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Hello and welcome to the 423rd episode of Linux in the Ham Shack. In this short-topics episode, the hosts discuss the upcoming third QSO Today Virtual Ham Expo along with ham radio emcomm in India and Pakistan, Missouri's bicentennial radio event, insecurity in Python libraries, an open source laptop, Linux sound subsystems and much more. Thanks for listening and we hope you have a great week.

73 de The LHS Crew

In this episode, Martin (M1MRB) is joined by Chris Howard (M0TCH), Martin Rothwell (M0SGL), Ed Durrant (DD5LP), Frank Howell (K4FMH) and Bill Barnes (WC3B) to discuss the latest Amateur / Ham Radio news. Colin (M6BOY) rounds up the news in brief and in the episode we feature QSO Today Summer Expo

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Ham College episode 79 is now available for download.

Extra Class Exam Questions – Part 17.
E4C Receiver performance characteristics: phase noise, noise floor, image rejection, MDS, signal-to-noise ratio, noise figure, reciprocal mixing, selectivity, effects of SDR receiver non-linearity, use of attenuators at low frequencies.
55:21

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It's time once again for The Weekender. This is our bi-weekly departure into the world of amateur radio contests, open source conventions, special events, listener challenges, hedonism and just plain fun. Thanks for listening and, if you happen to get a chance, feel free to call us or e-mail and send us some feedback. Tell us how we're doing. We'd love to hear from you.

73 de The LHS Crew

Hello and welcome to Episode 421 of Linux in the Ham Shack. In this episode, the hosts interview Neil Rapp, WB2VPG, coordinator of the IARU Region 2 YOTA camp and Peter Lafreniere, N8JPL, one of the youth participants. The topics include an in-depth look at what the campers experienced, events held, challenges faced, and the future of the event. We hope you enjoy this interview and deep and have a great week until the next time we meet.

73 de The LHS Crew

This was the first year I took part in the IOTA (islands on the air) contest and I very much enjoyed the time I spent in the contest. It was very well attended and many Island stations were there and waiting to be contacted. I found the band conditions on my end were very challenging at times with stations going from S9 to barley above the noise floor. This is one of the challenges of a contest and just makes things more interesting. I would say it was a nice change to hear lots of stations in the contest, a sure sign that the solar cycle is improving.  As a participant in the IOTA contest you can enter as CW, SSB or both and I choose to enter as a CW op. 

The radio I used was the Icom 7610 with the filter set to 250 Hz with the APF (Audio Peak Filter)  feature turned on. My antenna was an Endfed multiband antenna and my power output was 100 watts. One of the memorable contact I made was Cuba. With all the issues going on there it was nice to be able to make contact with that island. 

I was on the air for about 3 hours in total and made 53 contacts for a score of 5,124. It sure is not a record but I very much enjoyed my time on the radio and that's what it's all about. 

Decibels are commonly used in electronic communications to describe and compare signal levels. I’ve often heard that one dB is considered to be the smallest change that a typical person can detect by ear. I recently came across this website audiocheck.net that is set up to generate different audio tones and to do a blind test of how small of a change you can detect.

I started with testing for 6-dB and 3-dB changes. Easy Peasy. Then I tried the 1-dB test. I could detect the change in level fairly consistently but I did have to concentrate. Continuing on to the 0.5-dB change, I had a very high failure rate. It was very difficult to detect that small of a change. So I have to conclude that 1 dB is about the limit for a change I can hear.

How about you? Take the test on the website and let us know how you did.

There are many other audio tests to explore on that site, including the highest frequency you can hear, the minimum pitch change you can hear, etc. Check it out: www.audiocheck.net

73 Bob K0NR

The post Can You Hear a 1-dB Change? appeared first on The KØNR Radio Site.