring your own tables (or just open your tailgate) and set up shop).  The flea market takes place in a small gravel parking lot behind the building with overflow up the grassy hillside behind that. Ten-Tec has a big tent set up in front of the building where they show off their wares… with demo stations you can operate."

Click here to see a nice photo set by KE9V. One topic of discussion on this morning's 3740 QSO was the new Ten-Tec Model 599 Eagle transceiver that appeared at the hamfest. Gee, I wonder how they came up with that model number?

Huntsville Hamfest Photos

Photos from the Huntsville Hamfest are on the Bell Ringers web site. You can reach that page by going to Group Photos from the Bell Ringers home page, or click here for a shortcut.

You'll find the group photo previewed here, along with other small group and individual photos from N4OLN. A thumbnail below the group photo will take you to a set of 81 photos by W4BXI. These include both people and radio gear. Also featured are a few shots taken at some of the excellent forums. SDR and the FlexRadio display seemed to be popular. I noted that FlexRadio's web site includes a link to the W9OY Software Defined Ham Radio blog. A few of John's photos show slides from the ever-popular forum by David Hathaway on Solar Cycle Prediction.

Also included is this link to the extensive collection of people photos from MCARS.

QSO on 3740

Today's QSO on 3740 kHz included KB4XX and KB4PYR operating from the Smokemont camp at the the Great Smoky Mountains National Park. I captured some of the receive audio at my station south of Birmingham. I did not have my recording software running correctly when KB4PYR was on, but I did capture some of KB4XX, along with W4UOA and KE4ID.

Here are MP3 copies of selected audio clips of the QSO. These are compressed to 32 kb/s and are stored on Google docs, where you can open each file directly or download for listening. My transceiver was not tuned in exactly, so the voice pitch is not quite correct in some cases.

• KB4XX at 0852 CDT, starting out Q5, but fading later in the clip
• W4UOA at 0854 CDT operating at Mentone
• KB4XX at 0857 CDT
• KE4ID at 0858 CDT

KB4XX occasionally reached S9 at my station, but was mostly in the range of S2 to S6. According to Google Earth, the distance from Smokemont to Birmingham is about 249 miles.

73, John

More Field Day Photos

Bell Ringers have shared additional Field Day photos for your enjoyment.
Click here to visit a very nice collection provided by Tom KC5UN from the DeKalb Co. ARC event.
Click here to see a report and photos provided by Warren WD4NIT from the Wedixie Club event.

Thanks to Tom and Warren!